WO1999043385A1 - Cardiac rhythm management device using transthoracic impedance - Google Patents
Cardiac rhythm management device using transthoracic impedance Download PDFInfo
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- WO1999043385A1 WO1999043385A1 PCT/US1999/004169 US9904169W WO9943385A1 WO 1999043385 A1 WO1999043385 A1 WO 1999043385A1 US 9904169 W US9904169 W US 9904169W WO 9943385 A1 WO9943385 A1 WO 9943385A1
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- rate
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- cutoff frequency
- transthoracic impedance
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61N—ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY
- A61N1/00—Electrotherapy; Circuits therefor
- A61N1/18—Applying electric currents by contact electrodes
- A61N1/32—Applying electric currents by contact electrodes alternating or intermittent currents
- A61N1/36—Applying electric currents by contact electrodes alternating or intermittent currents for stimulation
- A61N1/362—Heart stimulators
- A61N1/365—Heart stimulators controlled by a physiological parameter, e.g. heart potential
- A61N1/36514—Heart stimulators controlled by a physiological parameter, e.g. heart potential controlled by a physiological quantity other than heart potential, e.g. blood pressure
- A61N1/36521—Heart stimulators controlled by a physiological parameter, e.g. heart potential controlled by a physiological quantity other than heart potential, e.g. blood pressure the parameter being derived from measurement of an electrical impedance
Definitions
- This invention relates generally to cardiac rhythm management devices and methods and particularly, but not by way of limitation, to a rate adaptive cardiac rhythm management device using transthoracic impedance information, such as a minute ventilation signal, to control the rate at which pacing therapy is delivered to a patient's heart.
- transthoracic impedance information such as a minute ventilation signal
- Pacemakers and other cardiac rhythm management devices deliver cardiac therapy to a patient's heart to assist in obtaining a rhythm of heart contractions that maintains sufficient blood flow through the patient's circulatory system under a variety of conditions.
- rate-adaptive pacemakers deliver electrical pacing pulses to stimulate contractions of the heart. The rate at which the pulses are delivered is adjusted to accommodate a metabolic need of the patient. During exercise, higher pacing rates are delivered, while lower pacing rates are delivered when the patient is at rest.
- Pacemakers include specific control algorithms for tracking the parameter indicating metabolic need, and providing a control signal for adjusting the pacing rate accordingly. A variety of difficulties exist that complicate sensing of the parameter indicating metabolic need and controlling the pacing rate.
- detecting blood pH encounters sensor stability problems. pH sensors may drift with age and time. Blood oxygenation saturation is measured using light emitters that complicate the lead system used to couple the pacemaker's pulse generator to the heart. Blood temperature is a poor indicator of metabolic need because of the long time lag between the onset of exercise and any detectable increase in blood temperature. ECG artifacts, such as QT interval, are difficult to detect in the presence of other myopotentials and motion artifacts. Breathing rate, also referred to as respiratory rate, is not particularly well correlated with the need for increased blood circulation. For example, it is possible for respiratory rate to increase while the patient is sleeping or talking.
- Minute ventilation is a respiratory-related parameter that is a measure of the volume of air inhaled and exhaled during a particular period of time. Minute ventilation correlates well with the patient's metabolic need for an increased heart rate over a range of heart rates.
- a minute ventilation signal can be obtained by measuring transthoracic (across the chest or thorax) impedance. Transthoracic impedance provides respiratory or ventilation information, including how fast and how deeply a patient is breathing.
- a component of transthoracic impedance varies as the patient inhales and exhales.
- Ventilation e.g., breathing rate, which is also referred to as “ventilation rate” or “NR”, and breathing volume, which is also referred to as “tidal volume” or “TV”
- a minute ventilation signal also referred to as “minute volume” or “MN”
- MV measures air flow rate (e.g., liters per minute)
- TV measures volume per breath (e.g., liters per breath)
- VR measures breathing rate (e.g., breaths per minute).
- a larger MV signal indicates a metabolic need for an increased heart rate, and the pacing rate can be adjusted accordingly by a cardiac rhythm management device.
- a cardiac rhythm management device For example, one approach for measuring transthoracic impedance is described in Hauck et al, U.S. Patent 5,318,597 entitled “RATE ADAPTIVE CARDIAC RHYTHM MANAGEMENT DEVICE CONTROL ALGORITHM USING TRANS-THORACIC VENTILATION,” assigned to the assignee of the present application, the disclosure of which is incorporated herein by reference.
- many problems must be overcome to provide the most effective cardiac rhythm management therapy to the patient in a device that can remain implanted in the patient for a long period of time before requiring a costly surgical explantation and replacement procedure.
- ventilation information included in the transthoracic impedance signal is confounded with a variety of extraneous signals that makes the ventilation information difficult to detect.
- cardiac "stroke volume” or "stroke” signal The change in the transthoracic impedance signal due to blood volume changes resulting from heart contractions is referred to as cardiac "stroke volume” or "stroke” signal.
- stroke volume The change in the transthoracic impedance signal due to blood volume changes resulting from heart contractions.
- the frequencies of the heart contractions e.g., 1-3 Hz
- the frequencies of the heart contractions are extremely close to the frequency of the patient's breathing (e.g., under 1 Hz). This complicates separation of the stroke signal and the ventilation signal.
- the frequency of the stroke and ventilation signals changes according to the patient's activity. For example, a resting patient may have a heart rate of 60 beats per minute and a ventilation rate of 10 breaths per minute. When exercising, the same patient may have a heart rate of 120 beats per minute and a ventilation rate of 60 breaths per minute. The changing frequencies of the stroke and ventilation signals further complicates the separation of these signals. Another aspect of heart contractions also masks the ventilation signal.
- Heart contractions are initiated by electrical depolarizations (e.g., a QRS complex) resulting from paced or intrinsic heart activity.
- electrical depolarizations e.g., a QRS complex
- Such electrical heart activity signals may be detected during the measurement of transthoracic impedance. This further diminishes the accuracy of the transthoracic impedance measurement, and increases the difficulty of obtaining accurate ventilation information.
- a further problem with certain other minute ventilation based cardiac rhythm management devices results from the use of a relatively high amplitude current pulse (e.g., 1 milliampere) to detect transthoracic impedance.
- a relatively high amplitude current pulse e.g. 1 milliampere
- risks capturing the heart i.e., evoking a contraction
- ECG electrocardiogram
- a cardiac rhythm management device that effectively manages the patient's heart rate based on an accurate indication of metabolic need.
- Such a cardiac rhythm management device must be sufficiently robust to operate in the presence of extraneous noise signals that confound the indication of metabolic need.
- There is a further need for such a device to operate at low power consumption, in order to maximize the usable life of the battery- powered implantable device.
- the present invention provides, among other things, a method of determining transthoracic impedance in a cardiac rhythm management device.
- a multiple phase stimulus is repeatedly delivered to a thorax region of a patient. More than one phase of each multiple phase stimuli is demodulated to obtain sample points of a response signal including transthoracic impedance information.
- a response to each phase is sampled, weighted to obtain a filtering function, and combined.
- a rate of delivering cardiac rhythm management therapy is adjusted based on ventilation information included in the transthoracic impedance information of a plurality of the sample points.
- a noise-response function inhibits rate-adjustment if the transthoracic impedance signal is too noisy.
- a interference avoidance function delays delivery of the multiple phase stimulus to avoid simultaneous occurrence with an interfering signal (e.g., a telemetry signal).
- Another aspect of the invention includes a method of determining transthoracic impedance in a cardiac rhythm management device that includes delivering stimuli to a thorax of the patient, sensing a response signal including transthoracic impedance information, attenuating a component of the response signal having frequencies above a lowpass cutoff frequency, and adaptively basing the lowpass cutoff frequency on a heart rate, and independent of a breathing rate signal, from the patient.
- a cardiac stroke signal is attenuated to obtain ventilation information.
- the lowpass cutoff frequency is adaptively selected to be below the heart rate by selecting between a number of discrete lowpass cutoff frequencies, each lowpass cutoff frequency corresponding to a particular range of values of the heart rate.
- the method includes detecting peaks and valleys of the response signal. Differences between peaks and valleys of the response signal provide tidal volume data points, which are integrated for a predetermined period of time to obtain minute ventilation data points. A rate of delivering cardiac rhythm management therapy is adjusted based on the minute ventilation data points. Alternatively, breath-by-breath minute ventilation data points are obtained. Instead of performing the integration, time differences between the peaks and valleys of the response signal provide respiration period data points corresponding to the tidal volume data points. The tidal volume data points are divided by the corresponding respiration period data points to obtain minute ventilation data points, upon which a rate of delivering cardiac rhythm management therapy is adjusted. Another aspect of the present invention includes a cardiac rhythm management device.
- the device includes an exciter, adapted to be coupled to a thorax of a patient for repeatedly delivering a multiphase stimulus thereto.
- a signal processor includes a receiver for obtaining transthoracic impedance information responsive to the stimuli.
- a demodulator included in the signal processor, includes sampling elements for demodulating the transthoracic impedance in response to different phases of the multiphase stimulus.
- a therapy circuit is adapted to be coupled to a heart of the patient for delivering cardiac rhythm management therapy thereto.
- a controller is coupled to the therapy circuit for adjusting a rate of delivery of the cardiac rhythm management therapy based on the transthoracic impedance.
- the device includes a noise-reversion circuit that inhibits rate-adjustment if the transthoracic impedance signal is too noisy.
- the device is included within a cardiac rhythm management system that also includes an endocardial lead, carrying first and second electrodes, and a housing including third and fourth electrodes.
- a cardiac rhythm management device that includes an exciter for delivering stimuli to a thorax.
- a signal processor includes a receiver for obtaining a transthoracic impedance responsive to the stimuli.
- the signal processor extracts ventilation information from the transthoracic impedance.
- the signal processor includes an adaptive lowpass filter for removing a cardiac stroke component of the transthoracic impedance signal.
- a cutoff frequency of the adaptive lowpass filter is adaptively based on a heart rate signal of the patient. The cutoff frequency of the adaptive lowpass filter is independent of a breathing rate signal from the patient.
- a therapy circuit is adapted to be coupled to a heart of the patient for delivering cardiac rhythm management therapy thereto.
- a controller is coupled to the therapy circuit for adjusting a rate of delivery of the cardiac rhythm management therapy based on the ventilation information.
- the present invention provides, among other things, a cardiac rhythm management system, device, and methods that sense transthoracic impedance and adjust a delivery rate of the cardiac rhythm management therapy based on information extracted from the transthoracic impedance.
- the present invention effectively manages the patient's heart rate based on an accurate indication of metabolic need. It provides robust operation in the presence of extraneous noise signals that confound the indication of metabolic need. It also provides low power consumption, increasing the usable life of the battery-powered implantable device.
- Figure 1 is a schematic/block diagram illustrating generally one embodiment of a cardiac rhythm management system according to the present invention, including a cardiac rhythm management device and electrode connections.
- Figure 2 is a schematic/block diagram illustrating generally one embodiment of particular circuits included within an exciter for delivering electrical excitation stimuli to a heart.
- Figure 3 illustrates generally a current waveform resulting from operation of an exciter according to one aspect of the present invention.
- Figure 4 is a block diagram illustrating generally one embodiment of portions of a signal processor.
- Figure 5 is a schematic diagram illustrating generally one embodiment of a preamplifier.
- Figure 6 is a schematic diagram illustrating generally one embodiment of a demodulator.
- Figure 7 is a signal flow diagram illustrating generally one embodiment of an adaptive filter.
- Figure 8 is a flow chart illustrating generally one example of a sequence of steps for calculating a minute ventilation indicated rate.
- Figure 9 is a flow chart illustrating generally a second example of a sequence of steps for calculating a minute ventilation indicated rate.
- FIG. 10 is a block diagram illustrating generally an alternate embodiment of a signal processor. Detailed Description of the Invention
- FIG. 1 is a schematic/block diagram illustrating generally, by way of example, but not by way of limitation, one embodiment of a cardiac rhythm management system 100 according to the present invention.
- System 100 includes, among other things, cardiac rhythm management device 105 and leadwire ("lead") 110 for communicating signals between device 105 and a portion of a living organism, such as heart 115.
- Embodiments of device 105 include bradycardia and antitachycardia pacemakers, cardioverters, defibrillators, 8 combination pacemaker/defibrillators, drug delivery devices, and any other cardiac rhythm management apparatus capable of providing therapy to heart 115.
- System 100 may also include additional components such as, for example, a remote programmer capable of communicating with device 105.
- system 100 is implantable in the living organism, such as in a pectoral or abdominal region of a human patient, or elsewhere.
- portions of system 100 e.g., device 105) are alternatively disposed externally to the human patient.
- portions of lead 110 are disposed in the right ventricle, however, any other positioning of lead 110 is included within the present invention.
- lead 110 may alternatively be positioned in the atrium or elsewhere.
- lead 110 is a commercially available bipolar pacing lead.
- System 100 can also include other leads in addition to lead 110, appropriately disposed, such as in or around heart 115, or elsewhere.
- system 100 includes at least four electrodes, such as described in Hauck et al. U.S.
- a first conductor of multiconductor lead 110 electrically couples a first electrode, such as tip electrode 120 (e.g., disposed at the apex of the right ventricle of heart 115), to device 105.
- a second conductor of multiconductor lead 110 independently electrically couples a second electrode, such as ring electrode 125, to device 105.
- device 105 includes a hermetically sealed housing 130, formed from a conductive metal, such as titanium.
- Housing 130 also referred to as a "case” or “can”
- a suitable insulator such as silicone rubber
- a header 140 is mounted on housing 130 for receiving lead 110.
- Header 140 is formed of an insulative material, such as molded plastic.
- Header 140 also includes at least one receptacle, such as for receiving lead 110 and electrically coupling conductors of lead 110 to device 105.
- Header 140 also includes a fourth electrode, referred to as indifferent electrode 145.
- FIG. 1 also illustrates generally portions of device 105, together with schematic illustrations of connections to the various electrodes.
- Device 105 includes an electrical stimulation source, such as exciter 150.
- Exciter 150 delivers an electrical excitation signal, such as a strobed sequence of current pulses or other measurement stimuli, to heart 115 (e.g., between ring electrode 125 and tip electrode 120, or using any other electrode configuration suitable for delivering the current pulses).
- an electrical excitation signal such as a strobed sequence of current pulses or other measurement stimuli
- heart 115 e.g., between ring electrode 125 and tip electrode 120, or using any other electrode configuration suitable for delivering the current pulses.
- signal processor 155 e.g., between tip electrode 120 and indifferent electrode 145, or any other suitable electrode configuration.
- the response signal sensed by signal processor 155 is a voltage that represents a transthoracic (i.e., across a portion of the chest or thorax) impedance.
- a minute ventilation signal also referred to as "minute volume” or "MN”
- MN minute volume
- signal processor 155 extracts ventilation information, including the MN signal, from the impedance signal. Based on the MN signal, signal processor 155 outputs an indicated rate signal at node 160 to controller 165.
- controller 165 Based on the indicated rate signal at node 160, controller 165 adjusts the rate of delivery of cardiac rhythm management therapy, such as electrical pacing stimuli, to heart 115 by therapy circuit 170.
