JP2006288838A - Fibrillation preventing apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fibrillation preventing apparatus by which the occurrence of ventricular fibrillation is prevented. <P>SOLUTION: A rectangular substrate 10 is sewn on the surface of epicardium of a left ventricle 38. The substrate 10 is provided with four Peltier elements 12 for cooling in its center and is provided with thermistors 18 for detecting the temperature in a part of their periphery. Several potential sensors/energizing electrodes 14 in circular and flat form for detecting the surface potential of the heart are arranged in the form of grid and are approximately equally spaced on the surface of the substrate 10. The potential sensors/energizing electrodes 14 also serve as energizing electrodes for applying pulse voltage/current to the heart. When ventricular tachycardia is detected, the Peltier elements 12 are energized. When the ventricular tachycardia is not stopped after cooling the heart, pulse voltage/current is applied through the several potential sensors/energizing electrodes 14 for clearing away the ventricular tachycardia by a low voltage and occurrence of fibrillation is prevented. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates generally to medical electronic devices, and more specifically to an anti-fibrillation device that prevents the occurrence of ventricular fibrillation.

  Conventionally, as disclosed in Patent Documents 1 to 6 below, when ventricular tachycardia or ventricular fibrillation of the heart is detected, the capacitor is charged with electric charge and discharged to the heart. Defibrillators that stop tachycardia and fibrillation by applying an electric shock are known. These devices are known as implantable defibrillators that are implanted in the human body.

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  However, these defibrillators are devices that stop ventricular fibrillation and restore normal myocardial excitement by applying a strong pulse current to the entire heart several seconds after ventricular fibrillation is detected. is there. For this reason, there existed the following faults. First, fainting associated with ventricular fibrillation could not be prevented, and people with such heart disease were unable to drive a car. Secondly, the patient's quality of life (QOL) has been impaired due to great discomfort and anxiety when applying the pulse voltage / current when the implantable defibrillator is activated. Thirdly, there is a problem that myocardial injury occurs due to energization of a strong current, the heart's pumping function is lowered, and a new arrhythmia is induced.

  The present invention has been made to solve the above-mentioned problems, and an object thereof is to prevent the occurrence of ventricular fibrillation. In addition, another object is a spiral-type rotational excitement (spiral reentry) that causes ventricular tachycardia (hereinafter, this wave, which is a potential distribution of the heart, is referred to as a “spiral reentry wave” in the claims) By adopting a configuration in which the current is erased by applying a relatively weak current, the heart is prevented from being damaged as much as possible, and a strong anxiety or discomfort is not given to humans. Desirably, a human is not allowed to sense the energization operation of the apparatus. In addition, another object is to prevent damage to the heart as much as possible by adopting a configuration that can suppress the energized power even when the apparatus is operated when ventricular fibrillation occurs. Is not to give a strong anxiety or discomfort.

  Each of these objects of the present invention is achieved by any invention, and each invention should not be construed as achieving all of the plurality of objects simultaneously, but only one object. Things can be used.

As we will see later, we have discovered the following facts:
(1) The ventricular tachycardia can be stopped by locally cooling a part of the heart to restore normal myocardial contraction.
(2) By locally cooling a part of the heart, the center of rotation (core region) of the spiral reentry wave, which is the potential distribution of the heart, can be constrained to the heart cooling location at a high rate.
(3) The spiral reentry wave may disappear spontaneously by cooling a part of the heart.
(4) A spiral reentry wave can be extinguished by constraining a spiral reentry wave at a cooling part of the heart and applying a pulse voltage / current to the constrained part.
(5) The pulse voltage / current that can constrain the spiral reentry wave at the cooling point and extinguish the wave is the pulse voltage / current that stops the ventricular fibrillation that has occurred without cooling the conventional heart. Can be much lower.
(6) In a computer simulation using a virtual heart, the application timing at which a spiral reentry wave can be constrained at a cooling location and the wave can be extinguished is the same as the conventional pulse voltage / current. It can be considerably wider than the application timing to stop ventricular fibrillation that has occurred without cooling.

The present invention has been completed based on the above findings, and has very originality.
A first invention for solving the above-described problems is an anti-fibrillation device for preventing the occurrence of fibrillation of the heart, an electrocardiogram signal detecting device for detecting an electrocardiogram signal composed of the potential of the heart, and the heart When a precursor phenomenon that may lead to ventricular fibrillation is detected based on the cooling device that cools the heart and the electrocardiogram signal detected by the electrocardiogram signal detection device, the cooling device is driven to cool the heart An anti-fibrillation device comprising a control device.

  The apparatus of the present invention is an apparatus that first operates to cool the heart when a precursor phenomenon that can lead to ventricular fibrillation is detected. If cooled, precursor phenomena such as ventricular tachycardia may disappear, preventing ventricular fibrillation. The cooling temperature is not limited, but is a temperature range that allows reversible cooling without killing heart tissue. For example, it is effective at a temperature 3 to 10 ° C. lower than the body temperature.

