ANALYSIS OF HEART-RATE DEPENDENCE OF VENTRICULAR ECTOPIC ACTIVITY

Dependence of occurrence of ventricular premature beats on heart rate was investigated by means of computer analysis of relationship between probability of ventricular ectopic activity and length of preceding R - R interval of sinus origin. Holter ECC recordings obtained from 107 patients with ventricular premature beats were used in the study. Pro babilities of ventricular extrasystoles (PVE) at given R - R intervals were estimated with the help of a computer program and number of mode s in distribution of PVE against R - R was determined. Correlation and regression analyses were used for evaluation of connection between PV E and R - R duration, Three main types of rate dependence of ventricul ar premature beats were identified: ''tachycardic'', ''bradycardic'' a nd ''indeterminate''. Analysis of rate dependence of ventricular ectop ic activity with determination of mode of PVE distribution curve allow ed to distinguish the following variants of rate dependence: 1) monomo dal tachycardic; 2) monomodal indeterminate; 3) monomodal bradycardic; 4) polymodal tachycardic; 5) polymodal bradycardic; 6) polymodal inde terminate. An assumption has been expressed concerning presumable mech anisms underlying each variant of rate dependence of ventricular ectop ic activity.