- cardiac rhythm management therapy such as electrical pacing stimuli
- Such pacing stimuli includes, for example, providing bipolar pacing between tip electrode 120 and ring electrode 125, providing unipolar pacing between can electrode 135 and either of tip electrode 120 or ring electrode 125, or providing pacing stimuli using any other suitable electrode configuration.
- Exciter and Resulting Stimuli Waveform Figure 2 is a schematic/block diagram illustrating generally, by way of example, but not by way of limitation, one embodiment of particular circuits included within exciter 150 for delivering electrical stimuli (e.g., strobed alternating-direction constant- amplitude current pulses) to heart 115.
- Exciter 150 includes, among other things, bridge switcher 200, comprising switches 10
- switches 200A-D are implemented as transistors, such as p-channel metal-oxide semiconductor (PMOS) field-effect transistors (FETs), or any other suitable switches.
- PMOS metal-oxide semiconductor
- FETs field-effect transistors
- Exciter 150 also includes current source 205 and current sink 210.
- each of current source 205 and current sink 210 include transistors in a regulated cascode or other suitable configuration.
- switcher 200 is electrically coupled to case electrode 135 and ring electrode 125 through respective dc blocking capacitors 215A and 215B and respective switches 220A and 220B (e.g., PMOS transistors).
- Switches 225A and 225B (e.g., PMOS transistors) precharge respective capacitors 215A and 215B.
- Exciter 150 also includes a clock circuit 230 receiving one or more clock or other control signals from controller 165 and providing signals to the control terminals of each of switches 200A-D, 220A-B, and 225A-B.
- Figure 3 illustrates generally a current waveform 300 between case electrode 135 and ring electrode 125 resulting from operation of exciter 150 according to one aspect of the present invention.
- waveform 300 includes a multiple phase (“multiphase") stimulus.
- the multiphase stimulus includes a square wave, such as four current pulses 301, 302, 303, and 304 in sequentially alternating polarity/direction, each current pulse being a phase of the multiphase stimulus.
- each one of current pulses 301-304 has a duration that is selected at approximately between 1 and 100 microseconds (e.g., approximately between 2 and 60 microseconds, such as at 20 microseconds), to allow adequate sampling of the transthoracic impedance signal obtained in response thereto.
- pulses 301-304 form a square wave having a carrier frequency of approximately 25 kilohertz.
- Other suitable durations of current pulses 301-304 could also be used, providing a different resulting carrier frequency.
- the sequence of current pulses 301-304 is strobed.
- the four pulse sequence 301-304 is repeated at a strobing frequency (also referred to as a repetition frequency or a sampling frequency) of approximately 20 Hertz (i.e., a 50 millisecond time interval).
- a strobing frequency also referred to as a repetition frequency or a sampling frequency
- Other suitable 11 strobing/repetition frequencies could also be used.
- any strobing/repetition time interval shorter than 55 milliseconds could be used.
- the amplitude of current pulses 301-304 was selected at less than approximately 1 milliampere. For example, approximately 320 microampere amplitude current pulses 301-304 provide an adequate excitation signal to obtain the desired response signal, while minimizing current drain of the implanted device 105, thereby increasing its implanted longevity. However, other amplitudes of current pulses 301-304 could also be used. Such amplitudes of current pulses 301-304 should be less than the tissue stimulation threshold of the heart to avoid any resulting cardiac depolarization.
- the strobing frequency is sufficiently fast to provide adequate sampling of ventilation or other information carried by the transthoracic impedance signal obtained in response to the electrical stimuli provided by exciter 150.
- Such ventilation information can appear at frequencies as high as approximately 1 Hertz, depending on the patient's breathing rate.
- the strobing frequency also minimizes aliasing of a "stroke volume" component of the transthoracic impedance signal (i.e., a portion of the transthoracic impedance signal that varies along with the patient's heartbeat instead of the patient's breathing rate).
- the stroke volume component of the transthoracic impedance signal can have frequencies as high as approximately 3 Hertz, depending on the patient's heart rate.
- dc blocking capacitors 215A-B Prior to each sequence of current pulses 301-304, dc blocking capacitors 215A-B are precharged by a bias circuit, such as by turning on switches 200 A-D and 225A-B, with switches 220A-B being off.
- Current source 205 and current sink 210 establish the operating point of a terminal of each of dc blocking capacitors 215A-B that is coupled to switcher 200.
- switches 225A-B are turned off.
- pulse 301 is produced by turning on switches 200A, 200D, and 220A-B, such that current delivered by current source 205 leaves case electrode 135. The current returns through ring electrode 125, and is sunk by current sink 210.
- pulse 302 is produced by turning on switches 200B-C and 220A-B, such that current delivered by current source 205 leaves ring electrode 125. The current returns through case electrode 135, and is sunk by current sink 210.
- pulse 303 is produced by again turning on switches 12
- clock circuit 230 provides nonoverlapping control signals to switches 225A-B and switches 220A-B. As a result, switches 225 A-B are not turned on at the same time as switches 220 A-B. This avoids any coupling of either of case electrode 135 and ring electrode 125 to the positive power supply voltage N DD .
- Waveform 300 provides several important advantages allowing efficient and accurate sensing of the MN signal, allowing system 100 to provide more effective delivery of rate-responsive cardiac rhythm management therapy to the patient.
- system 100 allows the use of relatively low amplitude current pulses (e.g., +/- 320 microamperes). This conserves power, allowing battery- powered portions of system 100 (e.g., device 105) to remain implanted in the patient for a longer usable lifetime. Because of their low amplitude, current pulses 301-304 do not produce any discernable artifacts on electrocardiogram (ECG) traces or on other diagnostic equipment. Such artifacts can confuse diagnosing physicians.
- ECG electrocardiogram
- the low amplitude current pulses 301-304 are also less likely to trigger false detection of intrinsic heart activity, such as by sense amplifiers included in device 105. False detection of intrinsic heart activity can inhibit proper delivery of pacing therapy, rendering cardiac rhythm management ineffective and increasing risk to the patient. According to one aspect of the present invention, the sensitivity setting of such sense amplifiers can be increased without being affected by interference from the current pulses 301-304 produced by exciter 150. Moreover, the low amplitude current pulses 301-304 avoid the risk of capturing heart 115 (i.e., inducing an electrical depolarization and heart contraction), particularly when current pulses 301-304 are delivered 13 from small electrodes that are also used for delivering pacing therapy to heart 115.
- waveform 300 includes current pulses 301-304 that are strobed at a frequency of approximately 20 Hertz.
- the 25 kilohertz carrier frequency is only present for a short fraction of the 50 millisecond strobing time interval (i.e., duty cycle of less than 1%).
- the strobing also reduces power consumption and obtains increased implanted longevity of device 105, as described above.
- Waveform 300 also provides balance in both amplitude and duration for each polarity/direction of the current pulses 301-304, thereby balancing the charge delivered to heart 115.
- Each +320 microampere pulse e.g., 301 and 303 is balanced by an equal duration corresponding -320 microampere pulse (e.g., 302 and 304). This method of balancing the amplitude and duration of waveform 300 reduces the likelihood of capturing heart 115 or inducing false sensing as intrinsic heart activity sensed by device 105.
- device 105 avoids delivering the multiphase stimulus in the presence of other interfering signals, such as telemetry signals, that increase the difficulty of accurately detecting a response.
- device 105 includes a telemetry transceiver 185 for communicating via telemetry signals (e.g., telemetry pulses) with an external programmer 190, such as by inductively coupled coils in each of the device 105 and the external programmer 190.
- telemetry signals e.g., telemetry pulses
- controller 165 delays delivery of the multiphase stimulus (e.g., current pulses 301-304), such as by approximately 1 millisecond. This avoids inaccuracies in the response signal to current pulses 301-304 that may result from the telemetry pulses or, similarly, from the presence of other interfering signals.
- the multiphase stimulus e.g., current pulses 301-304
- FIG. 4 is a block diagram illustrating generally, by way of example, but not by way of limitation, one embodiment of portions of signal processor 155.
- Signal processor 155 includes analog signal processing circuit 400 and digital 14 signal processing circuit 405.
- Inputs of a preamplifier 410 (also referred to as a preamp or a receiver) of analog signal processing circuit 400 are electrically coupled to each of indifferent electrode 145 and tip electrode 120 for receiving a signal in response to the above-described stimuli provided by exciter 150.
- Analog signal processing circuit 400 also includes demodulator 415, receiving the output of preamplifier 410, and providing an output signal to bandpass filter 420. An output signal from bandpass filter 420 is received by analog-to-digital (A/D) converter 425.
- A/D analog-to-digital
- An output signal from A/D converter 425 is received at highpass filter 430 of digital signal processing circuit 405.
- digital signal processing circuit 405 is included within controller 165 such as, for example, as a sequence of instructions executed by a microprocessor.
- digital signal processing circuit 405 includes separately implemented hardware portions dedicated to performing the digital signal processing tasks described below.
- An output signal from highpass filter 430 is received by adaptive lowpass filter 435 of digital signal processing circuit 405.
- Minute ventilation calculation module 440 receives an output signal from adaptive lowpass filter 435, and provides a resulting indicated rate signal at node 160 to controller 165.
- Preamplifier Figure 5 is a schematic diagram illustrating generally, by way of example, but not by way of limitation, one embodiment of preamplifier 410.
- Preamplifier 410 includes a switched-capacitor (SC) differential .amplifier 500.
- Preamplifier 410 is electrically coupled to indifferent electrode 145 and tip electrode 120 through respective switches 510 and 515 and respective resistors 520 and 525. Switches 510 and 515 are turned on only during the approximate time when the stimuli current pulses 301-304 are being delivered by exciter 150.
- Resistors 520 and 525 provide antialiasing bandlimiting of the input signals received from indifferent electrode 145 and tip electrode 120.
- Differential amplifier 500 includes input capacitors 530 and 535, coupled to resistors 520 and 525 respectively, and also coupled to a respective positive input at node 540 and a negative input, at node 545, of a differential- input/differential-output operational amplifier 550.
- Feedback capacitors 560 and 565 are coupled from a respective negative output, at node 570, and a positive 15 output, at node 575, of operational amplifier 550, to its respective positive input, at node 540, and negative input, at node 545.
- input capacitors 530 and 535 have approximately 10 times the capacitance value of respective feedback capacitors 560 and 565.
- Differential amplifier 500 also includes autozeroing input switches, 580 and 585, coupling respective input nodes 540 and 545 to respective reference voltages (e.g., a ground voltage).
- Autozeroing output switches 590 and 595 couple respective output nodes 570 and 575 to respective reference voltages (e.g., a ground voltage).
- Switches 580, 585, 590, and 595 provide zeroing of corresponding feedback capacitors 560 and 565.
- Switches 580 and 585 further establish the bias points of the input nodes 540 and 545 of operational amplifier 550, such as during sampling of signals from indifferent electrode 145 and tip electrode 120 onto input capacitors 530 and 535.
- Preamplifier 410 receives a voltage based on the transthoracic impedance between indifferent electrode 145 and tip electrode 120.
- a transthoracic impedance of 50 ohms results in a voltage between the inputs of differential amplifier 500 of approximately 16 millivolts.
- the transthoracic impedance varies as the patient breathes, increasing as air fills the patient's thoracic cavity during inspiration and decreasing as air is released during expiration.
- the transthoracic impedance may vary, for example, by approximately 2 ohms during respiration, resulting in an approximately 0.64 millivolt modulation of the approximately 16 millivolt baseline signal appearing between the inputs of differential amplifier 500.
- the electrodes used for delivering the excitation current are different from the electrodes used for sensing the response thereto (e.g., indifferent electrode 145 and tip electrode 120).
- the same electrodes could be used for delivering the excitation current and sensing the response thereto.
- differential amplifier 500 provides an effective voltage gain of approximately 6.
- the 16 millivolt baseline signal is amplified to approximately 100 millivolts by differential amplifier 500 and the resulting signal is provided to demodulator 415.
- Demodulator Demodulator 415 samples the signal obtained in response to current pulses 301-304 after the above-described amplification by preamplifier 410. According to one aspect of the invention, the output of preamplifier 410 is sampled at the end of each of current pulses 301-304. Demodulator 415 combines these four samples into a single value using a weighted average. The resulting weighted average represents the total impedance (i.e., including both baseline and ventilation components) obtained for the sequence of four current pulses 301-304.
- the weighted average is formed by weighting the second and third samples, obtained from respective current pulses 302 and 303, by a factor of approximately 3.0 relative to the first and fourth samples, obtained from respective current pulses 301 and 304. Weighting the samples advantageously provides an additional highpass filtering function, substantially transmitting the transthoracic impedance signal at the 25 kilohertz carrier frequency of the current pulses 301-304, while substantially rejecting out-of- band signals.
- demodulator 415 provides additional rejection of low-frequency signals, such as R-waves and other electrical signals produced by heart 115.
- a transfer function provided by one embodiment of demodulator 415 is described in the z-domain, as illustrated in Equation 2.
- demodulator 415 provides a voltage gain that is approximately between 1.75 and 2.0 for the in-band transthoracic impedance signal. Moreover, demodulator 415 also advantageously attenuates signals at 17 frequencies below 100 Hz by a factor of at least approximately 120 dB, including such signals as R-waves and other electrical intrinsic heart activity signals produced by heart 115, which can interfere with sensing the patient's transthoracic impedance.
- Figure 6 is a schematic diagram illustrating generally, by way of example, but not by way of limitation, one embodiment of a switched-capacitor demodulator 415.
- the output signal from preamplifier 410 is sampled onto capacitors 600A-B in response to current pulse 301, onto capacitors 605A-B in response to current pulse 302, onto capacitors 610A-B in response to current pulse 303, and onto capacitors 615A-B in response to current pulse 304.
- Capacitors 605 A-B and 610 A-B provide 3 times the capacitance value of capacitors 600 A-B and 615 A-B, in order to provide the above-described weighting of the samples.
- switched-capacitor integrator 620 also referred to as a summer.
- dummy capacitors 625 A-B are dummy capacitors 625 A-B.
- Each of dummy capacitors 625A-B has a capacitance value that is twice that of one of capacitors 600A-B, and twice that of one of capacitors 615A-B.
- Dummy capacitors 625A-B are switched in during sample of current pulses 301 and 304.
- demodulator 415 presents the same load capacitance to preamplifier 410 during sampling of each of the four current pulses 301-304.
- the charge that is sampled onto dummy capacitors 625A-B is not included in the weighted sample (i.e., the resulting charge is not included in the integration provided by integrator 620).
- integrator 620 includes input capacitors 650 and 655, which are autozeroed by switches, as illustrated, during the clock phase ⁇ . .An integration capacitor 660, which is in the feedback path around operational amplifier 665, sums the weighted samples obtained in response to the four current pulses 301-304 during an integration clock phase ⁇ j .
- a noise sampling/integration capacitor 630 which is also in the feedback path around 18 operational amplifier 665, sums the weighted samples obtained in the absence of delivered current pulses during a noise integration clock phase ⁇ M , as described below. Integrator 620 also provides a matching network 670 on the other input of operational amplifier 665 for matching the above-described switched capacitor operation.