The second invention is the anti-fibrillation device according to claim 1, wherein the precursor phenomenon is ventricular tachycardia.
The timing for starting cooling of the heart is generally when a ventricular tachycardia is detected. Ventricular tachycardia is most likely to lead to ventricular fibrillation. Ventricular tachycardia may disappear due to cooling of the heart, and ventricular fibrillation is prevented. If the ventricular tachycardia disappears, it is not necessary to apply a pulse voltage / current that may damage the heart.

According to a third aspect of the present invention, in the anti-fibrillation device according to claim 1, the precursor phenomenon includes a phenomenon based on generation of a spiral reentry wave.
There is a causal relationship between ventricular tachycardia or ventricular fibrillation and spiral reentry waves. When a spiral reentry wave is generated, ventricular tachycardia usually occurs. Spiral reentry waves cause ventricular fibrillation when the irregularity is increased by causing meandering or splitting. Therefore, the present invention is characterized in that the cooling device for cooling the heart is driven when the initial generation of the spiral reentry wave is detected.

  By locally cooling the heart, the spiral reentry wave can be constrained to the heart cooling location. By constraining to the cooling portion, irregularity of the spiral reentry wave can be suppressed, and in some cases, the spiral reentry wave can be eliminated. This can prevent ventricular fibrillation.

According to a fourth aspect of the present invention, there is provided an energization device that applies a pulse voltage / current to the heart, and the control device drives the energization device after a predetermined time has elapsed after driving the cooling device. It is a defibrillation prevention apparatus of any one of Claim 3.
After the cooling device is driven and the heart is cooled and a predetermined time has elapsed, the spiral reentry wave is often restrained at the cooling location. The predetermined time may be set to a time required for restraining the spiral reentry wave obtained experimentally. The energized location is preferably a location where the spiral reentry wave is restricted. If the spiral reentry wave is constrained to the cooling part when a predetermined time has elapsed after the start of cooling of the heart, the present invention can easily spiral even if the applied pulse voltage / current is small. It is based on our discovery that the reentry wave can be extinguished. It is desirable that the energized part is a constrained part of the spiral reentry wave, that is, an area including a cooling part. At this time, the spiral reentry wave can be extinguished even at a low voltage and a low current. By driving the energization device, it is possible to reliably prevent ventricular fibrillation.

5th invention has the energization apparatus which gives a pulse voltage and an electric current to a heart, a control apparatus detects that the spiral reentry wave was restrained by the cooling location of the heart after driving a cooling device, and the detection The fibrillation prevention device according to any one of claims 1 to 3, wherein the energization device is driven on the basis of the above.
A feature of the present invention is that a cooling device and an energization device are provided, the driving device is driven, and the energization device is driven at a timing when it is detected that the spiral reentry wave is constrained by the cooling part of the heart. This means that a pulse voltage / current is applied to the heart.
That is, the present invention is based on our discovery that the spiral reentry wave can be easily extinguished even when the applied pulse voltage / current is low when the spiral reentry wave is constrained to the cooling location. Is. It is desirable that the energized part is a constrained part of the spiral reentry wave, that is, an area including a cooling part. At this time, the spiral reentry wave can be extinguished even by applying a low voltage and a low current. By driving the energization device, it is possible to reliably prevent ventricular fibrillation.

A sixth invention has an energization device that applies a pulse voltage / current to the heart, and the control device drives the energization device when the precursor phenomenon has not disappeared after a lapse of a predetermined time after driving the cooling device. The anti-fibrillation device according to any one of claims 1 to 3, wherein the anti-fibrillation device is provided.
In the present invention, when a precursor phenomenon that may lead to ventricular fibrillation disappears after driving the cooling device, it is not necessary to apply a pulse voltage / current to the heart, so that the energizing device is not driven. It is a feature.

A seventh invention has an energization device that applies a pulse voltage / current to the heart, and the control device activates the energization device when ventricular tachycardia has not disappeared after a lapse of a predetermined time after driving the cooling device. The anti-fibrillation device according to claim 2, wherein the anti-fibrillation device is driven.
If the ventricular tachycardia disappears at the timing of applying the pulse voltage / current, it is not necessary to apply the pulse voltage / current to the heart, so the pulse voltage / current is applied when the ventricular tachycardia is detected. Like to do. As a result, the heart is not damaged unnecessarily, and no shock is given to humans.

The eighth invention is the anti-fibrillation device according to any one of claims 4 to 7, wherein the pulse voltage / current is applied to a portion cooled by the cooling device. .
When the heart is locally cooled, a spiral reentry wave is often restrained at the cooling point. If an energization electrode is provided at this location and a pulse voltage / current is applied, ventricular tachycardia can be effectively stopped even at a low voltage / low current.

According to a ninth aspect of the invention, in the anti-fibrillation device according to any one of the fourth to eighth aspects, the pulse voltage / current is applied to the ventricle and the atrium.
In the present invention, the pulse voltage / current is applied between the leads to the ventricle and the atrium of the conventional ICD or between the leads and the ICD body implanted subcutaneously. In addition to this, a pulse voltage / current may be applied at the cooling point.

