JP4521396B2 - Implantable subcutaneous device and cardiac stimulation device - Google Patents

Implantable subcutaneous device and cardiac stimulation device Download PDF

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JP4521396B2
JP4521396B2 JP2006509836A JP2006509836A JP4521396B2 JP 4521396 B2 JP4521396 B2 JP 4521396B2 JP 2006509836 A JP2006509836 A JP 2006509836A JP 2006509836 A JP2006509836 A JP 2006509836A JP 4521396 B2 JP4521396 B2 JP 4521396B2
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signal
cardiac
heart
arrhythmia
electrocardiogram
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JP2006524106A (en
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カマス、アパーヴ
ハフナー、ポール
ブロックウェイ、マリナ
ワーグナー、ダレル、オーヴィン
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カーディアック ペースメイカーズ, インコーポレイテッド
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Priority to US10/804,471 priority patent/US7218966B2/en
Priority to US10/816,464 priority patent/US7117035B2/en
Priority to US10/817,749 priority patent/US7302294B2/en
Application filed by カーディアック ペースメイカーズ, インコーポレイテッド filed Critical カーディアック ペースメイカーズ, インコーポレイテッド
Priority to PCT/US2004/010917 priority patent/WO2004091719A2/en
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    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/04Measuring bioelectric signals of the body or parts thereof
    • A61B5/0402Electrocardiography, i.e. ECG
    • A61B5/0452Detecting specific parameters of the electrocardiograph cycle
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/0059Detecting, measuring or recording for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
    • A61B5/0082Detecting, measuring or recording for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes
    • A61B5/0084Detecting, measuring or recording for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes for introduction into the body, e.g. by catheters
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/0059Detecting, measuring or recording for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence
    • A61B5/0082Detecting, measuring or recording for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes
    • A61B5/0084Detecting, measuring or recording for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes for introduction into the body, e.g. by catheters
    • A61B5/0086Detecting, measuring or recording for diagnostic purposes; Identification of persons using light, e.g. diagnosis by transillumination, diascopy, fluorescence adapted for particular medical purposes for introduction into the body, e.g. by catheters using infra-red radiation
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/02Detecting, measuring or recording pulse, heart rate, blood pressure or blood flow; Combined pulse/heart-rate/blood pressure determination; Evaluating a cardiovascular condition not otherwise provided for, e.g. using combinations of techniques provided for in this group with electrocardiography or electroauscultation; Heart catheters for measuring blood pressure
    • A61B5/02028Determining haemodynamic parameters not otherwise provided for, e.g. cardiac contractility or left ventricular ejection fraction
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/145Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/1459Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters invasive, e.g. introduced into the body by a catheter
    • AHUMAN NECESSITIES
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    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/68Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient
    • A61B5/6846Arrangements of detecting, measuring or recording means, e.g. sensors, in relation to patient specially adapted to be brought in contact with an internal body part, i.e. invasive
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/02Details
    • A61N1/04Electrodes
    • A61N1/05Electrodes for implantation or insertion into the body, e.g. heart electrode
    • AHUMAN NECESSITIES
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    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
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    • A61N1/05Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/056Transvascular endocardial electrode systems
    • A61N1/0565Electrode heads
    • A61N1/0568Electrode heads with drug delivery
    • AHUMAN NECESSITIES
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    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/362Heart stimulators
    • A61N1/365Heart stimulators controlled by a physiological parameter, e.g. heart potential
    • A61N1/36585Heart stimulators controlled by a physiological parameter, e.g. heart potential controlled by two or more physical parameters
    • AHUMAN NECESSITIES
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    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/38Applying electric currents by contact electrodes alternating or intermittent currents for producing shock effects
    • A61N1/39Heart defibrillators
    • A61N1/3956Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
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    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/38Applying electric currents by contact electrodes alternating or intermittent currents for producing shock effects
    • A61N1/39Heart defibrillators
    • A61N1/3956Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
    • A61N1/3962Implantable devices for applying electric shocks to the heart, e.g. for cardioversion in combination with another heart therapy
    • A61N1/39622Pacing therapy
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    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
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    • A61B5/04Measuring bioelectric signals of the body or parts thereof
    • A61B5/0402Electrocardiography, i.e. ECG
    • A61B5/0452Detecting specific parameters of the electrocardiograph cycle
    • A61B5/046Detecting fibrillation
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/04Measuring bioelectric signals of the body or parts thereof
    • A61B5/0402Electrocardiography, i.e. ECG
    • A61B5/0452Detecting specific parameters of the electrocardiograph cycle
    • A61B5/0464Detecting tachycardia or bradycardia
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61BDIAGNOSIS; SURGERY; IDENTIFICATION
    • A61B5/00Detecting, measuring or recording for diagnostic purposes; Identification of persons
    • A61B5/145Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue
    • A61B5/1455Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters
    • A61B5/14551Measuring characteristics of blood in vivo, e.g. gas concentration, pH value; Measuring characteristics of body fluids or tissues, e.g. interstitial fluid, cerebral tissue using optical sensors, e.g. spectral photometrical oximeters for measuring blood gases
    • A61B5/14552Details of sensors specially adapted therefor
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/02Details
    • A61N1/04Electrodes
    • A61N1/05Electrodes for implantation or insertion into the body, e.g. heart electrode
    • A61N1/0587Epicardial electrode systems; Endocardial electrodes piercing the pericardium
    • AHUMAN NECESSITIES
    • A61MEDICAL OR VETERINARY SCIENCE; HYGIENE
    • A61NELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
    • A61N1/00Electrotherapy; Circuits therefor
    • A61N1/18Applying electric currents by contact electrodes
    • A61N1/32Applying electric currents by contact electrodes alternating or intermittent currents
    • A61N1/36Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
    • A61N1/362Heart stimulators
    • A61N1/365Heart stimulators controlled by a physiological parameter, e.g. heart potential
    • A61N1/36514Heart stimulators controlled by a physiological parameter, e.g. heart potential controlled by a physiological quantity other than heart potential, e.g. blood pressure
    • A61N1/36542Heart stimulators controlled by a physiological parameter, e.g. heart potential controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by body motion, e.g. acceleration

Description

  The present invention relates generally to implantable cardiac monitoring and stimulation devices, and more specifically to multi-parameter arrhythmia identification using electrocardiogram information and information from alternative sensors.

  A healthy heart produces regular synchronized contractions. The rhythmic contraction of the heart is usually controlled by the sinoatrial (SA) node, a specialized group of cells located in the upper right atrium. SA nodules are normal pacemakers for the heart and typically cause 60 to 100 beats per minute. A heart is said to be in normal sinus rhythm if the SA node is pacing the heart rate normally.

  If the heart's electrical activity is irregular or irregular, it means that the heart is arrhythmic. Cardiac arrhythmias can impair heart efficiency and can be a potentially life-threatening event. There are many etiological sources of cardiac arrhythmias, including reduced cardiac function that generates or synchronizes electrical impulses that regulate tissue damage, infection, or contraction due to myocardial infarction.

  Bradycardia occurs when the heart rhythm is too slow. This condition can be caused, for example, by impaired function of the SA node (meaning sinus dysfunction syndrome) or by delay or blockage of electrical impulse propagation between the atrium and the ventricle. Bradycardia results in an excessively slow heart rate that cannot maintain sufficient blood circulation.

  A state in which the heart rate is excessively fast means tachycardia. The cause of tachycardia can be in the atria or ventricles. Tachycardia occurring in the heart atrium includes, for example, atrial fibrillation and atrial flutter. These conditions are characterized by a rapid contraction of the atria. A rapid contraction of the atrium is not only inefficient in hemodynamics but can also adversely affect ventricular rate.

  For example, ventricular tachycardia occurs when electrical activity occurs in the ventricular myocardium at a heart rate faster than normal sinus rhythm. Ventricular tachycardia can rapidly transform into ventricular fibrillation. Ventricular fibrillation is a condition signified by extremely fast and uncoordinated electrical activity within ventricular tissue. Rapid and irregular excitation of ventricular tissue inhibits synchronous contraction and impairs the heart's ability to effectively supply the body with blood. This condition is fatal unless the heart is returned to sinus rhythm within a few minutes.

  An implantable cardiac rhythm management system has been used as an effective treatment for patients with severe arrhythmia. These systems typically include one or more leads and circuitry for sensing signals from one or more inner and / or outer surfaces of the heart. Such systems also include circuitry that generates electrical pulses that are delivered to the heart tissue on one or more inner and / or outer surfaces of the heart. For example, a lead extending into the patient's heart is connected to an electrode in contact with the myocardium to sense the heart's electrical signals and send pulses to the heart according to various therapies for treating arrhythmias.

  A typical implantable defibrillator (ICD) includes one or more endocardial leads, to which at least one defibrillation electrode is connected. Such ICDs can deliver high energy shocks to the heart, stop ventricular tachyarrhythmias and ventricular fibrillation, and allow the heart to resume normal sinus rhythm. The ICD may further include a pacing function.

  Although ICD is very effective at preventing sudden cardiac death (SCD), most people at risk for SCD are not provided with implantable cardioverter defibrillators. The main reason for this disappointing reality is the limited number of physicians capable of performing lead / electrode transvenous implantation, and the availability of adequately equipped surgical facilities for such cardiac procedures. This includes a limited number and a limited number of at-risk patients who can safely receive the required endocardial or epicardial lead / electrode implantation therapy.

  The present invention relates generally to cardiac monitoring and / or stimulation methods and systems that provide transthoracic monitoring, defibrillation therapy, pacing therapy, or a combination of these functions. Embodiments of the present invention relate to subcutaneous cardiac monitoring and / or stimulation methods and systems for detecting and / or treating cardiac activity or arrhythmias.

  Embodiments of the present invention relate to an arrhythmia identification method that includes sensing an electrocardiogram signal at a subcutaneous location that is not within the thoracic cavity. The electrocardiogram signal may include a cardiac signal and one or both of noise and electrocardiographic artifacts. A signal associated with the alternative sensor is also received.

  Alternative sensors include non-electrophysiological heart sensors, blood sensors, patient activity sensors, impedance sensors, pulse wave sensors, blood oxygen sensors, transthoracic impedance sensors, blood volume sensors, acoustic sensors and / or pressure transducers, and accelerometers However, it is not limited to this. The sensed ECG signal is confirmed to be a cardiac signal using an alternative signal. A cardiac arrhythmia is detected using one or both of the sensed electrocardiogram signal and the confirmed cardiac signal. If the sensed signal is not confirmed to be a cardiac signal, cardiac arrhythmia treatment is withheld.

  An arrhythmia may be detected using an electrocardiogram signal, and the presence of the arrhythmia may be confirmed or denied using an alternative signal. A temporal relationship between the electrocardiogram signal and the alternative signal may be determined. A detection window may be initiated in response to receipt of the electrocardiogram signal and may be used to determine whether an alternative signal has been received at a time within the detection window.

  A heart rate may be calculated based on the series of electrocardiogram signals and the series of alternative signals. Heart rate may be used to distinguish between normal sinus rhythm and arrhythmia. The heart rate may be compared to an arrhythmia threshold, for example, in response to a first heart rate that exceeds the first arrhythmia threshold and a second heart rate that does not exceed the second arrhythmia threshold. It may be used to determine. The presence of an arrhythmia may be determined using the morphology of the electrocardiogram signal and then confirmed using an alternative signal. Examples of non-electrophysiological alternative signals include heart sound signals, subsonic acoustic signals indicative of heart activity, pulse pressure signals, impedance signals indicative of heart activity, and pulse oximetry signals.

  In another embodiment of the invention, delivery of defibrillation therapy may be prevented in response to detecting an arrhythmia using an electrocardiogram signal and non-detecting an arrhythmia using an alternative signal. A method of preventing treatment upon detection of an arrhythmia may include sensing an electrocardiogram signal at a subcutaneous location that is not within the thoracic cavity. The detection window may be defined by a start time determined from the electrocardiogram signal. A signal associated with a non-electrophysiological heart source may be received and evaluated within a detection window.

  The presence or absence of cardiac arrhythmia may be determined using an electrocardiogram signal and may be confirmed by the presence of cardiac arrhythmia detected by a non-electrophysiological heart signal. The start time of the detection window used for confirmation may be associated with an inflection point (for example, a maximum value or a minimum value) of the ECG signal. A correlation between an electrocardiogram signal and a non-electrophysiological heart signal may be performed.

  One embodiment of the invention relates to an implantable heart device that includes a housing and an electrode device configured to be placed subcutaneously rather than within the thoracic cavity. A detection circuit is provided in the housing and connected to the electrode configuration. The detection circuit is configured to detect an electrocardiogram signal that includes the heart signal and one or both of noise and electrocardiographic artifacts.