- demodulator 415 also provides a noise sensing mode of operation. In normal operation, demodulator 415 samples the output of filter/amplifier 410 in response to current pulses 301-304 provided by exciter 150. During a noise sensing mode of operation, exciter 150 is turned off (i.e., current pulses 301-304 are not provided), and demodulator 415 samples, onto switched-in noise sampling/integration capacitor 630, noise arising from external sources (e.g., heart signals or any environmental noise sources) and internal noise produced by circuits coupled to the input of the demodulator 415. In particular, demodulator 415 is capable of sensing noise that is at frequencies close to the 25 kilohertz carrier frequency of the current pulses 301-304.
- the gain of demodulator 415 is increased (e.g., by a factor of approximately 2.0-2.5) during noise sensing mode in order to provide more sensitive noise detection.
- the noise sampling/integration capacitor 630 used during noise sensing is different in value from a corresponding integration capacitor used during normal operation of demodulator 415, in order to provide a different gain during noise sensing.
- device 105 also includes a noise reversion circuit based on the noise sensed by demodulator 415 when exciter 150 is turned off.
- a noise comparator 635 receives a signal derived from the output of demodulator 415. Comparator 635 determines whether the detected noise exceeds a particular programmable threshold value.
- the programmable threshold value used by comparator 635 is implemented as a programmable switched-capacitor array, providing threshold voltages ranging between approximately 4-120 millivolts at the output of demodulator 415 (corresponding to an impedance noise threshold between approximately 0.4-12 ohms). 19
- bandpass filter 420 provides a passband between single pole corner frequencies at 0.1 Hz and 2.0 Hz, and includes a gain stage providing a voltage gain that is programmable (e.g., 6x, 12x, and 24x).
- the 0.1 Hz low frequency (highpass) pole substantially attenuates the baseline component of the transthoracic impedance signal, but substantially transmits the time-varying component of the transthoracic impedance signal representing ventilation.
- the 2.0 Hz high frequency (lowpass) pole substantially attenuates other time- varying components of the transthoracic impedance signal that do not contribute substantial ventilation information.
- the lowpass pole effectively contributes to the attenuation of signal components due to the cardiac stroke signal resulting from the beating of heart 115.
- removal of the stroke signal is both difficult and particularly important for properly adapting the delivered pacing rate based on minute ventilation, since the stroke signal is very close in frequency to the desired ventilation signal.
- the lowpass pole also filters out other noise at frequencies that exceed the lowpass pole frequency.
- bandpass filter 420 includes a switched-capacitor biquadratic filter stage, series-coupled with a subsequent switched-capacitor gain stage. Capacitance values of the switched- capacitor gain stage are user-programmable, thereby obtaining differing voltage gains, as described above.
- the output of the switched capacitor gain stage included in bandpass filter 420 is provided to the input of A D converter 425.
- Analog-to-Digital (A/U Converter) A/U Converter
- A/D converter 425 receives the output signal of bandpass filter 420 and provides a resulting digitized output signal to highpass filter 430 of digital signal processing circuit 405.
- A/D converter 425 is implemented as an 8-bit, successive approximation type switched-capacitor A/T) converter having an input range of approximately 1 Volt.
- A/D converter 425 provides one 8-bit digital word corresponding to each sequence of four current pulses 301-304 delivered by exciter 150.
- Many different implementations of A/D converter 425 will be suitable for use in the 20 present invention. For example, a different A/D converter resolution (greater than or less than 8 bits) may be used.
- Highpass filter 430 includes, in one embodiment, a single-pole infinite impulse response (IIR) digital filter that receives the 8-bit digital output signal from A/D converter 425, removing frequency components below its highpass cutoff frequency of approximately 0.1 Hz. Many other different embodiments of highpass filter 430 will also be suitable for use in the present invention. Highpass filter 430 advantageously further attenuates baseline dc components of the transthoracic impedance and any dc offset voltages created by A/D converter 425. The output of highpass filter 430 is provided to adaptive lowpass filter 435.
- IIR infinite impulse response
- Adaptive lowpass filter 435 receives the output signal of highpass filter 430 and attenuates frequency components of the signal that exceed the lowpass cutoff frequency of adaptive lowpass filter 435. Attenuated frequencies include the cardiac stroke signal, resulting from changes in blood volume in heart 115 as it contracts during each cardiac cycle, which appears as a component of the transthoracic impedance signal. Thus, the cardiac stroke signal confounds the desired ventilation information indicating the metabolic need for adjusting pacing rate. As described above, the component of the transthoracic impedance due to the stroke signal can be substantial. As a result, attenuation of the stroke signal is particularly important for properly adapting the delivered pacing rate based on minute ventilation.
- Adaptive lowpass filter 435 provides effective attenuation of the stroke component of the processed transthoracic impedance signal received from highpass filter 430. Frequency components above a lowpass cutoff frequency are attenuated. In one embodiment, the frequency components above the lowpass cutoff frequency are attenuated by at least 30 decibels while preserving 21 ventilation information having frequency components below the lowpass cutoff frequency.
- the lowpass cutoff frequency is adaptively based on a heart rate of the patient and, according to a further aspect of the invention, is independent of any breathing rate signal obtained from the patient.
- the patient's heart rate is detected by sense amplifiers 175, and provided to adaptive lowpass filter 435, such as by controller 165, for adjusting the lowpass cutoff frequency of adaptive lowpass filter 435 accordingly.
- Table 1 illustrates, by way of example, but not by way of limitation, one mapping of different lowpass cutoff frequencies of adaptive lowpass filter 435 to ranges of the patient's heart rate. Other mappings may also be used.
- Table 1 Exemplary lowpass cutoff frequencies of adaptive lowpass filter 435 based on different sensed heart rates.
- a 0.5 Hz cutoff frequency is used when the sensed heart rate is less than 68 beats per minute.
- adaptive lowpass filter 435 switches its lowpass cutoff frequency to 0.75 Hz.
- adaptive lowpass filter 435 switches its lowpass cutoff frequency to 1.0 Hz.
- adaptive lowpass filter 435 adjusts the lowpass cutoff frequency according to Table 1.
- the present invention bases adaptive adjustment of the lowpass cutoff frequency only on heart rate. Among other things, this reduces computational complexity and power consumption associated with monitoring the breathing rate for adjusting the lowpass cutoff frequency. This also ensures that adaptive 22 lowpass filter 435 removes the stroke signal for all particular combinations of respiration rate and heart rate, so that pacing rate is appropriately adjusted based on minute ventilation.
- adaptive filter 435 uses a 4-pole Chebyshev filter that is better suited to data represented by fewer bits (e.g., 8-bit fixed point arithmetic). This conserves power and avoids instability and other potential problems of quantization.
- adaptive lowpass filter 435 uses a state-space structure, rather than in a conventional direct form structure. The state-space structure further reduces the effects of coefficient quantization and roundoff noise.
- One example of such a state-space structure is described in Leland B. Jackson, "Digital Filters and Signal Processing," 2nd ed., pp. 332-340, Kluwer Academic Publishers, Boston, MA, the disclosure of which is incorporated herein by reference.
- Figure 7 is a signal flow diagram illustrating generally one embodiment of adaptive filter 435 having a state-space topology.
- Figure 7 includes scaling elements, delay elements, and summation elements. Signals output from summation elements are also scaled, as illustrated in Figure 7.
- saturation of signals at particular nodes should be avoided by adjusting the coefficients according to conventional DSP coefficient scaling techniques.
- One embodiment of hexadecimal values of filter coefficients is illustrated by way of example, but not by way of limitation, in Table 2.
- Adaptive lowpass filter 435 outputs a signal based on transthoracic impedance and carrying ventilation information.
- the stroke component of the transthoracic impedance signal is substantially removed.
- the output of adaptive lowpass filter 435 is provided to MV calculation module 440, which calculates a minute ventilation indicated pacing rate based on the ventilation information.
- MV calculation module 440 is implemented as a sequence of instructions executed on any suitable microprocessor, such as a Zilog Z80-type microprocessor.
- MV calculation module 440 is implemented as any other hardware or software configuration capable of calculating an indicated pacing rate based on ventilation information.
- a sequence of instructions executed on a microprocessor for 24 calculating a minute ventilation indicated rate is described below, and illustrated in the flow chart of Figure 8.
- MV calculation module 440 receives from adaptive lowpass filter 435 a digital signal representing a time-varying transthoracic impedance.
- the impedance signal is centered around zero, with positive values representing inhalation, and negative values representing exhalation.
- the maximum (most positive) and minimum (most negative) values of the impedance signal are stored in separate storage registers. After each breath, an interrupt is provided to the microprocessor, such as upon each positive-going zero-crossing.
- the tidal volume (TV) is calculated upon receiving the interrupt.
- the tidal volume is obtained by reading the storage registers, and taking the difference between the maximum and minimum values of the impedance signal held for the patient's previous breath. A larger tidal volume indicates a deeper breath than a smaller tidal volume.
- a tidal volume data point is produced at step 805 for each breath by the patient.
- the tidal volume is integrated (i.e., the tidal volume data points are summed) for a predetermined period of time (e.g., approximately 8 seconds), obtaining a minute ventilation data point, as described in Equation 1.
- a predetermined period of time e.g., approximately 8 seconds
- the minute ventilation data point is output, .and a new integration (i.e., summation) of tidal volume commences.
- Steps 815 and 820 include carrying out concurrent moving short term and long term averages, respectively.
- the short term average (“STA,” also referred to as a "boxcar” average) at step 815 represents, at a particular point in time, a moving average of the minute ventilation data points over the previous approximately 32 seconds.
- the short term average represents the present minute ventilation indication of metabolic need.
- the long term average (“LTA”) at step 820 represents, at a particular point in time, a moving average of the minute ventilation data points over the previous approximately 2 hours.
- the long term average approximates the resting state of the minute ventilation indicator.
- the long term average at step 820 is carried out by an IIR digital filter. 25
- the short term and long term averages are compared. In one embodiment, this comparison involves subtracting the long term average from the short term average. The difference is optionally scaled, and used to adjust the pacing rate when the short term average exceeds the long term average. In one embodiment, the rate is adjusted according to Equation 3.
- Equation 3 STA represents the short term average, LTA represents the long term average, K represents an optional scaling coefficient, LRL is a programmable lower rate limit to which the incremental sensor driven rate is added, and RATE MV is the minute ventilation indicated rate at which pacing therapy is delivered.
- RATE MV is a linear function of the difference STA-LTA.
- pacing therapy is delivered at the lower rate limit (LRL).
- LRL lower rate limit
- more than one scaling coefficient K is used, obtaining a piecewise linear mapping of minute ventilation to the resulting minute ventilation indicated rate.
- a smaller scaling coefficient K is used. This reduces the incremental increase in pacing rate for high pacing rates, when compared to the incremental increase in pacing rate for pacing rates close to the lower rate limit (LRL).
- Step 825 is alternatively implemented as a ratio STA/LTA, rather than the difference STA-LTA.
- the rate is adjusted according to Equation 4 when STA exceeds LTA.
- Equation 4 STA represents the short term average, LTA represents the long term average, C represents an optional scaling coefficient, LRL is a programmable lower rate limit to which the incremental sensor driven rate is 26 added, and RATE, ⁇ is the minute ventilation indicated rate at which pacing therapy is delivered. If the value of the short term average is less than the value of the long term average, pacing therapy is delivered at the lower rate limit (LRL). In this embodiment, reduced incremental rate at high pacing rates is obtained by using more than one scaling coefficient, as described above.
- rate modifiers can also be used to obtain a minute ventilation indicated rate.
- the minute ventilation indicated rate can be combined, blended, or otherwise used in conjunction with other rate indicators, such as those derived from different sensors providing different indicators of metabolic need (e.g., acceleration).
- Such indicators may have different response characteristics (e.g., time lag after onset of exercise) that are advantageously combined with the minute ventilation rate indication described above.
- the indicated rate (e.g., RATE MV ) is provided to controller 165, for adjusting the rate of pacing therapy delivered by therapy circuit 170.
- Minute Ventilation Calculation Alternate Embodiment
- Figure 9 is a flow chart, similar to that of Figure 8, illustrating generally another embodiment of the invention that uses a breath-by-breath minute ventilation calculation.
- time differences corresponding to the peaks and valleys of the response signal are used to obtain respiration period data points corresponding to the tidal volume data points obtained in step 805.
- a breath-by-breath indication of minute ventilation is obtained, such as by dividing the tidal volume data points by the corresponding respiration period data points to obtain minute ventilation data points.
- the rate of delivering cardiac rhythm management therapy is then adjusted based on the minute ventilation data points, as described above with respect to Figure 8.
- FIG. 10 is a block diagram illustrating generally one such variation on signal processor 155.
- the bandpass filter 420 of Figure 4 is implemented digitally in the signal 27 processor 155 of Figure 10.
- Other variations are also possible without departing from the present invention.
- the above description illustrates, by way of example, but not by way of limitation, a particular embodiment of the present invention in which ventilation information is extracted from a detected transthoracic impedance, and the rate of delivery of cardiac rhythm management therapy is adjusted based on an indicator derived from the ventilation information.
- the present invention also includes the extraction of other information (e.g., cardiac stroke information) from the transthoracic impedance, such as for adjusting the rate of delivery of cardiac rhythm management therapy based on an indicator extracted from such information.
- cardiac stroke information e.g., cardiac stroke information
- Another such example is disclosed in Spinelli U.S. Patent Number 5,235,976 entitled, “METHOD AND APPARATUS FOR MANAGING AND MONITORING CARDIAC RHYTHM MANAGEMENT USING ACTIVE TIME AS THE CONTROLLING PARAMETER,” which is assigned to the assignee of the present invention, and the disclosure of which is incorporated herein by reference.
- the present invention provides, among other things, a cardiac rhythm management device that senses transthoracic impedance and adjusts a delivery rate of the cardiac rhythm management therapy based on information extracted from the transthoracic impedance.
- an adaptive lowpass filter removes the stroke signal from the transthoracic impedance signal while preserving the ventilation information.
- the adaptive filter includes a lowpass cutoff frequency that is adaptively based on the patient's heart rate, but independent of a breathing rate signal.
- a weighted demodulation provides filtering that enhances rejection of unwanted signals.
- Minute ventilation is obtained from tidal volume obtained from the ventilation information.
- An 28 indicated rate is based on a difference between, or ratio of, short and long term averages of the minute ventilation information, unless noise exceeding a threshold is detected.
- the present invention effectively manages the patient's heart rate based on an accurate indication of metabolic need. It provides robust operation in the presence of extraneous noise signals that confound the indication of metabolic need. It also provides low power consumption, increasing the usable life of the battery-powered implantable device.