A tenth aspect of the invention is the anti-fibrillation device according to any one of claims 1 to 9, wherein the cooling device is a Peltier element energized by the control device.
The cooling device is not limited to a Peltier element, but it is simple to use a Peltier element that performs heat conversion by energization. In particular, when this device is an implantable type, it can be made compact and has many advantages.

  The first, second and third inventions are characterized in that a cooling device for cooling the heart is provided, and the precursor phenomenon leading to ventricular fibrillation can be extinguished by driving the cooling device. For example, ventricular tachycardia and spiral reentry waves can be eliminated. Thus, ventricular fibrillation is prevented. Moreover, since only the heart is cooled, the burden on the patient is small. Since the operation of the device can be configured to be insensitive to the patient, the device can be implanted to improve the patient's QOL.

  In the fourth, fifth, sixth, seventh, eighth, and ninth inventions, energization is performed in a state where a part of the heart is cooled. Spiral reentry waves can be eliminated and ventricular fibrillation can be prevented.

  When the heart is cooled, it is possible to prevent the spiral reentry wave from continuing or to fix the center of rotation. In this state, the energy, pulse voltage, and current required for the disappearance of the spiral reentry wave and the termination of ventricular tachycardia may be low. Therefore, since a low pulse voltage / current is applied to the heart, there is little or no damage to the heart, and the burden on the patient is small.

In addition, the device can effectively eliminate its precursor phenomenon at a low voltage before ventricular fibrillation occurs, so that the patient hardly senses the drive of the device, thus improving the QOL. be able to.
Even if ventricular fibrillation has occurred, the heart is cooled, so it is possible to stop ventricular fibrillation with a low pulse voltage / current. Thus, damage to the heart can be eliminated or minimized.

  The energization timing is when a predetermined time (for example, several seconds) elapses after cooling and the spiral reentry wave is restrained.

  In the sixth and seventh inventions, when a precursor phenomenon that may lead to ventricular fibrillation has disappeared at the drive timing of the energization device (for example, when ventricular tachycardia stops (claim 7), that is, When the precursor phenomenon (for example, ventricular tachycardia (Claim 7) or spiral reentry wave) disappears only by driving the cooling device, the energization device is not driven, so there is no burden on the patient. , QOL can be improved.

  This anti-fibrillation device is most effective when implanted in the human body. QOL can be improved without obstructing human activities.

  Hereinafter, the present invention will be described based on embodiments. In addition, this invention is not limited to the following embodiment, A various deformation | transformation is possible.

  The major cause of sudden cardiac death is ventricular fibrillation, most of which occurs with ventricular tachycardia. In recent years, the technology of optical mapping experiments for observing the complex excitement of the heart as a fluorescence signal image has advanced, and it has been clarified that the spiral relintory wave plays an important role in the establishment of ventricular tachycardia and ventricular fibrillation.

  We apply mild cooling (3-10 ° C) to a part of the ventricle to localize the central part (core region) of the spiral reentry wave at that site, and the most myocardium in the excitatory swirl path The idea was to eliminate the spiral reentry wave by efficiently applying weak electrical stimulation in the vicinity of the core region, which is easy to excite.

  By cooling a part of the heart, the spiral reentry wave can be extinguished by applying a pulse voltage / current that is far lower than the conventional pulse voltage / current applied to stop ventricular fibrillation. We confirmed this by animal experiments. In addition, as for animal experiment results, the causal relationship between the local cooling of the heart and the low voltage / low current of cardioversion was theoretically proved by computer simulation experiments using a virtual heart.

Animal experiments were conducted as follows.
The rabbit heart was removed and arterial perfusion was performed. A myocardial tissue on the left ventricular endocardium side was frozen and coagulated to prepare a two-dimensional pericardial muscle two-dimensional perfusion specimen in which only the submyocardial layer (thickness: about 1 mm) remained. In such specimens, spiral reentry waves are always present on the surface of the heart, so the details of their dynamics can be analyzed.

  In some experiments, microbeads were injected into rabbit coronary arteries to produce subendocardial myocardial infarction, and rabbits that had passed 2 weeks after the operation were used. In experiments using this myocardial infarction model, the ventricular muscle was not frozen and coagulated. The heart was stained with a membrane potential sensitive dye (Di-4-ANEPPS), and a myocardial potential fluorescent signal image in front of the left ventricle was taken using a high-speed video camera. Using a stainless steel cooling probe (diameter 8-10 mm) or a cold water perfusion device (diameter 10 mm) incorporated in a transparent acrylic plate, the myocardial temperature of the front part of the left ventricle was lowered by 3-5 ° C.

  By applying electrical stimulation (basic stimulation) at 2.5 Hz (400 ms interval) from the apex of the heart, the action potential duration (APD) and excitation conduction velocity of the ventricular muscle were measured. During the period of the basic stimulation action potential, the heart was electrically stimulated from the electrodes placed so as to sandwich the left and right ventricles, and ventricular tachycardia was induced by spiral reentry waves. Furthermore, we tried to stop the spiral reentry wave by applying a biphasic direct current from a monopolar or bipolar electrode placed near the cooling part of the heart.