  Connected to the detection circuit is a sensor configured to sense an alternative signal associated with the non-electrophysiological heart source. A processor is provided within the housing and is connected to detection circuitry, sensors and energy delivery circuitry to distinguish between normal sinus rhythm and arrhythmia using an electrocardiogram and alternative signals. The processor uses the non-electrophysiological signal to confirm that the sensed electrocardiogram signal is a cardiac signal. If the sensed signal is not confirmed to contain a cardiac signal, the processor suspends treatment for cardiac arrhythmia.

  The energy delivery circuit may include one or both of a defibrillation therapy circuit and a pacing therapy circuit. The sensor may be provided inside or on the surface of the housing, or may be provided inside or on the surface of the lead connected to the housing.

  According to one embodiment of the present invention, the medical system includes a housing in which the energy delivery circuit and the detection circuit are provided. One or more electrodes are connected to the energy delivery and detection circuit and are used to sense heart and muscle activity. A processor is provided within the housing and is connected to energy delivery and detection circuitry. The processor may detect a ventricular arrhythmia using a cardiac signal generated from the sensed cardiac activity, or detect an activity state of the patient using an activity signal generated from the sensed muscle activity. Good. The processor may change the delivery of therapy to treat the arrhythmia in response to the muscle activity signal.

  In another embodiment of the invention, the processor blocks delivery of arrhythmia therapy in response to an activity signal that exceeds an activity threshold indicative of patient awareness or movement. In response to an activity signal exceeding the activity threshold, the processor may block delivery of the arrhythmia therapy for a predetermined time, and if the predetermined time expires and the arrhythmia stops, suspends delivery of the arrhythmia therapy. Also good. In response to detecting a life-threatening arrhythmia, the processor may immediately deliver an arrhythmia therapy regardless of the activity signal.

  In another embodiment, the processor may receive an electrocardiogram from the detection circuit and may identify the heart signal and the activity signal from the electrocardiogram using an electrode device configured to detect the muscle signal.

  The method according to the present invention includes detecting a signal using one or more electrodes and identifying a cardiac signal from the detected signal. From the detected signal, an activity signal associated with the patient activity is also identified. The cardiac signal may be used to detect arrhythmia, and the activity signal may be used to detect the activity level of the patient. The arrhythmia therapy may be modified to treat the arrhythmia in response to the activity signal. In response to an activity signal that exceeds an activity threshold using a signal indicative of patient awareness or movement, delivery of an arrhythmia therapy may be prevented. In response to an activity signal exceeding the activity threshold, delivery of the arrhythmia therapy may be blocked for a predetermined time, and if the predetermined time expires and the arrhythmia stops, delivery of the arrhythmia therapy may be suspended.

  According to one embodiment of the present invention, a medical device includes a housing configured to be placed subcutaneously rather than in the thoracic cavity. A detection circuit is provided in the housing and is configured to generate an electrophysiological cardiac signal. An energy delivery circuit is also provided in the housing. Connected to the detection and energy delivery circuit is at least one electrode configured to be placed subcutaneously rather than in the thoracic cavity. The apparatus is also provided with an implantable blood sensor configured to generate a blood sensor signal and is connected to a processor provided within the housing. The processor is also connected to detection and energy delivery circuitry and is used to assess cardiac rhythm using electrophysiological heart signals and blood sensor signals. In one approach, the processor is configured to use the blood sensor signal to verify that the electrophysiological heart signal includes a heart signal, and the blood sensor signal and the electrophysiological heart signal that includes the heart signal. Used to assess heart rhythm.

  The blood sensor may be configured to be placed subcutaneously, not within the thoracic cavity, may be provided on the interior or surface of the housing, may be provided on a lead surface connected to the housing, and is separate from the housing. And may be connected to the processor via a wired or wireless link. The blood sensor may include a sensor configured to sense optical signals, such as a blood oxygen saturation sensor or a pulse oximeter. A suitable pulse oximeter may include two light emitting diodes and a photodetector. The photodetector may include a circuit having a detection threshold that is periodically adjusted to account for signal variations.

  In another configuration, a suitable pulse oximeter includes a first light emitting diode having a peak emission wavelength in the range of about 550 nanometers and about 750 nanometers, and about 750 nanometers and about 1050 nanometers. And a second light emitting diode having a peak emission wavelength within the range. The blood sensor may include a photoelectric pulse wave circuit and may be connected to a processor. The processor may identify a cardiac rhythm that is a tachyarrhythmia using the electrophysiological heart signal and the blood sensor signal.

  The processor may identify a heart rhythm that is a tachyarrhythmia using the electrophysiological heart signal and the relative change in the blood sensor signal, and selects a blood sensor in response to detecting the tachyarrhythmia It may be started and stopped automatically. The processor may activate the blood sensor using the electrophysiological heart signal and may evaluate tachyarrhythmia using the electrophysiological heart signal and the blood sensor signal. The processor may further confirm or deny the presence of tachyarrhythmia using the electrophysiological heart signal and the blood sensor signal.

  The device may deliver a therapy to treat tachyarrhythmia and the processor may stop the blood sensor before or after delivery of the therapy. The processor may determine hemodynamics using the electrophysiological heart signal and the blood sensor signal. The processor may activate the blood sensor to facilitate identification of the indistinguishable heart rhythm using the blood sensor signal in response to detection of the indistinguishable heart rhythm using the electrophysiological heart signal. . The processor may use the blood sensor signal to assess cardiac function, oxygen saturation and changes in oxygen saturation, and / or afterload, for example by analyzing the morphology of the blood sensor signal.

  Embodiments of the rhythm evaluation method according to the present invention may include sensing an electrocardiogram signal at a subcutaneous position that is not within the thoracic cavity and obtaining a blood sensing signal from a subcutaneously sensed position that is not within the thoracic cavity. Cardiac rhythm may be evaluated using an electrocardiogram signal and a blood sensor signal. One approach includes verifying that the electrocardiogram signal includes a cardiac signal and assessing cardiac rhythm using the blood sensing signal and the electrocardiogram signal including the cardiac signal. A tachyarrhythmia may be detected by performing analysis based on heart rate or analysis based on morphology using one or both of the electrocardiogram signal and the blood sensing signal.

  The activation pattern of the electrocardiogram signal may be analyzed using a plurality of electrodes, and the detected tachyarrhythmia may be treated after confirming the presence of the tachyarrhythmia using the blood sensing signal. Blood sensing signals may be used to distinguish between tachyarrhythmias and noise. Assessing the heart rhythm may include detecting cardiac arrhythmia by performing a correlation (or calculating a transfer function) between the electrocardiogram signal and the blood sensing signal. Obtaining the blood sensing signal may include selectively turning on and off a blood sensor that generates the blood sensing signal.

  Evaluating heart rhythms includes detecting tachyarrhythmia using an electrocardiogram signal, powering on a blood sensor that generates a blood sensing signal, and the presence of tachyarrhythmia using the blood sensing signal. And confirming that the blood sensor is turned off. The blood sensing signal may include, for example, blood perfusion information, blood oxygen saturation information, photoelectric pulse wave information, pulse oximetry information, and / or other information from a blood sensor.

  The above summary of the present invention is not intended to describe each embodiment or every implementation of the present invention. Advantages and achievements of the present invention, as well as a more complete understanding of the present invention, will become apparent and appreciated by referring to the following detailed description and claims taken in conjunction with the accompanying drawings.

  While the invention is susceptible to various modifications and alternative forms, specifics thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the invention is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined in the appended claims.

  In the following description of exemplary embodiments, reference is made to the accompanying drawings that form a part hereof, and in which are shown by way of illustration various embodiments in which the invention may be practiced. It should be understood that other embodiments may be used and structural and functional changes may be made without departing from the scope of the invention.

  An implantable device according to the present invention may include one or more of the features, configurations, methods, or combinations thereof described below. For example, a cardiac monitor or cardiac stimulator may be implemented to include one or more advantageous features and / or processes described below. Such a monitor, stimulator, or other implantable or partially implantable device need not include all of the features described herein, but has been selected to provide unique structure and / or functionality. It is contemplated that it may be implemented to include features. Such a device may be implemented to provide various therapeutic or diagnostic functions.

  Embodiments of the present invention relate to an arrhythmia identification method that includes sensing an electrocardiogram signal at a subcutaneous location that is not within the thoracic cavity. The electrocardiogram signal may include a cardiac signal and one or both of noise and electrocardiographic artifacts. A signal associated with the alternative sensor is also received. Alternative sensors include non-electrophysiological heart sensors, blood sensors, patient activity sensors, impedance sensors, pulse wave sensors, blood oxygen sensors, transthoracic impedance sensors, blood volume sensors, acoustic sensors and / or pressure transducers, and Includes but is not limited to accelerometers. An alternative signal may be used to confirm that the sensed electrocardiogram signal is a cardiac signal. Furthermore, cardiac arrhythmias may be detected using one or both of the sensed electrocardiogram signal and the confirmed cardiac signal. If the sensed signal is not confirmed to be a cardiac signal, cardiac arrhythmia treatment may be withheld.

  In general, cardiac signal identification configurations and methods can be used with cardiac monitoring and / or stimulating subcutaneous devices. Such a device is an implantable transthoracic heart sensing and / or stimulation (ITCS) device that can be implanted subcutaneously in the patient's chest region. An ITCS device, for example, allows all or selected elements of the device to be placed at the front, back, side or other body location of the patient suitable for sensing cardiac activity and delivering cardiac stimulation therapy. Alternatively, it may be implanted subcutaneously. It should be noted that the elements of the ITCS device may be placed at a plurality of different body positions, such as the chest region, abdominal region, or subclavian region, and each electrode element may be located near the heart, around the heart, in the heart, or on a different region May be arranged respectively.

  The main housing of the ITCS device (eg, an active or non-active can) can be used, for example, in the intercostal or subcostal space, in the abdomen, in the upper region of the chest (eg, above the third rib). It may be configured to be arranged at a subclavian position). In one implementation, one or more electrodes may be placed on the main housing and / or at other locations around the heart, large blood vessels or coronary vasculature and not in direct contact.

  In another implementation, the one or more leads incorporating the electrodes may be connected to the heart, large blood vessels, or coronary veins, for example, via one or more leads implanted using conventional transvenous delivery techniques. It may be arranged to be in direct contact with the tube structure. In yet another implementation, one or more subcutaneous electrode subsystems or subcutaneous electrodes to sense cardiac activity and deliver cardiac stimulation energy, eg, in an ITCS device configuration using an active can or a configuration using a non-active can An array may be used. The electrodes may be placed in an anterior and / or posterior position relative to the heart. Examples of useful subcutaneous electrodes, electrode arrays and their orientation are described in commonly-owned US patent application Ser. No. 10/738 entitled “Noise Canceling Cardiac Electrodes”, filed Dec. 17, 2003. , 608, and a US patent application entitled “Methods And Systems Involving Subcutaneous Electrode Positioning Relative To A Heart” filed Jun. 19, 2003. 10 / 465,520, which are hereby incorporated by reference.

  The particular configuration shown herein is generally described as being capable of implementing various functions traditionally performed by an implantable cardioverter defibrillator (ICD), and is well known in the art. It can operate in cardioversion / defibrillation mode. Examples of ICD circuits, structures and functionality that can be incorporated into ITCS devices according to the present invention are described in commonly owned US Pat. Nos. 5,133,353, 5,179,945, 5,314,459. No. 5,318,597, 5,620,466, and 5,662,688, each of which is incorporated herein by reference in its entirety.

  In certain configurations, the system and method perform functions traditionally performed by pacemakers, such as providing various pacing therapies well known in the art in addition to cardioversion / defibrillation therapy. Also good. Examples of pacemaker circuits, structures and functionality that can be incorporated into ITCS devices according to the present invention are described in commonly owned US Pat. Nos. 4,562,841, 5,284,136, 5,376,106. No. 5,036,849, 5,540,727, 5,836,987, 6,044,298, and 6,055,454, where Each of which is incorporated herein by reference in its entirety. It should be noted that the ITCS device configuration may provide non-physiological pacing assistance in addition to or in addition to bradycardia and / or anti-tachycardia pacing therapy.

  An ITCS device according to the present invention may implement diagnostic and / or monitoring functions and may provide cardiac stimulation therapy. Examples of cardiac monitoring circuits, structures and functionality that can be incorporated into the ITCS device of the present invention are described in commonly owned US Pat. Nos. 5,313,953, 5,388,578, and 5,411. , 031, each of which is incorporated herein by reference in its entirety.

  The ITCS device may be used to implement various diagnostic functions that may include heart rate based, pattern and heart rate based and / or morphological tachyarrhythmia discrimination analysis. To enhance the detection and termination of tachyarrhythmia, subcutaneous, skin, and / or external sensors may be used to obtain physiological and non-physiological information. It should be noted that the configurations, features, and combinations of features described in this disclosure may be implemented in a wide range of implantable medical devices, and such embodiments and features are limited to the specific devices described herein. Not.

