JPS5982831A - Apparatus for sensing signal in hart - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Background of the Invention] Techniques and equipment for sensing electrical signals within the heart, 7:, 1. i) and specify,
The present invention relates to techniques and apparatus for differentially sensing local intracardiac electrical patterns beneath a sensing device f5 and distinguishing them from all unwanted out-of-field electrical patterns.

The human heart is basically a pump through which blood is drawn into the atria or upper chambers and then fills the ventricles or lower chambers via the connecting sweat. Blood is then pumped out of the ventricle to the body's organs. Each cycle of this pump begins with a specific series of 11 (6) events.
) rate is determined in part by the order and relationship of these electrical events.

Electrical recycling begins with spontaneous depolarization of cells in the sinoatrial node, a specific tissue in a small region adjacent to the superior vena cava-right atrium border.

The anterior surface of the deponization ('?FB, shuttle) warmly expands the sinoatrial nodal circle and then activates the atrial myocardium through the perinodal tissue at °C. Atrial myocardium, fI tissue is i! ;i
When activated, an electrical event occurs. When the waves are detected at the surface of the body, they are called P waves. When detected from within the cardiac chamber, this same event is referred to as an "EMG." The characteristics of the atrial electrogram and the surface-recorded P wave are a function of the activated atrial myocardial mass and the activation mode of activation that occurs in the human stone skin P3. It is this electrical activation that results in contraction of the atrial myocardium and at least partial filling of the ventricles.

However, the atrial electrical excitation wave may end up at the filamentous boundary if a specific multicomponent atrioventricular (AV) transmission system does not undertake the transmission of electrical information across the fibrillar boundary between the atria and ventricles. It will be put away. The AV node is a small 1- to 2-cell structure located on the floor of the atrium midway between the entrance of the coronary sinus and the central lamina of the IW♂ heart. This structure, consisting of three separate cells, acts as a focal filter and provides sufficient deceleration transmission area between the atrium and ventricle to allow adequate atrial filling. Electrical input to the AV node is partly through the normal atrial myocardium; partly through the normal atrial myocardium;
This occurs via three specific intra-atrial pathways that are responsible for the transmission of electrical information between the regions adjacent to the lateral node and the upper, middle, and lower regions of the atrial-myocardial node. The transmission within the AV node is
Autonomic sensitivity, extremely sensitive to the effects of cardiovascular drugs and heart disease.

As the electrical depolarization front advances through the kV node, it enters the AV or H2S bundle. It is responsible for the transmission of electrical impulses between the anatomical atria and ventricles. This structure actually traverses the fibrous skeleton of the heart and advances several centimeters within the membranous ventricular corner wall.

At the apex of the intraventricular septum, the special AV transmission system is divided into two main branches: the left bundle and the conventional.

Conventionally, it is divided into nine specific fibers that control activation of the ventricular septum, activation of the upper lateral ventricular myocardium, and a posterior portion that controls activation of the septal mass and left ventricular myocardium. The left bundle controls activation of the right ventricle.

Although electrical activity is detected from specific regions of the heart's conduction system by using special techniques, surface electrocardiography techniques detect distinct electrical activity occurring in either the A, V nodes, AV bundles, or bundle branches. electrical events cannot be indicated.

No electrical activity is seen on the surface electrogram following the P wave until the ventricular myocardial mass begins to be activated and the OR8 group is marked. This group of pulses, when recorded at the body surface, typically
It has a considerably larger amplitude than the P wave. This is because a fairly large ventricular myocardial mass causes this. When recorded from inside the pericardial chamber, this event is referred to as a "ventricular electrogram." The atrial myocardial volatility event is
Whether detected from the surface of the cardiac body or inside the ventricles, they are referred to as T waves.

Normal diastolic depolarization of the lateral nodes followed by normal propagation of electrical excitation through the atria and ventricles in response to nervous system actions that change the discharge rate of the lateral nodes and the rate of atrial and cardiac excitation. produces a normal heart rhythm with a frequency. However, various disease states can affect the dominant natural heart rhythms as well as electrical excitation patterns. Abnormal rhythms occur in the following cases: That is, if lateral nodal impulses are not derived intermittently from the lateral nodal.

In the case of abnormalities of the atrial myocardium, this results in rapid atrial arrhythmias such as palpitations and fibrillation. In the case of abnormality or presence of AI nodal transmission, this causes an insufficiently slow intrinsic base maker to emerge from the lower part within the ventricles, resulting in an abnormally slow heart rhythm. In case of disease of one or all of the bundle branches, this results in partial or complete AV block, which also results in slow and insufficient heart rate. In the case of ventricular myocardial abnormalities, this results in rapid development of ventricular fibrillation and death. Modern medical techniques suggest that such defective electrical devolatilization modes of operation can be treated symptomatically by electronically stimulating the heart using external or implanted electronic devices, commonly considered as base manufacturers. It has progressed to the point where it can be done.

The simplest and most often employed electronic device is the standard VVI type base maker.

The device senses the ventricular electrogram and when the depolarization rate falls below a predetermined level, stimulation is co-delivered to the ventricular myocardium, producing an electrical depolarization wave and subsequent ventricular myocardial contraction. make me wake up Such electrical escape or assist devices may be connected to the ventricle (VVI)
or at the atrial (AAI) level to correct abnormalities in AV transmission or sinoatrial node function. Newer BaseMaker devices employ electrodes at the atrial and ventricular levels, with sensing and regulation at either or both sites, to restore normal operating patterns of atrial and ventricular electrical excitation. . Other implantable electrical devices may be used to convert atrial and/or ventricular hyperthermia and provide a portion of the input to an implantable electrical device designed to terminate ventricular fibrillation. Ta.

However, the ability of any of these devices to function properly is in no way determined by the adequacy of the electrical signals K sensed from the atria or ventricles. However, the appropriate pacemaker output is determined only by the appropriate signal or sensing input. Generally, most conventional devices utilize the same electrodes used for myocardial stimulation to sense myocardial devolization in the absence of stimulation. In general, most devices consist of one electrode implanted in the atrial or ventricular myocardium, or in the form of a ring placed in close proximity to the stimulation electrode along the same catheter body (bipolar sensing) or the base manufacturer itself ( monopolar sensing) consisted of a second electrode. The mean signal amplitudes of the P and QR8 complexes detected using frame or bipolar sensing have been well described in the cardiac literature for more than a decade.

