RU2372114C2 - Method for evaluating atrio-ventricular delay in dual-chamber pacemakers - Google Patents

Abstract

FIELD: medicine.

SUBSTANCE: invention concerns medicine, namely to arythmology. Recording of transoesophageal electrocardiogram involves programming of the implanted pacemaker for frequency exceeding that of spontaneous sinus rhythm by 10 pulses per minute, and atrio-ventricular delay 200 ms. It is followed with measuring the interval between atrial spike of the pacemaker and the termination of left atrial potential A in the transoesophageal electrogram. This interval is also programmed in the pacemaker as an atrio-ventricular delay.

EFFECT: invention allows improving accuracy of evaluating individual atrio-ventricular delay in the patients with implanted dual-chamber pacemakers.

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Description

The invention relates to medicine, namely to arrhythmology, and can be used when programming pacemakers (EX) for quick and accurate selection of individual atrioventricular delay.

Bicameral stimulators due to the sequential application of electrical impulses to the atrial and ventricular myocardium allow for synchronized physiological stimulation. One of the main parameters of such EX is the atrioventricular delay (AVZ), which is the time between the application of pulses to the atrium and ventricle. AVZ is a programmable parameter and can be changed by a doctor in the range from 50 ms to 400 ms. It is generally recognized that the definition of individual AVZ and its programming allows not only to synchronize the work of the heart chambers and improve intracardiac hemodynamics.

A known method for determining atrioventricular delay in two-chamber pacemakers based on the evaluation of echocardiographic markers of the left ventricle [1].

At the same time, a transesophageal echocardiography is performed in a patient with an implanted two-chamber pacemaker, during which stepwise sequential programming of the AVZ values from 200 ms to 50 ms is performed in increments of 10 ms in a decreasing order and, after waiting 3-5 minutes after programming each value to adapt the circulatory system, carry out the measurement according to the standard method of the following parameters:

- end-diastolic volume of the left ventricle (BWW LV),

- end-systolic volume of the left ventricle (CSR LV),

- peaks E and A with diastolic filling of the left ventricle.

Based on the measured parameters, the following indicators are calculated:

- shock volume (UO) according to the formula UO = KDO LV - KSO LV,

- ejection fraction (EF) according to the formula EF = UO / BWW LV,

- the ratio of the peaks E / A.

After completing the protocol of echocardiographic examination at all intervals of the AVZ, the AVZ value is programmed into the pacemaker, on which the best hemodynamic characteristics are obtained: systolic (decrease in LV CSR, LV BW, increase in PV, UO) and diastolic (increase in E / A ratio).

However, this method has several disadvantages:

1) requires a lot of time (90-120 minutes per study),

2) the effect of improving hemodynamics is temporary and after a few weeks-months, research is required to re-optimize the AVZ and reprogram the ECS to a new value,

3) long multiple transesophageal echocardiography procedures make the technique quite expensive,

4) an orientation toward a change in cardiac contractile function leads to ignoring the processes of propagation of electrical excitation in the heart.

Normally, atrial excitation emanates from the sinus node and spreads from right to left (from the right atrium to the left atrium). Excitation of the ventricles is carried out by the His-Purkinje system and extends from the interventricular septum in both directions (to the right and left ventricle).

Atrial Excitation Time (IATG) is the time during which the excitation travels from the right atrium to the left atrium. Atrial-ventricular arousal time (URTI) - the time during which the excitation travels from the right atrium to ventricular activation. Normally, ventricular contraction begins after the completion of atrial systole, that is, after both the atria and the ventricular arterial hypertrophy of> atrial fibrillation are excitatory (FIG. 1A).

With constant two-chamber stimulation, atrial activation comes from the area of contact with the atrial electrode (right atrial ear), and ventricular activation comes from the area of contact with the ventricular electrode (right ventricle apex). Typically, AVZ is programmed empirically for values of 170-200 ms, that is, AVZ corresponds to normal VLVV and the dynamics of excitation of the heart chambers does not change (AVZ> VVMV) (Fig. 1B).

But when selecting AVZ by the above method, hemodynamically optimal values usually correspond to the range of 80-120 ms, that is, AVZ is shortened. However, in this case, the value of AVZ can exceed VMPV (AVZ <VMPV), especially in patients with heart failure, and then systole of the right ventricle will begin with incomplete systole of the left atrium (Fig.1B), which with prolonged functioning of the pacemaker in this mode will lead to deterioration hemodynamics and will require re-optimization of AVZ.

Figure 1 presents a diagram of cardiac activation at the sinus rhythm (A) and with 2-chamber pace with medium (B) and shortened (C) atrioventricular delay. Arrows indicate the direction of activation of the heart chambers. The length of the arrow and curly brackets are directly proportional to the corresponding values (VMPV and VPZHV).

The aim of this invention is to improve the accuracy of determining individual atrioventricular delay in patients with implanted two-chamber pacemakers.

This goal is achieved by the fact that based on the transesophageal electrocardiogram, the activation time of the cardiac chambers is recorded at different values of AVZ.

The method is as follows:

transesophageal electrode is installed in the projection of the left atrium (Figure 2),

on the monitor of the electrophysiological complex output standard leads (I, II, III, aVR, aVL, aVF) of the surface electrocardiogram, as well as transesophageal electrogram of the left atrium (Fig. 3, PE),

program the frequency of the implanted two-chamber pacemaker, 10 pulses per minute higher than the frequency of the spontaneous sinus rhythm, and an atrioventricular delay of 200 ms,

in this mode of pacemaking, the BMPV is measured as the St-A interval, that is, the time from the atrial spike of the pacemaker to the end of the left atrial potential A in the transesophageal electrogram (Fig. 3);

The measured value VMPZH is programmed as an AVZ in a pacemaker.

