[Study of the inotropic effect of potassium-canrenoate by systolic time intervals technique (author's transl)].

Systolic time intervals (TS) were determined before and after intravenous injection of 400 mg of Potassium-Canrenoate (CK) in 33 patients 30 days after acute myocardial infarction, in order to evaluate the inotropic effect of this drug. It was observed a reduction of the pre-ejection period (I. PEP) and of the pre-ejection period/left ventricle ejection time (PEP/LVET) ratio without any significant changes in the electromechanical systole (I. Q-2), left ventricle ejection time (I. LVET) and isometric contraction time (ICT). These results do not allow to attribute positive inotropic effect to CK. In fact drugs which share this activity, like digitalis glycosides, shorten also I. Q-S2, I. LVET and ICT, with a reduction of I. PEP and PEP/LVET ratio by far greater than that determined by CK. TS determination, in 10 patients, 15, 30 and 45 min after the injection of CK yields results confirming these conclusions.