[Acute myocardial infarct and pindolol. Effect of a beta sympatholytic with intrinsic sympathomimetic activity on hemodynamics and contractility].
After acute circumscribed myocardial infarction the effects of the beta-sympatholytic agent 1-(indol-4-yl-oxy)-3-isopropyl-amino-propan-2-ol (pindolol; Visken) on hemodynamics and contractility were examined. Hemodynamic changes after application of pindolol are of small extent only. Heart rate shows a rising tendency whereas systolic and diastolic aortic pressure decreases only after higher doses. Left ventricular end-diastolic pressure (LVEDP) does not change remarkably. Cardiac output is reduced by small doses of pindolol and reaches starting values again before the administration of higher doses. Changes of the contractility parameters (dp/dt)max, t-(dp/dtmax, and PEP in the sense of a beta-sympatholysis appear only in the lower range of the doses given. Thus maximum decrease of contractility is 20% measured at (dp/dt)max, which consequently reaches the starting value again. The other contractility parameters change accordingly. These typical dose-response relations between pindolol and contractility parameters are considered to be due to lacking cardiac depressive properties combined with significant so-called positive intrinsic activity. Our results show that no contraindication can be derived from the small influence of pindolol on contractility in acute myocardial infarction.