[Effect of trimecaine on myocardial contractility and the rhythmoinotropic properties of the myocardium in hypoxia].

In the papillary muscles from 14 adult rats and myocardial specimens from 14 newborn ones, trimecaine in doses of 1.10(-6) and 5.10(-6) g/ml produced a dose-dependent negative inotropic effect, reversed the rhythmoinotropic correlation into a negative one and minimized the efficiency of postextrasystolic potentiation. Trimecaine in the former dose reduced hypoxic damage of myocardial specimens in the both groups as reflected by a smaller amplitude of hypoxic contracture and better contractility recovery following a hour hypoxia. It is suggested that reduction in hypoxic contracture and damage to the myocardium occur in the presence of trimecaine from limited Ca2+ entry into myocytes via the Na-Ca turnover mechanism.