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.