RU2119765C1 - Method for estimating coronary and myocardial reserves of the heart in tachycardia cases under two-chamber electric cardiac stimulation - Google Patents

Abstract

FIELD: medicine. SUBSTANCE: method involves modeling tachycardia in patient with two-chamber system of electric cardiac stimulation. Coronary and myocardial heart reserves are estimated at the same time. Electric pulses sent by exterior stimulation device are produced at frequency of 100-800 pulses per 1 min and amplitude 5-10 times exceeding the magnitude of intracavitary potentials of spontaneous auricle excitation. Stenocardia, ischemic disorders being detected on patient cardiogram, lowered coronary reserve is determined to be the case. Lowered contraction index being determined, lowered myocardial heart reserve is considered to be the case. EFFECT: enhanced accuracy in determining cardiac reserve with no tachycardia paroxysm taking place. 4 dwg

Description

 The invention relates to medicine, namely to cardiac surgery and can be used to evaluate specific coronary and myocardial reserves of the heart in patients with a two-chamber cardiac pacing system.

 Currently, more than half of the population of patients who undergo annual implantation of the pacemaker system in the world suffer from sinus node syndrome (SSS). The brady-tachycardic form of CVS, up to 20% among the pathology of the sinoatrial node, is an important indication for the use of two-chamber systems of electrical stimulation of the heart (ES), because when prescribing antiarrhythmic drugs that control the development and course of attacks of supraventricular tachycardia, inhibition occurs as a function of the sinoatrial node with the development of chronotropic myocardial insufficiency, as well as the state of atrioventricular conduction up to transverse blockade of the heart at the level of atrioventricular Nogo compound.

 It was shown that a two-chamber sequential ES of the heart has a number of important cardiodynamic advantages over a single-chamber ventricular regime: it reduces the frequency of pacemaker syndrome, chronic atrial fibrillation, thromboembolic complications, congestive heart failure, increases stroke and minute cardiopulmonary bypass, compensates for non-chronotropic function failure the frequency of spontaneous and imposed by the pacemaker cardiac contractions under load), h about as a result can achieve a sense of well-being of the patient and improve the survival of patients after surgery.

 At the same time, it was shown that in 10 - 15% of patients with implanted bicameral ES systems of the heart, for whom the indication for surgery was a heart rhythm disorder other than bradytachycardia syndrome, the development of a paroxysmal form of supraventricular tachycardia as a result of the further course of the disease is noted in the separated postoperative period. hearts.

 It is known that SSSU is characterized by the presence of retrograde ventriculoatrial conduction (VAP) of the heart, leading to the development in a patient with an implanted two-chamber pacemaker of "pacemaker tachycardia with an endless loop" (Yu. Yu. Bredikis, A.D. Drogaytsev, P.P. Stirbis Programmable electrical stimulation of the heart (clinical aspects).-M .: Medicine, 1989, S. 63 - 88). The problem of radical elimination of such a complication of ES of the heart by introducing special algorithms that automatically change a number of parameters of the implanted two-chamber sequential ECS, despite the progress of modern technology, has not yet been solved.

 As a result, pacemaker tachycardia with an endless loop of development develops due to retrograde VAP in 8 - 10% of patients with bicameral ES systems of the heart.

 The assessment of coronary and myocardial reserves of the heart during tachycardia in the conditions of application of modern two-chamber ES systems of the heart is carried out on the basis of assessing the patient’s condition and complaints, analyzing the surface electrocardiogram, studying the pulse repetition rate of bifocal EX, blood pressure, and central hemodynamics in various ways (for example, ultrasound hearts in M- and B-modes, dopplerochocardiography, tetrapolar rheocardiography, radionuclide ventriculogr aphia and others) with frequent ventricular ES of the heart, due to the tracking of the accelerated atrial activity or retrograde ventricular atrial excitation by the electronic ECS circuit. (Yu. Yu. Bredikis, A.D. Drogaytsev, P.P. Stirbis. Programmable electrical stimulation of the heart (clinical aspects). - M .: Medicine, 1989, p. 63 - 88.

 Significant disadvantages of the available methods for assessing coronary and myocardial reserves of the heart with bicameral ES of the heart are the need for a patient with an implanted bifocal EX at the time of examination of the patient's general condition and complaints, central hemodynamics, blood pressure, pulse frequency of EX paroxysm of supraventricular tachycardia or retrograde VAP, as really existing anatomical functional substrates, as well as the impossibility of testing the reserves of the heart in "ho in the “cold” period in the absence of induced paroxysm of tachycardia (Yu. Yu. Bredikis, AD Drogaytsev, PP Stirbis. Programmable cardiac electrical stimulation (clinical aspects). - M .: Medicine, 1989, p. 63 - 88). The invention is aimed at solving the problem of increasing the efficiency of assessment of coronary and myocardial reserves of the heart due to the possibility of its implementation in any period of observation of a patient with a two-chamber system of ES of the heart in the absence of a real paroxysm of supraventricular tachycardia.