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Abstract
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Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
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AT99908486T ATE300332T1 (en) | 1998-02-27 | 1999-02-26 | DEVICE FOR CONTROLLING HEART RHYTHM USING TRANSTHORACAL IMPEDANCE |
DE69926347T DE69926347T2 (en) | 1998-02-27 | 1999-02-26 | DEVICE FOR CONTROLLING HEART RTHYTHMING USING THE TRANSTHORACOUS IMPEDANCE |
CA002322174A CA2322174A1 (en) | 1998-02-27 | 1999-02-26 | Cardiac rhythm management device using transthoracic impedance |
EP99908486A EP1061998B1 (en) | 1998-02-27 | 1999-02-26 | Cardiac rhythm management device using transthoracic impedance |
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US09/032,731 | 1998-02-27 | ||
US09/032,731 US6076015A (en) | 1998-02-27 | 1998-02-27 | Rate adaptive cardiac rhythm management device using transthoracic impedance |
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WO1999043385A1 true WO1999043385A1 (en) | 1999-09-02 |
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PCT/US1999/004169 WO1999043385A1 (en) | 1998-02-27 | 1999-02-26 | Cardiac rhythm management device using transthoracic impedance |
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US (4) | US6076015A (en) |
EP (1) | EP1061998B1 (en) |
AT (1) | ATE300332T1 (en) |
CA (1) | CA2322174A1 (en) |
DE (1) | DE69926347T2 (en) |
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Cited By (7)
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---|---|---|---|---|
US7092757B2 (en) * | 2002-07-12 | 2006-08-15 | Cardiac Pacemakers, Inc. | Minute ventilation sensor with dynamically adjusted excitation current |
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Families Citing this family (373)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7081095B2 (en) * | 2001-05-17 | 2006-07-25 | Lynn Lawrence A | Centralized hospital monitoring system for automatically detecting upper airway instability and for preventing and aborting adverse drug reactions |
US6609016B1 (en) | 1997-07-14 | 2003-08-19 | Lawrence A. Lynn | Medical microprocessor system and method for providing a ventilation indexed oximetry value |
US7758503B2 (en) | 1997-01-27 | 2010-07-20 | Lynn Lawrence A | Microprocessor system for the analysis of physiologic and financial datasets |
US20050062609A9 (en) * | 1992-08-19 | 2005-03-24 | Lynn Lawrence A. | Pulse oximetry relational alarm system for early recognition of instability and catastrophic occurrences |
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US6022322A (en) | 1998-02-06 | 2000-02-08 | Intermedics Inc. | Non-invasive cardiorespiratory monitor with synchronized bioimpedance sensing |
US6076015A (en) * | 1998-02-27 | 2000-06-13 | Cardiac Pacemakers, Inc. | Rate adaptive cardiac rhythm management device using transthoracic impedance |
US6061551A (en) | 1998-10-21 | 2000-05-09 | Parkervision, Inc. | Method and system for down-converting electromagnetic signals |
US7515896B1 (en) | 1998-10-21 | 2009-04-07 | Parkervision, Inc. | Method and system for down-converting an electromagnetic signal, and transforms for same, and aperture relationships |
US7039372B1 (en) | 1998-10-21 | 2006-05-02 | Parkervision, Inc. | Method and system for frequency up-conversion with modulation embodiments |
US6370371B1 (en) | 1998-10-21 | 2002-04-09 | Parkervision, Inc. | Applications of universal frequency translation |
US7236754B2 (en) | 1999-08-23 | 2007-06-26 | Parkervision, Inc. | Method and system for frequency up-conversion |
US7295826B1 (en) * | 1998-10-21 | 2007-11-13 | Parkervision, Inc. | Integrated frequency translation and selectivity with gain control functionality, and applications thereof |
US6721600B2 (en) * | 2000-01-19 | 2004-04-13 | Medtronic, Inc. | Implantable lead functional status monitor and method |
US7209725B1 (en) | 1999-01-22 | 2007-04-24 | Parkervision, Inc | Analog zero if FM decoder and embodiments thereof, such as the family radio service |
US6317628B1 (en) * | 1999-01-25 | 2001-11-13 | Cardiac Pacemakers, Inc. | Cardiac rhythm management system with painless defribillation lead impedance measurement |
US6879817B1 (en) | 1999-04-16 | 2005-04-12 | Parkervision, Inc. | DC offset, re-radiation, and I/Q solutions using universal frequency translation technology |
US6853690B1 (en) | 1999-04-16 | 2005-02-08 | Parkervision, Inc. | Method, system and apparatus for balanced frequency up-conversion of a baseband signal and 4-phase receiver and transceiver embodiments |
US7693230B2 (en) | 1999-04-16 | 2010-04-06 | Parkervision, Inc. | Apparatus and method of differential IQ frequency up-conversion |
US7110444B1 (en) | 1999-08-04 | 2006-09-19 | Parkervision, Inc. | Wireless local area network (WLAN) using universal frequency translation technology including multi-phase embodiments and circuit implementations |
US7065162B1 (en) | 1999-04-16 | 2006-06-20 | Parkervision, Inc. | Method and system for down-converting an electromagnetic signal, and transforms for same |
US8295406B1 (en) | 1999-08-04 | 2012-10-23 | Parkervision, Inc. | Universal platform module for a plurality of communication protocols |
US6718198B2 (en) | 1999-08-24 | 2004-04-06 | Cardiac Pacemakers, Inc. | Arrhythmia display |
US6535763B1 (en) * | 1999-08-22 | 2003-03-18 | Cardia Pacemakers, Inc. | Event marker alignment by inclusion of event marker transmission latency in the real-time data stream |
US6963734B2 (en) * | 1999-12-22 | 2005-11-08 | Parkervision, Inc. | Differential frequency down-conversion using techniques of universal frequency translation technology |
US7010286B2 (en) | 2000-04-14 | 2006-03-07 | Parkervision, Inc. | Apparatus, system, and method for down-converting and up-converting electromagnetic signals |
IL143418A (en) * | 2000-05-31 | 2004-09-27 | Given Imaging Ltd | Measurement of electrical characteristics of tissue |
US6522914B1 (en) * | 2000-07-14 | 2003-02-18 | Cardiac Pacemakers, Inc. | Method and apparatuses for monitoring hemodynamic activities using an intracardiac impedance-derived parameter |
US7428436B2 (en) * | 2000-11-02 | 2008-09-23 | Cardiac Pacemakers, Inc. | Method for exclusion of ectopic events from heart rate variability metrics |
US7069070B2 (en) | 2003-05-12 | 2006-06-27 | Cardiac Pacemakers, Inc. | Statistical method for assessing autonomic balance |
US7454453B2 (en) | 2000-11-14 | 2008-11-18 | Parkervision, Inc. | Methods, systems, and computer program products for parallel correlation and applications thereof |
US8548576B2 (en) | 2000-12-15 | 2013-10-01 | Cardiac Pacemakers, Inc. | System and method for correlation of patient health information and implant device data |
US6941167B2 (en) * | 2000-12-15 | 2005-09-06 | Cardiac Pacemakers, Inc. | System and method for displaying cardiac events |
US6665558B2 (en) | 2000-12-15 | 2003-12-16 | Cardiac Pacemakers, Inc. | System and method for correlation of patient health information and implant device data |
US7181285B2 (en) | 2000-12-26 | 2007-02-20 | Cardiac Pacemakers, Inc. | Expert system and method |
US7062641B1 (en) * | 2001-01-10 | 2006-06-13 | Cisco Technology, Inc. | Method and apparatus for unified exception handling with distributed exception identification |
US9053222B2 (en) | 2002-05-17 | 2015-06-09 | Lawrence A. Lynn | Patient safety processor |
US6987998B2 (en) * | 2001-02-28 | 2006-01-17 | Cardiac Pacemakers, Inc. | Cardiac rhythm management patient report |
US7386344B2 (en) * | 2004-08-11 | 2008-06-10 | Cardiac Pacemakers, Inc. | Pacer with combined defibrillator tailored for bradycardia patients |
US6751502B2 (en) * | 2001-03-14 | 2004-06-15 | Cardiac Pacemakers, Inc. | Cardiac rhythm management system with defibrillation threshold prediction |
US20050283197A1 (en) * | 2001-04-10 | 2005-12-22 | Daum Douglas R | Systems and methods for hypotension |
US6907288B2 (en) | 2001-04-10 | 2005-06-14 | Cardiac Pacemakers, Inc. | Cardiac rhythm management system adjusting rate response factor for treating hypotension |
US6912420B2 (en) | 2001-04-10 | 2005-06-28 | Cardiac Pacemakers, Inc. | Cardiac rhythm management system for hypotension |
US6684101B2 (en) | 2001-04-25 | 2004-01-27 | Cardiac Pacemakers, Inc. | Implantable medical device employing single drive, dual sense impedance measuring |
US6748271B2 (en) * | 2001-07-27 | 2004-06-08 | Cardiac Pacemakers, Inc. | Method and system for treatment of neurocardiogenic syncope |
US7191000B2 (en) * | 2001-07-31 | 2007-03-13 | Cardiac Pacemakers, Inc. | Cardiac rhythm management system for edema |
FR2829917B1 (en) * | 2001-09-24 | 2004-06-11 | Ela Medical Sa | ACTIVE MEDICAL DEVICE INCLUDING MEANS FOR DIAGNOSING THE RESPIRATORY PROFILE |
US7340303B2 (en) | 2001-09-25 | 2008-03-04 | Cardiac Pacemakers, Inc. | Evoked response sensing for ischemia detection |
US8781587B2 (en) * | 2001-10-01 | 2014-07-15 | Eckhard Alt | Detecting and treatment of sleep apnea |
US8359097B2 (en) * | 2001-10-01 | 2013-01-22 | Eckhard Alt | Method of detecting sleep apnea and treatment thereof |
US7383088B2 (en) * | 2001-11-07 | 2008-06-03 | Cardiac Pacemakers, Inc. | Centralized management system for programmable medical devices |
US7085335B2 (en) * | 2001-11-09 | 2006-08-01 | Parkervision, Inc. | Method and apparatus for reducing DC offsets in a communication system |
US7072427B2 (en) | 2001-11-09 | 2006-07-04 | Parkervision, Inc. | Method and apparatus for reducing DC offsets in a communication system |
US6728575B2 (en) * | 2001-11-30 | 2004-04-27 | St. Jude Medical Ab | Method and circuit for detecting cardiac rhythm abnormalities using a differential signal from a lead with a multi-electrode tip |
US6973349B2 (en) | 2001-12-05 | 2005-12-06 | Cardiac Pacemakers, Inc. | Method and apparatus for minimizing post-infarct ventricular remodeling |
US7127289B2 (en) * | 2001-12-05 | 2006-10-24 | Cardiac Pacemakers, Inc. | Cardiac resynchronization system employing mechanical measurement of cardiac walls |
US6963778B2 (en) * | 2002-01-17 | 2005-11-08 | Cardiac Pacemakers, Inc. | Maximum pacing rate limiter implemented using the evoked response-T-wave interval |
FR2834881B1 (en) * | 2002-01-23 | 2004-10-22 | Ela Medical Sa | PHYSIOLOGICAL SIGNAL RECORDER, IN PARTICULAR HOLTER ECG SIGNAL RECORDER, INCLUDING MEANS OF DETECTION OF THE DISCONNECTION OR CUTTING OF THE LINK CABLES |
US20040122296A1 (en) * | 2002-12-18 | 2004-06-24 | John Hatlestad | Advanced patient management for triaging health-related data |
US20040122294A1 (en) | 2002-12-18 | 2004-06-24 | John Hatlestad | Advanced patient management with environmental data |
US7468032B2 (en) * | 2002-12-18 | 2008-12-23 | Cardiac Pacemakers, Inc. | Advanced patient management for identifying, displaying and assisting with correlating health-related data |
US7043305B2 (en) | 2002-03-06 | 2006-05-09 | Cardiac Pacemakers, Inc. | Method and apparatus for establishing context among events and optimizing implanted medical device performance |
US20040122487A1 (en) | 2002-12-18 | 2004-06-24 | John Hatlestad | Advanced patient management with composite parameter indices |
US7983759B2 (en) * | 2002-12-18 | 2011-07-19 | Cardiac Pacemakers, Inc. | Advanced patient management for reporting multiple health-related parameters |
US8391989B2 (en) | 2002-12-18 | 2013-03-05 | Cardiac Pacemakers, Inc. | Advanced patient management for defining, identifying and using predetermined health-related events |
US6957105B2 (en) | 2002-03-26 | 2005-10-18 | Cardiac Pacemakers, Inc. | Method and apparatus for detecting oscillations in cardiac rhythm with electrogram signals |
US7039462B2 (en) * | 2002-06-14 | 2006-05-02 | Cardiac Pacemakers, Inc. | Method and apparatus for detecting oscillations in cardiac rhythm |
US7113825B2 (en) | 2002-05-03 | 2006-09-26 | Cardiac Pacemakers, Inc. | Method and apparatus for detecting acoustic oscillations in cardiac rhythm |
AU2003232060A1 (en) | 2002-05-03 | 2003-11-17 | Cardiac Pacemakers, Inc. | Method and apparatus for detecting oscillations in cardiac rhythm |
US8417327B2 (en) * | 2002-06-20 | 2013-04-09 | Physio-Control, Inc. | Variable frequency impedance measurement |
US7142912B2 (en) * | 2002-07-12 | 2006-11-28 | Cardiac Pacemakers, Inc. | Method and apparatus for assessing and treating atrial fibrillation risk |
US7460584B2 (en) | 2002-07-18 | 2008-12-02 | Parkervision, Inc. | Networking methods and systems |
US7379883B2 (en) | 2002-07-18 | 2008-05-27 | Parkervision, Inc. | Networking methods and systems |
US6965797B2 (en) * | 2002-09-13 | 2005-11-15 | Cardiac Pacemakers, Inc. | Method and apparatus for assessing and treating myocardial wall stress |
US7226422B2 (en) * | 2002-10-09 | 2007-06-05 | Cardiac Pacemakers, Inc. | Detection of congestion from monitoring patient response to a recumbent position |