  Referring now to FIGS. 1A and 1B, a transthoracic heart sensing and / or stimulation (ITCS) device configuration is shown having components implanted at different locations in a patient's chest region. In the particular configuration shown in FIGS. 1A and 1B, the ITCS device includes a housing 102 in which various cardiac sensing, detection, processing and energy delivery circuits may be housed. It should be noted that the components and functionality shown and described herein may be implemented in hardware, software, or a combination of hardware and software. Furthermore, components and functionality illustrated as separate or separate blocks / elements may be implemented in combination with other components and functionality, and such components and functionality may be implemented in separate forms or It is shown in an integrated form for clarity of explanation and is not so limited.

  Within housing 102, communication to facilitate communication between the ITCS device and an external communication device (eg, a portable or clinical communication station, a patient portable / wearable communication station, or an external programmer). A circuit is placed. The communication circuitry may facilitate one-way or two-way communication with one or more external or physiological sensors, skin sensors, or subcutaneous sensors. The housing 102 is generally configured to include one or more electrodes (eg, can electrodes and / or indifferent electrodes). The housing 102 is generally configured as an active can, but an inactive can configuration may be implemented, in which case at least two electrodes spaced from the housing 102 are used.

  In the configuration shown in FIGS. 1A and 1B, the subcutaneous electrode 104 may be placed subcutaneously in the thoracic region and may be located distally from the housing 102. The subcutaneous electrode and, if applicable, the housing electrode may be placed at various positions and orientations around the heart (eg, various positions forward and / or posterior to the heart). Subcutaneous electrode 104 is connected to circuitry in housing 102 via lead assembly 106. One or more conductors (eg, coils or cables) are provided within the lead assembly 106 to electrically couple the subcutaneous electrode 104 to circuitry within the housing 102. On the elongated structure of the electrode support, the housing 102 and / or the distal electrode assembly (shown as the subcutaneous electrode 104 in the configuration shown in FIGS. 1A and 1B), one or more sensing electrodes, sensing / pacing electrodes, Alternatively, a defibrillation electrode may be placed.

  In one configuration, the lead assembly 106 is generally flexible and has a structure similar to a conventional implantable medical electrical lead (eg, a defibrillation lead or a combined defibrillation / pacing lead). In another configuration, the lead assembly 106 is configured to be somewhat flexible, but has an elastic, springy, or mechanical (shape) memory that retains the desired configuration after shaping or manipulation by the clinician. For example, the lead assembly 106 may incorporate a gooseneck or blade (braid) system that can be distorted by hand force to assume the desired shape. As such, the lead assembly 106 may have shape adaptability to accommodate a given patient's unique anatomical configuration and generally retains a customized shape after implantation. The shaping of the lead assembly 106 according to this configuration can be performed before and during implantation of the ITCS device.

  According to yet another configuration, the lead assembly 106 includes a rigid electrode support assembly, such as a rigid elongated structure that positionally stabilizes the subcutaneous electrode 104 relative to the housing 102. In this configuration, the rigidity of the elongated structure maintains the desired spacing between the subcutaneous electrode 104 and the housing 102 and the desired orientation of the subcutaneous electrode 104 / housing 102 relative to the patient's heart. The elongate structure may be formed from a structural plastic material, a composite material, or a metal material, and includes or is covered with a biocompatible material. When the elongated structure is formed of a conductive material such as a metal, appropriate electrical isolation is provided between the housing 102 and the subcutaneous electrode 104.

  In one configuration, the rigid electrode support assembly and housing 102 define a single structure (eg, a single housing / unit). The electronic components and electrode conductor / connector are placed in or on the integral ITCS device housing / electrode support assembly. At least two electrodes are supported near the ends of the housing / electrode support assembly on a single structure. A single structure may have, for example, an arcuate shape or an angled shape.

  According to another configuration, the rigid electrode support assembly defines a unit that is physically separable relative to the housing 102. The rigid electrode support assembly includes mechanical and electrical couplings that facilitate mating engagement with corresponding mechanical and electrical couplings of the housing 102. For example, the header block configuration may be configured to include an electrical and mechanical coupling for mechanical and electrical connection between the rigid electrode support assembly and the housing 102. The header block configuration may be provided on the housing 102 or on a rigid electrode support assembly. Alternatively, a mechanical / electrical coupler may be used to establish a mechanical and electrical connection between the rigid electrode support assembly and the housing 102. In such a configuration, a variety of different electrode support assemblies having various shapes, sizes and electrode configurations may be made available for physical and electrical connection to the standard ITCS device housing 102.

  Note that the electrode and lead assembly 106 may be configured to take various shapes. For example, the lead assembly 106 may have a wedge shape, a V shape, a flat oval shape, or a ribbon shape, and the subcutaneous electrode 104 may include a plurality of spaced electrodes, such as an array or band of electrodes. In addition, two or more subcutaneous electrodes 104 may be attached to a plurality of electrode support assemblies to achieve a desired spacing relationship between the subcutaneous electrodes 104.

  ITCS devices are described in common US Pat. Nos. 5,203,348, 5,230,337, 5,360,442, 5,366,496, 5,397,342, , 391,200, 5,545,202, 5,603,732 and 5,916,243, each of which is incorporated herein by reference in its entirety. The circuitry, structure and functionality of some implantable subcutaneous medical devices may be incorporated.

  FIG. 1C is a block diagram illustrating various components of an ITCS device according to one configuration. According to this configuration, the ITCS device incorporates a processor-based control system 205 that includes a microprocessor 206 connected to a suitable (volatile and non-volatile) memory 209. A control architecture based on any logic may be used. The control system 205 is connected to circuitry and components to sense, detect and analyze the electrical signals generated by the heart and deliver electrical stimulation energy to the heart to treat cardiac arrhythmias under predetermined conditions. In certain configurations, the control system 205 and its associated components also provide pacing therapy to the heart. The electrical energy delivered by the ITCS device may be in the form of a low energy pacing pulse or a high energy pulse for cardioversion or defibrillation.

  The cardiac signal is sensed using a subcutaneous electrode 214 and a can or indifferent electrode 207 provided on the ITCS device housing. For example, in an inactive can configuration, cardiac signals may be sensed using only the subcutaneous electrode 214. Thus, monopolar, bipolar, or monopolar / bipolar composite electrode configurations, multi-element electrodes, and combinations of noise cancellation electrodes and standard electrodes may be used. The sensed cardiac signal is received by sensing circuit 204. The sensing circuit 204 includes a sense amplifier circuit and may further include a filtering circuit and an analog-to-digital (A / D) converter. The sensed cardiac signal processed by the sensing circuit 204 may be received by a noise reduction circuit 203 that may further reduce noise before the signal is transmitted to the detection circuit 202.

  The noise reduction circuit 203 may be incorporated after the sensing circuit 202 if a high power or computationally intensive noise reduction algorithm is required. The noise reduction circuit 203 may perform the function of the sensing circuit 204 using an amplifier that is used to perform an operation using an electrode signal. Combining the functions of the sensing circuit 204 and the noise reduction circuit 203 can be useful to minimize the required components and reduce the system power requirements.

  In the exemplary configuration shown in FIG. 1C, the detection circuit 202 is connected to or otherwise incorporates the noise reduction circuit 203. The noise reduction circuit 203 operates to improve the signal-to-noise ratio (SNR) of the sensed heart signal by removing noise introduced from various sources contained in the sensed heart signal. Typical types of transthoracic heart signal noise include, for example, electrical noise and noise resulting from skeletal muscle.

  The detection circuit 202 generally includes a signal processor that adjusts the analysis of sensed cardiac signals and / or other sensor inputs to detect cardiac arrhythmias, such as tachyarrhythmias in particular. The signal processor of the detection circuit 202 may implement a heart rate based and / or morphological identification algorithm for detecting and confirming the presence and severity of arrhythmia symptoms. Examples of arrhythmia detection and identification circuits, configurations and techniques that can be implemented by the ITCS device according to the present invention are disclosed in commonly owned US Pat. Nos. 5,301,677 and 6,438,410. Each of which is incorporated herein by reference in its entirety.

  The detection circuit 202 transmits cardiac signal information to the control system 205. The memory circuit 209 of the control system 205 stores data representing cardiac signals received by the detection circuit 202 as well as parameters for operating in various modes of sensing, defibrillation, and pacing where applicable. The memory circuit 209 may be configured to store historical ECG (electrocardiogram) data and treatment data. Historical ECG data and treatment data may be used for a variety of purposes and may be transmitted to an external receiving device as needed or desired.

  In certain configurations, the ITCS device may include a diagnostic circuit 210. The diagnostic circuit 210 generally receives input signals from the detection circuit 202 and the sensing circuit 204. The diagnostic circuit 210 provides diagnostic data to the control system 205. Note that the control system 205 may incorporate all or part of the diagnostic circuit 210 or its functionality. The control system 205 may store and use information provided by the diagnostic circuit 210 for various diagnostic purposes. This diagnostic information may be stored, for example, following a trigger event or at predetermined intervals, and may include system diagnostics (eg, power status, treatment delivery history, and / or patient diagnostics). The diagnostic information may take the form of electrical signals or other sensor data that is acquired immediately prior to delivery of the therapy.

  According to the configuration for providing cardioversion and defibrillation therapy, the control system 205 processes the cardiac signal data received from the detection circuit 202 to terminate cardiac arrhythmia symptoms and return the heart to normal sinus rhythm. Appropriate tachyarrhythmia treatment is initiated to Control system 205 is connected to shock therapy circuit 216. The shock therapy circuit 216 is connected to the subcutaneous electrode 214 and the can or indifferent electrode 207 of the ITCS device housing. The shock therapy circuit 216 delivers cardioversion and defibrillation stimulation energy to the heart according to the command in accordance with the selected cardioversion or defibrillation therapy. In a simpler configuration, the shock therapy circuit 216 is controlled to deliver a defibrillation therapy as opposed to a configuration that provides both cardioversion and defibrillation therapy delivery. Examples of ICD high energy delivery circuits, structures and functionality that can be incorporated into available types of ITCS devices are described in commonly owned US Pat. Nos. 5,372,606, 5,411. , 525, 5,468,254, and 5,634,938, each of which is incorporated herein by reference in its entirety.

  According to another configuration, the ITCS device may incorporate cardiac pacing functions in addition to cardioversion and / or defibrillation functions. As indicated by the dotted lines in FIG. 1C, the ITCS device may include a pacing therapy circuit 230. Pacing therapy circuit 230 is connected to control system 205, subcutaneous electrode 214, and can / indifferent electrode 207. The pacing therapy circuit sends pacing pulses to the heart according to the selected pacing therapy in response to the command. In accordance with the pacing therapy, the control signal generated by the pacemaker circuit in the control system 205 is initiated and sent to the pacing therapy circuit 230 where pacing pulses are generated. The pacing therapy may be modified by the control system 205.

  A number of cardiac pacing therapies can be useful in transthoracic heart monitoring and / or stimulation devices. Such cardiac pacing therapy may be routed through pacing therapy circuit 230, as shown in FIG. 1C. Alternatively, cardiac pacing therapy may be delivered via shock therapy circuit 216, which effectively eliminates the need for a separate pacemaker circuit.

  The ITCS device shown in FIG. 1C is configured to receive signals from one or more physiological and / or non-physiological alternative sensors according to embodiments of the present invention. The signal generated by the alternative sensor may be sent to a transducer circuit connected directly to the detection circuit 202 or indirectly connected via the sensing circuit 204, depending on the type of sensor used. Note that a specific alternative sensor may transmit the sensing data to the control system 205 without being processed by the detection circuit 202.

  An alternative non-electrophysiological heart sensor may be directly connected to the detection circuit 202 or indirectly connected via the sensing circuit 204. Non-electrophysiological heart sensors sense cardiac activity of a non-electrophysiological nature. Examples of alternative sensors that are non-electrophysiological heart sensors include blood oxygen sensors, transthoracic impedance sensors, blood volume sensors, acoustic sensors, and / or pressure transducers, and accelerometers. Signals from these sensors are generated based on cardiac activity, but are not directly obtained from electrophysiological sources (eg, R waves or P waves). As shown in FIG. 1C, alternative sensor 261 may be connected to one or more of sensing circuit 204, detection circuit 202 (connection not shown for clarity), and control system 205.

  The communication circuit 218 is connected to the microprocessor 206 of the control system 205. The communication circuit 218 allows the ITCS device to communicate with one or more receiving devices or systems located outside the ITCS device. For example, the ITCS device may communicate with a patient wearable, portable, or clinical communication system via the communication circuit 218. In one configuration, one or more physiological or non-physiological (subcutaneous, skin, or patient-external) alternative sensors are short, such as an interface that is compliant with well-known communication standards (such as Bluetooth or IEEE 802 standards). A distance wireless communication interface may be provided. Data acquired by such a sensor may be communicated to the ITCS device via the communication circuit 218. Note that a physiological or non-physiological alternative sensor with a wireless transmitter or transceiver may communicate with a receiving system external to the patient.