The need to provide signals derived only from the myocardium in contact with which implanted electrodes are placed has been identified. The problem of electromechanical interference external to the patient, such as external magnetic and electric fields and the electromagnetic fields generated by electric shavers and microwave ovens, is also now well recognized by the general public. However, over the past decade, there has been increasing awareness of the susceptibility to erroneous measurements of cardiac electrical events due to other electrical events occurring within the body. For example, the Electromagnetic Interference Symposium,
PACE, VOl, 5. January-February 1982, reference. Particularly in unipolar electrode devices, the sensing of electrical signals from the skeletal myocardium adjacent to the pacemaker anode itself (myopotential sensing) has been recognized as a frequent cause of false inhibition of these basemakers.

Although standard bipolar ring electrodes help reduce the rate at which myopotential and EMI sensing occurs, these devices
Too insensitive to electrical phenomena occurring in the outside world, in the patient, and in the surroundings. A device that is insensitive to EMI would have clinical value in dogs.

Placing either a monopolar or bipolar contact electrode device within the ventricle to sense activation of the ventricular myocardium (ventricular electrogram) typically provides a sufficient ventricular electrogram signal of 10-12 mV, and Because the mass of the ventricular myocardium is large compared to the ventricular myocardium, electrical activity reflecting atrial devolization is hardly detected by this catheter. However, this is not the case and electrograms are derived from various locations within the atrium. Contacting electrical sensing devices, whether unipolar or bipolar, all suffer from the same drawbacks: their location within the right atrial appendage, their location within the right atrium lateral wall or the proximal-distal coronary sinus is largely independent. . The problem appears to be unique to the hexatibial anatomy. That is,
The mass of the atrium is small, and as a result, P waves are also generally quite small, 1-2 mv, even when sensed from within the atrium. The mass of the ventricular myocardium is calculated from the mass of the atrial myocardium by a certain amount of culm.
Ventricular depolarization can be captured as a separate electrical event even from within the atrium. This electrical event is thus distinguishable from the atrial electrical event in signal magnitude and form.

Because of this shortcoming alone, the development and development of atrial arrest (AAI) and P-wave gated (VAT or VDD) type systems has been very slow. This is a dual-chamber demand-type base manufacturer (1) D D system designed to sense at the atrial and ventricular levels.
In the development of , this became an almost insurmountable problem. The development of suitable rapid cardiac conversion pacemakers at the ventricular and atrial levels has also been severely hampered by the lack of signal discrimination between atrial and ventricular events sensed by standard basemaker systems.

These base manufacturer techniques attempted to generate a reliable trigger signal for stimulation pulses by sensing the electrogram through a catheter inserted into the heart via a vein. Generally, a signal sensed in one heart chamber, or its absence, provided the information needed to govern that same heart chamber. It has long been the goal of cardiologists to create a pacemaker system that senses electrical activity in the upper part of the heart, the atria, and can regulate the ventricles at a rate appropriate to the rate sensed in the atria. Most conventional systems employ two catheters, one placed in contact with the right atrial appendage and the other placed in contact with the right ventricular apex. In this way, the signal sensed in the atrium can be extracted by a pulse generator and stimulation can be delivered to the ventricle at the appropriate rate.

There are also several prior art descriptions of harpoon catheters that can be used to sense atrial activity and regulate at the ventricular level. Generally, in each case the sensing element was an electrode similar to the stimulation electrode, but placed anywhere along the axis of the catheter. For example, placing one or two ring electrodes at the atrial level to sense the atrial electrogram is disclosed in US Pat. .81
It is shown in No. 7. Other similar designs include O'Ne1l
U.S. Patent No. 4.154.24 entitled "Deformable Cardiac Pacer Lead and Assembly and Attachment to Body Organs"
No. 7, U.S. Pat. No. 3, entitled "Single Catheter for Atrial and Ventricular Stimulation,"
No. 825,015, 13 Hres, U.S. Pat. No. 3,865,118 entitled "Transvenous Axial Catheter." In most cases, it has hitherto been considered necessary to physically contact the electrode with the inner surface of the atrium. This is because heart waves are generated within the myocardial tissue and 0'Ne1
This is because contact was considered essential as shown in the U.S. patents of 11 and 13 ures.

In some prior art approaches, atrial contact was not considered essential. One prior art device is described in U.S. Pat. No. 4.091.817 to Thaler.

This shows a pacemaker sensing P waves from two circumferential ring electrodes E1 and E2 and generating ventricular stimulation. 'I'haler's patent is an illustration of the complex circuitry that the prior art attempted to devise to distinguish P waves from ventricular depolarization and the wave components of subsequent cardiac wave complexes. This is problematic because the P wave sensed from the non-contact ring electrode is substantially identical to the subsequent QR5 complex.
There is no reliable way to distinguish a wave from its associated QR8T wave train by spectral analysis or other methods by automated means. Other complex circuits used in conjunction with cardiac pacers include
13Erkovits, Lin et al.
U.S. Patent No. 4,0 titled "Interval Base Maker"
No. 60.090 and F'unke, U.S. Pat. No. 5.937.226 entitled "Anti-arrhythmia Device."

The problem of signal discrimination at the atrial and ventricular levels becomes even more complex when considering the effects of electrical stimulation by the base manufacturer itself at the atrial or ventricular level. When attempting to sense myocardial depolarization induced by unipolar or bipolar 5 volt electrical artificial stimulation with the same electrode used for that stimulation, an electrical phenomenon (afterpotential) occurs at the electrode-myocardial interface. ) occurs.

This has an amplitude of a few volts and 200 to 5 TlOl
'T] is the potential for a duration of sec. This may overwhelm the evoked adjacent myocardial response, and absent extremely complex circuitry, the stimulated hair muscle event may be sensed by the base maker itself. As a result, the prior art recognizes what is referred to as a 1M sensing period following every stimulus or induced debtorization. "Afterpotentials" act at the ventricular level as a result of ventricular stimulation only, but at the atrial level, they result in obscuring the atrial electrogram for a significant period of time as a result of stimulation of either the atria or the ventricles.

In any case, the prior art has had little success in devising acceptable P-synchronized, VDD, and DDD demand pacemakers because the P waves cannot be well extracted from the subsequent cardiac wave complex; I gave up. This failure was exacerbated by the fact that the sensing electrodes and associated circuitry were overwhelmed by the strong stimulation pulses generated by the pacemaker itself, thus blinding the basemaker to whether or not the devolization was successfully stimulated. It was done.

A problem encountered with increasing frequency in complex dual-chamber pacer systems is that of abnormal retrograde activation of the atria. This results from spontaneous premature depolarization of the ventricles or slowing of retrograde or retrograde conduction across the ventricles and the AV node.