FR2846246B1 (en) * | 2002-10-25 | 2005-06-24 | Ela Medical Sa | ACTIVE IMPLANTABLE MEDICAL DEVICE OF CARDIAC STIMULATOR, DEFIBRILLATOR, CARDIOVERTOR, OR MULTISITE DEVICE WITH IMPROVED MANAGEMENT OF RESPIRATORY BREAKS OR HYPOPNEES |
US7155280B2 (en) * | 2002-11-01 | 2006-12-26 | Cardiac Pacemakers, Inc. | Rate-adaptive pacemaker with compensation for long-term variations in average exertion level |
US7072711B2 (en) | 2002-11-12 | 2006-07-04 | Cardiac Pacemakers, Inc. | Implantable device for delivering cardiac drug therapy |
US7016730B2 (en) * | 2002-11-15 | 2006-03-21 | Cardiac Pacemakers, Inc. | Method of operating implantable medical devices to prolong battery life |
US7313434B2 (en) * | 2002-11-25 | 2007-12-25 | Regents Of The University Of Minnesota | Impedance monitoring for detecting pulmonary edema and thoracic congestion |
US6868346B2 (en) * | 2002-11-27 | 2005-03-15 | Cardiac Pacemakers, Inc. | Minute ventilation sensor with automatic high pass filter adjustment |
US7189204B2 (en) | 2002-12-04 | 2007-03-13 | Cardiac Pacemakers, Inc. | Sleep detection using an adjustable threshold |
US7986994B2 (en) | 2002-12-04 | 2011-07-26 | Medtronic, Inc. | Method and apparatus for detecting change in intrathoracic electrical impedance |
US20050080348A1 (en) * | 2003-09-18 | 2005-04-14 | Stahmann Jeffrey E. | Medical event logbook system and method |
US7972275B2 (en) | 2002-12-30 | 2011-07-05 | Cardiac Pacemakers, Inc. | Method and apparatus for monitoring of diastolic hemodynamics |
US7272442B2 (en) * | 2002-12-30 | 2007-09-18 | Cardiac Pacemakers, Inc. | Automatically configurable minute ventilation sensor |
US8050764B2 (en) | 2003-10-29 | 2011-11-01 | Cardiac Pacemakers, Inc. | Cross-checking of transthoracic impedance and acceleration signals |
US7378955B2 (en) * | 2003-01-03 | 2008-05-27 | Cardiac Pacemakers, Inc. | System and method for correlating biometric trends with a related temporal event |
US7136707B2 (en) | 2003-01-21 | 2006-11-14 | Cardiac Pacemakers, Inc. | Recordable macros for pacemaker follow-up |
US20040220636A1 (en) * | 2003-04-29 | 2004-11-04 | Medtronic, Inc. | Cardiac pacing therapy parameter programming |
US8414498B2 (en) * | 2003-05-12 | 2013-04-09 | Cheetah Medical, Inc. | System, method and apparatus for measuring blood flow and blood volume |
US7477932B2 (en) | 2003-05-28 | 2009-01-13 | Cardiac Pacemakers, Inc. | Cardiac waveform template creation, maintenance and use |
US7186220B2 (en) * | 2003-07-02 | 2007-03-06 | Cardiac Pacemakers, Inc. | Implantable devices and methods using frequency-domain analysis of thoracic signal |
US7050853B2 (en) * | 2003-07-07 | 2006-05-23 | Cardiac Pacemakers, Inc. | Detection of patient mortality by an implantable medical device |
US7616988B2 (en) * | 2003-09-18 | 2009-11-10 | Cardiac Pacemakers, Inc. | System and method for detecting an involuntary muscle movement disorder |
US7396333B2 (en) | 2003-08-18 | 2008-07-08 | Cardiac Pacemakers, Inc. | Prediction of disordered breathing |
US8002553B2 (en) | 2003-08-18 | 2011-08-23 | Cardiac Pacemakers, Inc. | Sleep quality data collection and evaluation |
US7510531B2 (en) | 2003-09-18 | 2009-03-31 | Cardiac Pacemakers, Inc. | System and method for discrimination of central and obstructive disordered breathing events |
US7469697B2 (en) * | 2003-09-18 | 2008-12-30 | Cardiac Pacemakers, Inc. | Feedback system and method for sleep disordered breathing therapy |
US7680537B2 (en) * | 2003-08-18 | 2010-03-16 | Cardiac Pacemakers, Inc. | Therapy triggered by prediction of disordered breathing |
US7668591B2 (en) * | 2003-09-18 | 2010-02-23 | Cardiac Pacemakers, Inc. | Automatic activation of medical processes |
US20050142070A1 (en) * | 2003-09-18 | 2005-06-30 | Hartley Jesse W. | Methods and systems for assessing pulmonary disease with drug therapy control |
US8192376B2 (en) | 2003-08-18 | 2012-06-05 | Cardiac Pacemakers, Inc. | Sleep state classification |
US7720541B2 (en) * | 2003-08-18 | 2010-05-18 | Cardiac Pacemakers, Inc. | Adaptive therapy for disordered breathing |
US7967756B2 (en) * | 2003-09-18 | 2011-06-28 | Cardiac Pacemakers, Inc. | Respiratory therapy control based on cardiac cycle |
US8251061B2 (en) | 2003-09-18 | 2012-08-28 | Cardiac Pacemakers, Inc. | Methods and systems for control of gas therapy |
US8606356B2 (en) * | 2003-09-18 | 2013-12-10 | Cardiac Pacemakers, Inc. | Autonomic arousal detection system and method |
US7468040B2 (en) * | 2003-09-18 | 2008-12-23 | Cardiac Pacemakers, Inc. | Methods and systems for implantably monitoring external breathing therapy |
US7787946B2 (en) | 2003-08-18 | 2010-08-31 | Cardiac Pacemakers, Inc. | Patient monitoring, diagnosis, and/or therapy systems and methods |
US7678061B2 (en) * | 2003-09-18 | 2010-03-16 | Cardiac Pacemakers, Inc. | System and method for characterizing patient respiration |
US7572225B2 (en) * | 2003-09-18 | 2009-08-11 | Cardiac Pacemakers, Inc. | Sleep logbook |
US7336996B2 (en) * | 2003-09-18 | 2008-02-26 | Cardiac Pacemakers, Inc. | Rate regularization of cardiac pacing for disordered breathing therapy |
US7662101B2 (en) | 2003-09-18 | 2010-02-16 | Cardiac Pacemakers, Inc. | Therapy control based on cardiopulmonary status |
US7591265B2 (en) | 2003-09-18 | 2009-09-22 | Cardiac Pacemakers, Inc. | Coordinated use of respiratory and cardiac therapies for sleep disordered breathing |
US7887493B2 (en) | 2003-09-18 | 2011-02-15 | Cardiac Pacemakers, Inc. | Implantable device employing movement sensing for detecting sleep-related disorders |
US7757690B2 (en) | 2003-09-18 | 2010-07-20 | Cardiac Pacemakers, Inc. | System and method for moderating a therapy delivered during sleep using physiologic data acquired during non-sleep |
US7320675B2 (en) * | 2003-08-21 | 2008-01-22 | Cardiac Pacemakers, Inc. | Method and apparatus for modulating cellular metabolism during post-ischemia or heart failure |
US7194306B1 (en) * | 2003-09-05 | 2007-03-20 | Pacesetter, Inc. | Cardiac optimization through low-frequency analysis of hemodynamic variables |
US7392084B2 (en) * | 2003-09-23 | 2008-06-24 | Cardiac Pacemakers, Inc. | Demand-based cardiac function therapy |
US7286872B2 (en) * | 2003-10-07 | 2007-10-23 | Cardiac Pacemakers, Inc. | Method and apparatus for managing data from multiple sensing channels |
US7572226B2 (en) | 2003-10-28 | 2009-08-11 | Cardiac Pacemakers, Inc. | System and method for monitoring autonomic balance and physical activity |
US7657312B2 (en) * | 2003-11-03 | 2010-02-02 | Cardiac Pacemakers, Inc. | Multi-site ventricular pacing therapy with parasympathetic stimulation |
US7248923B2 (en) | 2003-11-06 | 2007-07-24 | Cardiac Pacemakers, Inc. | Dual-use sensor for rate responsive pacing and heart sound monitoring |
US7184821B2 (en) * | 2003-12-03 | 2007-02-27 | Regents Of The University Of Minnesota | Monitoring thoracic fluid changes |
US7319900B2 (en) | 2003-12-11 | 2008-01-15 | Cardiac Pacemakers, Inc. | Cardiac response classification using multiple classification windows |
US20060247693A1 (en) | 2005-04-28 | 2006-11-02 | Yanting Dong | Non-captured intrinsic discrimination in cardiac pacing response classification |
US7774064B2 (en) | 2003-12-12 | 2010-08-10 | Cardiac Pacemakers, Inc. | Cardiac response classification using retriggerable classification windows |
US8521284B2 (en) | 2003-12-12 | 2013-08-27 | Cardiac Pacemakers, Inc. | Cardiac response classification using multisite sensing and pacing |
US7203540B2 (en) | 2003-12-22 | 2007-04-10 | Cardiac Pacemakers, Inc. | Method and system for setting cardiac resynchronization therapy parameters |
US7471980B2 (en) * | 2003-12-22 | 2008-12-30 | Cardiac Pacemakers, Inc. | Synchronizing continuous signals and discrete events for an implantable medical device |
US7389141B2 (en) * | 2003-12-22 | 2008-06-17 | Cardiac Pacemakers, Inc. | Biatrial pacing optimization for biventricular pacing |
US7194307B2 (en) * | 2003-12-22 | 2007-03-20 | Cardiac Pacemakers, Inc. | Pacing method and device for preserving native conduction system |
US7123960B2 (en) | 2003-12-22 | 2006-10-17 | Cardiac Pacemakers, Inc. | Method and system for delivering cardiac resynchronization therapy with variable atrio-ventricular delay |
US7783353B2 (en) | 2003-12-24 | 2010-08-24 | Cardiac Pacemakers, Inc. | Automatic neural stimulation modulation based on activity and circadian rhythm |
US8200331B2 (en) | 2004-11-04 | 2012-06-12 | Cardiac Pacemakers, Inc. | System and method for filtering neural stimulation |
US7869881B2 (en) | 2003-12-24 | 2011-01-11 | Cardiac Pacemakers, Inc. | Baroreflex stimulator with integrated pressure sensor |
US8126560B2 (en) | 2003-12-24 | 2012-02-28 | Cardiac Pacemakers, Inc. | Stimulation lead for stimulating the baroreceptors in the pulmonary artery |
US7460906B2 (en) | 2003-12-24 | 2008-12-02 | Cardiac Pacemakers, Inc. | Baroreflex stimulation to treat acute myocardial infarction |
US7486991B2 (en) | 2003-12-24 | 2009-02-03 | Cardiac Pacemakers, Inc. | Baroreflex modulation to gradually decrease blood pressure |
US7647114B2 (en) | 2003-12-24 | 2010-01-12 | Cardiac Pacemakers, Inc. | Baroreflex modulation based on monitored cardiovascular parameter |
US7769450B2 (en) * | 2004-11-18 | 2010-08-03 | Cardiac Pacemakers, Inc. | Cardiac rhythm management device with neural sensor |
US8396560B2 (en) | 2004-11-18 | 2013-03-12 | Cardiac Pacemakers, Inc. | System and method for closed-loop neural stimulation |
US7509166B2 (en) | 2003-12-24 | 2009-03-24 | Cardiac Pacemakers, Inc. | Automatic baroreflex modulation responsive to adverse event |
US7643875B2 (en) | 2003-12-24 | 2010-01-05 | Cardiac Pacemakers, Inc. | Baroreflex stimulation system to reduce hypertension |
US7706884B2 (en) | 2003-12-24 | 2010-04-27 | Cardiac Pacemakers, Inc. | Baroreflex stimulation synchronized to circadian rhythm |
US8024050B2 (en) | 2003-12-24 | 2011-09-20 | Cardiac Pacemakers, Inc. | Lead for stimulating the baroreceptors in the pulmonary artery |
US20050149132A1 (en) | 2003-12-24 | 2005-07-07 | Imad Libbus | Automatic baroreflex modulation based on cardiac activity |
US9020595B2 (en) | 2003-12-24 | 2015-04-28 | Cardiac Pacemakers, Inc. | Baroreflex activation therapy with conditional shut off |
US20050149129A1 (en) * | 2003-12-24 | 2005-07-07 | Imad Libbus | Baropacing and cardiac pacing to control output |
US8025624B2 (en) | 2004-02-19 | 2011-09-27 | Cardiac Pacemakers, Inc. | System and method for assessing cardiac performance through cardiac vibration monitoring |
US7697990B2 (en) * | 2004-02-20 | 2010-04-13 | Resmed Limited | Method and apparatus for detection and treatment of respiratory disorder by implantable device |
US7299086B2 (en) | 2004-03-05 | 2007-11-20 | Cardiac Pacemakers, Inc. | Wireless ECG in implantable devices |
US7260431B2 (en) | 2004-05-20 | 2007-08-21 | Cardiac Pacemakers, Inc. | Combined remodeling control therapy and anti-remodeling therapy by implantable cardiac device |
US20050261596A1 (en) * | 2004-05-24 | 2005-11-24 | Smith Brian A | Passive switched capacitor high-pass filter for implantable cardiac device |
US7142920B2 (en) * | 2004-05-25 | 2006-11-28 | Cardiac Pacemakers, Inc. | Chronotropic status monitor for implantable cardiac device |
US7996083B2 (en) * | 2004-06-02 | 2011-08-09 | Cardiac Pacemakers, Inc. | Far-field sensing channel for implantable cardiac device |
US20070191901A1 (en) * | 2004-06-04 | 2007-08-16 | Pacesetter, Inc. | Quantifying systolic and diastolic cardiac performance from dynamic impedance waveforms |
US7747323B2 (en) | 2004-06-08 | 2010-06-29 | Cardiac Pacemakers, Inc. | Adaptive baroreflex stimulation therapy for disordered breathing |
US7329226B1 (en) | 2004-07-06 | 2008-02-12 | Cardiac Pacemakers, Inc. | System and method for assessing pulmonary performance through transthoracic impedance monitoring |
US7751890B2 (en) * | 2004-07-14 | 2010-07-06 | Cardiac Pacemakers, Inc. | Self-diagnostic method and system for implantable cardiac device |
US7480528B2 (en) * | 2004-07-23 | 2009-01-20 | Cardiac Pacemakers, Inc. | Method and apparatus for monitoring heart failure patients with cardiopulmonary comorbidities |
US7559901B2 (en) * | 2004-07-28 | 2009-07-14 | Cardiac Pacemakers, Inc. | Determining a patient's posture from mechanical vibrations of the heart |
US7269458B2 (en) * | 2004-08-09 | 2007-09-11 | Cardiac Pacemakers, Inc. | Cardiopulmonary functional status assessment via heart rate response detection by implantable cardiac device |
US7389143B2 (en) * | 2004-08-12 | 2008-06-17 | Cardiac Pacemakers, Inc. | Cardiopulmonary functional status assessment via metabolic response detection by implantable cardiac device |
US7277756B2 (en) * | 2004-08-16 | 2007-10-02 | Cardiac Pacemakers, Inc. | Risk of death indicator |
US20060041279A1 (en) * | 2004-08-18 | 2006-02-23 | Yinghong Yu | Detection and treatment of prolonged inter-atrial delay in cardiac resynchronization patients |
US7387610B2 (en) * | 2004-08-19 | 2008-06-17 | Cardiac Pacemakers, Inc. | Thoracic impedance detection with blood resistivity compensation |