  Communication circuit 218 may allow the ITCS device to communicate with an external programmer. In one configuration, the communication circuit 218 and programmer unit (not shown) are connected between the programmer unit and the communication circuit 218 using a wire loop antenna and radio frequency telemetry link, as is well known in the art. Send and receive signals and data. In this way, program instructions and data are transferred between the ITCS device and the programmer unit during and after implantation. A physician can use a programmer to set or modify various parameters used by the ITCS device. For example, the physician may set or modify parameters that affect the sensing, detection, pacing and defibrillation functions of the ITCS device, including pacing and cardioversion / defibrillation therapy modes.

  Generally, the ITCS device is housed and hermetically sealed in a housing suitable for implantation into the human body, as is well known in the art. Power to the ITCS device is supplied by an electrochemical power source 220 housed within the ITCS device. In one configuration, the power source 220 includes a rechargeable battery. According to this configuration, a charging circuit is connected to the power source 220 to facilitate non-invasive charging of the power source 220 that is repeated many times. Communication circuit 218, or a separate receiver circuit, is configured to receive radio frequency energy transmitted by an external radio frequency energy transmitter. The ITCS device may include a non-rechargeable battery in addition to the rechargeable power source. Note that it is not necessary to use a rechargeable power source, and in that case, a long-life non-rechargeable battery is used.

  FIG. 1D shows the configuration of the detection circuit 302 of the ITCS device. The detection circuit 302 includes one or both of a heart rate detection circuit 310 and a morphology analysis circuit 312. Arrhythmia detection and confirmation may be accomplished using a heart rate based identification algorithm well known in the art, implemented by heart rate detection circuit 310. Arrhythmia symptoms may be detected and confirmed by analysis based on the morphology of the sensed cardiac signal, as is well known in the art. Both heart rate-based and morphological-based methods may be used to implement a layered or parallel arrhythmia identification algorithm. Further, for example, US Pat. Nos. 6,487,443, 6,259,947, 6,141,581, 5,855,593, which are hereby incorporated herein by reference, and By using the approach disclosed in US Pat. No. 5,545,186, arrhythmia detection and identification techniques based on heart rate and pattern may be used to detect and / or confirm arrhythmia symptoms.

  A detection circuit 302 connected to the microprocessor 306 incorporates or communicates with dedicated circuitry for processing sensed cardiac signals in a manner particularly useful in transthoracic heart sensing and / or stimulating devices. It may be configured as follows. As illustrated in FIG. 1D, the detection circuit 302 may receive information from a plurality of physiological and non-physiological alternative sensors. For example, transthoracic sound may be monitored using an appropriate acoustic sensor. For example, a heart sound may be detected and processed by the alternative sensor processing circuit 318 for various purposes. The acoustic data is sent to the detection circuit 302 via a wired or wireless link and used to enhance cardiac signal detection and / or arrhythmia detection. For example, acoustic information may be used in accordance with the present invention to confirm arrhythmia identification based on ECG heart rate.

  The detection circuit 302 may receive information from one or more alternative sensors that monitor skeletal muscle activity. Transthoracic electrodes readily detect skeletal muscle signals in addition to cardiac activity signals. Such skeletal muscle signals may be used to determine a patient's activity level. In the context of cardiac signal detection, such skeletal muscle signals are considered artifacts of cardiac activity signals and can be considered noise. The processing circuit 316 receives signals from one or more skeletal muscle sensors and sends processed skeletal muscle signal data to the detection circuit 302. This data may be used to distinguish normal sinus rhythm with skeletal muscle noise from cardiac arrhythmias.

  As already mentioned, the detection circuit 302 is connected to the noise processing circuit 314 or otherwise incorporates the noise processing circuit 314. A noise processing circuit 314 processes the sensed heart signal and improves the SNR of the heart signal by reducing noise contained in the sensed heart signal.

  Referring now to FIG. 1E, a block diagram of various components of an ITCS device according to one configuration is shown. FIG. 1E shows a number of components related to the detection of various physiological and non-physiological parameters. As shown, the ITCS device includes a microprocessor 406, which is typically integrated into the control system of the ITCS device and connected to the detection circuit 402. Sensor signal processing circuitry 410 can receive sensor data from a plurality of different electrocardiogram sensors and / or alternative sensors.

  For example, the ITCS device may cooperate with or otherwise incorporate various types of non-physiological sensors 421, physiological external / skin sensors 422 and / or physiological internal sensors 424. Such sensors can include, for example, acoustic sensors, impedance sensors, oxygen saturation sensors, blood volume sensors, and blood pressure sensors. Each of these sensors 421, 422, 424 may be communicatively connected to the sensor signal processing circuitry 410 via a short-range wireless communication link 420. Alternatively, certain sensors, such as physiological internal sensor 424, may be communicatively connected to sensor signal processing circuitry 410 via wired connections (eg, electrical or optical connections). A useful photoelectric pulse wave sensor that can be implemented in the ITCS device of the present invention and techniques using it are disclosed in US Pat. No. 6,491,639, which is hereby incorporated herein by reference.

  The components, functionality and structural configurations shown in FIGS. 1A-1E are intended to provide an understanding of the various features and combinations of features that can be incorporated into an ITCS device. It should be understood that a wide range of ITCS and other implantable cardiac monitoring and / or stimulation device configurations are possible, from relatively complex designs to relatively simple designs. Thus, certain ITCS or cardiac monitoring and / or stimulation device configurations may include certain features described herein, and other such device configurations may be identified as described herein. This feature may not be included.

  According to embodiments of the present invention, an ITCS device may be implemented to include a subcutaneous electrode system that provides one or both of cardiac sensing and arrhythmia therapy delivery. According to one approach, the ITCS device may be implemented as a long-term implantable system that performs monitoring, diagnostic and / or therapeutic functions. The ITCS device may automatically detect and treat cardiac arrhythmias.

  In one configuration, the ITCS device includes a pulse generator and one or more electrodes that are implanted subcutaneously in the chest region of the body, such as the anterior ribcage region of the body. The ITCS device may be used to provide atrial and / or ventricular treatment for bradycardia and tachyarrhythmia. Tachyarrhythmia treatment may include, for example, cardioversion, defibrillation and anti-tachycardia pacing (ATP) to treat atrial or ventricular tachycardia or fibrillation. Bradycardia treatment may include temporary post-shock pacing for bradycardia or cardiac arrest. A method and system for implementing post-shock pacing for bradycardia and cardiac arrest was filed on Feb. 28, 2003, entitled “Subcutaneous Cardiac Stimulation with Post-Shock Transthoracic Pacing to Prevent Cardiac Arrest”. Cardiac Stimulator Employing Post-Shock Transthoracic Asystole Prevention Pacing "), which is described in commonly owned US patent application Ser. No. 10 / 377,274, hereby incorporated by reference in its entirety.

  In one configuration, an ITCS device according to one approach may use conventional pulse generators and subcutaneous electrode implantation techniques. The pulse generator and electrode may be implanted subcutaneously over time. Such ITCS may be used to automatically detect and treat arrhythmias, similar to conventional implantable systems. In another configuration, the ITCS device may include a single structure (eg, a single housing / unit). The electronic components and electrode conductors / connectors are placed in or on the integral ITCS device housing / electrode support assembly.

  The ITCS device includes electronic components and may be similar to a conventional implantable defibrillator. High voltage shock therapy may be performed between two or more electrodes placed subcutaneously in the thoracic region of the body, one of which may be a pulse generator housing (eg, a can).

  In addition or alternatively, the ITCS device may provide low energy electrical stimulation for bradycardia therapy. The ITCS device may provide bradycardia pacing similar to conventional pacemakers. The ITCS device may provide temporary post-shock pacing for bradycardia or cardiac arrest. Sensing and / or pacing may be accomplished with sensing / pace electrodes placed on an electrode subsystem that also incorporates shock electrodes, or with each separate electrode implanted subcutaneously.

  The ITCS device may detect various alternative signals that may be used in connection with various diagnostic, therapeutic, or monitoring implementations according to the present invention. For example, the ITCS device may include sensors or circuits for detecting non-electrophysiological signals related to pulse pressure signals, blood oxygen levels, heart sounds, cardiac acceleration, and other cardiac activities. In one embodiment, the ITCS device senses intrathoracic impedance from which various respiratory parameters can be derived, including, for example, tidal volume of breathing and minute ventilation. One or more sensors for detecting signals related to body movement or position and circuitry associated therewith may be incorporated in connection with the ITCS device. For example, accelerometers and GPS devices may be used to detect patient activity, patient position, body orientation or torso position.

  The ITCS device may be used in the configuration of an advanced patient management (APM) system. An advanced patient management system may allow a physician to remotely and automatically monitor a patient's cardiac and respiratory functions and other conditions. In one example, implantable cardiac rhythm management systems, such as cardiac pacemakers, defibrillators, and resynchronizers, include a variety of telecommunications and information technologies that enable patient real-time data collection, diagnosis, and treatment. May be. Various embodiments described herein may be used in connection with advanced patient management. The methods, configurations and / or techniques described herein that may be configured to provide remote patient / device monitoring, diagnosis, treatment or other APM-related methodologies are hereby incorporated herein by reference. U.S. Patent Nos. 6,221,011, 6,270,457, 6,277,072, 6,280,380, 6,312,378, 6,336, One or more features of 903, 6,358,203, 6,368,284, 6,398,728, and 6,440,066 may be incorporated.

  An ITCS device according to one approach provides an easily implantable therapeutic, diagnostic or monitoring system. The ITCS system can be implanted without the need for intravenous or intrathoracic access, provides a simpler and less invasive implantation procedure, and minimizes lead and surgical complexity. obtain. Furthermore, this system would be beneficial for use on patients who have complications caused by a transvenous lead system. Such complications include, among others, surgical complications, infections, inadequate vascular opening, complications associated with the presence of prosthetic valves, and limitations due to the growth of pediatric patients. It is not limited. An ITCS system according to this approach differs from conventional approaches in that it can be configured to include a combination of two or more electrode subsystems implanted subcutaneously in the anterior chest.

  As shown in FIG. 2, in one configuration, the electrode subsystem of the ITCS system is placed around the patient's heart 510. The ITCS system includes a first electrode subsystem that includes a can electrode 502 and a second electrode subsystem 504 that includes one or more electrodes and / or one or more multi-element electrodes. The second electrode subsystem 504 may include a plurality of electrodes used for sensing and / or electrical stimulation and may further include alternative sensors.

  In various configurations, the second electrode subsystem 504 may include a combination of electrodes. The electrode combinations of the second electrode subsystem 504 include coil electrodes, tip electrodes, ring electrodes, multi-element coils, spiral coils, spiral coils attached to non-conductive supports, screen patch electrodes, and other electrode configurations Can be included. A suitable non-conductive support material is, for example, silicone rubber.

  The can electrode 502 is disposed on a housing 501 that houses the electronic components of the ITCS device. In one embodiment, can electrode 502 includes the entire outer surface of housing 501. In another embodiment, various portions of housing 501 may be electrically isolated from can electrode 502 or from tissue. For example, the active area of the can electrode 502 may include all or a portion of the front or back surface of the housing 501 to guide the flow of current in favor of cardiac sensing and / or stimulation.

According to one embodiment, the housing 501 may be similar to the housing of a conventional implantable ICD, where the volume of the housing 501 is about 20-100 cc, the thickness is 0.4-2 cm, and the surface area of each side is it is about 30~100cm 2. As described above, a portion of the housing may be electrically isolated from the tissue in order to optimally guide the current flow. For example, a portion of the housing 501 may be covered with a non-conductive or otherwise electrically resistive material to guide current flow. Suitable non-conductive material coatings include, for example, those formed from silicone rubber, polyurethane or parylene.

  In addition or alternatively, the entire or part of the housing 501 may be treated with varying conductivity characteristics to optimally guide current flow. In order to optimize the current flow, various known techniques may be used to change the conductivity characteristics of the surface of the housing 501 by increasing or decreasing the surface conductivity. Such techniques can include techniques that mechanically or chemically alter the surface of the housing 501 to achieve the desired conductivity characteristics.

  As described above, the heart signal collected from the subcutaneously implanted electrode may be mixed with noise. Furthermore, certain noise sources have frequency characteristics similar to cardiac signals. Such noise can lead to excessive sensing and unnecessary shock delivery. Since the amplitude of the noise signal is relatively high and may include overlapping frequencies, filtering alone does not completely suppress noise. Furthermore, the filter performance is typically not robust enough for all types of noise encountered. Furthermore, known adaptive filtering techniques often require an unknown reference signal for situations where the patient has VF (ventricular fibrillation) or high amplitude noise.