Retrograde transmission is a normal capability of the AV node and is seen in 9[]X patients with lateral nodal dysfunction. Therefore, this problem is of great importance for DDD pacer systems. Attempts to determine whether retrograde transmission is responsible for a given P-wave require extremely complex circuits, as they inherently lack common electrical sensors to accurately analyze the direction in which myocardial activation is occurring. Depends on usage.

This same difficulty can be overcome by utilizing standard ventricular sensing systems.
When trying to distinguish between the normally derived inno (lus) and the inno (lus) generated by abnormal foci within the ventricle, i.e. when trying to distinguish normal forward conduction from early ventricular devolatilization, even in alternative systems. encounter.

This latter capability becomes extremely important when considering the problems of polymorphic base manufacturers. Now & then, in the absence of suitable sensors, only the rate at which ventricular events occur can be used to distinguish desired from undesired events. Normal lateral rhythm, atrial tachycardia with 1:1 transmission, atrial flutter with variable transmission, as well as ventricular FA diaphragm, all at a rate exceeding a preselected ratio to ventricular tachycardia conversion. Let's arise. Thus, using percentages alone to determine the presence of ventricular tachycardia results in substantial diagnostic errors;
Dew.

What is needed, therefore, is the following method and apparatus.

1. The local electrogram obtained from the tissue adjacent to the regulating catheter is differentiated from all external electrical events generated by other regions of the same chamber, the applied electrical stimulation, or the devolatilization of the opposite chamber. something that can be sensed.

2. The local electrogram is rendered insensitive to the effects of EMI and myopotential sensing.

3. The induced devolization can be sensed without interference due to the effect of devolization at the electrode-myocardial interface (afterpotential sensing).

4. Electrograms derived from the atrial myocardium can be recorded at fairly high amplitudes and can be clearly distinguished from ventricular electrical events even though the magnitude of the electrical force causing the ventricular events is inherently large.

5. Regional myocardial devolization recorded from multiple regions can be used to discriminate normal activation patterns from abnormal activation patterns.

The development of a separate and specific electrical sensor of this type, when applied to the problems encountered in the treatment of electrical disturbances, could lead to the development of accurate and reliable electrical devices for the treatment of cardiac arrhythmias. Probably.

SUMMARY OF THE INVENTION The present invention provides a method for detecting a desired electrical diagram through one or more points lying in the y-perpendicular plane to a devolization vector in cardiac tissue proximate to a pair of points at which localized excitation waves are sensed. Improving methods for sensing cardiac electrical activity, including discriminating desired local cardiac electrical events from complex series of waves, base maker stimulation, and/or extracardiac electrical events by sensing It depends. The signals sensed at this pair or pairs of points are electrically compared (to induce a difference signal specific to the desired local electrogram), but these signals are Substantially independent of all other elements or external electrical events. It depends on the fact that the latter is an "out-of-field" electrical event.

According to this method, any cardiac electrical event is reliably and unambiguously sensed and selected from any complex cardiac wave or non-local electrical event. And this is possible even though these non-local events generate signals with fairly large magnitudes.

The desired local electrogram discrimination is characterized in particular by not having a pair of sensing electrodes necessarily in contact with the myocardium (heart tissue). In other words, the sensing electrode is free floating within the cardiac cavity.

In particular, it is equipped with an electrode dedicated to electrogram sensing that is not used for myocardial stimulation, and is capable of sensing electrical events evoked (stimulated) in a manner that is not hidden by the volatility effect (afterpotential sensing) at the electrode-myocardial interface. Characterized by enabling.

More specifically, the step of differentiating intraatrial electrograms (P waves) from all other depolarizations, such as depolarizations occurring at the ventricular level, involves the step of Characterized by good things.

Whether positioned in the right atrium or the right atrial appendage, the sensing electrode is free floating within the cardiac cavity.

In a second embodiment of the invention, the step of discriminating P-waves also includes sensing P-waves at two or more points in a plane perpendicular to the depolarization vector in nearby cardiac tissue. include. In one embodiment, the cardiac signal is transmitted in three equally spaced circles around a circle in this plane.
or 4, and from this sensing two or more signals are derived.

In addition, the normal atrium or ventricular activation behavior, which results from the normal spread of electrical activity within the heart, is similar to
The use of 1.5 or more sensors can differentiate rapid arrhythmias from abnormal activation modes such as single early debtorization or retrograde transmission. The characteristics of the sensor in each region are the same as described above. and a sensing signal instructing the activation mode of each induced electrogram.
Logic shall be applied to ensure that normal or abnormal activation patterns can be distinguished.

These and other objects of the invention will become apparent from the following description of preferred embodiments, taken in conjunction with the drawings.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

The present invention is local cardiopulmonary; the signal is separated from all other unwanted electrical signals, whether these electrical signals are generated in other regions of the same heart chamber, in other heart chambers, or A method in which focal cardiac electrical activity is sensed in a manner that is identifiably sensed, whether generated as an electrical event external to the heart, such as generated by skeletal muscle or external electrical noise. including.

The electromagnetic field mechanism on which the methodology of the present invention is based is not well understood. However, sensing the heart waves at two or more points that lie substantially in a plane perpendicular to the direction of the local devolization vector in the nearest or adjacent myocardial tissue, and these two or more sensed It has been found that by differentially amplifying the signals, high amplitude local electrograms are generated with very high signal-to-noise ratios (SNR). For example, the very high amplitude QR3 complex, the accompanying T waves, or the large number of stimulation pulses generated by the associated pacemaker reliably sense the very small P waves of the heart, thereby displacing this P wave with all other It has been found that there is no impact on the efficacy of the methodology to reliably distinguish from natural or artificially introduced electrical activity.

Figure 1 shows the normal surface of a normal heartbeat, or skin electrocardiogram (
EKG) is exemplified by line 10, and this electrocardiogram shows P wave 1, which is a surface indication of depolarization of the atrial myocardium.
2. Similarly, it reflects gvolalization of ventricular myocardium.

The P wave 12 is shown followed by <QR8 complex 14 and the T wave 16 following it reflects ventricular volume volatility. Line 18 is connected to the normal atrial 'FJK' as typically measured by a prior art ring electrode probe floating within the atrium or in contact with the right atrial appendage.
It is G. A normal atrial EKG typically includes reference numeral 2.
It has a bipolar P-wave response indicated generally by 0, followed by a bipolar QRS response of slightly lower amplitude, indicated generally by reference numeral 22. The waveform of the QRS response 22 is generally the same as the P wave response 20, but tends to be smoother and of smaller amplitude.