  A preliminary experiment (using a two-dimensional perfused heart in which the left ventricular endocardium side of a normal rabbit was frozen and solidified) was applied to a rabbit heart 81 with a 10 mm diameter stainless steel cooling probe 80 shown in FIG. In the experiment, when a circular local cooling region (temperature decreased by 3-5 ° C) was created in front of the left ventricle, the action potential duration (APD) of the cooling region was extended by 30-40%, as shown in FIG. However, the change was reversible. There was no significant change in the excitatory conduction velocity.

  When electrical stimulation was applied to a two-dimensional perfused heart of a normal rabbit to induce ventricular tachycardia, a spiral reentry wave was observed in the observation area in front of the left ventricle in 8 of 21 cases (unidirectional in the remaining 13 cases). The excitement wave propagating to the surface was observed, and the center of the spiral reentry wave was thought to exist outside the observation area). Many spiral reentry waves cause a wandering movement with a linear center of rotation. When such a single spiral reentry wave exists, ventricular tachycardia occurs, and if it splits into multiple or causes a large meandering, it becomes easier to transition to ventricular fibrillation (precursor phenomenon) .

  On the other hand, as shown in FIG. 14, the spiral reentry wave induced after applying local cooling to the front surface of the left ventricle using the stainless-steel cooling probe 80 is always fixed at the edge 82 of the cooling region. In 17 out of 20 cases, spiral reentry waves stopped as shown in FIG. This means that by applying local cooling to a part of the heart, it is possible to constrain the spiral reentry wave at the cooling location, and also has an effect of promoting its disappearance.

  Furthermore, by applying local cooling after inducing the spiral reentry wave, 4 out of 11 cases stopped, and even in 7 cases that did not stop, as shown in FIG. By applying a relatively low voltage direct current to point b, 4 out of 7 spiral reentry waves could be stopped. This means that local cooling encourages the suspension of spiral reentry waves by energization, which we discovered for the first time in the world.

  In an experiment using a rabbit heart with a subendocardial infarction, ventricular fibrillation was induced by applying electrical stimulation (DC shock). In the two-dimensional phase diagram of the membrane potential fluorescence signal during ventricular fibrillation, as shown in the measurement diagram before cooling in FIG. 18, there are always a plurality of phase singularities (corresponding to the center of spiral reentry wave rotation), Their numbers and locations were constantly changing. This means that when ventricular fibrillation occurs, the spiral reentry wave repeats splitting and is in an unstable state.

  When local cooling (10 mm in diameter) is applied to a part of the left ventricle with a cold water perfusion device, the phase singularity becomes localized at the edge of the cooling region 84 in 8 of 8 cases, Stoppage of movement was observed in 2 cases. Furthermore, when a relatively low voltage direct current was applied in the vicinity of the cooling region, ventricular fibrillation stopped in 3 of 6 cases as shown in the local cooling of FIG. The DC energization voltage (defibrillation threshold) that caused defibrillation dropped to about 50% after local cooling. This means that the strength (voltage × current) of electrical stimulation (pulse) that stops ventricular fibrillation can be reduced by applying local cooling.

By cooling the heart through the above animal experiments, the spiral reentry wave is constrained at the center of rotation at the cooling point. When voltage / current is applied in this state, the spiral reentry wave disappears at a low voltage / current, and the ventricle It was confirmed that tachycardia and ventricular fibrillation stopped and normal heart excitement recovered. It was also confirmed that spiral reentry waves disappear and ventricular tachycardia and ventricular fibrillation may cease only by local cooling of the heart.
The present invention is a novel and original anti-fibrillation device devised based on this demonstration.

FIG. 1 shows a state in which the anti-fibrillation device according to the present embodiment is attached to the heart 30.
An atrial lead 32 is provided through the superior vena cava 33 to the right atrium 31. An electrode 321 is provided at the tip of the atrial lead 32, and the cardiac potential of the right atrium 31 is detected. Similarly, a ventricular lead 34 that extends through the superior vena cava 33 to the right ventricle 37 is provided. An electrode 341 is provided at the tip of the ventricular lead 34, and the cardiac potential of the right ventricle 37 is detected. Arrangement positions of these lead electrodes in the heart are arbitrary. The heart potential detection position may be appropriately selected according to the type of heart state information to be obtained and the control method. For example, a lead may be provided in the left atrium or the left ventricle so that the electrode is disposed.

  A flexible rectangular base material 10 according to the feature of the present invention is sewn on the epicardial surface of the left ventricle 38. As shown in FIG. 2, four Peltier elements 12 (cooling devices) for cooling are provided at the center of the base material 10. Further, a thermistor 18 (temperature detector) for detecting temperature is provided in a part of the periphery of each Peltier element 12. On the surface of the substrate 10, a plurality of circular plate-shaped potential sensors / energization electrodes 14 for detecting the surface potential of the heart are arranged in a lattice at substantially equal intervals. The potential sensor / energization electrode 14 is also an energization electrode for applying a pulse voltage / current to the heart. The Peltier element 12, the thermistor 18, and the plurality of potential sensors / energization electrodes 14 are fixed so as to be in close contact with the epicardial surface of the left ventricle of the heart.