  The heart signal collected from the subcutaneously implanted electrode may be mixed with noise. Furthermore, certain noise sources have frequency characteristics similar to cardiac signals. Such noise can lead to excessive sensing and unnecessary shock delivery. Since the noise signal has a relatively high amplitude and may include overlapping frequencies, filtering alone may not completely suppress noise. Furthermore, the filter performance may not be robust enough for all types of noise encountered. Furthermore, known adaptive filtering techniques often require an unknown reference signal for situations where the patient has VF (ventricular fibrillation) or high amplitude noise.

  According to one approach of the present invention, the ITCS device uses an alternative signal to identify a cardiac signal from a group of separated signals (eg, separated signals obtained with blind source separation (BSS) technology). May be. All or specific aspects of the signal identification technology described later may be implemented by a device or system (implantable or non-implantable) other than the ITCS device, and the BSS technology as a separation method implemented by the ITCS device. It should be understood that this description is for purposes of illustration and not limitation.

  Signal separation techniques separate many individual signals from a composite signal. For example, a composite signal detected on the patient's surface or within the patient may have multiple signal components originating from various signal sources (such signal components may include cardiac signals, skeletal muscle motion related signals, electromagnetic interference signals, and generations). Source includes unknown signal). Signal separation techniques separate the composite signal into individual signals, but do not necessarily indicate the source of such signals.

  Using the largest eigenvalue resulting from principal component analysis on the composite signal matrix provides one way to identify the separated signal that is most likely the cardiac signal that the ITCS device is intended for. However, analyzing all separated signals is a computationally intensive operation. The present invention provides an efficient way to provide an indication of the signal most likely to be the heart signal of interest by using an alternative signal that assists in distinguishing between the noise signal and the heart signal, thereby enabling This greatly reduces the time required to distinguish the heart signal of interest from the many isolated signals.

  According to one approach of the present invention, the ITCS device may be implemented to identify a cardiac signal from a group of separated signals, such as obtained with blind source separation (BSS) technology. An apparatus and method for blind source separation is further described in co-owned US patent application Ser. No. 10 / 741,814 filed Dec. 19, 2003, which is hereby incorporated by reference herein. Has been. An apparatus and method relating to another useful signal separation technique using a noise canceling electrode is described in commonly owned US patent application Ser. No. 10 / 738,608, filed Dec. 17, 2003 (see here). Incorporated herein by reference).

  Information from the alternative sensor 503 as described above may be used to increase the accuracy of arrhythmia identification, such as arrhythmia identification based on ECG or other heart rate, for example. To improve the detection and identification of arrhythmias from normal sinus rhythm (NSR) in the presence of noise, for example, cardiac sound signals, accelerometers, blood sensors or other non-electrophysiological source sensors, etc. A signal independent of electrical activity may be used. As shown in FIG. 2, the alternative sensor 503 may be provided in or on the housing 501 or may be provided as part of the second electrode subsystem 504 as described above. Alternate sensor 503 may be directly connected to housing 501 using additional leads, or may be wirelessly connected as described with reference to FIGS. 1C and 1D.

  In one embodiment of the present invention, heart sounds are used to assist signal identification in detecting various heart rhythms in the presence of electrical noise and / or electrocardiographic artifacts. Since this additional alternative identification signal is time-correlated with the electrophysiological heart signal, the alternative signal provides information about the state of the patient's rhythm, even in the presence of electrical noise and / or electrocardiographic artifacts. obtain. For example, this alternative signal may be used to confirm that the ECG signal includes a cardiac signal having a QRS complex, where only the ECG signal having a QRS complex is the confirmed ECG signal. Subsequent analysis may require that only confirmed ECG signals be used, for example, for heart rate calculations. This provides a more robust algorithm that is less susceptible to electrical interference and noise contamination.

  In one embodiment, a subcutaneous sensor such as an accelerometer or acoustic transducer may be used to detect heart sounds. Heart sounds may be used with heart rate, curvature, and other ECG information to distinguish normal sinus rhythms with electrical noise from potentially fatal arrhythmias (eg, ventricular tachycardia and ventricular fibrillation) . The ITCS device may use one or more of the presence, characteristics and frequency of occurrence of heart sounds in combination with ECG information when performing signal or rhythm identification.

  The heart rate determined from the ECG signal may be analyzed together with heart sound information for diagnostic purposes, for example. If a high ECG heart rate is detected along with a normal heart rate heart sound, it will indicate that there is noise in the ECG signal. If a high ECG heart rate is detected with a degenerated heart sound, a potentially fatal arrhythmia will be indicated. It should be noted that the heart rate in the above example could be replaced with ECG morphology or other techniques. It would also be possible to replace the heart sound with a signal obtained from another sensor. For example, impedance, pulse pressure, blood volume / flow rate or cardiac acceleration could be used.

  Various types of acoustic sensors may be used for detecting heart sounds. Examples of such acoustic sensors include diaphragm-based acoustic sensors, MEMS-based acoustic sensors (such as MEMS-based acoustic transducers), fiber optic acoustic sensors, piezoelectric sensors, accelerometer-based acoustic sensors and arrays. These sensors may be used to detect sound frequency pressure waves associated with heart sounds and may be used to detect other non-electrophysiological heart related signals.

  The presence of a patient's heart pulse or heartbeat is typically detected by palpating the patient's neck and sensing changes in the patient's carotid artery volume by blood supplied from the patient's heart. . At the top of FIG. 3 is a graph of a carotid wave signal 810 representing the physical stretch of the patient's carotid artery between two consecutive pulses, or beats. When the heart ventricle contracts during a beat, a pressure wave is sent to every corner of the patient's peripheral circulatory system. The carotid wave signal 810 shown in FIG. 3 rises with blood from the ventricle during systole and peaks when the pressure wave from the heart reaches a maximum. As pressure decreases toward the end of each pulse, the carotid wave signal 810 drops again.

  Opening and closing of the patient's heart valve during the heartbeat causes high frequency vibrations in adjacent heart walls and blood vessels. These vibrations can be heard as heart sounds in the patient's body and can be detected by sensors as described above. A conventional electrocardiogram (PCG) transducer placed on the patient's surface converts the acoustic energy of the heart sound into electrical energy, which can be recorded and displayed as shown in the upper graph in the middle of FIG. Produce.

  As shown by the PCG waveform 820 shown in FIG. 3, a typical heartbeat produces two major heart sounds. The first heart sound 830, denoted S1, is generally caused by vibration associated with the first tricuspid and mitral valve closure during systole. Generally, heart sound 830 is about 14 milliseconds long and includes frequencies up to about 500 Hz. The second heart sound 840, denoted S2, is generally associated with vibrations resulting from the closing of the aortic and pulmonary valves at the end of systole. The duration of the second heart sound 840 is generally shorter than the first heart sound 830, and the spectral bandwidth of the second heart sound 840 is generally greater than the spectral bandwidth of the first heart sound 830.

  An electrocardiogram (ECG) waveform 850 describes the electrical activity of the patient's heart. 3 shows an example of an ECG waveform 850 for two beats, and temporally corresponds to the carotid wave signal 810 and the PCG waveform 820 shown in FIG. Referring to the first shown beating, the portion of the ECG waveform 850 that represents the depolarization of the atrial muscle fiber is called the “P” wave. The depolarization of ventricular muscle fibers is collectively represented by the “Q”, “R” and “S” waves of the ECG waveform and is called QRS complex. Finally, the portion of the waveform that represents the repolarization of the ventricular muscle fibers is known as the “T” wave. Between beats, the ECG waveform 850 returns to the equipotential level.

  Variations in the patient's transthoracic impedance signal 860 correlate with blood flow that occurs with each pulse of the heart. The bottom graph of FIG. 3 shows an example of the patient's filtered transthoracic impedance signal 860, and the impedance variation is shown in the carotid artery signal 810, PCG waveform 820 and ECG waveform also shown in FIG. It corresponds to 850 in time.

  Referring now to FIG. 4, in another embodiment of the invention involving heart sounds, such sounds may be used to distinguish arrhythmias from normal sinus rhythms. FIG. 4 is a graph representing two consecutive PQRS complexes in the ECG signal 850 and their associated non-electrophysiological components resulting from the accelerometer signal 835. Also shown is a detection window 870 that is used to evaluate correlation between signals according to an embodiment of the invention. As shown in FIG. 4, S1 heart sound 832 and S1 heart sound 834, and QRS complex 852 and QRS complex 854 are approximately closely correlated with each other in time. S1 heart sound 832, S2 heart sound 833, and S1 heart sound 834 are shown as detected from an accelerometer implanted in the body. S1 heart sounds can be closely time correlated with heart signals, but not time and noise and artifact signals. Thus, heart sounds may be used to identify arrhythmias from NSR.

  In one embodiment of the method according to the present invention, the arrhythmia detection method uses an ECG signal to define a detection window. Next, the alternative source signal within the detection window is evaluated for cardiac information. If the alternate source signal includes a cardiac event within the window, the ECG signal corresponding to the cardiac event is validated. This can be used, for example, in heart rate based arrhythmia detection algorithms to provide a heart rate that is more robust than a heart rate calculated using only ECG information. The algorithm may consider only the heartbeat of the identified ECG if, for example, the heartbeat is confirmed by the associated alternate (sensor) sensed heartbeat.

  As shown in FIGS. 1C and 1D, the ITCS device may be implemented to include signal processing circuitry and / or signal processing software. With continued reference to FIG. 4, signal processing is used to correlate heart sounds, such as S1 heart sounds, with R-wave peaks or other QRS complex features to provide arrhythmia discrimination from the NSR in the presence of noise. You may let them.

  In the approach shown in FIG. 4, the inspection or detection window 870 is defined to start at a start time 875 based on the Q position of the QRS complex 852. Next, the ITCS algorithm searches for the accelerometer signal 835 in the detection window 870 for the S1 heart sound 832. This algorithm may look for a time correlation between the peak amplitude of the S1 heart sound 832 and the peak R of the QRS complex 852. For example, the ECG signal 850 has an R wave peak 856 within the inspection window 870 and an R wave peak 858 within the inspection window 872. The R wave peak 856 within the examination window 870 produces a large correlation value indicating that the ECG signal 850 is time correlated with the S1 heart sound signal 832 within the examination window 870. Similarly, an R wave peak 858 within the examination window 872 produces a large correlation value indicating that the ECG signal 850 is time correlated with the S1 heart sound signal 834 within the examination window 872. The heart rate may be determined, for example, between successive heart beats having a large correlation value between QRS complexes 852, 854 and their associated S1 heart sounds 832, 834.

  Referring now to FIG. 5, a signal identification method according to the present invention is illustrated in flowchart 900. The electrocardiogram signal 902 is received at a subcutaneous location that is not within the thoracic cavity. The electrocardiogram signal 902 may include a heart signal and one or both of noise and electrocardiographic artifacts. Alternative signals such as non-electrophysiological signal 904 associated with the non-electrophysiological heart source are also received. The surrogate signal provides non-electrophysiological cardiac function information (eg, heart sound information, blood flow information, blood oxygen information, and information from other surrogate sensors described above). Both the electrocardiogram signal 902 and the non-electrophysiological signal 904 are used to distinguish between normal sinus rhythm and arrhythmia via some arbitrary path shown in the flowchart 900 of FIG.

  An arrhythmia may be detected using the electrocardiogram signal 902, and the presence of the arrhythmia may be confirmed using a comparison 903 between the electrocardiogram signal 902 and the non-electrophysiological signal 904. The temporal relationship between the electrocardiogram signal 902 and the non-electrophysiological signal 904 may be determined using, for example, a comparison 905 between the morphology 907 of the electrocardiogram signal 902 and the morphology 909 of the non-electrophysiological signal 904.

  Detection window 906 may be initiated in response to receipt of electrocardiogram signal 902, for example using correlation 911 to determine whether non-electrophysiological signal 904 was received at a time within the range of detection window 906. May be used to The start time of the detection window 906 used for confirmation may be associated with an inflection point (eg, local maximum, local minimum, or any other suitable morphological attribute) of the electrocardiogram signal.

  The heart rate may be calculated based on both the series of electrocardiogram signals 902 and the series of non-electrophysiological signals 904. ECG heart rate 908 and signal rate 916 may be used to distinguish between normal sinus rhythm and arrhythmia. The ECG heart rate 908 may be compared to the arrhythmia threshold 910, for example, the first heart rate exceeds the first arrhythmia threshold, but the second heart rate signal rate 916 exceeds the second arrhythmia threshold 918. In response to not, it may be used to determine the presence / absence of arrhythmia.