However, even among normal individuals, one person's heart waves may differ significantly from the measured heart waves of another individual, or from the same individual's heart waves measured at different times. There is. Slight variations in the intervals between the various component responses from the component responses shown by line 18 in the atrial EKG, including variations in the relative amplitudes of each component response, are to be expected in an abnormal heart. The waveform and amplitude fluctuations of the P wave response 20 and the Q RS response 22 make it extremely difficult for even a human observer to completely distinguish between the two in any environment. Therefore, it is even more difficult for electronic circuits and logic to reliably distinguish between P-wave responses 20 and QRS responses 22 than it is for human observers, and this shortcoming is common in current cardiac pacemaker development. was giving restrictions.

Line 24 is a normal ventricular electrogram obtained from a standard contact electrode system, and line 100 corresponds to the QR8 and T waves shown on the surface electrogram. Shows great response. This ventricular EKG has no discernible response corresponding to P wave 12. Line 28 is an electrogram taken from the right atrial appendage by using the orthogonal probe devised by the present invention. The sensed signal is a response collectively indicated by the reference numeral 30 indicating a P wave, 2-1 omV, 15-
It has a sharp recognizable spike shape of 40 ms duration and virtually no other responses to other cardiac electrical events. Line 62 is a ventricular electrogram sensed in accordance with the present invention, with a large recognizable QRS response indicated generally by reference numeral 34 and a very small T-wave response indicated generally by reference numeral 36. , and there are no other discernible responses, including atrial P waves, to other cardiac events.

Lines 10.18 and 24 are lines 28 and 3
2, which significantly exemplifies the delocalized individual responses obtained in the centripetal electrograms retrieved according to the present invention when compared to those detectable by prior art devices and methods. . Lines 28 and 32 of the invention
The electrogram shown not only has a considerably better signal-to-noise ratio, but also shows only localized field or nearby cardiac events in response duration. For example, the right atrium.

The probe placed in the ventricle produces the response illustrated in line 28, which, in marked contrast to the normal atrial electrogram illustrated in line 18, is completely unresponsive to any cardiac activity in the ventricles. Not affected.

FIG. 2 further illustrates that the present invention senses only events in the vicinity of the heart's field and responds by providing sharp devolization spikes with very high signal-to-noise ratios. The surface EKG is line 1 in Figure 2.
The normal atrial electrogram is reproduced as line 16 in FIG. This is an electrogram sensed with a catheter having multiple orthogonal sensing electrodes, i.e., an electrogram exemplified by line 38 from a sensing electrode placed in the right atrium's two parts and a sensing electrode placed in the lower right atrium. compared to the electrical diagram exemplified by line 40 from . P sensed in the upper right atrium during normal progressive conduction
Wave response 42 is clearly indicated by line 38 as starting at some time during the early phase of the P wave. However, line 40 sensed by the electrode in the lower right atrium
The P wave 44 is a P wave that appears at a delayed time compared to the response 42. This interval represents the normal propagation delay within the heart from the top to the bottom of the atrium. In each case,
Electrograms taken in the upper or lower regions of the right atrium are virtually unresponsive to large ventricular signals generated near the ventricles.

Continuing to refer to FIG. 2, a normal surface electrogram of a counter-propagating cardiac wave is illustrated by line 46, with the P wave sponse 12' inverted and followed by the QR8 complex.

The same sensing electrode used in FIG. 1, whose output is depicted by lines 38 and 40, produces an electrogram from the upper right atrium as shown by line 48 and from the lower right atrium as shown by line 50. Generate electrical diagram. As mentioned above,
The upper right atrium response is a sharp P wave with a sponse of 52, and the lower right atrium response is a sharp P wave with a sponse of 54.
It is. These EKG 48 and 50 waveforms are EKG 48 and 50, with the exception that their time sequences are opposite to each other.
Essentially the same waveform as KG38 and 40. Right atrium upper P wave response 52 is right atrium lower response 54
It is more clearly delayed in time (this retrograde atrial devolization results in an inversion of the P wave 12').

However, a normal atrial electrogram corresponding to a retrograde heart wave, such as that shown at line 53, is effectively the same as a normal atrial electrogram that corresponds to a normal heart wave, such as that shown at line 18.
I can't tell the difference. Thus, by using multiple sensing regions according to the present invention, for the first time, the propagation sequence of events within a particular cardiac chamber can be accurately detected and used to distinguish normal heart beats from abnormal heart beats. It was.

FIG. 6 shows the method of the present invention applied to a human heart. A cross-sectional perspective view of a portion of the heart, designated generally by the reference numeral 56, is schematically illustrated in FIG. A striated catheter 58 is shown. Although FIG. 3 represents a generalized location within the heart, it should be interpreted to include any location within at least the atrium or ventricle. Catheter 58 includes at least two electrodes 60 positioned in a plane generally perpendicular to a depolarization vector 62 of adjacent myocardial tissue 64 .

Depolarization vector 62 is a mathematical symbolization of the direction of the heart wave traveling within myocardial tissue 64 and is perpendicular to the wavefront at each point. Sensing signals received at electrode 6o are connected to a pacemaker circuit (not shown) by means of conventional flexible conductive leads contained within catheter 58.
sent to. Conventional pacemaker circuits can be used, although the present invention is expected to yield many pacemakers that were not previously possible.

4 is a schematic cross-sectional view taken along line 4-4 in FIG.
This is an example of the vicinity of 0.

It has been determined by the present invention that regardless of the angular orientation of the electrodes 600 in the plane illustrated in FIG. 4, the electrodes 60 only sense electrical activity in their immediate vicinity. Electrode 60 produces no response to cardiac activity occurring in other chambers of the heart, external to the heart, but occurring in adjacent muscle tissue, or to external electromagnetic interference. Although catheter 58 and electrode 60 are not in contact with the inner wall of heart 56 in FIG. 4, catheter 58 and electrode 60 are not in contact with the inner wall of heart 56 in order to generate useful signals, as was incorrectly believed in the prior art. It should be noted that there is no need to contact the inner wall.

FIG. 5 is a cross-sectional view of FIG. 3 taken along line 5-5,
It illustrates the arrangement of the electrode 6o of the catheter 58 within the plane symbolized by the dotted line 68. This plane 68 is approximately perpendicular to the local devolization vector 62 in adjacent myocardial tissue 64 .