 The task is achieved by modeling tachycardia in a patient with a two-chamber pacemaker system with simultaneous assessment of coronary and myocardial heart reserves. This is achieved by modeling a controlled short-term paroxysm of tachycardia by creating a frequent, synchronized with electrical impulses external stimulating device that simulates atrial activity, electrical stimulation of the ventricles of the heart by applying electrical impulses through the esophagus to the atrial region from the external stimulating device with a frequency of 100 - 800 pulses per minute and amplitude, 5 - 10 times higher than the value of intracavitary potentials of spontaneous atrial excitation th, and when the patient has angina, ischemic disorders on the electrocardiogram, a decrease in the coronary reserve is detected, and with a decrease in contractility, a low myocardial reserve of the heart is determined.

 The method is as follows.

In a non-invasive way, using the programming device, the following parameters are set for the two-chamber EX:
1. ES mode of the heart - atrial-synchronized (DDD, VDD modes);
2. The maximum sensitivity of the two-chamber EX on the atrial canal is 0.7 - 1.0 mV;
3. The minimum sensitivity of the two-chamber EX on the ventricular canal is 4.5 - 6.0 mV;
4. The basic frequency of repetition of stimuli EX-70 impulses / min;
5. the upper frequency limit of tracking atrial ventricular activity - by the value according to age (according to R. Shepherd's monogram) - 120 - 160 pulses / min;
6. atrial refractory period - at 437 ms;
7. polarity of impulses EX - monopolar;
8. The duration of the atrioventricular interval is 125 - 187 ms.

 To register the transesophageal electrogram of the heart and to simulate tachycardia, the PEDSP-1, PEDSP-2 wire electrode is used. The electrode is inserted into the esophagus of the subject through the nasal passage (less often through the mouth) in a sitting or lying position. The patient lying on his back presses his chin to the sternum, which prevents the electrode from entering the trachea.

 First, the electrode is carried out effortlessly by 7-10 cm and after swallowing it is carried out to a depth of 40-45 cm, then it is gradually pulled out with simultaneous recording of the transesophageal electrogram of the heart (the distal segment is connected to the chest lead of the stationary electrocardiogram recorder). When the maximum amplitude of biphasic atrial teeth with the initial positive phase is manifested on the electrogram, the wall of the left atrium is located close to the esophagus. In this position, the electrode is fixed with adhesive tape to the upper lip of the subject. The transesophageal electrode is attached to the cathode of an external stimulating device (for example, the KORDELECTRO-04 electrophysiological diagnostic pacemaker). Another electrode connected to the anode of the external stimulating device is placed cutaneously on the surface of the chest at the level of the fifth intercostal space on the right parasternal line of the body.

 During the study, the electrocardiogram is recorded on a stationary recorder. Arterial pressure on the brachial artery is evaluated by the Korotkov method.

 The assessment of the parameters of central hemodynamics is carried out by means of an ultrasound examination of the heart in the supine position using an ultrasound apparatus (for example, an U-2000 apparatus manufactured by Fukuda Denshi, Japan).

 Use a sensor with a frequency of 3.5 MHz in M and B modes. The following parameters of the heart are evaluated: finite systolic (CSD) and finite diastolic (CSD) sizes, finite systolic (CSR) and finite diastolic (BWW) volumes, stroke volume (UO), ejection fraction (EF) and shortening fraction (FU) of the transverse diameter of the left ventricle) at rest and when modeling tachycardia in a patient with a two-chamber system of electrostimulation of the heart.

 Using an external stimulating device and an applied pair of electrodes (cutaneous and transesophageal), which form an electric dipole directed sagittally to the body axis and located in the immediate vicinity of the atrial electrode of the two-chamber ECS implanted into the right atrium, frequent electrical pulses are applied with a frequency of 100 - 800 pulses per minute . Electrical pulses from the external stimulating device are sensed by the electronic circuit of the atrial channel of the two-chamber pacemaker and, after a specified interval of the atrioventricular delay, are transmitted by the electronic circuit of the ventricular canal in the form of output pulses of the pacemaker to the ventricle of the heart within the specified limits (determined by the upper frequency limit for tracking atrial activity). The amplitude of the pulses of the external stimulating device is determined based on the value of the intracavitary potentials of spontaneous atrial excitation, which can be obtained by intraoperative electrophysiological examination during implantation of the atrial electrode, or by telemetry of the patient’s intracardiac electrogram. The amplitude of the pulses of the external stimulating device is set to a value 5 to 10 times higher than the measured amplitude of the intracavitary potentials of spontaneous atrial excitation. With such an amplitude of pulses of the external stimulating device, there is no imposed electrical stimulation of the atria and induction of supraventricular tachycardia with competitive atrial activity.