US7647108B2 (en) * | 2004-09-30 | 2010-01-12 | Cardiac Pacemakers, Inc. | Methods and systems for selection of cardiac pacing electrode configurations |
US8175705B2 (en) | 2004-10-12 | 2012-05-08 | Cardiac Pacemakers, Inc. | System and method for sustained baroreflex stimulation |
US7996075B2 (en) * | 2004-10-20 | 2011-08-09 | Cardionet, Inc. | Monitoring physiological activity using partial state space reconstruction |
US8332047B2 (en) | 2004-11-18 | 2012-12-11 | Cardiac Pacemakers, Inc. | System and method for closed-loop neural stimulation |
US8060219B2 (en) | 2004-12-20 | 2011-11-15 | Cardiac Pacemakers, Inc. | Epicardial patch including isolated extracellular matrix with pacing electrodes |
US7981065B2 (en) | 2004-12-20 | 2011-07-19 | Cardiac Pacemakers, Inc. | Lead electrode incorporating extracellular matrix |
JP2006185060A (en) * | 2004-12-27 | 2006-07-13 | Fujitsu Ltd | Method for inputting password |
US7295874B2 (en) * | 2005-01-06 | 2007-11-13 | Cardiac Pacemakers, Inc. | Intermittent stress augmentation pacing for cardioprotective effect |
US7662104B2 (en) | 2005-01-18 | 2010-02-16 | Cardiac Pacemakers, Inc. | Method for correction of posture dependence on heart sounds |
US7447543B2 (en) * | 2005-02-15 | 2008-11-04 | Regents Of The University Of Minnesota | Pathology assessment with impedance measurements using convergent bioelectric lead fields |
US8388545B2 (en) * | 2005-02-15 | 2013-03-05 | Cheetah Medical, Inc. | System, method and apparatus for measuring blood flow and blood volume |
US7680534B2 (en) | 2005-02-28 | 2010-03-16 | Cardiac Pacemakers, Inc. | Implantable cardiac device with dyspnea measurement |
US7587238B2 (en) | 2005-03-11 | 2009-09-08 | Cardiac Pacemakers, Inc. | Combined neural stimulation and cardiac resynchronization therapy |
EP1863564B1 (en) | 2005-03-11 | 2016-11-23 | Cardiac Pacemakers, Inc. | Combined neural stimulation and cardiac resynchronization therapy |
US7660628B2 (en) | 2005-03-23 | 2010-02-09 | Cardiac Pacemakers, Inc. | System to provide myocardial and neural stimulation |
US7542800B2 (en) | 2005-04-05 | 2009-06-02 | Cardiac Pacemakers, Inc. | Method and apparatus for synchronizing neural stimulation to cardiac cycles |
US7630763B2 (en) | 2005-04-20 | 2009-12-08 | Cardiac Pacemakers, Inc. | Thoracic or intracardiac impedance detection with automatic vector selection |
US8538519B2 (en) * | 2005-04-25 | 2013-09-17 | Cardiac Pacemakers, Inc. | Method and system for treatment of mechanical cardiac asynchrony |
US7392086B2 (en) | 2005-04-26 | 2008-06-24 | Cardiac Pacemakers, Inc. | Implantable cardiac device and method for reduced phrenic nerve stimulation |
US7603170B2 (en) * | 2005-04-26 | 2009-10-13 | Cardiac Pacemakers, Inc. | Calibration of impedance monitoring of respiratory volumes using thoracic D.C. impedance |
US8781847B2 (en) | 2005-05-03 | 2014-07-15 | Cardiac Pacemakers, Inc. | System and method for managing alert notifications in an automated patient management system |
US7742813B2 (en) * | 2005-05-06 | 2010-06-22 | Cardiac Pacemakers, Inc. | Minimizing hemodynamic compromise during post-mi remodeling control pacing |
US7907997B2 (en) | 2005-05-11 | 2011-03-15 | Cardiac Pacemakers, Inc. | Enhancements to the detection of pulmonary edema when using transthoracic impedance |
US7340296B2 (en) | 2005-05-18 | 2008-03-04 | Cardiac Pacemakers, Inc. | Detection of pleural effusion using transthoracic impedance |
US7424321B2 (en) * | 2005-05-24 | 2008-09-09 | Cardiac Pacemakers, Inc. | Systems and methods for multi-axis cardiac vibration measurements |
US20060271121A1 (en) * | 2005-05-25 | 2006-11-30 | Cardiac Pacemakers, Inc. | Closed loop impedance-based cardiac resynchronization therapy systems, devices, and methods |
US7430447B2 (en) * | 2005-06-06 | 2008-09-30 | Pacesetter, Inc. | Evoked response and impedance measures for monitoring heart failure and respiration |
US7922669B2 (en) | 2005-06-08 | 2011-04-12 | Cardiac Pacemakers, Inc. | Ischemia detection using a heart sound sensor |
US8620436B2 (en) | 2005-07-08 | 2013-12-31 | Boston Scientific Neuromodulation Corporation | Current generation architecture for an implantable stimulator device having coarse and fine current control |
US8606362B2 (en) * | 2005-07-08 | 2013-12-10 | Boston Scientific Neuromodulation Corporation | Current output architecture for an implantable stimulator device |
DE102005038864A1 (en) * | 2005-08-17 | 2007-03-01 | Stryker Leibinger Gmbh & Co. Kg | Surgical power tool and operating unit therefor |
US8494618B2 (en) * | 2005-08-22 | 2013-07-23 | Cardiac Pacemakers, Inc. | Intracardiac impedance and its applications |
US7711425B2 (en) * | 2005-08-22 | 2010-05-04 | Cardiac Pacemakers, Inc. | Defibrillation threshold prediction methods and systems |
US9839781B2 (en) | 2005-08-22 | 2017-12-12 | Cardiac Pacemakers, Inc. | Intracardiac impedance and its applications |
US7877140B2 (en) * | 2005-09-06 | 2011-01-25 | Cardiac Pacemakers, Inc. | Pressure sensing for feedback control of post-MI remodeling control pacing |
US20070055115A1 (en) * | 2005-09-08 | 2007-03-08 | Jonathan Kwok | Characterization of sleep disorders using composite patient data |
US8992436B2 (en) * | 2005-09-16 | 2015-03-31 | Cardiac Pacemakers, Inc. | Respiration monitoring using respiration rate variability |
US7974691B2 (en) | 2005-09-21 | 2011-07-05 | Cardiac Pacemakers, Inc. | Method and apparatus for controlling cardiac resynchronization therapy using cardiac impedance |
EP1933938B1 (en) * | 2005-10-11 | 2016-09-14 | St. Jude Medical AB | Method and implantable medical device for measuring an electrical bio-impedance of a patient |
US7616990B2 (en) | 2005-10-24 | 2009-11-10 | Cardiac Pacemakers, Inc. | Implantable and rechargeable neural stimulator |
US8046060B2 (en) | 2005-11-14 | 2011-10-25 | Cardiac Pacemakers, Inc. | Differentiating arrhythmic events having different origins |
US20070118180A1 (en) | 2005-11-18 | 2007-05-24 | Quan Ni | Cardiac resynchronization therapy for improved hemodynamics based on disordered breathing detection |
US8108034B2 (en) | 2005-11-28 | 2012-01-31 | Cardiac Pacemakers, Inc. | Systems and methods for valvular regurgitation detection |
US7662105B2 (en) | 2005-12-14 | 2010-02-16 | Cardiac Pacemakers, Inc. | Systems and methods for determining respiration metrics |
US7920912B2 (en) * | 2005-12-15 | 2011-04-05 | Ivy Biomedical Systems, Inc. | System and method for triggering a device based on an electrocardiogram signal |
US8204585B2 (en) * | 2005-12-20 | 2012-06-19 | Cardiac Pacemakers, Inc. | Bio-impedance sensor and sensing method |
US7826897B2 (en) * | 2005-12-22 | 2010-11-02 | Cardiac Pacemakers, Inc. | Cardiac pacemaker with pacing rate monitoring |
US7706852B2 (en) | 2006-01-30 | 2010-04-27 | Nellcor Puritan Bennett Llc | System and method for detection of unstable oxygen saturation |
US7937150B2 (en) * | 2006-01-31 | 2011-05-03 | Medtronic, Inc. | Lead-carried proximal electrode for quadripolar transthoracic impedance monitoring |
US7668579B2 (en) | 2006-02-10 | 2010-02-23 | Lynn Lawrence A | System and method for the detection of physiologic response to stimulation |
US20070208390A1 (en) * | 2006-03-01 | 2007-09-06 | Von Arx Jeffrey A | Implantable wireless sound sensor |
US7729753B2 (en) * | 2006-03-14 | 2010-06-01 | Cardionet, Inc. | Automated analysis of a cardiac signal based on dynamical characteristics of the cardiac signal |
US7780606B2 (en) | 2006-03-29 | 2010-08-24 | Cardiac Pacemakers, Inc. | Hemodynamic stability assessment based on heart sounds |
US7744542B2 (en) * | 2006-04-20 | 2010-06-29 | Cardiac Pacemakers, Inc. | Implanted air passage sensors |
US7678058B2 (en) * | 2006-06-22 | 2010-03-16 | Cardiac Pacemakers, Inc. | Apnea type determining apparatus and method |
US8360983B2 (en) | 2006-06-22 | 2013-01-29 | Cardiac Pacemakers, Inc. | Apnea type determining apparatus and method |
US8000780B2 (en) | 2006-06-27 | 2011-08-16 | Cardiac Pacemakers, Inc. | Detection of myocardial ischemia from the time sequence of implanted sensor measurements |
US8226570B2 (en) * | 2006-08-08 | 2012-07-24 | Cardiac Pacemakers, Inc. | Respiration monitoring for heart failure using implantable device |
US20080071185A1 (en) * | 2006-08-08 | 2008-03-20 | Cardiac Pacemakers, Inc. | Periodic breathing during activity |
US7680536B2 (en) * | 2006-08-17 | 2010-03-16 | Cardiac Pacemakers, Inc. | Capture threshold estimation for alternate pacing vectors |
US8343049B2 (en) * | 2006-08-24 | 2013-01-01 | Cardiac Pacemakers, Inc. | Physiological response to posture change |
US7818058B2 (en) * | 2006-08-25 | 2010-10-19 | Ivy Biomedical Systems, Inc. | Automated ECG lead impedance measurement integrated into ECG gating circuitry |
US8457734B2 (en) | 2006-08-29 | 2013-06-04 | Cardiac Pacemakers, Inc. | System and method for neural stimulation |
US7860567B2 (en) * | 2006-08-31 | 2010-12-28 | Cardiac Pacemakers, Inc. | Sensor for edema |
US8209013B2 (en) | 2006-09-14 | 2012-06-26 | Cardiac Pacemakers, Inc. | Therapeutic electrical stimulation that avoids undesirable activation |
US8948867B2 (en) * | 2006-09-14 | 2015-02-03 | Cardiac Pacemakers, Inc. | Capture detection with cross chamber backup pacing |
US7877139B2 (en) | 2006-09-22 | 2011-01-25 | Cameron Health, Inc. | Method and device for implantable cardiac stimulus device lead impedance measurement |
US7890163B2 (en) * | 2006-10-19 | 2011-02-15 | Cardiac Pacemakers, Inc. | Method and apparatus for detecting fibrillation using cardiac local impedance |
US8948868B2 (en) * | 2006-10-31 | 2015-02-03 | Medtronic, Inc. | Methods and apparatus for manually suspending intrathoracic impedance fluid status measurements |
US20080119749A1 (en) | 2006-11-20 | 2008-05-22 | Cardiac Pacemakers, Inc. | Respiration-synchronized heart sound trending |
US8096954B2 (en) | 2006-11-29 | 2012-01-17 | Cardiac Pacemakers, Inc. | Adaptive sampling of heart sounds |
US8798749B2 (en) * | 2006-12-14 | 2014-08-05 | Cardiac Pacemakers, Inc. | Cardiac stimulation device for sinus rate modulation |
US8406879B2 (en) | 2006-12-20 | 2013-03-26 | Cardiac Pacemakers, Inc. | Rate adaptive cardiac pacing systems and methods |
US8033998B2 (en) * | 2006-12-28 | 2011-10-11 | Medtronic, Inc. | Device and method for automatic threshold setting |
US7736319B2 (en) | 2007-01-19 | 2010-06-15 | Cardiac Pacemakers, Inc. | Ischemia detection using heart sound timing |
US8014863B2 (en) * | 2007-01-19 | 2011-09-06 | Cardiac Pacemakers, Inc. | Heart attack or ischemia detector |
US20080177156A1 (en) * | 2007-01-19 | 2008-07-24 | Cardiac Pacemakers, Inc. | Ischemia detection using pressure sensor |
US8265769B2 (en) * | 2007-01-31 | 2012-09-11 | Medtronic, Inc. | Chopper-stabilized instrumentation amplifier for wireless telemetry |
US7385443B1 (en) * | 2007-01-31 | 2008-06-10 | Medtronic, Inc. | Chopper-stabilized instrumentation amplifier |
US7391257B1 (en) * | 2007-01-31 | 2008-06-24 | Medtronic, Inc. | Chopper-stabilized instrumentation amplifier for impedance measurement |
US9615744B2 (en) * | 2007-01-31 | 2017-04-11 | Medtronic, Inc. | Chopper-stabilized instrumentation amplifier for impedance measurement |
US8523771B2 (en) | 2007-02-12 | 2013-09-03 | Cardiac Pacemakers, Inc. | Cardiovascular pressure annotations and logbook |
US9095271B2 (en) | 2007-08-13 | 2015-08-04 | Cheetah Medical, Inc. | Dynamically variable filter |
US8876725B2 (en) * | 2007-02-23 | 2014-11-04 | Cheetah Medical, Inc. | Method and system for estimating exercise capacity |
US8764667B2 (en) * | 2007-03-07 | 2014-07-01 | Cheetah Medical, Inc. | Method and system for monitoring sleep |
US8052611B2 (en) | 2007-03-14 | 2011-11-08 | Cardiac Pacemakers, Inc. | Method and apparatus for management of heart failure hospitalization |
US7840267B2 (en) | 2007-03-23 | 2010-11-23 | Cardiac Pacemakers, Inc. | Closed-loop resynchronization therapy for mechanical dyssynchrony |
US7890167B2 (en) * | 2007-04-03 | 2011-02-15 | Cardiac Pacemakers, Inc. | Pain free defibrillation threshold estimation |
US7853327B2 (en) | 2007-04-17 | 2010-12-14 | Cardiac Pacemakers, Inc. | Heart sound tracking system and method |
AU2008242145B2 (en) * | 2007-04-19 | 2013-05-02 | Cheetah Medical, Inc. | Method, apparatus and system for predicting electromechanical dissociation |
US8781595B2 (en) * | 2007-04-30 | 2014-07-15 | Medtronic, Inc. | Chopper mixer telemetry circuit |
US8630704B2 (en) | 2007-06-25 | 2014-01-14 | Cardiac Pacemakers, Inc. | Neural stimulation with respiratory rhythm management |
US8221323B2 (en) * | 2007-08-03 | 2012-07-17 | Cardiac Pacemakers, Inc. | Using acoustic energy to compute a lung edema fluid status indication |
US9037239B2 (en) | 2007-08-07 | 2015-05-19 | Cardiac Pacemakers, Inc. | Method and apparatus to perform electrode combination selection |