  Further, signals from a plurality of potential sensors / energization electrodes 14 installed on the substrate 10 and electrocardiographic signals from the atrial lead 32 and the ventricular lead 34 are inputted, and a pulse voltage is passed through these electrodes and leads. A main body 20 including a control device for performing control for outputting current is implanted under the skin of a human body.

  The electrical configuration of the anti-fibrillation device of this embodiment is shown in FIG. The control device mainly includes an MPU (microprocessor unit) 50 that detects an electrocardiogram signal, processes the detection signal, and controls energization, and A / D converters 52 and 54. Electrocardiographic signals from the plurality of potential sensors / energization electrodes 14 are input to the A / D converter 54 via the switch 56, converted into digital signals, read by the MPU 50, and processed.

  The energizing device 60 mainly includes a battery 62, a booster circuit 64 that boosts the voltage of the battery 62 in accordance with a command from the MPU 50, a capacitor 66 that stores electric charges by the voltage boosted by the booster circuit 64, and an input / output terminal The switch 68 includes a switch 68 for controlling conduction and switching input / output terminals, and a current control device 70 for controlling a current supplied to the Peltier element 12 according to a command from the MPU 50. The main body 20 shown in FIG. 1 incorporates the control device and the energization device.

  The switch 68 controls to switch the transmission system of the next circuit. The switch 68 receives a command from the MPU 50, and sends an electrocardiogram signal from the electrode 321 at the tip of the atrial lead 32 and an electrocardiogram signal from the electrode 341 at the tip of the ventricular lead 34 to the A / D converter 52. It can be switched to output. Further, the switch 68 is switched so as to output the voltage from the capacitor 66 to the electrodes 321 and 341 in accordance with a command from the MPU 50.

  Further, the switch 56 is switched so as to output the voltage from the capacitor 66 to the plurality of potential sensors / energization electrodes 14 provided on the substrate 10 in accordance with a command from the MPU 50.

  The output signal of the thermistor 18 is read by the MPU 50 via the A / D converter 52. The current control device 70 operated by the control of the MPU 50 controls the heart temperature so that the Peltier element 12 is energized to change the cooling capacity of the Peltier element 12 and the temperature detected by the thermistor 18 becomes equal to the target temperature. Yes.

  In the present embodiment, the electrocardiogram signal detection apparatus mainly includes an atrial lead 32 and an electrode 321 at the tip of the lead, a ventricular lead 34 and an electrode 341 at the lead tip, and a plurality of potential sensors / energization electrodes 14. . The control device mainly includes an MPU 50, A / D converters 52 and 54, and the thermistor 18. The cooling device includes a Peltier element 12. The energization device mainly includes a battery 62, a booster circuit 64, a capacitor 66, switches 68 and 56, a potential sensor / energization electrode 14, and a current control device 70.

Next, the operation of the anti-fibrillation device of the present embodiment will be described with reference to FIG. 4 showing the processing procedure of the MPU 50.
First, in step 100, the switch 68 is switched to the side for inputting signals from the atrial lead 32 and the ventricular lead 34. Thereby, the potential of the myocardium of the right atrium 31 and the right ventricle 37 is detected. Further, the switch 56 is switched to the side where the potential signal is input from the plurality of potential sensors / energization electrodes 14, and these potential signals are input to detect the potential distribution of the epicardial surface of the left ventricle. These signals are electrocardiographic signals indicating myocardial excitation. Next, in step 102, these electrocardiographic signals are analyzed to determine whether ventricular tachycardia or ventricular fibrillation has occurred. Whether or not it is a ventricular tachycardia is basically determined by the excitation cycle (rate) and its duration (beat rate). In this case, it is important not to misidentify supraventricular arrhythmia such as sinus tachycardia or atrial fibrillation as ventricular tachycardia.

    Ventricular tachycardia is detected as a precursor that is likely to lead to ventricular fibrillation. Here, the presence or absence of ventricular tachycardia is determined from the period and duration of the electrocardiographic signal obtained from the tip electrode 341 of the right ventricular lead 34 and the plurality of potential sensors / energization electrodes 14. It is possible to detect a spiral reentry wave from the time / space distribution of an electrocardiogram signal obtained from the potential sensor / energization electrode 14. The presence or absence of supraventricular arrhythmia such as sinus tachycardia, atrial fibrillation, or coarse movement is determined from the electrocardiographic signal obtained from the tip electrode 321 of the right atrial lead 32. In the case of such supraventricular arrhythmia, this apparatus is not driven. The device is also driven when ventricular fibrillation is detected. For detecting ventricular tachycardia and ventricular fibrillation, an arrhythmia detection algorithm employed in a known ICD can be used.

  When ventricular tachycardia or ventricular fibrillation is not detected, the apparatus is not driven. Therefore, the process proceeds to step 104, waits for a predetermined time, returns to step 100, and loops of steps 100-102-104 Monitoring of the heart's electrocardiogram signals continues.

  If ventricular tachycardia or ventricular fibrillation is detected in step 102, a control signal is output to the booster circuit 64, and the storage battery 66 is charged to a predetermined voltage. That is, preparation for applying the pulse voltage / current to the heart is performed in advance. This voltage / current is lower than the conventional ICD.