FIG. 6 illustrates in a schematic cross-sectional view of the heart 56 the insertion of the cav-chill 58 into the fluid-filled chambers of the heart 56, namely the right atrium 7o and the right ventricle 72. The sensing electrode 6o shown in FIG. 6 in the atrial sensing and ventricular stimulation embodiment is positioned in the upper right atrium region 6A, shown enlarged in FIG. 6A.

Catheter 58 extends through atrium 7o, through the tricuspid valve, and down to apex 76 of heart 56.

A stimulating tip 78 is provided at the end of the catheter 58 for implantation within the apex 76 of the ventricle, as shown enlarged in FIG. 6B illustrating the area of the heart 56 designated 6B in FIG. It is being A stimulating tip 78 is provided at the end of the catheter 58 for direct contact with the myocardial tissue at the apex 76 of the ventricle.

High voltage stimulation pulses are applied to the chip 78 by a conventional pacemaker to initiate the necessary ventricular contractions according to established medical principles.

Stimulating tip 78 may be any conventional tip including any fixture (not shown) that facilitates implantation and anchoring of tip 78 within the myocardial tissue adjacent to ventricular apex 76.

FIG. 7 schematically and fragmentarily illustrates an enlarged view of ventricle 72 in accordance with another embodiment of the present invention, in which catheter 58 is illustrated as including a sensing electrode 80 contained within ventricle 72. exemplify. Electrode 80 is positioned in the ventricular wall of heart 56 proximate ventricular myocardial tissue 82 . As previously mentioned, the signals sensed by electrodes 80 are coupled via conventional flexible leads to conventional pacemaker circuitry for subsequent processing and generation of stimulation pulses delivered to chip 78. .

When sensing is performed according to prior art methods, chip 7
A large stimulation pulse supplied to 8 is inside the ventricle! This would completely overwhelm the sensing pathway of ρ. Therefore, the cardiac activity that could be initiated by the stimulation pulses applied to the chip 78 would not be as strong as is known in the art. However, the electrical activity of the heart is sensed at the location of the electrode 8o, which is positioned in a plane approximately perpendicular to the nearest devolization vector of the adjacent myocardial tissue 82;
When the sensed signals are differentiated in a differential amplifier, a localized electrogram response 64, as shown by line 32 in FIG. The sensing electrode 8o receives stimulation pulses 1 to 5.
Even the application shown in 7M, which is within the 0 m delivery range, is unaffected by the stimulation pulses delivered to the tip 78.

The method of the invention therefore results in the first true demand pacemaker. In other words, a stimulation pulse can only be generated in response to whether a previous ventricular stimulation pulse caused a contraction of the heart.

FIG. 8 shows a third embodiment of the invention in which stimulation of the heart is applied to the right atrial appendage, indicated by the reference numeral 86, shown schematically and in fragments on an enlarged scale.

Catheter 88 is J-shaped to allow atrial sensing at the upper lateral atrial wall by gJ9o, ie at the right atrial appendage 86.

Again, the electrode 90 lies generally in a plane approximately perpendicular to the depolarization vector, which is also close to the grain of adjacent myocardial tissue (not shown). The end of the catheter 88 is shown in FIG. 7 and includes the conventional stimulation tip 78 described in connection with FIG.
It is equipped with a stimulation chip 92 similar to the above. The atrial appendage 86 illustrated in FIG. 8 is in close proximity to the right ventricular outflow tract designated by reference numeral 94. Despite the electrical activity that may be associated with the ventricle or outflow tract 94, the electrode 90 in the atrial appendage 86 senses only the nearest cardiac activity in the field vicinity, as illustrated by line 28 in FIG. , generates a large signal-to-noise output signal.

The present invention can implement a fourth embodiment shown in FIG. 9 in which sensing local myocardial devolization from multiple regions can be achieved. Electrograms are recorded by electrode 100 from the lower right atrial region 98 and by electrode 104 from near the atrial bed 102. As mentioned above, the upper right atrial signal is sensed by electrode 60. Electrodes 6o, i
oo, and 104 are each approximately perpendicular to the nearest devolization vector in the adjacent myocardial tissue. Each of the electrodes 60, 100 and 104 generates an individual spike-shaped response of the type shown in lines 38.4o, 43 and 50 of FIG. 2, most proximately indicative of local cardiac activity. These electrodes 60,1
Each of 00 and 104 is coupled to a pacemaker circuit (not shown) through a corresponding flexible lead within catheter 1o6 for subsequent processing and appropriate generation of stimulation pulses. The use of multiple sensing electrodes, as illustrated in FIG. 9, results in processing of the heart that is not based on the mere absence or presence of cardiac activity within the heart, but is based on the sequential progression of cardiac activity. .

Thus, it is clear that the methodologies and probes of the present invention can be used anywhere in or near cardiac structures and with a wide variety of probe shapes.

For example, although shown sensing in the atrial appendage, various locations within the atrium, and in the ventricle, the probe can also be placed in the coronary sinus.

Again, only events local or near the field of the coronary sinus are received by the probe, ensuring that these events can be monitored without interference from nearby large amplitude signal sources.

Figures 10 to 12 illustrate enlarged, schematic and fragmentary embodiments of the probe. for example,
The probe shown enlarged in FIG. 10 is used symbolically in each of the previous figures and is comprised of two opposing electrode plates 10B and 110. Each electrode plate 108, 110 has a corresponding flexible wire lead 112 and 114, respectively. Electrode plate 1
0B and 110 are disposed circumferentially around catheter 116 on the surface of imaginary cylinder 118.

The surface of cylinder 118 is the physical surface 12 of catheter 116.
It may actually be directly below 0. The skin of catheter 116, which may be an external protective and insulating coating, is cut away to expose electrode plates 108 and 110, which are in direct contact with the surrounding blood.

In this way, electrode plates 108 and 110
2 and 114, respectively, to a differential amplifier 122, shown schematically in FIG. 1D.

The output of this differential amplifier 122 is the trigger pulse shown and described in FIGS. 1 and 2. Although the IJ leads 112 and 114 are schematically illustrated as straight lines, in reality these leads would be multi-layered with very high fatigue tolerances developed to accommodate the curvature expected within the human heart. 1, consisting of a land coil wire;
In the case illustrated in FIG. 10 where only two points, electrode plates 10B and 110, are used to sense the nearest devolization vector 150, the two signals are input as inputs to a conventional differential amplifier 122. used. The output of the differential amplifier 122, a spike-shaped response, is a processing and pulse generation circuit 124 which may be of conventional design contained within a subcutaneous pacemaker generally indicated by the reference numeral 126.
is combined with Processing and pulse generation (logic) circuit 12
4 is a trigger pulse provided by a differential amplifier 122 which generates stimulation pulses in response according to principles well known in the art. 116 (not shown) to the stimulation electrode tip.