US8265736B2 (en) | 2007-08-07 | 2012-09-11 | Cardiac Pacemakers, Inc. | Method and apparatus to perform electrode combination selection |
WO2009042172A2 (en) * | 2007-09-26 | 2009-04-02 | Medtronic, Inc. | Frequency selective monitoring of physiological signals |
US8380314B2 (en) | 2007-09-26 | 2013-02-19 | Medtronic, Inc. | Patient directed therapy control |
EP2219518B1 (en) | 2007-10-12 | 2012-08-22 | Cardiac Pacemakers, Inc. | Decompensation detection based on heart failure co-morbidities |
WO2009051638A1 (en) | 2007-10-16 | 2009-04-23 | Medtronic, Inc. | Therapy control based on a patient movement state |
US9078627B2 (en) * | 2008-01-04 | 2015-07-14 | Texas Heart Institute | Introducer sheath with electrodes |
US8961417B2 (en) * | 2008-01-04 | 2015-02-24 | Texas Heart Institute | Catheter with electrodes for impedance and/or conduction velocity measurement |
US9357944B2 (en) * | 2008-01-08 | 2016-06-07 | Cardiac Pacemakers, Inc. | Impedance measurement and demodulation using implantable device |
AU2009206541B2 (en) * | 2008-01-22 | 2012-02-09 | Cardiac Pacemakers, Inc. | Respiration as a trigger for therapy optimization |
WO2009094050A1 (en) | 2008-01-25 | 2009-07-30 | Medtronic, Inc. | Sleep stage detection |
JP5199394B2 (en) * | 2008-01-29 | 2013-05-15 | 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 | Configurable intermittent pacing therapy |
AU2009214920B2 (en) | 2008-02-14 | 2012-02-09 | Cardiac Pacemakers, Inc. | Method and apparatus for phrenic stimulation detection |
US8275553B2 (en) | 2008-02-19 | 2012-09-25 | Nellcor Puritan Bennett Llc | System and method for evaluating physiological parameter data |
DE102008010651B4 (en) * | 2008-02-22 | 2019-04-25 | Biotronik Se & Co. Kg | System and method for evaluating an impedance curve |
US8483826B2 (en) * | 2008-03-17 | 2013-07-09 | Cardiac Pacemakers, Inc. | Deactivation of intermittent pacing therapy |
US8365730B2 (en) | 2008-03-24 | 2013-02-05 | Covidien Lp | Method and system for classification of photo-plethysmographically detected respiratory effort |
US20090247837A1 (en) * | 2008-03-27 | 2009-10-01 | Nellcor Puritan Bennett Llc | System And Method For Diagnosing Sleep Apnea |
US9713701B2 (en) | 2008-07-31 | 2017-07-25 | Medtronic, Inc. | Using multiple diagnostic parameters for predicting heart failure events |
US8255046B2 (en) * | 2008-07-31 | 2012-08-28 | Medtronic, Inc. | Detecting worsening heart failure based on impedance measurements |
US9849294B2 (en) * | 2008-08-11 | 2017-12-26 | Cardiac Pacemakers, Inc. | Systems and methods for controlling rate responsive pacing |
US8398555B2 (en) | 2008-09-10 | 2013-03-19 | Covidien Lp | System and method for detecting ventilatory instability |
US8231536B2 (en) * | 2008-09-19 | 2012-07-31 | Medtronic, Inc. | Method and apparatus for detecting respiratory effort in a medical device |
US8319648B2 (en) * | 2008-09-22 | 2012-11-27 | Cardiac Pacemakers, Inc. | System and method for detection of HF decompensation based on signs and symptoms |
US8738119B2 (en) * | 2008-10-10 | 2014-05-27 | Cardiac Pacemakers, Inc. | Multi-sensor strategy for heart failure patient management |
US8419645B2 (en) * | 2008-10-16 | 2013-04-16 | Biotronik Crm Patent Ag | Respiration measurement by means of morphological operators |
US8478402B2 (en) * | 2008-10-31 | 2013-07-02 | Medtronic, Inc. | Determining intercardiac impedance |
US20100113964A1 (en) * | 2008-10-31 | 2010-05-06 | Wahlstrand John D | Determining intercardiac impedance |
US8632473B2 (en) * | 2009-01-30 | 2014-01-21 | Medtronic, Inc. | Detecting worsening heart failure based on fluid accumulation with respiratory confirmation |
US8200319B2 (en) * | 2009-02-10 | 2012-06-12 | Cardionet, Inc. | Locating fiducial points in a physiological signal |
WO2010123679A1 (en) * | 2009-04-22 | 2010-10-28 | Cardiac Pacemakers, Inc. | Dynamic selection of algorithms for arrhythmia detection |
US8634915B2 (en) | 2009-05-27 | 2014-01-21 | Cardiac Pacemakers, Inc. | Activity sensor processing for phrenic nerve activation detection |
EP2659931B1 (en) | 2009-05-27 | 2017-07-19 | Cardiac Pacemakers, Inc. | Phrenic nerve activation detection |
US8626292B2 (en) * | 2009-05-27 | 2014-01-07 | Cardiac Pacemakers, Inc. | Respiration sensor processing for phrenic nerve activation detection |
US9149642B2 (en) * | 2009-05-27 | 2015-10-06 | Cardiac Pacemakers, Inc. | Method and apparatus for phrenic nerve activation detection with respiration cross-checking |
US8781430B2 (en) * | 2009-06-29 | 2014-07-15 | Qualcomm Incorporated | Receiver filtering devices, systems, and methods |
US20110009753A1 (en) | 2009-07-10 | 2011-01-13 | Yi Zhang | Respiration Rate Trending for Detecting Early Onset of Worsening Heart Failure |
US20110009760A1 (en) * | 2009-07-10 | 2011-01-13 | Yi Zhang | Hospital Readmission Alert for Heart Failure Patients |
WO2011005953A2 (en) | 2009-07-10 | 2011-01-13 | Cardiac Pacemakers, Inc. | System and method of pulmonary edema detection |
US8031094B2 (en) * | 2009-09-11 | 2011-10-04 | Apple Inc. | Touch controller with improved analog front end |
US8521285B2 (en) * | 2009-10-22 | 2013-08-27 | Cardiac Pacemakers, Inc. | Estimation of dedicated bipolar pacing vector threshold |
US8457741B2 (en) | 2009-10-22 | 2013-06-04 | Cardiac Pacemakers, Inc. | Estimation of dedicated bipolar pacing vector threshold |
US8271072B2 (en) * | 2009-10-30 | 2012-09-18 | Medtronic, Inc. | Detecting worsening heart failure |
US9770204B2 (en) | 2009-11-11 | 2017-09-26 | Medtronic, Inc. | Deep brain stimulation for sleep and movement disorders |
US20110130666A1 (en) * | 2009-11-30 | 2011-06-02 | Yanting Dong | Enhanced reporting of pathological episodes |
US10328267B2 (en) * | 2010-02-15 | 2019-06-25 | Cardiac Pacemakers, Inc. | Methods for constructing posture calibration matrices |
US8491491B2 (en) * | 2010-03-02 | 2013-07-23 | Data Sciences International, Inc. | Respiration measurements and dosimetry control in inhalation testing systems |
US9000914B2 (en) * | 2010-03-15 | 2015-04-07 | Welch Allyn, Inc. | Personal area network pairing |
US8957777B2 (en) | 2010-06-30 | 2015-02-17 | Welch Allyn, Inc. | Body area network pairing improvements for clinical workflows |
US8907782B2 (en) | 2010-06-30 | 2014-12-09 | Welch Allyn, Inc. | Medical devices with proximity detection |
EP2407100A1 (en) * | 2010-07-15 | 2012-01-18 | Tanita Corporation | Respiration characteristic analysis |
EP2407102A1 (en) * | 2010-07-15 | 2012-01-18 | Tanita Corporation | Respiration characteristic analysis apparatus and respiration characteristic analysis system |
US10216893B2 (en) | 2010-09-30 | 2019-02-26 | Fitbit, Inc. | Multimode sensor devices |
US9132275B2 (en) | 2010-11-18 | 2015-09-15 | Cardiac Pacemakers, Inc. | Automatic determination of chronotropic incompetence using atrial pacing at rest |
JP2014502526A (en) | 2010-12-15 | 2014-02-03 | 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 | Detection of cardiac decompensation using multiple sensors |
WO2012082698A2 (en) | 2010-12-15 | 2012-06-21 | Cardiac Pacemakers, Inc. | Posture detection using thoracic impedance |
US10596381B2 (en) | 2010-12-20 | 2020-03-24 | Cardiac Pacemakers, Inc. | Physiologic response to posture |
US10893824B2 (en) | 2010-12-20 | 2021-01-19 | Cardiac Pacemakers, Inc. | Heart failure detection with a sequential classifier |
US8858448B2 (en) | 2010-12-20 | 2014-10-14 | Cardiac Pacemakers, Inc. | Monitoring projections along principal components of multiple sensors as an indicator of worsening heart failure |
US8639324B2 (en) * | 2011-02-02 | 2014-01-28 | Cardiac Pacemakers, Inc. | Respiratory parameters for arrhythmia detection and therapy |
US8467870B2 (en) * | 2011-05-09 | 2013-06-18 | Medtronic, Inc. | Techniques for modifying breathing rate using cardiac pacing |
US8483833B2 (en) | 2011-05-09 | 2013-07-09 | Medtronic, Inc. | Techniques for modifying breathing rate using cardiac pacing |
ITMI20111177A1 (en) * | 2011-06-28 | 2012-12-29 | St Microelectronics Srl | METHOD AND DEVICE FOR MEASURING THE ELECTRICAL IMPEDANCE OF BIOLOGICAL FABRICS |
US8805511B2 (en) | 2011-07-27 | 2014-08-12 | Medtronic, Inc. | Method and apparatus to detect subcerebral ischemia |
US8706235B2 (en) | 2011-07-27 | 2014-04-22 | Medtronic, Inc. | Transvenous method to induce respiration |
US8478413B2 (en) | 2011-07-27 | 2013-07-02 | Medtronic, Inc. | Bilateral phrenic nerve stimulation with reduced dyssynchrony |
EP2739207B1 (en) * | 2011-08-02 | 2017-07-19 | Valencell, Inc. | Systems and methods for variable filter adjustment by heart rate metric feedback |
EP2750759B1 (en) | 2011-08-29 | 2016-12-21 | Cardiac Pacemakers, Inc. | Algorithm for narrative generation |
US8983611B2 (en) | 2011-09-27 | 2015-03-17 | Cardiac Pacemakers, Inc. | Neural control of central sleep apnea |
US8897879B2 (en) | 2011-11-04 | 2014-11-25 | Medtronic, Inc. | Method and apparatus for therapies of the cardiovascular and cardiorenal system |
US9295850B2 (en) * | 2012-04-24 | 2016-03-29 | Medtronic, Inc. | Charge-balancing during electrical stimulation |
US8948832B2 (en) | 2012-06-22 | 2015-02-03 | Fitbit, Inc. | Wearable heart rate monitor |
US9044149B2 (en) | 2012-06-22 | 2015-06-02 | Fitbit, Inc. | Heart rate data collection |
US9005129B2 (en) * | 2012-06-22 | 2015-04-14 | Fitbit, Inc. | Wearable heart rate monitor |
WO2014018592A1 (en) | 2012-07-25 | 2014-01-30 | Cardiac Pacemakers, Inc. | Electrode displacement detection |
US9039614B2 (en) | 2013-01-15 | 2015-05-26 | Fitbit, Inc. | Methods, systems and devices for measuring fingertip heart rate |
US20140267919A1 (en) * | 2013-03-15 | 2014-09-18 | Quanta Computer, Inc. | Modifying a digital video signal to mask biological information |
US10512407B2 (en) | 2013-06-24 | 2019-12-24 | Fitbit, Inc. | Heart rate data collection |
US9592327B2 (en) | 2013-09-06 | 2017-03-14 | Cardiac Pacemakers, Inc. | Systems and methods for heart failure management |
US9456763B2 (en) * | 2013-09-11 | 2016-10-04 | Medtronic, Inc. | Apparatus and method for simultaneous capture of biopotential and tissue impedance signals |
ES2537351B1 (en) | 2013-11-04 | 2015-12-03 | Universidad De Sevilla | Intelligent bioimpedance sensor for biomedical applications |
CN105828710B (en) | 2013-11-26 | 2020-10-30 | 心脏起搏器股份公司 | Detecting chronic obstructive pulmonary disease exacerbations from breathing patterns |
US9814424B2 (en) | 2013-12-06 | 2017-11-14 | Cardiac Pacemakers, Inc. | Chronic obstructive pulmonary disease drug titration and management |
US9649496B2 (en) | 2013-12-06 | 2017-05-16 | Cardiac Pacemakers, Inc. | Physiologic response to a therapy change using a ventricular filling characteristic |
WO2015088695A1 (en) | 2013-12-10 | 2015-06-18 | Cardiac Pacemakers, Inc. | Measuring atrial fibrillation burden using implantable device based sensors |
EP3151727A1 (en) | 2014-06-05 | 2017-04-12 | Cardiac Pacemakers, Inc. | The absolute thoracic impedance for heart failure risk stratification |
US9924904B2 (en) | 2014-09-02 | 2018-03-27 | Medtronic, Inc. | Power-efficient chopper amplifier |
WO2016057823A1 (en) * | 2014-10-08 | 2016-04-14 | MAD Apparel, Inc. | Method and system for measuring beat parameters |
US9392946B1 (en) | 2015-05-28 | 2016-07-19 | Fitbit, Inc. | Heart rate sensor with high-aspect-ratio photodetector element |
US10750996B2 (en) | 2015-06-02 | 2020-08-25 | Cardiac Pacemakers, Inc. | Multi-sensor body fluid volume index |
US10166001B2 (en) | 2015-10-27 | 2019-01-01 | Cardiac Pacemakers, Inc. | Trending S1 heart sounds amplitudes in ambulatory patients for worsening HF detection |
WO2017095776A1 (en) * | 2015-12-04 | 2017-06-08 | Cardiac Pacemakers, Inc. | Device-based sensor tracking for optimizing a cardiovascular medication administration protocol |
US11206989B2 (en) | 2015-12-10 | 2021-12-28 | Fitbit, Inc. | Light field management in an optical biological parameter sensor |
US10568525B1 (en) | 2015-12-14 | 2020-02-25 | Fitbit, Inc. | Multi-wavelength pulse oximetry |
WO2017120560A1 (en) | 2016-01-08 | 2017-07-13 | Cardiac Pacemakers, Inc. | Obtaining high-resolution information from an implantable medical device |
WO2017120558A1 (en) | 2016-01-08 | 2017-07-13 | Cardiac Pacemakers, Inc. | Syncing multiple sources of physiological data |
US10888702B2 (en) | 2016-01-08 | 2021-01-12 | Cardiac Pacemakers, Inc. | Progressive adaptive data transfer |
CN108601941B (en) | 2016-02-12 | 2021-12-28 | 心脏起搏器股份公司 | Triggering storage of initiation of physiological conditions |
CN108697361A (en) | 2016-03-04 | 2018-10-23 | 心脏起搏器股份公司 | Reduce the false positive in detecting potential cardiac standstill |
US10850093B2 (en) | 2016-04-13 | 2020-12-01 | Cardiac Pacemakers, Inc. | Lead integrity monitoring |
US10631744B2 (en) | 2016-04-13 | 2020-04-28 | Cardiac Pacemakers, Inc. | AF monitor and offline processing |
CN109195510A (en) | 2016-04-29 | 2019-01-11 | 飞比特公司 | Multi-channel optical Power Capacity pulse wave sensor |