  Next, the process proceeds to step 108, in which the Peltier element 12 as a cooling device is energized, and the control signal for cooling the temperature of the local portion of the epicardial surface of the left ventricle 38 to about −5 ° C. with respect to the body temperature. Is output to the current controller 70. In this case, the temperature detection signal from the thermistor 18 is input, and the supply current by the current control device 70 is feedback-controlled so that the detected temperature becomes the target temperature. As a result, the temperature of the local portion of the epicardial surface of the left ventricle 38 becomes the commanded target temperature.

  Next, in step 110, the process waits until the epicardial surface temperature reaches the target set temperature. After the voltage increase variable n is initially set to 1, the process proceeds to step 112, where In exactly the same manner, the electrocardiogram is detected from each sensor. Next, the process proceeds to step 114, where it is determined whether or not ventricular tachycardia and ventricular fibrillation have disappeared. If they have disappeared, the process proceeds to step 116 and the Peltier element 12 serving as a cooling device. Shut off the power to the. In this way, the processing of the MPU 50 returns to step 100, and the above-described cardiac monitoring loop 100-102-104 is executed.

  Next, when it is determined in step 114 that ventricular tachycardia or ventricular fibrillation has not disappeared, the process proceeds to step 118, and the potential sensor / energization electrode 14 is connected to the energization device 60. The switch 56 is switched so that a pulse voltage / current can be applied. Then, the energization device 60 is operated to apply a pulse voltage / current to the potential sensor / energization electrode 14. The voltage of the pulse voltage / current uses a biphasic voltage waveform as shown in FIG. In this case, the voltage V1 and the pulse width T1 are changed in proportion to the voltage increase variable n. The voltage / current is applied between the plurality of potential sensors / energization electrodes 14 divided into two groups so as to sandwich the cooling portion.

  In this manner, in step 118, a pulse voltage / current is applied between the plurality of potential sensors / energization electrodes 14, and the pulse current flows to the cooled cooling portion of the left ventricle. Next, when the control repetition variable n is less than or equal to the maximum value a in step 120, the repetition variable n is incremented by 1 in step 121, and the process returns to step 112 to detect the electrocardiogram, and the ventricle The loop in which it is determined whether tachycardia and ventricular fibrillation have disappeared is repeated.

  If ventricular tachycardia or ventricular fibrillation does not disappear, in step 118, the voltage value of the pulse voltage / current is increased by a predetermined amount, the pulse width is increased, the energization power is improved, and energization is executed. The This is performed until ventricular tachycardia or ventricular fibrillation disappears, or until the number of repetitions n exceeds the maximum number of repetitions a. If ventricular tachycardia or ventricular fibrillation does not disappear even after the maximum number of repetitions a is exceeded, power supply to the Peltier element 12 serving as a cooling device is cut off in step 122. In step 124, the electrocardiogram is detected again by each sensor 14, the atrial lead 32, and the ventricular lead 34.

    If a ventricular tachycardia is detected in step 126, the process proceeds to step 128, and a pulse voltage / current for removing the ventricular tachycardia performed in the conventional ICD is applied. Here, a pulse voltage / current is applied to the electrode 341 and the electrode 321 via the ventricular lead 34 and the atrial lead 31. That is, in the method of applying a pulse voltage / current to the cooling point, when the ventricular tachycardia cannot be eliminated, the voltage / current is applied between the ventricle and the atrium performed in the conventional ICD and the ICD main body. The Thereafter, in step 134, when the conventional ICD process is executed and the conventional ICD control end condition is satisfied, the control of the apparatus is ended. Then, the process is executed again from step 100.

  Also, if it is determined in step 130 that ventricular fibrillation cannot be eliminated, the process proceeds to step 132 and, as is done in the conventional ICD, via the ventricular lead 34 and the atrial lead 31, The electrode 341 and the electrode 321 apply a voltage / current between the ventricle and the atrium and the ICD body. In this case, it is carried out at a high voltage and high current. After that, in step 136, processing by the conventional ICD is executed, and when the conventional ICD control end condition is satisfied, the control of this apparatus is ended. Then, the process is executed again from step 100.

  In the above embodiment, in step 118, a pulse voltage / current is applied between the divided potential sensor / energizing electrode 14, but the electrode 341 at the tip of the ventricular lead 34 and a number of potential sensors / currents are applied. A pulse voltage / current may be applied between the energization electrodes 14. Alternatively, a pulse voltage / current may be applied between these combinations, that is, between the divided potential sensor / energization electrode 14 and between one group of the potential sensor / energization electrode 14 and the ventricular lead 34. good. Further, a pulse voltage / current may be applied between the plurality of potential sensors / energization electrodes 14 and the main body 20.