 During the induced frequent ventricular electrical stimulation of the heart, synchronized with simulated atrial activity (by means of electrical stimuli of the external device), the patient's general condition is assessed, electrocardiogram is recorded, blood pressure, heart rate and central hemodynamics are measured by ultrasound, and if the subject with a two-chamber pacemaker of angina pectoris, ischemic disorders on the electrocute Radiogram reveals a decrease in coronary reserve, with a decrease in contractility (ejection fraction, fraction of shortening, stroke volume) determine the decrease in myocardial reserve.

 Examples of specific performance.

 The method is illustrated using electrocardiograms, where in FIG. 1 is given an electrocardiogram of the examined P. (example 1).

1 A - effective two-chamber ES of the heart in DDD mode;
1 B - modeling of tachycardia paroxysm at a frequency of an external stimulating device of 120 pulses per minute, tracking of simulated atrial activity by the ventricular canal of the bifocal EX is shown;
AVR, III - lead of the registrar of the electrocardiogram;
V = 25 mm / s - the speed of the tape recorder electrocardiogram;
St is the electrical impulse of an external stimulating device.

 In FIG. 2, 3 shows the electrocardiogram of the examined B. (example 2).

2 A - effective two-chamber ES of the heart in DDD mode;
2 B - modeling of tachycardia paroxysm at the frequency of an external stimulating device of 137 pulses per minute, tracking of simulated atrial activity of the ventricular canal of the bifocal EX is shown;
2 V - electronic atrioventricular blockade of the functioning algorithm of the bifocal EX with the frequency of the external stimulating device more than 137 pulses per minute;
3 A - frequency of the external stimulating device 400 imp / min;
3 B - frequency of the external stimulating device 600 imp / min;
3 V - frequency of the external stimulating device 800 imp / min.

 The remaining conventions are the same as in FIG. one.

 Example 1

Surveyed P., 70 years old
Clinical diagnosis:
Coronary heart disease. Atherosclerotic coronary cardiosclerosis. Binodal lesion. Sick sinus syndrome (sinoatrial block II stage). Atrioventricular block III art. with syncopal conditions. The implanted two-chamber pacemaker EKS-444 in the endocardial version. Effective ES of the heart.

During an intraoperative electrophysiological study, the amplitude of the spontaneous excitation of the heart chambers was: the right atrium - 1.6 mV (0.8 mA), the right ventricle - 2 mV (1.0 mA). Using the PROGREX 04 programmer, the parameters of the implanted two-chamber pacemaker EKS-444 were programmed;
1. The mode of ES of the heart - DDD.

 2. The sensitivity of EMC in the atrial canal is 0.7 mV.

 3. The sensitivity of the EMC through the ventricular canal is 4.5 mV.

 4. The basic pulse repetition rate of the ECS pulses is 70 imp / min.

 5. The upper frequency limit for tracking atrial ventricular activity is 137 cpm.

 6. Atrial refractory period - 437 ms.

 7. The polarity of the impulses EX - monopolar.

 8. The duration of the atrioventricular interval is 125 ms.

 HELL at rest (according to the Korotkov method) - 140/90 mm Hg ECG is an effective ES of the heart in DDD mode (Fig. 1A).

 Indices of central hemodynamics (according to the ultrasound examination of the heart) at rest of the subject: CRC - 5.7 cm, CRC - 4.5 cm, CSR - 92 ml, BWW - 160 ml, UO - 68 ml, IOC - 4.760 l / min FV - 42.5%, FU - 21%. When modeling tachycardia by applying electrical pulses using a transesophageal-cutaneous pair of electrodes into the area of the implanted atrial electrode of a two-chamber pacemaker, the energy parameters of the pulses of the external stimulating device were: amplitude - 4 mA, duration - 0.5 ms.

At a pulse repetition rate of an external stimulating device of 120 cpm (Fig. 1B), the patient noted the occurrence of angina pectoris in the heart, a study of central hemodynamics showed the following results:
KDR - 5.6 cm, KSR - 4.7 mi, KSO - 112.814 ml, BWW - 153.64 ml, UO - 40.82 ml, IOC - 5.307 l / min, PV - 26.6%, FU - 16%.