  Delivery of defibrillation therapy in response to detection of arrhythmia using electrocardiogram signal 902 and confirmation or denial of arrhythmia using, for example, comparison 903, comparison 941, and / or correlation 911, by any path of flowchart 900. May be blocked (920) or treated (921).

  FIG. 6 is a flowchart illustrating a multi-parameter arrhythmia identification method according to another embodiment of the present invention. An arrhythmia identification method 950 is shown that includes sensing 951 an electrocardiogram signal at a subcutaneous location that is not within the thoracic cavity. An alternative signal associated with the non-electrophysiological heart source is received (952) and verified to determine whether the sensed electrocardiogram signal includes a heart signal (953). A cardiac arrhythmia is detected (954) using one of the sensed electrocardiogram signal and the confirmed cardiac signal. If the sensed signal is not a cardiac signal, cardiac arrhythmia treatment is suspended (955). The confirmation method according to this and other embodiments provides an unnecessary cardiac shock by ensuring that the sensed signal underlying the arrhythmia detection, confirmation and treatment decision is indeed a cardiac signal. Conveniently reduce or eliminate the delivery of

  FIG. 7 is a graph showing an electrocardiogram 1410 and an alternative signal, which is a patient activity signal 1420. The graph shown in FIG. 7 includes a threshold 1450 according to one embodiment of the invention. This graph includes time on the horizontal axis and signal voltage level on the vertical axis. The ECG signal 1410 and patient activity signal 1420 shown in FIG. 7 are amplified and filtered. In this example, both ECG signal 1410 and patient activity signal 1420 are obtained from cardiac electrodes. In this case, patient activity signal 1420 is derived from a cardiac electrode configuration that is preferentially placed to provide a signal indicative of skeletal muscle activity. It should be noted that although the patient activity signal 1420 includes a significant ECG component, muscle movement can be clearly identified at least within the muscle noise detection window 1440.

  For example, muscle movement when the patient activity signal 1420 exceeds the threshold 1450 may be defined as indicating a conscious and active patient. The threshold 1450 may be adaptive, dynamic, or fixed, and may be an absolute value, as a percentage of the baseline, or other known signal morphology methodology or statistical methodology. It may be determined by using. For example, if the ECG signal 1410 indicates the occurrence of an arrhythmia that requires a shock to the patient, but the patient activity signal 1420 indicates that the patient is movable and active, the ITCS device algorithm is: The shock to the patient's heart may be delayed by a predetermined time, such as delay 1460.

  The delay 1460 provides time for the ITCS device to evaluate whether a pseudo signal is present in the ECG signal 1410 or whether it is actually necessary to shock the patient. The duration of the delay 1460 is further followed by an initial arrhythmia detection to confirm the presence of the detected arrhythmia using one or more non-cardiac signals (eg, skeletal muscle signals or patient motion signals). Time is selected to provide to the ITCS device. The delay period 1460 should be sufficiently long as long as the health of the patient is not compromised to allow re-evaluation of the detected arrhythmia. The duration of the delay 1460 can vary from 2 seconds to 60 seconds, for example. The device may give a notification when the delay time is called.

  After the delay 1460, the ITCS device may begin charging the defibrillation capacitor in preparation for delivering a shock to the patient and may re-evaluate the patient activity signal 1420 before delivering the shock. The patient activity signal 1420 is reevaluated to determine the patient activity status prior to delivering a shock at shock time 1470.

  At the shock time 1470 shown in the graph of FIG. 7, the patient activity signal 1420 is below the threshold value 1450, indicating that the patient is no longer active. This may be because the patient has succumbed to an inadequate blood supply and may be unconscious. Clearly a shock 1470 is suggested, in which case the shock 1470 is sent to resuscitate the patient. However, if the ECG signal 1410 at the shock time 1470 indicates that the arrhythmia has ended, no shock is delivered to the patient regardless of the status of the patient activity signal 1420.

  The delay 1460 may be used in a hierarchical manner such that it is selectively used depending on the detected severity of the arrhythmia. For example, if the ECG signal 1410 clearly indicates the presence of a dangerous or life-threatening arrhythmia, the delay 1460 may be bypassed to immediately shock the patient. However, if the ECG signal 1410 is not deterministic but indicates a possible arrhythmia, delivery of the arrhythmia therapy is delayed so that the patient activity signal 1420 can be evaluated.

  FIG. 8 illustrates various processes associated with one method of using subcutaneous skeletal muscle signal detection in combination with rhythm detection based on ECG or EGM. The skeletal muscle signal detection circuit may be enabled after using other arrhythmia detection means such as an algorithm based on an electrocardiogram. To conserve energy, for example, skeletal muscle signal detection may be activated after detecting an arrhythmia using a cardiac signal detection circuit, and may be stopped after delivery of an arrhythmia therapy or after the arrhythmia stops. Good. Thus, identifying arrhythmia events from noise using skeletal muscle signal detection can reduce the occurrence of inappropriate shock delivery and offer the potential to greatly improve patient comfort.

  With continued reference to FIG. 8, an ECG based detection algorithm 600 is used to detect cardiac arrhythmias in accordance with one embodiment of the present invention. If a ventricular arrhythmia is detected using the ECG based detection 601 (602), a check 604 is performed to determine the state of the skeletal muscle signal. If the current state of the skeletal muscle signal is unknown or unavailable, a skeletal muscle signal is obtained (606). This may include activating (ie turning on) a skeletal muscle sensor or detection circuit.

  If the comparison 607 of the skeletal muscle signal to the threshold indicates patient inactivity, the defibrillation capacitor is charged (608) and a shock is sent (610) to treat the arrhythmia. However, if the comparison 607 of the skeletal muscle signal to the threshold indicates patient activity or consciousness, a delay period is initiated and an ECG signal reconfirmation 614 is performed after the delay period expires. If the electrocardiogram signal suggests or confirms the continued presence of ventricular arrhythmia after having previously checked the skeletal muscle signal at block 606, the defibrillation capacitor is charged (608) and a shock is delivered (610). ).

  In this exemplary approach, a re-evaluation of the detected ventricular arrhythmia using the skeletal muscle signal is performed only once so that treatment of the identified ventricular arrhythmia is not overly delayed. It should be noted that a ventricular arrhythmia reconfirmation routine may be executed while charging the capacitor before delivering the shock.

  In another embodiment of the invention, a blood sensor is used to provide an alternative signal for arrhythmia identification and confirmation. ECG signals often include true heart signals and various arrhythmia-like noise signals and artifacts. In accordance with the present invention, the use of a blood sensor as an alternative sensor provides the ability to distinguish true arrhythmia conditions from various noisy conditions. Furthermore, by using a blood sensor as an alternative sensor according to the present invention, the signal underlying the arrhythmia detection and treatment delivery decision is not a pseudo signal that may have characteristics similar to those of a true heart signal, but a heart signal ( For example, the ability to verify that it contains a QRS complex) is provided.

  The ITCS device may be implemented to include multi-parameter cardiac signal verification capabilities and / or arrhythmia identification capabilities to improve denoising of cardiac ECG signals sensed by subcutaneous electrodes. This denoising / reduction technique advantageously reduces the risk of false positives in the detection algorithm by providing multi-parameter arrhythmia discrimination.

  For example, an alternative signal may be used to confirm that the ECG signal includes a cardiac signal having a QRS complex and that only an ECG signal having a QRS complex is considered a confirmed ECG signal. Subsequent cardiac rhythm analysis (including arrhythmia analysis in particular) may require, for example, that only confirmed ECG signals be used to calculate the heart rate used for such analysis. This cardiac signal verification technique reduces the occurrence of improper delivery of tachyarrhythmia therapy by providing a more robust algorithm that is less susceptible to electrical interference and noise.

  One approach to cardiac signal verification involves determining the temporal relationship between an electrocardiogram signal and an alternative signal. The detection window may be initiated, for example, in response to detection of an electrocardiogram signal and may be used to determine whether an alternative signal has been received at a time within the detection window. For example, in one arrhythmia detection technique, a detection window is defined using an ECG signal. Next, non-electrophysiological source signals, such as blood sensor signals within the detection window, are evaluated for cardiac information. If the non-electrophysiological source signal includes a cardiac event within the window, the ECG signal is validated as corresponding to the cardiac event. This may be used, for example, in an arrhythmia detection algorithm based on heart rate to provide a heart rate that is more robust than the heart rate calculated using only ECG information. If the heartbeat is confirmed by the non-electrophysiologically sensed heartbeat associated therewith, the algorithm may consider only this identified ECG heartbeat, for example.

  The heart rate may be calculated based on, for example, a series of electrocardiogram signals and a series of alternative signals. These heart rates may be used to distinguish between normal sinus rhythm and arrhythmia. These heart rates may be compared to an arrhythmia threshold, for example, the absence of an arrhythmia in response to a first heart rate that exceeds the first arrhythmia threshold and a second heart rate that does not exceed the second arrhythmia threshold. May be used to determine The presence of an arrhythmia may be determined using the morphology of the electrocardiogram signal and then confirmed using an alternative signal.

  In another embodiment of the present invention, an electrocardiogram signal is used to detect an arrhythmia, but using an alternative signal (eg, a blood sensor signal) prevents delivery of defibrillation therapy in response to no arrhythmia being detected or It may be put on hold. The method for sensing arrhythmia and preventing treatment may include sensing an electrocardiogram signal at a subcutaneous location that is not within the thoracic cavity. The detection window may be defined by a start time determined from the electrocardiogram signal. Within the detection window, signals associated with non-electrophysiological heart sources may be received and evaluated. The presence or absence of cardiac arrhythmia may be determined using an electrocardiogram signal and may be confirmed by the presence of cardiac arrhythmia detected by a non-electrophysiological heart signal. The start time of the detection window used for confirmation may be associated with an inflection point (for example, a maximum value or a minimum value) of the ECG signal. A correlation between the electrocardiogram signal and the non-electrophysiological heart signal may be performed.

  According to one embodiment, a photoelectric pulse wave method is used to provide an alternative signal that assists in noise discrimination in detecting various heart rhythms in the presence of electrical noise or artifacts. Since this additional identification signal is based on the blood oxygen level or pulsatile blood volume level and not on the electrical heart signal, this signal may be subject to patient rhythm or even in the presence of electrical noise. Information regarding hemodynamics may be provided.

  A subcutaneous sensor may be used for detection of blood oxygen measurements. One such sensor is, for example, a pulse oximetry sensor. Blood oxygen level information along with heart rate, curvature, and other ECG information to identify normal sinus rhythm with electrical noise from potentially fatal arrhythmias such as ventricular tachycardia and ventricular fibrillation It may be used. The ITCS device may utilize the characteristics of blood oxygen information combined with typical ECG information for identification.

  According to one embodiment of the present invention, subcutaneous photoelectric pulse wave technique may be used to generate a non-electrophysiological heart signal as an alternative signal for detection and / or confirmation of heart rhythm. This feature can be used as part of a subcutaneous ICD system (eg ITCS device) to detect cardiac rhythm or hemodynamics, particularly in the presence of electrical noise, as an alternative or additional signal to the electrocardiogram. Use.

  Photoelectric pulse waves may be used subcutaneously to confirm the patient's cardiac arrhythmia detected by the implantable cardioverter / defibrillator. Subcutaneous photoelectric pulse wave techniques may be used to characterize patient hemodynamics for implantable cardioverter / defibrillators. For example, the afterload may be evaluated using a subcutaneous photoelectric pulse wave method. The afterload is a systolic load applied to the left ventricle after the start of contraction of the left ventricle. The resistance associated with afterload arises from the resistance of the vasculature as it pushes blood clots into the vasculature during each heartbeat. Hypertension and aortic stenosis can result in a chronic increase in afterload, which can lead to left ventricular hypertrophy and subsequent heart failure.

  In addition, a subcutaneous photoelectric pulse wave technique may be used for pulse oximetry to measure characteristics associated with changes in patient oxygen saturation for implantable cardioverter / defibrillators. In general, it is desirable to reduce the overall energy of the photoelectric pulse wave method, such as using the photoelectric pulse wave method only for confirmation of arrhythmia after using another detection algorithm.

  In one particular approach, subcutaneous photoelectric pulse waves are used to confirm or prove that the heart signal used for cardiac rhythm analysis is not a pseudo signal, such as a skeletal noise signal, but really a heart signal. For example, subcutaneous photoelectric pulse waves may be used to confirm that the cardiac signal used to make a decision to deliver tachyarrhythmia therapy is an electrocardiogram that indicates the patient's actual heart rhythm. According to this method, the subcutaneous photoelectric pulse wave is mainly used to confirm that the signals used for arrhythmia analysis and treatment delivery determination are really heart signals. This is separate from using this signal to separately confirm the presence or absence of arrhythmia. However, it should be understood that the subcutaneous photoelectric pulse wave may be used as a signal for separately confirming the presence or absence of arrhythmia separately from or in addition to using this signal for confirming the cardiac signal. .