FIG. 11 schematically illustrates a portion of catheter 130 with four sensing electrodes 132-138.

As in the case of electrode plates 10B and 110 in FIG.
Electrodes 132 - 138 each reside on the surface of a virtual cylinder 140 defined within catheter 130 . In reality, the cylindrical support surface, described herein as virtual cylinder 140, may be a sheathing on the underside of catheter 130 or a non-conductive material that acts as a mold for supporting electrodes 132-138. It may also be a cylindrical ring. If four electrodes are used as shown in FIG. 11, true orthogonal sensing signals can be extracted. For example, electrode 1
62-168 are evenly spaced around the circumference of catheter 1300 and are therefore 90° apart from each other. Electrode 134 is paired with electrode 138 and electrode 10
6 is paired with an electrode 132. The six pairs are routed to the associated differential amplifier via their corresponding flexible leads. For example, electrodes 134 and 138 provide the input signal to differential amplifier 142K, while electrodes 166 and 1
62 provides an input signal to differential amplifier 144. The outputs of differential amplifiers 142 and 144 are provided as input signals to a processing and pulse generation circuit 146, similar to circuit 124, contained within a subcutaneous pacemaker 148. The outputs of the two differential amplifiers are shown in Figures 10 to 12.
The Configure the signal.

In the embodiment of FIG. 12, electrodes 152-156 are equally spaced on the surface of a virtual cylinder 158 defined within catheter 160. In the embodiment of FIG. In this example where three electrodes are used, each electrode is 120 degrees apart, but two of these electrodes, e.g. electrodes 152 and 156, are placed diametrically opposite each other, with electrode 154 facing electrodes 152 and 156. It has been found that sensing is also possible when spaced midway between them and 90° from each of them.

In either case, electrodes 152-156 may be associated in any logical manner to form electrode pairs for deriving quasi-orthogonal signals. For example, electrode 156 can optionally be selected as a common electrode, and a first signal is generated between electrodes 152 and 156 in differential amplifier 162. A second signal is similarly applied to electrodes 156 and 15.
4 and is provided as an input to differential amplifier 164. The outputs of differential amplifiers 162 and 164 thus constitute pseudo X and Y signals that can be subsequently processed by circuit 146 in the manner described in connection with FIG.

Figures 10 to 12 are shown as if the poles were points associated with the sensing environment in the applications described in conjunction with Figures 1 to 9, even though the electrodes are described. , illustrating that these electrodes are clearly two-dimensional. Obviously, point sensing is a concept on g=that is never realized in practice. However, these electrodes are small enough and therefore close to point sensing. It has been determined experimentally that the diameter of the catheter may range from 1 to 4 mm, with the optimal area for each electrode being about 1 to 4 mm. It has been found that as the area of each electrode is increased, for example to 10 2 2 , the amplitude of the signal decreases.

Observing FIGS. 10-12, arrow 150 symbolically represents the direction of the devolization vector in the adjacent myocardial tissue closest to the sensing electrode of each catheter. The angular orientation of the electrodes with respect to the depolarization vector 150 is determined as long as the electrodes are close together, i.e. within one box of each other, and the geometric center of each electrode is in a plane substantially perpendicular to the depolarization vector 150. It's not important as long as it's mostly within you. Maximum sensing appears to occur when the plane of each electrode's surface is approximately parallel to the imaginary plane in which the devolization vector lies. Small variations from this ideal condition do not materially reduce the operational ability or effectiveness of the present invention.

Furthermore, in each of the embodiments described in connection with FIGS. 1-9, the sensing electrodes were placed within the heart so as not to contact adjacent myocardial tissue. This is contrary to the prior art belief that it is necessary to bring the electrode into contact with the tissue in order to obtain a reliable and useful signal. This is largely the case when delivering stimulation pulses to the heart. This was true, but has been shown to be incorrect regarding the sensing signal.In fact, the effectiveness of sensing local electrical heart facts from the nearest myocardial tissue is limited by the fact that in the absence of contact, Prolonged contact can lead to fibrosis, resulting in bodily tissue covering all or part of the contacting portion of the catheter. Fibrosis generally reduces the signal that can be sensed from the thus covered electrodes. Although incompletely understood, local electrical cardiac events appear to be more effectively sensed when the electrodes are not in direct physical contact with adjacent myocardial tissue. Thus, provision for contacting or fixating frost, poles: complete tissue is not included within the methodology of the present invention, contrary to the teachings of the prior art.Indeed, FIG. The electrodes described in connection with each of the embodiments shown in Figure 1 are slightly recessed within their respective catheters, so that even if the catheter were to make physical contact with adjacent tissue, the electrodes themselves would not physically will not be contacted.

Figure 13 shows the second probe shown in Figures 10-12.
9 is a flowchart generally summarizing the implementation of the method described in connection with the embodiments described in FIGS.

The flow diagram of FIG. 13 illustrates a single cardiac cycle.

The heart waves are sensed in step 166 and a local electrogram obtained as described above. In the case of the catheter of FIG. 10, a single signal is generated as the output of the differential amplifier 122, whereas in each of the embodiments of FIGS. sexual signals are generated.

In either case, multiple pairs of signals are sensed in step 166 and the difference of each associated pair is taken in step 168 to generate one or more trigger or response pulses. In the illustrated embodiment, the difference taking is described as being performed by an analog differential amplifier. However, any equivalent means can be used, such as digitizing the sensed signals and taking their arithmetic mean in step 166.

The trigger signal obtained in step 166 may be generated in any number of different ways, according to well-understood design principles and principles that would be expected to be established if a reliable sensing signal were obtained as in the present invention. at step 168.

One way the signal can be processed in step 168 is to provide variable pulse width adjustment. The voltage of the series of stimulation pulses can be varied depending on the success of the immediately preceding pulse or the percent success of the previous series of pulses in stimulating responsive heart contractions. Thus, if the stimulation pulse is unable to devolatize the myocardium due to insufficient strength, this failure will be sensed and there will be no response or trigger pulse at the output of the differential amplifier coupled to the sensing electrode. This is detected by the processing circuitry in step 168. The next pulse can be generated with a predetermined increase in stimulation intensity. It can be repeated until a successful pulse output is obtained, at which point the regulated pulse output can be held stable until the cardiac condition changes again. This is to be expected, for example, in situations where the responsiveness of myocardial tissue is altered by drugs or ischemy.

