[Clinical and functional assessment of electric heart instability in patients with painless myocardial ischemia].

Markers of electric myocardial instability were studied in 82 patients during painless episodes of coronary heart disease (CHD). Clinical examination was supplemented by 12-lead ECG, 24-hour ECG monitoring, functional tests, echocardiography, signal-averaged ECG, recording of LVP, analysis of cardiac rhythm variability, and assessment of ventricular repolarization time. It is concluded that a combination of 24-hr ECG monitoring and functional tests (veloergometer) is indispensable for diagnostics of CHD and the evaluation of the patient"s condition. Daily dynamics of myocardial ischemia and the number of its painless episodes are shown to correlate with the results of signal-averaged ECG, Q-T dispersion and LF/HF ratio. Patients with painless CHD show enhanced frequency of myocardial infarction with the Q-wave, high-grade ventricular extrasystole, and LVP coupled to disordered autonomous vegetative control of the sinus rhythm.

[Clinical functional assessment of electric cardiac instability in diastolic dysfunction of the left ventricle in patients with coronary heart disease].

AIM: To study parameters characterizing electric myocardial unstability in coronary heart disease (CHD) patients with different variants of diastolic dysfunction (DD) of the left ventricle (LV). MATERIAL AND METHODS: The study included 86 outpatients (26 females, 60 males, mean age 57.3 +/- 5.6 years) who had myocardial infarction (MI) more than 1 year before the trial with stable course of CHD during a previous month, LV ejection fraction more than 45% and with a stable sinus rhythm. Group 1 consisted of 36 patients with abnormal LV relaxation, group 2--of 28 patients with pseudo-normal LV DD, group 3--22 patients with a restrictive type of LV DD. The following examinations were made: Holter ECG monitoring, echocardiography, signal-average ECG with isolation of late ventricular potentials (LVP), estimation of heart rate variability, ventricular repolarization (Q-T interval dispersion, corrected interval Q-T). RESULTS: The following variants of LV DD were detected: type 1--42%, type 2--32.5%, type 3--25.5%. LV DD progression was accompanied with enhancing vegetative imbalance and sympathetic activity: in the group with abnormal relaxation--in 52.5% patients, in the group with a restrictive type--in 93.3%. CHD patients with restrictive DD had more frequent LVP (chi-square = 4.1; p < 0.05) and visualization of anomalous contractility zones (60%), ventricular extrasystole (VE) was registered in 100% cases (VE of grade IV-V in 43.3%), QT(c) and QT(d) were higher than threshold--450.2 +/- 5.4 and 71.2 +/- 6.5 ms. CONCLUSION: Because of multifactorial genesis of electric unstability, perfection of diagnosis and prognosis of risk in CHD patients with aggravation of LV DD demands a complex analysis of parameters respecting functional condition of the myocardium, relations between electric and structural-geometric remodeling of the heart.