  Further, in the above embodiment, the precursor phenomenon that is likely to lead to ventricular fibrillation is assumed to be ventricular tachycardia, and the ventilator tachycardia is detected as the heart cooling start condition. If there are others, the time when the phenomenon is detected may be set as the cooling start time. Further, if a program for measuring the potential distribution of the entire heart and detecting the spiral reentry wave is possible, the heart may be cooled when the spiral reentry wave is detected. In addition, the pulse voltage / current is applied to the heart when a predetermined time has elapsed after the heart is cooled. The pulse voltage / current may be applied when the spiral reentry wave is constrained by the detection at 14.

  Although the voltage value and pulse width of the pulse voltage / current are changed according to the voltage increase variable n which is a repetitive variable, the application of the pulse voltage / current may be completed once. When ventricular tachycardia is detected, the voltage value and pulse width of the pulse voltage and current are gradually increased according to the voltage increase variable n. When ventricular fibrillation is detected, the predetermined value is used. The pulse voltage / current having a high voltage value of may be applied only once. In the above embodiment, the main body 20 is an implantable anti-fibrillation device that is implanted subcutaneously in the chest of the human body. However, the device may be controlled from outside the human body without being implanted.

Further, as shown in FIG. 6, the potential sensor 14 and the energizing electrode 16 may be separated. In this case, the circuit configuration of the apparatus is as shown in FIG. The energization electrode 16 is controlled by a switch 68, and the potential sensor 14 directly inputs to the A / D converter 54. The pulse voltage / current is applied between the two energization electrodes 16.
Also in this case, a pulse voltage / current may be applied between the electrode 341 at the tip of the ventricular lead 34 and the two energizing electrodes 16, or between the two energizing electrodes 16 and one energizing electrode 16. A pulse voltage / current may be applied between the electrode 341 at the tip of the ventricular lead 34 and a pulse voltage / current may be applied between the two energization electrodes 16 and the main body 20. Also good.

  Further, as shown in FIG. 8, the detection of the electrocardiographic signal may be performed by the atrial lead 32 and the ventricular lead 34, and the potential sensor 14 on the base material 10 may be eliminated, and only the energizing electrode 16 may be provided. In this case, the method described in the embodiment shown in FIG. 6 can be applied to the pulse voltage / current application method.

  Furthermore, as shown in FIG. 9, only a device for locally cooling the heart may be attached to a conventional ICD. As shown in FIG. 9, only the Peltier element 12 and the thermistor 18 are disposed on the base material 10. In this case, an electrocardiogram signal is detected by the atrial lead 32 and the ventricular lead 34, and a pulse voltage / current for stopping ventricular tachycardia and ventricular fibrillation is applied to the heart via the signal.

  As described above, in this embodiment, when ventricular fibrillation or ventricular tachycardia is detected, the cooling device is driven, the ventricle is cooled, and a pulse voltage / current is applied to the cooling location, thereby efficiently. Ventricular tachycardia can be stopped by eliminating the spiral reentry wave. This prevents ventricular fibrillation. In this device, since the heart is cooled and the pulse voltage / current is applied, the applied voltage may be low, so that the wearer is less anxious and uncomfortable with the energization. Therefore, a patient's QOL can be improved. Further, when a pulse voltage / current is applied to the cooling location after the heart is cooled, the voltage / current may be low, so that damage to the heart can be minimized.

    The apparatus configuration shown in FIGS. 6 and 7 was used. The processing procedure of the MPU 50 is the procedure shown in FIG. This device is an implantable ventricular fibrillation prevention device for the purpose of preventing ventricular fibrillation when a ventricular tachycardia, which is a precursor phenomenon leading to ventricular fibrillation, is detected. The first embodiment stops the ventricular tachycardia by detecting the ventricular tachycardia, while the fibrillation stop function operates even when ventricular fibrillation is detected in addition to the ventricular tachycardia. I am doing so. Steps 200 to 226 correspond to steps 100 to 126 in FIG. Thus, when a ventricular tachycardia is detected, first, the cooling device is driven to cool the ventricle, and after a predetermined time, a pulse voltage / current is applied to the cooling location to efficiently generate a spiral reentry wave. Can be extinguished to stop ventricular tachycardia. This prevents ventricular fibrillation. A patient wearing a conventional ICD device is greatly uneasy at the time of defibrillation due to a strong pulse voltage / current, and the patient's QOL is significantly impaired. In contrast, in the case of this apparatus, since a strong pulse voltage / current is not applied, such anxiety is small and the QOL of the patient can be improved.

    In the present apparatus, when ventricular fibrillation is detected, a processing procedure as shown in FIG. 11 may be used. That is, when a ventricular tachycardia is detected, the processing procedure shown in FIG. 10 of Example 2 may be used, and when ventricular fibrillation is detected, the processing procedure shown in FIG. 11 may be used. Steps 300 to 326 correspond to steps 200 to 226. However, when ventricular fibrillation is detected, unlike the processing in the case of ventricular tachycardia, after the heart is cooled, the voltage value of the pulse voltage / current is not gradually increased, and a predetermined value is applied to the cooling point. A configuration is adopted in which a pulse voltage / current having a pulse width and a pulse width of 1 is applied once. This is because in the case of fibrillation, it is necessary to stop fibrillation as quickly as possible. If ventricular fibrillation still does not stop, in steps 328 and 334, a high-voltage pulse voltage / current is applied to the heart via the atrial lead 32 and the ventricular lead 34 as in the conventional ICD. become. At this time, a pulse voltage / current may be applied using the energization electrode 16 provided on the substrate 10.