Thus, the magnitude of the current in a stimulation pulse can be increased depending on the success of a previous pulse, or any group of previous pulses, in producing a cardiac contraction or any other predetermined pattern of cardiac activity. . The criteria by which the temporal spacing of stimulation pulses or the pulse magnitude is conditionally varied can be determined in a multi-step manner according to well-understood medical principles. The manner in which information is processed by the sensing methods described herein is not a limitation of the invention.

Step 170 may include decision logic that results in a determination to inhibit generation of cardiac stimulation pulses, thereby resetting the pacemaker to its initial state in step 172. On the contrary, based on objective criteria,
making a decision to generate or trigger cardiac stimulation;
This may lead to step 174 in which an appropriate stimulus is generated and delivered. Thereafter, the pacemaker is reset and returned to its default state at step 176.

As a result of the processing at step 170, a decision is made in accordance with processing rules as to whether or not a stimulation pulse should be generated, and if so, what type of stimulation pulse. Not only can the timing and amplitude of the pulses be varied as described above, but the location of the pulses can also be selected. For example, 2
Two stimulation electrodes may be provided on the same or different catheters to select the point at which stimulation is applied to adjacent cardiac tissue. 2-1: A vertical or multi-tip catheter can be used to deliver appropriate stimulation to any one of multiple cardiac locations, such as the ventricular apex on one side and the atrial appendage on the other. Good too. Similarly, selective stimulation of the atria and ventricles can be easily achieved depending on the cardiac activity observed according to the invention at any point within the heart.

FIG. 16 thus illustrates the flexibility and power of the sensing methodology of the present invention. It is only by being able to reliably and identifiably extract local electrical heart waves from the undulations of both natural and artificial signals present in the human heart that the heart becomes a virtually unrestricted, voluntary system. can be adjusted (paced) in different ways. The ability of the present method to sense local heart wave events anywhere within the heart considerably increases the ability to detect and selectively respond to previously unmonitored conditions and patterns within the heart.

It should be understood that the various embodiments of the method of the invention described above are set forth for illustrative purposes only and are not intended to limit the scope of the invention. It will be appreciated that many modifications and variations can be made by those skilled in the art without departing from the spirit of the invention as claimed.

[Brief explanation of the drawing]

FIG. 1 shows a conventional surface electrogram and the temporal relationship of atrial and ventricular electrical equivalents obtained from the right atrial appendage and the right ventricular apex for comparison with the electrogram recorded by the sensing probe of the present invention. Graph, Figure 2, shows the temporal relationship between the normal surface electrogram of a normal heartbeat, the standard atrial appendage electrogram, and the upper right atrium and lower right atrium electrograms obtained with the sensing probe of the present invention. 3 is a fragmentary schematic oblique view showing a catheter containing the sensor of the present invention adjacent to myocardial tissue; FIG. 4 is a cross-sectional view taken along line 4--4 of FIG. 3; FIG. 5 is a cross-sectional view taken along the line 5-5 of FIG.
FIG. 6B is an enlarged view of the circled area 6A in FIG. 6; FIG. 7 is a fragmentary schematic of the ventricular sensing and ventricular stimulation glove at the apex of the ventricle. figure,
Figure 8 is a fragmentary schematic of a J-shaped cardiac N sensing and atrial stimulation probe placed in the right atrial appendage; Figure 9 is a single strand catheter with multiple sensing electrodes placed in the atrium. FIG. 10 is an enlarged fragmentary schematic view of a portion of a catheter in which two electrodes are provided for sensing; FIG. 11 is a catheter showing an embodiment in which four electrodes are used. FIG. 12 is an enlarged schematic diagram of a portion of a catheter illustrating an embodiment in which three electrodes are used; FIG. 13 is a flowchart outlining the methodology of the present invention. 56: Heart 58: Single filament catheter 60: Electrode 62: Depolarization vector 64: Myocardial tissue 70: Right atrium 72: Right ventricle 76: Apex of heart 78: Stimulating tip 80: Sensing electrode 82: Myocardial tissue 86: Right atrial appendage 88: Catheter 90: Electrode 92: Stimulation tip 94: Right ventricular outflow tract 98 Bi' lower right atrial region 100: Electrode 102: Atrial floor 104: fi pole 108.110: Electrode plate 112 .114: Flexible Wire Lead 116: Catheter 118: Virtual Cylinder 120: Physical Surface of Catheter 116 122: Differential Amplifier 124: Processing and Pulse Generation Circuit 126: Pacemaker 130: Catheter 132-138: Sensing Electrode 140: Virtual Cylinder 142.144: Differential amplifier 146: Processing and pulse generation circuit 14B-Pacemaker 152-156: Electrode 158: Virtual cylinder 160: Catheter 162.164: Differential amplifier 165: Pacemaker F/G, 2 F/G, 5 F/G, 6A F/G, 4 〆F/G, GB Procedure Tadashi Ura 9-1-: (Method) December 2, 1982 Commissioner of the Patent Office Kazuo Wakasugi Case Indication 1988 Special Application No. 143601 Name of the invention Relationship to the case of a person correcting an intracardiac signal sensing device Patent applicant's agent: 〒'O;3 Address: Oil and Fat Industry Hall, 3-13-11 H Motobashi, Chuo-ku, Tokyo Telephone: 273- 64. No. 36 - J! ・'1 Notice of amendment order ``1-1'' November 29, 1988 sign ``h deyo - Chii Moe ``Wataru of the invention of the lock -' Inventor of Tanshin -''・Publication - Request for Change - Contents of the amendment: Engraving of the Ming MIH book as attached (no changes to the content)

Claims (1)