  For example, the control system processor may deliver tachyarrhythmia therapy until the ECG signal used to detect the presence of the arrhythmia includes a cardiac signal (eg, QRS complex) is confirmed using the photoelectric pulse wave signal. You may block it. The processor may, for example, block delivery of tachyarrhythmia therapy for a predetermined time, during which time a verification process is performed and if such verification process is unsuccessful or in response to arrhythmia cessation. Suspend delivery of tachyarrhythmia therapy at the expiration of a predetermined time. The processor may send a tachyarrhythmia therapy in response to a good result of the verification process. The processor may also immediately send tachyarrhythmia therapy in response to detection of a life-threatening arrhythmia regardless of the validation process.

  Several advantages can be achieved through the use of subcutaneous photoelectric pulse wave technique. For example, a subcutaneous photoelectric pulse wave technique may be used to reduce the number of inappropriate shocks by improving the specificity of the shock. To prepare for ventricular arrhythmia based on the level of blood perfusion or the relative change in blood perfusion, subcutaneous photoelectric pulse wave techniques may be used. Furthermore, the subcutaneous photoelectric pulse wave method may be used to supplement the electrocardiogram-based algorithm by using a non-electric photo-based detection method. In addition, a subcutaneous photoelectric pulse wave method may be used for redetection and reconfirmation of arrhythmia.

  9-14 illustrate various embodiments and processes associated with the use of subcutaneous blood sensing that provides an alternative signal used for detection and / or confirmation of cardiac rhythms. FIG. 9 illustrates one implementation of a photoelectric pulse wave sensing system 500 suitable for use with a subcutaneous cardiac stimulator 511 (eg, an ITCS device).

  FIG. 9 illustrates the deployment of a subcutaneous photoelectric pulse wave sensor 520 oriented between the layer of skin 530 and the layer of muscle tissue 540. The illustrative example of FIG. 9 shows a light source 550 (ie, LED) and a detector 560 that faces the muscle tissue 540. This orientation advantageously reduces interference from ambient light sources, particularly when using an opaque barrier 570 to guide the light to the detector 560, reducing noise artifacts on the pulse wave. Other configurations may include a light source 550 and a detector 560 that faces or faces the skin.

  When the cardiac stimulator 511 encounters an uninterpretable electrocardiogram or to confirm the detection of an arrhythmia that is hemodynamically unstable, the light source 550 is activated and the output of the photodetector 560 is measured synchronously. The Next, the algorithm of the cardiac stimulator 511 is called to determine the pulse rate from the photoelectric pulse wave and inform the treatment determination. Measurements from this signal may be used to inform or adapt the ECG noise identification and / or arrhythmia detection algorithm.

  Use of the subcutaneous photoelectric pulse wave method according to this embodiment advantageously provides for detection of cardiac rhythm in the presence of electrical noise or artifacts. Since the photoelectric pulse wave is an optical signal, this algorithm is robust in that it is less susceptible to the same noise sources as ECG.

  The exploded view 580 shows the light path 570 from the light source 550 to the detector 560. Perfusion of blood within muscle tissue 540 affects the properties of light reflected from tissue 540 to detector 560 along optical path 570, blood oxygen saturation level, blood volume, pulse, and other blood characteristics. Provide blood information such as.

  The implementation shown in FIG. 10 includes a light source circuit 515 that includes an LED control 525 connected to each of a red LED 535 and an infrared (IR) LED 545. Two light sources and one detector may be used to measure the change in oxygen saturation level in tissue 542. In general, one light source (for example, IR LED 545 that emits light at a wavelength up to 960 nm) has an absorption characteristic that is largely unaffected by changes in blood color, and the other light source (for example, red light that emits at a wavelength up to 660 nm) The LED 535) has an absorption characteristic that is influenced by changes in blood color. In regions where perfusion is low, errors may occur when calculating the absolute value of oxygen saturation using reflectivity, so the embodiments shown in FIGS. 10-13 are not changes in absolute levels of oxygen saturation, only changes. To monitor. Information from changes in blood oxygen saturation is sufficient to discriminate between potentially fatal arrhythmias and noise artifacts (this noise artifact is the patient's unnecessary shock treatment in the absence of discrimination). Can lead to).

  With continued reference to FIG. 10, the photodetection circuit 555 includes a detector 565 connected to a photodiode 576. In this configuration, the processing circuit 575 is connected to the light source circuit 515 and the light detection circuit 555. Processing circuit 575 includes a multiplexer 585 connected to LED control 525 and detection circuit 555. A red signal channel 586 and an IR signal channel 587 are connected between the multiplexer 585 and the signal processing circuit element 575, respectively. The signal processing circuit 575 manipulates the signals received from the red signal channel 586 and the IR signal channel 587 and uses such algorithms to detect and / or confirm heart rhythm, including arrhythmia detection and confirmation, using various algorithms. To evaluate.

  The enlarged view 582 shows the light path 572 from the first light source 552 and the light path 574 from the second light source 554 to the detector 562. Perfusion of blood within muscle tissue 542 affects the properties of light reflected along the optical path 572 and optical path 574 from tissue 542 to detector 562 and may result in blood oxygen saturation levels, blood volume, pulse, or other Provides blood information such as blood characteristics.

  FIG. 11 and FIG. 12 are graphs of data obtained from a living pig subject, and in accordance with one embodiment of the present invention, ECG and photoelectric pulse wave methods are used to distinguish between normal sinus rhythm and arrhythmia. An example of combination is shown. FIG. 11 shows an electrocardiogram 700 and a photoelectric pulse 710 shown over 2 seconds for a normal sinus rhythm state 730 and a ventricular fibrillation state 740. FIG. 12 shows an electrocardiogram 760 and a time-correlated photoelectric pulse 770 in a 38 second period 780 followed by a normal sinus rhythm 762 followed by a ventricular fibrillation event 764. 11 and 12 show that the characteristics of the electrocardiograms 700 and 760 and the photoelectric pulse waves 710 and 770 greatly change when the normal sinus rhythm 730 and 762 shift to the ventricular fibrillation 740 and 764 state.

  Referring again to FIG. 11, it should be noted that the normal sinus rhythm 730 graph and the ventricular fibrillation 740 graph are different in scale. Although the photoelectric pulse wave 710 of the ventricular fibrillation 740 appears to be equivalent to the photoelectric pulse wave 710 of the normal sinus rhythm 730, the peak-to-peak amplitude of the photoelectric pulse wave 710 of the graph of the ventricular fibrillation 740 is the same as that of the graph of the normal sinus rhythm 730. It is much smaller than the peak-to-peak amplitude of the photoelectric pulse wave 710. The vertical scale of the graph of ventricular fibrillation 740 is equal to the vertical scale of the graph of normal sinus rhythm 730.

  Referring now to FIG. 12, RMS blood oxygen level 772 corresponds to normal sinus rhythm 762 and RMS blood oxygen level 774 corresponds to ventricular fibrillation event 764. The threshold 776 may be predetermined or may be adaptively adjusted to assist in distinguishing between normal sinus rhythm 762 and ventricular fibrillation event 764. The time between the normal sinus rhythm 762 and the ventricular fibrillation event 764 indicates a loss of electrocardiogram data 760 during intentional triggering of the ventricular fibrillation 764.

  FIG. 13A is a schematic diagram of an LED current source unit 1810 of a photoelectric pulse wave circuit according to an embodiment of the present invention. As shown in FIG. 13A, the current source unit 1810 is configured as a constant current source and uses a source LED circuit 1811 to generate a drive pulse 1813 having a period of 1 ms and a pulse width of 0.1 ms, for example. Driven by.

  FIG. 13B is a schematic diagram of the photodetector portion 1820 of the photoelectric pulse wave circuit according to one embodiment of the present invention. The detector unit shown in FIG. 13B includes a photodiode 1821, a photocurrent-voltage amplifier 1822, a high-pass filter 1823, a voltage integrator 1824, and a low-pass filter 1825. The circuit shown in FIGS. 13A and 13B is useful for providing a photoelectric pulse wave signal, such as signal 770 shown in FIG.

  FIG. 14 illustrates various processes associated with one method that utilizes subcutaneous photoelectric pulse waves in combination with electrocardiogram-based rhythm detection. The method shown in FIG. 14 presents details regarding energy utilization. The photoelectric pulse wave circuit may be enabled only after other arrhythmia detection methods such as an electrocardiogram based algorithm are used. In order to save energy, the photoelectric pulse wave method may be used only before potential shock delivery. When the use of the photoelectric pulse wave is over, the circuit may be disabled. According to one implementation, the additional energy required when using the photoelectric pulse wave method for 10 seconds is about 0.5 Joules. This energy is very low compared to the energy used for defibrillation (> 5 joules). Therefore, by using the photoelectric pulse wave method to identify one arrhythmia event identified on the electrocardiogram as noise, there is a potential saving of 4.5 Joules or more. It should be noted that eliminating unnecessary shocks extends the useful life of the ITCS while improving patient comfort.

  With reference to FIG. 14 and further reference to FIGS. 11 and 12, an ECG based detection algorithm 1600 is used to detect cardiac arrhythmias. When a ventricular arrhythmia is detected (1602) using ECG-based detection 1601, a decision 1604 is made to ascertain whether the photoelectric pulse wave has been checked. The obtained photoelectric pulse wave check 1606 is performed.

  If the photoelectric pulse wave suggests or confirms the presence of a ventricular arrhythmia, for example using a threshold 1607, the defibrillation capacitor is charged (1608) and a shock is sent (1610). Note that a ventricular arrhythmia reconfirmation routine may be executed during the charging of the capacitor and before the delivery of the shock. If the photoelectric pulse wave signal exceeds a predetermined threshold value 1607 such as the threshold value shown in FIG. 12, for example (the RMS level of the photoelectric pulse wave may be used for this comparison), a predetermined time later An ECG signal recheck 1614 is performed.

  In the method shown in FIG. 14, the photoelectric pulse wave sensor that generates the photoelectric pulse wave signal may be selectively turned on and off. For example, the photoelectric pulse wave sensor may be in a power-off state until a tachyarrhythmia is detected using an ECG signal in blocks 1601 and 1602 of FIG. The photoelectric pulse wave sensor may remain powered until the cardiac signal and / or arrhythmia detection verification process is complete. For example, the photoelectric pulse wave sensor may have completed the processing associated with blocks 1606 and 1607 and before the defibrillation capacitor is charged at block 1608 (which may take about 20 seconds to fully charge the capacitor). The power may be turned off.

  The approach to cardiac signal identification described herein includes the use of alternative signals for a variety of purposes, including cardiac signal presence confirmation, arrhythmia and associated ECG signal identification and / or confirmation. ITCS devices using aspects of the present invention may operate in batch mode or adaptively, allowing for online or offline implementation. In order to conserve power, this system is well known in the art to identify the presence of arrhythmia or noise in the collected signal and to intelligently turn on / off cardiac signal identification in accordance with the present invention. Options for hierarchical decision routines using algorithms may be included.

  Various changes and additions can be made to the preferred embodiments described above without departing from the scope of the invention. Accordingly, the scope of the invention should not be limited by the particular embodiments described above, but should be defined only by the appended claims and their equivalents.

FIG. 3 illustrates a transthoracic heart sensing and / or stimulation device implanted in a patient according to an embodiment of the present invention. FIG. 3 illustrates a transthoracic heart sensing and / or stimulation device implanted in a patient according to an embodiment of the present invention. FIG. 2 is a block diagram illustrating various components of a transthoracic heart sensing and / or stimulating device, according to an embodiment of the invention. FIG. 2 is a block diagram illustrating various processing and detection elements of a transthoracic heart sensing and / or stimulating device, according to one embodiment of the invention. FIG. 2 is a block diagram illustrating one configuration of various components of an ITCS device according to an embodiment of the present invention. FIG. 2 illustrates components of a transthoracic heart sensing and / or stimulation device including an electrode array, according to one embodiment of the present invention. FIG. 6 shows a carotid pulse waveform, a cardiac phonogram (PCG) waveform, an electrocardiogram (ECG) waveform, and a filtered transthoracic impedance signal for two consecutive beats. FIG. 5 is a graph showing two consecutive PQRS complexes, their associated pseudo-accelerometer signals, and a detection window for signal correlation according to one embodiment of the present invention. 3 is a flowchart illustrating a multi-parameter arrhythmia identification method according to the present invention. 3 is a flowchart illustrating a multi-parameter arrhythmia identification method according to the present invention. 4 is a graph of an electrocardiogram signal and a skeletal muscle signal including a threshold according to an embodiment of the present invention. 3 is a flowchart of an arrhythmia identification method according to an embodiment of the present invention. 1 is a plan view of an ICD having a photoelectric pulse wave function implanted subcutaneously according to an embodiment of the present invention; FIG. It is a block diagram which shows the two-color photoelectric pulse wave system by one Embodiment of this invention. FIG. 6 is a graph showing a signal of normal sinus rhythm versus a signal of ventricular fibrillation. It is a graph which shows the RMS photoelectric pulse wave level in normal sinus rhythm versus the RMS photoelectric pulse wave level in ventricular fibrillation. 1 is a circuit diagram of an LED transmission circuit and an LED detection circuit according to an embodiment of the present invention. 1 is a circuit diagram of an LED transmission circuit and an LED detection circuit according to an embodiment of the present invention. 3 is a flowchart of an arrhythmia identification method according to an embodiment of the present invention.