    In the present invention, when a precursor phenomenon of ventricular fibrillation (ventricular tachycardia, spiral reentry wave) is detected, the heart is cooled, or cooling is started and a predetermined time elapses or the spiral reentry wave is cooled. It is also effective as a treatment method for preventing the occurrence of fibrillation by applying a pulse voltage / current after confirming that the region is restrained.

  Furthermore, when ventricular fibrillation occurs, it is also effective as a treatment method for stopping the fibrillation by cooling the heart or applying a relatively low pulse voltage / current after cooling.

  The present invention is extremely effective as a medical device because it can prevent the occurrence of ventricular fibrillation for a patient who has heart disease and is likely to have ventricular fibrillation. In addition, even when ventricular fibrillation occurs, the device can be effectively stopped, so that it is extremely effective for use as a medical device.

Explanatory drawing which showed the state equipped with the fibrillation prevention apparatus which concerns on one specific Example of this invention in the heart of a human body. The top view which showed the structure of the base material of the fibrillation prevention apparatus which concerns on the Example apparatus. The block diagram which showed the electrical structure of the fibrillation prevention apparatus which concerns on the Example apparatus. The flowchart which showed the process sequence of MPU of the fibrillation prevention apparatus which concerns on the Example. The wave form diagram which showed the voltage waveform of the pulse voltage and electric current of the defibrillation apparatus based on the Example. The top view which showed the structure of the base material of the fibrillation prevention apparatus which concerns on the modification of the Example. The block diagram which showed the electrical structure of the fibrillation prevention apparatus which concerns on the modification. The top view which showed the structure of the base material of the fibrillation prevention apparatus which concerns on another modification. The top view which showed the structure of the base material of the fibrillation prevention apparatus which concerns on another modification. 9 is a flowchart showing a processing procedure of an MPU of an anti-fibrillation device according to Embodiment 2. 9 is a flowchart illustrating a processing procedure of an MPU of an anti-fibrillation device according to a third embodiment. A photograph showing the structure of an animal experiment. The figure which showed the change of the heart potential distribution and action potential duration before and behind cooling by animal experiment. The measurement figure which showed a mode that the spiral reentry wave after cooling was restrained by the cooling location. The waveform figure of the electrocardiogram signal which showed that ventricular fibrillation stopped by cooling. The measurement figure which showed the spiral reentry wave when the heart was cooled. The measurement figure which showed the mode of the change of the electrocardiogram signal when a pulse voltage and an electric current were applied without cooling, and when a pulse voltage and an electric current were applied after cooling. The measurement figure which showed the spiral reentry wave when a pulse voltage and an electric current are applied without cooling, and when a pulse voltage and an electric current are applied after cooling.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Base material 12 ... Peltier element 14 ... Electrode for potential sensor / energization 16a, 16b ... Electrode for conduction 32 ... Atrial lead 34 ... Ventricular lead

Claims (10)

An implantable anti-fibrillation device for preventing the occurrence of fibrillation of the heart,
An electrocardiogram signal detection device for detecting an electrocardiogram signal comprising a cardiac potential;
A cooling device for cooling the heart;
A control device that drives the cooling device to cool the heart when a precursor phenomenon that may lead to ventricular fibrillation is detected based on the electrocardiogram signal detected by the electrocardiogram signal detection device; Anti-fibrillation device provided. The anti-fibrillation device according to claim 1, wherein the precursor phenomenon is ventricular tachycardia. The anti-fibrillation device according to claim 1, wherein the precursor phenomenon includes a phenomenon based on generation of a spiral reentry wave. The power supply device for applying a pulse voltage / current to the heart, wherein the control device drives the power supply device after a predetermined time has elapsed after driving the cooling device. 4. The anti-fibrillation device according to any one of 3 above. An energization device that applies a pulse voltage / current to the heart, and the control device detects that the spiral reentry wave is constrained to the cooling location of the heart after driving the cooling device, and based on the detection, The defibrillation prevention device according to any one of claims 1 to 3, wherein the energization device is driven. An energization device that applies a pulse voltage / current to the heart, and the control device drives the energization device when the precursor phenomenon has not disappeared after a lapse of a predetermined time after driving the cooling device. The anti-fibrillation device according to any one of claims 1 to 3, wherein the anti-fibrillation device is provided. An energization device that applies a pulse voltage / current to the heart, and the control device drives the energization device when the ventricular tachycardia has not disappeared after a lapse of a predetermined time after driving the cooling device. The anti-fibrillation device according to claim 2, wherein The anti-fibrillation device according to any one of claims 4 to 7, wherein the pulse voltage / current is applied to a portion cooled by the cooling device. The anti-fibrillation device according to any one of claims 4 to 8, wherein the pulse voltage / current is applied to a ventricle and an atrium. The anti-fibrillation device according to any one of claims 1 to 9, wherein the cooling device is a Peltier element energized by the control device.