[Claims] (1) The devolization vector in the proximal staggered center 1i; ii −r+<tartar 1jfj: 1. Means for discriminating information from another heart) 1・r, and the ratio of the signals sensed at the pair of points in the plane 11!・Instructs the local dental calculus H1<“: signal and substantially ts!p
: 1511 and 1511 difference signals, so that the local inter-core; A certain activity was carried out in the northern part of the country. (2) The discriminating means includes means for sensing the heart 11Nji activity at a position within the plane that is close to the heart 11Nji tissue, and neither of the pair of points is connected to the heart tissue. and a sensing device according to claim 1 which is not in contact. (3) The discrimination means selects two or more points within the flat 1iji;! 2.Claim 1 or 2 comprising means for sensing activity? sensing device. (1) The discriminating means includes means for sensing the heart'iX activity at six points. .) the activity is sensed at six points equidistantly spaced around a circle in the plane; 1. (6) the sensing device; The discriminating means is in close proximity to the ventricular tissue and the heart j!
- A sensing device according to claim 1, which includes means for sensing surface activity. 7. The sensing apparatus of claim 1, further comprising means for processing said difference signal to generate a response to said differentially sensed local heart signal. (8) The sensing device according to claim 7, wherein the response generating means includes means for generating a ventricular rate regulating signal. (9) The generation of said ventricular regulating signal is conditional on the confirmation of the presence of said differentially sensed local cardiac signal, and said ventricular regulating signal is conditioned on the confirmation of said differentially sensed local cardiac signal 1i! '
(Sensing device at the time of the 8th annotation between (L'C generated /, i) of the patent claim where δ is absent. (10) t3i The ventricular π,' (speed signal is The sum of the local cardiac signals that were previously sensed separately.
Saki 1. 9. The sensing device according to claim 9, wherein the sensing device is generated at a rate determined by the measured value. (11) The scope of the present invention is such that the ventricular rate regulating signal is generated with a magnitude that variably changes in response to the presence or absence of a previously differentially sensed local heart. Sensing device according to item 8. (12) The sensing device according to item 1, wherein the discrimination means includes means for sensing the cardiac activity proximate to the atrial atrial tissue. 14. The sensing device according to claim 1, wherein the means for sensing the cardiac activity comprises means for sensing the cardiac activity in close proximity to a high lateral region of the atrium. Part 8, comprising means for sensing said cardiac eye activity proximate to the atrial appendage
``Claim 'j'ij, paragraph 12, paragraph 12. (1) The scope of the claim 1, wherein the means for sensing cardiac activity includes means for sensing the cardiac activity proximate to the coronal side.
Sensing device according to paragraph 12 of I.1. 0(}) front of mind if;7. 13. The sensing device 11-7 of claim 12, wherein the means for sensing activity includes means for detecting said stone activity in proximity to the floor of the atrium. (17) After disposing of the difference, a patent including means for generating a response to the locally sensed local center of gravity, 14+1 signal, is transferred to the f′+1) enclosure of the old tree. The sensing device described. (i?) The response generating means is a ventricle. Xl? 18. The sensing device τ. of claim 17 including means for generating a first speed signal. 9? . (+!l) The sensing device according to claim 17, wherein the response generating means includes means for generating an atrial regulating signal. ! 20) means for sensing cardiac activity within the heart at at least two closely spaced locations, each on or near a plane perpendicular to a depolarization vector in adjacent myocardial tissue; means for taking a difference in the sensed signal at a location and inducing a trigger pulse indicative of the local heart signal; A device for discriminating the local center of gravity 1.ili from the internal signal of the center of gravity, which is capable of being detected and reversed reliably and clearly from the center of gravity regardless of the selection. (21 ) Said IXq, Chisendan 7);, 7ir 5 do plane funerals, three attachments near the plane fl'i ((including means for sensing local heart signals, *I H'! ': 3
The two A-' devices are associated with the 5-C so as to include two pairs of positions, one of said three positions serving as a common position i9 for this four-speed transmission. A discriminator according to the box spacing ε1λ20 of '4'. (7 tMJ sensing means are six 4, Q; I+1
1) The discriminating device as described above in the range mark 21J, which includes a means for detecting a request. {23} position IF)''. means for sensing the local center of gravity at each of the locations by means of a positive electrode lying approximately in a plane generally parallel to the volatization vector in the proximal myocardial tissue; Section 20 of the scope of the 14th permission request, including means for sensing 4;
Uno discrimination gear? +. C24) The discrimination device according to claim 20 or 23, wherein the sensing means includes means for sensing at each position r. (25) The means for sensing the local cardiac signal by means of the electrode has a geometrical form defined by a geometrical plane defined by a plane 2 in the 11th to 4th tones 2. Menshin iIV'! . . 24. A discriminating device according to claim 24, comprising means for sensing a signal, wherein each of said positions is separated from said each other position by within 1 Qmm, +l. (,!l) Sensing the local electrical activation J1 in the heart at a plurality of close points in or near a plane perpendicular to the devolization vector in the adjacent myocardial tissue TTi- means and said local 1f. sensed at said plurality of points. ''A. means for observing at least one trigger pulse indicative of a local calculus signal, and processing the at least one trigger signal to generate a stimulation pulse; and means for generating said stimulation pulse and coupling said stimulation pulse to the heart to cause stimulation of the heart, whereby demand regulation of the heart N1 is performed. Now, let's get the wave train and the heart +1.
:! 1. Local center of gravity from outside heavy magnetic miscellaneous pursuit 11.;5. Coloring for differentially sensing signals 1° (27j) wherein said sensing means includes means for sensing at said plurality of points with a corresponding algebra of electromagnetism, and each of said τ poles is in contact with said myocardial tissue; Po1λ[L of patent claims that are not
"1ζp 26: The discriminative sensing device described in jJi. The discrimination sensing device according to claim 26, further comprising means for determining whether or not the biting mosquito is Place the intensity of the stimulation pulse according to whether a particular local cardiac signal was present in the pulse train at the sensed location (lζ) following the pulse occurrence. and means for determining that the absence of said particular local cardiac signal is indicated means that the magnitude of said stimulation pulse is increased and the presence of said particular local center of gravity 11J4 (No. 6 is indicated). Sometimes, the magnitude of the sting 6t pulse is increased by a force i!
i's square sensing device F\n(:yo(υ) The processing means is
Said sensing and decoupling means are located at a particular local center of gravity 1i,i
27. The discriminative sensing device of claim 26, including means for determining the current interval between the intervening stimulation pulses according to the force indicating the presence or absence of the signal. (31) The sensing means includes means for sensing electromagnetic activity at the location of the nemesis (i-?), and each location has a polarization vector in the adjacent myocardial tissue
The discriminative sensing device according to claim 7i1jl.426, in which the plane of j is located at a plurality of close points in the vicinity of the txI' plane. (, 33) f''iiJ differential r reversal means extracts the difference in the degree of electrical activity at each of the positions sensed at the plurality of corresponding points, and generates a plurality of corresponding trigger signals. 62. The discriminative sensing device according to claim 61, wherein the processing means processes the plurality of trigger signals to detect differentially sensed local sequential patterns of cardiac activity. Claim 31 or 32 including means for
Discrimination sensing device as described in section.