Claims (10)

  1. A housing configured to be placed subcutaneously not in the thoracic cavity;
    A detection circuit provided in the housing and configured to generate an electrocardiogram signal including at least one of noise and electrocardiographic artifacts and a cardiac signal that is an electrical signal generated from cardiac activity;
    An energy delivery circuit provided in the housing;
    At least one electrode configured to be placed subcutaneously not in the thoracic cavity and connected to the detection circuit and the energy delivery circuit;
    An implantable sensor configured to be placed subcutaneously not in the thoracic cavity and configured to generate a sensor signal other than an electrocardiogram signal;
    A processor provided in the housing and connected to the sensor, the detection circuit and the energy delivery circuit, configured to use the sensor signal to confirm that the electrocardiogram signal includes a cardiac signal; And a processor configured to evaluate cardiac rhythm using the sensor signal and the electrocardiogram signal;
    An implantable subcutaneous device.
  2.   The apparatus of claim 1, wherein the processor is configured to determine hemodynamics using the electrocardiogram signal and the sensor signal.
  3. The sensor is configured to sense cardiac activity and sense a signal associated with a source other than the source for the electrocardiogram signal, and the processor confirms that the detected electrocardiogram signal includes the cardiac signal configured to use the pre-Symbol feeling known signals to,
    The apparatus of claim 1.
  4. Means for sensing an electrocardiogram signal at a subcutaneous location other than the thoracic cavity, comprising at least one of noise and electrocardiographic artifacts and a cardiac signal that is an electrical signal generated from cardiac activity;
    Means for acquiring a sensing signal other than an electrocardiogram signal from a sensor provided at a subcutaneous sensing position that is not in the thoracic cavity;
    Means for verifying that the electrocardiogram signal comprises a cardiac signal;
    Means for evaluating cardiac rhythm using the sensing signal and the electrocardiogram signal including the cardiac signal;
    An implantable subcutaneous device.
  5.   The apparatus of claim 4, wherein the sensor comprises a blood sensor and the sensing signal includes one or more of blood perfusion information, blood oxygen saturation information, photoelectric pulse wave information, and pulse oximetry information.
  6.   The means for evaluating the cardiac rhythm includes means for identifying a normal sinus rhythm and a cardiac arrhythmia using an electrocardiogram signal and a sensing signal, and the means for identifying the presence of the arrhythmia using the electrocardiogram signal; The apparatus of claim 4, comprising means for determining and means for confirming the presence of an arrhythmia using the sensed signal.
  7. A housing configured to be placed subcutaneously not within the patient's thoracic cavity;
    An energy delivery circuit provided in the housing;
    A detection circuit provided in the housing;
    One or more electrodes connected to the energy delivery and detection circuit and configured to be placed subcutaneously not in the patient's thoracic cavity, wherein the one or more electrodes sense heart and muscle activity;
    A processor provided in the housing and connected to the energy delivery and detection circuit for detecting an arrhythmia using a cardiac signal generated from the sensed cardiac activity and generating from the sensed muscle activity A processor configured to detect a patient activity state using the generated activity signal, and configured to modify the delivery of therapy to treat the arrhythmia in response to the activity signal;
    An implantable cardiac stimulating device.
  8.   8. The apparatus of claim 7, wherein the processor receives an electrocardiogram using the detection circuit and identifies a cardiac signal and an activity signal from the electrocardiogram.
  9.   The apparatus of claim 8, wherein the processor is configured to distinguish the cardiac signal and the activity signal using signal separation techniques.
  10. The one or more electrodes;
    A first electrode combination configured to preferentially sense a cardiac signal associated with the cardiac activity;
    A second electrode combination configured to preferentially sense a noise signal associated with the muscle activity;
    9. The apparatus of claim 8, comprising:
JP2006509836A 2003-04-11 2004-04-09 Implantable subcutaneous device and cardiac stimulation device Expired - Fee Related JP4521396B2 (en)

Priority Applications (5)

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US46227203P true 2003-04-11 2003-04-11
US10/804,471 US7218966B2 (en) 2003-04-11 2004-03-19 Multi-parameter arrhythmia discrimination
US10/816,464 US7117035B2 (en) 2003-04-11 2004-04-01 Subcutaneous cardiac stimulation system with patient activity sensing
US10/817,749 US7302294B2 (en) 2003-04-11 2004-04-02 Subcutaneous cardiac sensing and stimulation system employing blood sensor
PCT/US2004/010917 WO2004091719A2 (en) 2003-04-11 2004-04-09 Multi-parameter arrhythmia discrimination

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Families Citing this family (33)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7174203B2 (en) * 2004-11-18 2007-02-06 Inovise Medical, Inc. Method and system relating to monitoring and characterizing heart condition
US7333855B2 (en) * 2004-12-01 2008-02-19 Medtronic, Inc. Method and apparatus for determining oversensing in a medical device
US9089691B2 (en) 2004-12-07 2015-07-28 Cardiac Pacemakers, Inc. Stimulator for auricular branch of vagus nerve
US7805191B2 (en) 2005-01-31 2010-09-28 Physio-Control, Inc. CPR time indicator for a defibrillator data management system
US7615012B2 (en) * 2005-08-26 2009-11-10 Cardiac Pacemakers, Inc. Broadband acoustic sensor for an implantable medical device
US7742815B2 (en) * 2005-09-09 2010-06-22 Cardiac Pacemakers, Inc. Using implanted sensors for feedback control of implanted medical devices
WO2007053820A1 (en) * 2005-10-31 2007-05-10 Medtronic, Emergency Response Systems, Inc. Motion detection system for an external defibrillator
WO2007069963A1 (en) * 2005-12-16 2007-06-21 St. Jude Medical Ab Implantable medical device with condition detection
US7844331B2 (en) * 2005-12-20 2010-11-30 Cardiac Pacemakers, Inc. Method and apparatus for controlling anti-tachyarrhythmia pacing using hemodynamic sensor
DE602008004225D1 (en) 2007-02-28 2011-02-10 Medtronic Inc
US8755892B2 (en) 2007-05-16 2014-06-17 Cardiac Pacemakers, Inc. Systems for stimulating neural targets
WO2008156981A2 (en) 2007-06-14 2008-12-24 Cardiac Pacemakers, Inc. Multi-element acoustic recharging system
US8260415B2 (en) * 2007-12-21 2012-09-04 Medtronic, Inc. Optical sensor and method for detecting a patient condition
US8165676B2 (en) 2007-12-21 2012-04-24 Medtronic, Inc. Optical sensor and method for detecting a patient condition
US8452402B2 (en) 2008-04-23 2013-05-28 Medtronic, Inc. Optical sensing device for use in a medical device
JP5209787B2 (en) 2008-06-19 2013-06-12 カーディアック ペースメイカーズ, インコーポレイテッド Cardiac rhythm management system with hemodynamic tolerance analyzer
US8273032B2 (en) 2008-07-30 2012-09-25 Medtronic, Inc. Physiological parameter monitoring with minimization of motion artifacts
US8391944B2 (en) 2009-01-15 2013-03-05 Medtronic, Inc. Implantable medical device with adaptive signal processing and artifact cancellation
WO2010083366A1 (en) 2009-01-15 2010-07-22 Medtronic, Inc. Implantable medical device with adaptive signal processing and artifact cancellation
US8121682B2 (en) 2009-03-23 2012-02-21 Medtronic, Inc. Combined hemodynamic and EGM-based arrhythmia detection
WO2010144652A1 (en) 2009-06-10 2010-12-16 Medtronic, Inc. Tissue oxygenation monitoring in heart failure
US8391979B2 (en) 2009-06-10 2013-03-05 Medtronic, Inc. Shock reduction using absolute calibrated tissue oxygen saturation and total hemoglobin volume fraction
US8352008B2 (en) 2009-06-10 2013-01-08 Medtronic, Inc. Active noise cancellation in an optical sensor signal
US8634890B2 (en) 2009-06-10 2014-01-21 Medtronic, Inc. Device and method for monitoring of absolute oxygen saturation and tissue hemoglobin concentration
WO2010144662A1 (en) 2009-06-10 2010-12-16 Medtronic, Inc. Absolute calibrated tissue oxygen saturation and total hemoglobin volume fraction
AU2010273710B2 (en) 2009-06-29 2016-05-26 Cameron Health, Inc. Adaptive confirmation of treatable arrhythmia in implantable cardiac stimulus devices
US8521245B2 (en) 2009-09-11 2013-08-27 Medtronic, Inc. Method and apparatus for post-shock evaluation using tissue oxygenation measurements
US8781547B2 (en) 2011-10-28 2014-07-15 Medtronic, Inc. Method and apparatus for calibrating an absolute oxygen saturation sensor
WO2016160674A1 (en) 2015-04-02 2016-10-06 Cardiac Pacemakers, Inc. Atrial fibrillation detection
US9901741B2 (en) * 2015-05-11 2018-02-27 Physio-Control, Inc. Wearable cardioverter defibrillator (WCD) system using sensor modules with reassurance code for confirmation before shock
US10716500B2 (en) 2015-06-29 2020-07-21 Cardiac Pacemakers, Inc. Systems and methods for normalization of chemical sensor data based on fluid state changes
US10485442B2 (en) 2015-11-06 2019-11-26 Cardiac Pacemakers, Inc. Method and apparatus for enhancing ventricular based atrial fibrillation detection using atrial activity
KR101777583B1 (en) 2015-12-02 2017-09-13 한양대학교 에리카산학협력단 Method for processing an ECG signal and Apparatus thereof

Family Cites Families (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5203348A (en) 1990-06-06 1993-04-20 Cardiac Pacemakers, Inc. Subcutaneous defibrillation electrodes
US5184614A (en) * 1990-10-19 1993-02-09 Telectronics Pacing Systems, Inc. Implantable haemodynamically responsive cardioverting/defibrillating pacemaker
US6144879A (en) * 1991-05-17 2000-11-07 Gray; Noel Desmond Heart pacemaker
US5313953A (en) 1992-01-14 1994-05-24 Incontrol, Inc. Implantable cardiac patient monitor
US5417714A (en) * 1992-03-05 1995-05-23 Pacesetter, Inc. DDI pacing with PVC-protected hysteresis and automatic AV interval adjustment
US5342404A (en) * 1992-04-03 1994-08-30 Intermedics, Inc. Implantable medical interventional device
US5496362A (en) 1992-11-24 1996-03-05 Cardiac Pacemakers, Inc. Implantable conformal coil patch electrode with multiple conductive elements for cardioversion and defibrillation
US5411031A (en) 1993-11-24 1995-05-02 Incontrol, Inc. Implantable cardiac patient monitor
US5556421A (en) * 1995-02-22 1996-09-17 Intermedics, Inc. Implantable medical device with enclosed physiological parameter sensors or telemetry link
US5995860A (en) * 1995-07-06 1999-11-30 Thomas Jefferson University Implantable sensor and system for measurement and control of blood constituent levels
US5620466A (en) 1995-08-14 1997-04-15 Cardiac Pacemakers, Inc. Digital AGC using separate gain control and threshold templating
US5662688A (en) 1995-08-14 1997-09-02 Cardiac Pacemakers, Inc. Slow gain control
US5978707A (en) * 1997-04-30 1999-11-02 Cardiac Pacemakers, Inc. Apparatus and method for treating ventricular tachyarrhythmias
US6055454A (en) 1998-07-27 2000-04-25 Cardiac Pacemakers, Inc. Cardiac pacemaker with automatic response optimization of a physiologic sensor based on a second sensor
US6044298A (en) 1998-10-13 2000-03-28 Cardiac Pacemakers, Inc. Optimization of pacing parameters based on measurement of integrated acoustic noise
US6198952B1 (en) * 1998-10-30 2001-03-06 Medtronic, Inc. Multiple lens oxygen sensor for medical electrical lead
US6904319B2 (en) * 2001-04-06 2005-06-07 Cardiac Pacemakers, Inc. Method and apparatus for inhibiting atrial tachyarrhythmia therapy
WO2003020367A1 (en) * 2001-08-30 2003-03-13 Medtronic,Inc. System and method for detecting myocardial ischemia

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