US10945670B2 (en) * | 2016-07-06 | 2021-03-16 | Cardiac Pacemakers, Inc. | Minute volume sensor optimization using quadripolar leads |
US10952686B2 (en) | 2016-08-02 | 2021-03-23 | Medtronic, Inc. | Mobile application to prompt physical action to measure physiologic response in implantable device |
US11051706B1 (en) | 2017-04-07 | 2021-07-06 | Fitbit, Inc. | Multiple source-detector pair photoplethysmography (PPG) sensor |
KR102049598B1 (en) * | 2017-10-26 | 2019-11-27 | 계명대학교 산학협력단 | Implantable impedance measurement devices and heart failure monitoring system using it |
US11717186B2 (en) | 2019-08-27 | 2023-08-08 | Medtronic, Inc. | Body stability measurement |
US11602313B2 (en) | 2020-07-28 | 2023-03-14 | Medtronic, Inc. | Determining a fall risk responsive to detecting body position movements |
US20230068431A1 (en) | 2021-08-13 | 2023-03-02 | 3Ive Labs, Llc | Negative Pressure Therapy System and Methods |
WO2024059244A1 (en) | 2022-09-15 | 2024-03-21 | 3Ive Labs, Llc | Negative pressure therapy devices, systems, and treatment methods with indwelling urinary catheters |
Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4781201A (en) * | 1984-12-27 | 1988-11-01 | American Home Products Corporation (Del.) | Cardiovascular artifact filter |
EP0447024A2 (en) * | 1990-03-08 | 1991-09-18 | Cardiac Pacemakers, Inc. | Rate adaptive cardiac pacer incorporating switched capacitor filter with cutoff frequency determined by heart rate |
US5156147A (en) | 1991-02-05 | 1992-10-20 | Cardiac Pacemakers, Inc. | Variable rate pacemaker having upper rate limit governor based on hemodynamic performance |
US5235976A (en) | 1991-12-13 | 1993-08-17 | Cardiac Pacemakers, Inc. | Method and apparatus for managing and monitoring cardiac rhythm using active time as the controlling parameter |
US5284136A (en) | 1990-04-04 | 1994-02-08 | Cardiac Pacemakers, Inc. | Dual indifferent electrode pacemaker |
WO1994006512A1 (en) * | 1992-09-17 | 1994-03-31 | Biotronik Mess- Und Therapiegeräte Gmbh & Co. | Circuit for measuring impedance in the heart |
US5318597A (en) | 1993-03-15 | 1994-06-07 | Cardiac Pacemakers, Inc. | Rate adaptive cardiac rhythm management device control algorithm using trans-thoracic ventilation |
EP0702977A2 (en) * | 1994-09-21 | 1996-03-27 | Medtronic, Inc. | Apparatus for detecting and treating obstructive airway disorders |
EP0765632A2 (en) * | 1995-09-29 | 1997-04-02 | Siemens Medical Systems, Inc. | Method and apparatus for respiration monitoring |
US5824029A (en) * | 1994-04-28 | 1998-10-20 | Medtronic, Inc. | Implantable medical system for performing transthoracic impedance measurements associated with cardiac function |
Family Cites Families (53)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB1410761A (en) * | 1971-08-06 | 1975-10-22 | Atlantic Richfield Co | Implantable respiratory pacer |
DE2805482C2 (en) * | 1978-02-09 | 1987-03-05 | Hellige Gmbh, 7800 Freiburg | Fail-safe QRS detector with automatic threshold determination |
US5190035A (en) * | 1981-06-18 | 1993-03-02 | Cardiac Pacemakers, Inc. | Biomedical method and apparatus for controlling the administration of therapy to a patient in response to changes in physiological demand |
US4686987A (en) * | 1981-06-18 | 1987-08-18 | Cardiac Pacemakers, Inc. | Biomedical method and apparatus for controlling the administration of therapy to a patient in response to changes in physiologic demand |
US4722351A (en) * | 1981-12-21 | 1988-02-02 | American Home Products Corporation | Systems and methods for processing physiological signals |
EP0151689B1 (en) * | 1984-02-07 | 1990-12-27 | SCHIAPPARELLI MEDTRONIC S.p.A. | Minute ventilation dependent rate responsive pacer |
US4702253A (en) * | 1985-10-15 | 1987-10-27 | Telectronics N.V. | Metabolic-demand pacemaker and method of using the same to determine minute volume |
US4827935A (en) * | 1986-04-24 | 1989-05-09 | Purdue Research Foundation | Demand electroventilator |
US4830008A (en) * | 1987-04-24 | 1989-05-16 | Meer Jeffrey A | Method and system for treatment of sleep apnea |
US4858611A (en) * | 1987-06-03 | 1989-08-22 | Dimed, Inc. | Sensing system and method for sensing minute ventilation |
GB2214813A (en) * | 1988-01-14 | 1989-09-13 | Stuart Charles Webb | Rate-responsive pacemaker |
US4901725A (en) * | 1988-01-29 | 1990-02-20 | Telectronics N.V. | Minute volume rate-responsive pacemaker |
US5063927A (en) * | 1988-02-17 | 1991-11-12 | Webb Stuart C | Rate-responsive pacemaker |
US5027813A (en) * | 1990-03-05 | 1991-07-02 | Cardiac Pacemakers, Inc. | Rate responsive pacemaker apparatus having an electrode interface sensor |
CA2033765C (en) * | 1990-03-08 | 1999-10-19 | Brian D. Pederson | Variation in cardiac chamber volume or pressure as a controlling parameter |
US5085215A (en) * | 1990-03-20 | 1992-02-04 | Telectronics Pacing Systems, Inc. | Metabolic demand driven rate-responsive pacemaker |
FR2671012B1 (en) * | 1990-12-27 | 1993-03-19 | Ela Medical Sa | METHOD FOR CONTROLLING A HEART STIMULATOR. |
FR2671013B1 (en) * | 1990-12-27 | 1996-09-13 | Ela Medical Sa | HEART STIMULATOR WITH SERVO STIMULATION FREQUENCY. |
DE69209324T2 (en) * | 1991-01-09 | 1996-11-21 | Medtronic Inc | Servo control for muscles |
US5199428A (en) * | 1991-03-22 | 1993-04-06 | Medtronic, Inc. | Implantable electrical nerve stimulator/pacemaker with ischemia for decreasing cardiac workload |
SE9101276D0 (en) * | 1991-04-26 | 1991-04-26 | Siemens Elema Ab | IMPLANT MEDICAL DEVICE |
US5674259A (en) * | 1992-10-20 | 1997-10-07 | Gray; Noel Desmond | Multi-focal leadless apical cardiac pacemaker |
US5201808A (en) * | 1992-02-10 | 1993-04-13 | Telectronics Pacing Systems, Inc. | Minute volume rate-responsive pacemaker employing impedance sensing on a unipolar lead |
US5271395A (en) * | 1992-04-17 | 1993-12-21 | Medtronic, Inc. | Method and apparatus for rate-responsive cardiac pacing |
US5197467A (en) * | 1992-06-22 | 1993-03-30 | Telectronics Pacing Systems, Inc. | Multiple parameter rate-responsive cardiac stimulation apparatus |
US5379776A (en) * | 1993-04-01 | 1995-01-10 | Telectronics Pacing Systems, Inc. | Heart rhythm classification method, and implantable dual chamber cardioverter/defibrillator employing the same |
US5441524A (en) * | 1993-08-30 | 1995-08-15 | Medtronic, Inc. | Energy efficient multiple sensor cardiac pacemaker |
US5423870A (en) * | 1993-11-22 | 1995-06-13 | Cardiac Pacemakers, Inc. | Rate responsive cardiac pacemaker |
US5524632A (en) * | 1994-01-07 | 1996-06-11 | Medtronic, Inc. | Method for implanting electromyographic sensing electrodes |
US5800470A (en) * | 1994-01-07 | 1998-09-01 | Medtronic, Inc. | Respiratory muscle electromyographic rate responsive pacemaker |
US5626622A (en) * | 1994-09-21 | 1997-05-06 | Telectronics Pacing Systems, Inc. | Dual sensor rate responsive pacemaker |
US5540733A (en) * | 1994-09-21 | 1996-07-30 | Medtronic, Inc. | Method and apparatus for detecting and treating obstructive sleep apnea |
US5562712A (en) * | 1994-11-25 | 1996-10-08 | Dow Corning Corporation | Minute volume rate-responsive pacemaker using dual unipolar leads |
US5562711A (en) * | 1994-11-30 | 1996-10-08 | Medtronic, Inc. | Method and apparatus for rate-responsive cardiac pacing |
US5507785A (en) * | 1994-12-21 | 1996-04-16 | Intermedics, Inc. | Rate responsive cardiac pacemaker with biphasic impedance sensing and method |
US6044294A (en) * | 1995-12-15 | 2000-03-28 | Pacesetter, Inc. | Methods and apparatus for measuring impedance in the body |
US6006134A (en) * | 1998-04-30 | 1999-12-21 | Medtronic, Inc. | Method and device for electronically controlling the beating of a heart using venous electrical stimulation of nerve fibers |
US5836976A (en) * | 1997-04-30 | 1998-11-17 | Medtronic, Inc. | Cardioversion energy reduction system |
US5978707A (en) * | 1997-04-30 | 1999-11-02 | Cardiac Pacemakers, Inc. | Apparatus and method for treating ventricular tachyarrhythmias |
US5824020A (en) * | 1997-05-02 | 1998-10-20 | Pacesetter, Inc. | Rate-responsive pacemaker with rapid minute volume determination |
US5817135A (en) * | 1997-05-02 | 1998-10-06 | Pacesetter, Inc. | Rate-responsive pacemaker with noise-rejecting minute volume determination |
US5817136A (en) * | 1997-05-02 | 1998-10-06 | Pacesetter, Inc. | Rate-responsive pacemaker with minute volume determination and EMI protection |
US6022322A (en) * | 1998-02-06 | 2000-02-08 | Intermedics Inc. | Non-invasive cardiorespiratory monitor with synchronized bioimpedance sensing |
US6076015A (en) * | 1998-02-27 | 2000-06-13 | Cardiac Pacemakers, Inc. | Rate adaptive cardiac rhythm management device using transthoracic impedance |
US6493579B1 (en) * | 1999-08-20 | 2002-12-10 | Cardiac Pacemakers, Inc. | System and method for detection enhancement programming |
US6459929B1 (en) * | 1999-11-04 | 2002-10-01 | Cardiac Pacemakers, Inc. | Implantable cardiac rhythm management device for assessing status of CHF patients |
US6415183B1 (en) * | 1999-12-09 | 2002-07-02 | Cardiac Pacemakers, Inc. | Method and apparatus for diaphragmatic pacing |
US6522914B1 (en) * | 2000-07-14 | 2003-02-18 | Cardiac Pacemakers, Inc. | Method and apparatuses for monitoring hemodynamic activities using an intracardiac impedance-derived parameter |
US6904315B2 (en) * | 2000-12-14 | 2005-06-07 | Medtronic, Inc. | Atrial aware VVI: a method for atrial synchronous ventricular (VDD/R) pacing using the subcutaneous electrode array and a standard pacing lead |
US7027861B2 (en) * | 2001-10-09 | 2006-04-11 | Medtronic, Inc. | Method and apparatus for affecting atrial defibrillation with bi-atrial pacing |
US6868346B2 (en) * | 2002-11-27 | 2005-03-15 | Cardiac Pacemakers, Inc. | Minute ventilation sensor with automatic high pass filter adjustment |
US7101339B2 (en) * | 2002-12-13 | 2006-09-05 | Cardiac Pacemakers, Inc. | Respiration signal measurement apparatus, systems, and methods |
US7200440B2 (en) * | 2003-07-02 | 2007-04-03 | Cardiac Pacemakers, Inc. | Cardiac cycle synchronized sampling of impedance signal |
-
1998
- 1998-02-27 US US09/032,731 patent/US6076015A/en not_active Expired - Lifetime
-
1999
- 1999-02-26 DE DE69926347T patent/DE69926347T2/en not_active Expired - Lifetime
- 1999-02-26 EP EP99908486A patent/EP1061998B1/en not_active Expired - Lifetime
- 1999-02-26 AT AT99908486T patent/ATE300332T1/en not_active IP Right Cessation
- 1999-02-26 CA CA002322174A patent/CA2322174A1/en not_active Abandoned
- 1999-02-26 WO PCT/US1999/004169 patent/WO1999043385A1/en active IP Right Grant
- 1999-05-21 US US09/316,690 patent/US6161042A/en not_active Expired - Lifetime
-
2000
- 2000-01-20 US US09/492,912 patent/US6463326B1/en not_active Expired - Lifetime
-
2002
- 2002-10-08 US US10/268,023 patent/US20030105499A1/en not_active Abandoned
Patent Citations (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4781201A (en) * | 1984-12-27 | 1988-11-01 | American Home Products Corporation (Del.) | Cardiovascular artifact filter |
EP0447024A2 (en) * | 1990-03-08 | 1991-09-18 | Cardiac Pacemakers, Inc. | Rate adaptive cardiac pacer incorporating switched capacitor filter with cutoff frequency determined by heart rate |
US5284136A (en) | 1990-04-04 | 1994-02-08 | Cardiac Pacemakers, Inc. | Dual indifferent electrode pacemaker |
US5156147A (en) | 1991-02-05 | 1992-10-20 | Cardiac Pacemakers, Inc. | Variable rate pacemaker having upper rate limit governor based on hemodynamic performance |
US5235976A (en) | 1991-12-13 | 1993-08-17 | Cardiac Pacemakers, Inc. | Method and apparatus for managing and monitoring cardiac rhythm using active time as the controlling parameter |
WO1994006512A1 (en) * | 1992-09-17 | 1994-03-31 | Biotronik Mess- Und Therapiegeräte Gmbh & Co. | Circuit for measuring impedance in the heart |
US5318597A (en) | 1993-03-15 | 1994-06-07 | Cardiac Pacemakers, Inc. | Rate adaptive cardiac rhythm management device control algorithm using trans-thoracic ventilation |
US5824029A (en) * | 1994-04-28 | 1998-10-20 | Medtronic, Inc. | Implantable medical system for performing transthoracic impedance measurements associated with cardiac function |
EP0702977A2 (en) * | 1994-09-21 | 1996-03-27 | Medtronic, Inc. | Apparatus for detecting and treating obstructive airway disorders |
EP0765632A2 (en) * | 1995-09-29 | 1997-04-02 | Siemens Medical Systems, Inc. | Method and apparatus for respiration monitoring |
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Also Published As
Publication number | Publication date |
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US6076015A (en) | 2000-06-13 |
ATE300332T1 (en) | 2005-08-15 |
US6161042A (en) | 2000-12-12 |
DE69926347T2 (en) | 2006-05-24 |
CA2322174A1 (en) | 1999-09-02 |
EP1061998A1 (en) | 2000-12-27 |
DE69926347D1 (en) | 2005-09-01 |
US6463326B1 (en) | 2002-10-08 |
US20030105499A1 (en) | 2003-06-05 |
EP1061998B1 (en) | 2005-07-27 |
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