[Experiences with parenteral administration of diltiazem in coronary surgery patients]

Diltiazem is a calcium channel blocker whose effects lie between those of the two other important calcium antagonists nifedipine and verapamil. In addition to vasodilation, it has a negative dromotropic effect with prolongation of the A-V interval. In animal experiments and human investigations, diltiazem improves the function of ischemic myocardium due to a direct dilating effect on coronary vessels. The purpose of the present study was to investigate the hemodynamic effects of diltiazem in patients before and during coronary revascularization. METHODS. The study included 60 consenting male patients with coronary heart disease. Twenty premedicated patients randomly received 0.3 mg/kg diltiazem or placebo within 3 min before induction of anesthesia. Hemodynamic measurements (arterial pressure, heart rate, mean pulmonary arterial pressure, pulmonary capillary pressure, right atrial pressure and cardiac output) were taken during the following 21 min. Before cannulation of the great vessels for institution of extracorporeal circulation (ECC), 20 other patients received 0.014 mg diltiazem or placebo/kg per min over 20 min. In addition to the above mentioned hemodynamic measurements, left ventricular parameters (LVP, LVEDP, dp/dt) were directly registered, and 5 min after the end of ECC the measurements were repeated with the same preload as before the ECC. Twenty additional patients received 0.014 mg diltiazem or placebo/kg per min within 21 min during ECC observing arterial perfusion pressure and oxygenator volume. RESULTS. Pre- and intraoperatively diltiazem caused a decrease in mean arterial pressure; cardiac index increased only during the preoperative investigation period (Tables 1, 2), whereas stroke volume index increased pre- and intraoperatively; heart rate decreased in all patients as well as dp/dt (Fig. 1).(ABSTRACT TRUNCATED AT 250 WORDS)