A comparison was made of two groups of patients by whom AVZ was calculated by the method proposed by us (group I) and its prototype (group II). All patients were implanted with two-chamber EX. Indications for implantation were: iatrogenic complete AV block after radiofrequency ablation of the AV compound in 6 patients and post-infarction complete AV block in 14 patients. The groups were comparable by gender, age, functional class of heart failure. However, in the group where AVZ was selected by the method described by us, its values were higher (112 ± 2.4 ms and 102 ± 3.4 ms, respectively), and the indicators of intracardiac hemodynamics were better (LV BW = 210.2 ± 10.3 ml and 221 ± 12.3, respectively, LVEF = 49.2 ± 3.4% and 45.92 ± 4.2%, respectively). For all patients in the prototype group, it was necessary to perform 2-4 reprogramming per year to new values of AVZ, while in the group of the presented method only 5 patients needed to carry out one reprogramming to new values (table 1). Thus, the proposed method led to the determination of AVZ, which created the best conditions for cardiac hemodynamics and required further less intensive correction.

Table 1. Comparison of the definitions of AVZ presented by our method and its prototype Options I group (n = 10) II group (n = 10) Men: women 6: 4 6: 4 Average age, years 52.3 ± 4.5 50.3 ± 3.9 FC NYHA 3,1 2.9 BWW, ml 210.2 ± 10.3 221 ± 12.3 PV,% 49.2 ± 3.4 45.92 ± 4.2 Number of reprogramming per year 3,1 0.5 Optimal AVZ, ms 112 ± 2.4 102 ± 3.4

The application of the method is illustrated by the following examples.

Example 1. Patient Aev, 63 years old. In 2002, he underwent inpatient treatment for dilated cardiomyopathy. For 3 years, frequent paroxysms of atrial fibrillation have been recorded, in connection with which catheter ablation of the AV connection has been performed and a 2-chamber pacemaker has been implanted. The patient was selected AV delay based on echocardiography. The optimal AVZ corresponded to a value of 90 ms. An increase in PV is noted by 6% in comparison with AVZ 170 ms. For several months, the patient's well-being did not change, then shortness of breath and weakness began to increase. According to another echocardiography, the deterioration of left ventricular contractility. Echocardiography was performed in the conditions of stepwise programming of AVZ. Optimal AVZ changed to 100 ms. The patient was discharged with improvement. After 4 months - there are signs of progression of heart failure. In a second study, the optimal value of AVZ corresponded again to 90 ms. Another deterioration occurred after 3 months. The patient underwent repeated echocardiography with stepwise reprogramming of the ECS and with continuous recording of the transesophageal electrogram. EKS is reprogrammed at AVZ 200 ms. Measured VMPV, which amounted to 110 ms. Then, at each stage of the AVZ: 180-170-160-150-140-130-120-110-100-90 ms (Fig. 4), the measurement of the ejection fraction of the left ventricle, as well as the distance from the potential of the left atrium on the transesophageal electrogram to ventricular commissure EX (A-St interval, ms). The indicated interval decreased with a decrease in AVZ inversely with LVEF, and a further increase in PV was also noted at AVZ values (100 ms and 90 ms) below the BMV (10 and 20 ms, respectively). Despite this, the AVZ is set according to the VMPV parameter (110 ms) described in our method. During the follow-up (1 year), the patient's condition stabilized, physical exercise tolerance improved, shortness of breath, edema did not increase. Repeated reprogramming of the EX for 1 year was not required.

Thus, the application of our proposed method allowed us to stabilize the course of congestive heart failure despite the seemingly obvious improvement in LVEF using its prototype.

Example 2. Patient B-va, 40 years. The patient undergoes continuous pacemaking for 18 years due to congenital complete AV blockade. During this time, she underwent eight reimplantations. The last two-chamber apparatus EKS-4000 was installed in 2004. In order to select the optimal AVZ, a stepwise programming of this parameter was performed from 200 ms to 90 ms with a decrease of 10 ms at each step. At the same time, a transesophageal electrogram was recorded. Figure 5 shows that with a decrease in AVZ, the potential of the left atrium on the transesophageal electrogram approaches the stimulus of the right ventricle, and with a value of 110 ms, a spike to the right ventricle is applied immediately after the end of the systole of the left atrium (this value corresponded to the BMPV). A further decrease in AVZ to 100 ms led to the fact that pancreatic activation was ahead of the left atrial systole. According to the proposed method, AB3 110 ms is programmed into the device. During subsequent follow-up (8 months), the patient disappeared signs of heart failure, angiotensin-converting enzyme inhibitors, diuretics were canceled. Thus, the use of the proposed method allowed us to optimize the AVZ, which eliminated the manifestations of heart failure in a patient who had non-physiological stimulation for 17 years.

Thus, the method allows to determine the value of atrioventricular delay based on synchronous coordinated electrical activity of the left atrium and right ventricle. The method is simple to use and can be used in any medical institution, it takes 10-15 minutes to complete it.

Literature

1. Capucci A. et al. Dual chamber pacing with optimal AV delay in congestive heart failure: a randomized study // Europace, 1999, N1 (3), p. 174-178.

Claims (1)

A method for determining atrioventricular delay in two-chamber pacemakers, including reprogramming a pacemaker, characterized in that the reprogramming is carried out at a frequency 10 pulses per minute higher than the frequency of the spontaneous sinus rhythm, and an atrioventricular delay of 200 ms is programmed during which the transesophageal spike of the pacemaker to the end of the left atrial potential A on the transesophageal elec the trilogram and this interval are programmed into the pacemaker as an atrioventricular delay.

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