[Rhythmic inotropic phenomena in ventricular extrasystoles].

Mechanic activity of the heart was examined in 310 patients of different age groups with ventricular premature heart beat. Tetrapolar impedance rheocardiography was used to study postextrasystolic potentiation and mechanic restitution. It is shown that mechanic restitution is a sensitive indicator of heart failure. The time of complete restitution progressively increases with developing heart failure. With progression of heart failure, postextrasystolic potentiation increases. The authors describe potentiation and mechanic restitution in children. Emphasis is laid on the necessity of an analysis of postextrasystolic potentiation and mechanic restitution of heart contractility only with regard to concrete correlations between durations of the pre-extrasystolic and postextrasystolic intervals. Provided the method of determining postextrasystolic potentiation and mechanic restitution is adhered to, these indicators can be used in comprehensive assessment of heart failure.