 Blood pressure in this period was 160/100 mm Hg.

 During the study, when modeling tachycardia in a patient with an implanted system of two-chamber electrocardiostimulation, a pronounced decrease in coronary and myocardial reserves of the heart was revealed, which was an indication for programming a two-chamber EX in an isolated ventricular ES heart mode (VVI mode).

 Example 2

Surveyed B., 37 years old
Clinical diagnosis:
Binodal heart disease. Sick sinus syndrome (sinoatrial block II stage). Atrioventricular block I st. with presyncopal conditions. The implanted two-chamber pacemaker EKS-444 in the endocardial version.

 Effective ES of the heart.

During an intraoperative electrophysiological study, the amplitude of the spontaneous excitation of the heart chambers was: the right atrium - 1.4 mB (0.7 mA), the right ventricle - 2.4 mV (1.2 mA). Using the PROGREX 04 programmer, the parameters of the implanted two-chamber pacemaker EKS-444 were programmed:
1. ES mode of the heart - DDD
2. The sensitivity of the pace of the atrial canal - 0.7 mV
3. The sensitivity of the EX on the ventricular canal is 4.5 mV
4. The basic pulse repetition rate of the ECS pulses is 70 imp / min
5. The upper frequency limit of monitoring atrial ventricular activity is 137 cpm
6. Atrial refractory period - 437 ms
7. Polarity of impulses EX - monopolar
8. Duration of an atrioventricular interval - 125 ms
HELL at rest (according to the Korotkov method) - 130/90 mm RT. Art. ECG at rest - effective ES of the heart in DDD mode (Fig. 2A)
Indicators of central hemodynamics (according to ultrasound examination of the heart) at rest of the subject:
KDR - 4.2 cm, KSR - 3.2 cm, BWW - 78 ml, KSO - 41 ml, UO - 37 ml, IOC - 2.590 l / min, PV - 47.4%. FU - 23.8%.

When modeling tachycardia by applying electrical impulses using a transesophageal-cutaneous pair of electrodes into the area of the implanted atrial electrode of a two-chamber pacemaker, the energy parameters of the pulses of the external stimulating device were:
amplitude - 7 mA, duration - 0.5 ms.

At a pulse repetition rate of the external stimulating device of 137 cpm / min (Fig. 2B), which was the maximum monitored frequency of atrial activity, the patient felt satisfactory, a study of central hemodynamics showed:
KDR - 4.1 cm, KSR - 3.3 cm, BWW - 44.1 ml, KSO - 74.2 ml, UO - 34.1 ml, IOC - 4.671 l / min, PV - 45.9%. FU - 20%.

 Blood pressure in this period was 155/90 mm RT. Art.

 With a further increase in the frequency of pulses of the external stimulating device over 137 cpm, an electronic atrioventricular block appeared (the effective operation of the algorithm for tracking the high frequency of the atrial activity of the two-chamber pacemaker EX-444) (Fig. 2B). With a short-term increase in the pulse repetition rate of the external stimulating device to 400, 600, 800 pulse / min, the development of pacemaker tachycardia or a frequent ventricular response was not observed (Fig. 3 A, B, C), while the patient felt satisfactory.

 Conclusion: in a patient with an implanted two-chamber pacemaker system, when modeling tachycardia, there is a sufficient coronary reserve and the myocardial reserve of the heart is moderately reduced. The change in the program of the implanted pacemaker in the patient was not carried out.

 A method for evaluating coronary and myocardial reserves of the heart during tachycardia in a two-chamber pacemaker system increases the efficiency of surgical treatment of patients with cardiac arrhythmias, increases the accuracy of diagnosis of coronary and myocardial insufficiency in patients with implanted bifocal pacemakers in case of development of supraventricular tachycardia.

Claims (1)

 A method for assessing coronary and myocardial reserves of the heart during tachycardia under conditions of two-chamber pacemaking, including recording an electrocardiogram, measuring blood pressure, heart rate and central hemodynamics, characterized in that a patient with a bifocal pacemaker creates a frequency synchronized external electric device stimulating simulating atrial activity, electrical stimulation of the ventricles of the heart by nan through the esophagus in the projection of the atria of electrical impulses from an external stimulating device with a frequency of 100-800 pulses per minute and an amplitude 5-10 times higher than the value of the intracavitary potentials of spontaneous atrial excitation and when the patient has angina, ischemic disturbances in the electrocardiogram reveal a decrease in coronary reserve , and with a decrease in contractility, a low myocardial reserve of the heart is determined.

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