Haemodynamic effects of diltiazem at rest and during exercise in patients with previous myocardial infarction.

A single blind study between placebo and diltiazem (25 mg i.v. single dose) was carried out on 20 male patients with previous myocardial infarction and without exertional ischaemia. Patients, 50 ±6.1 (mean±SD) years of age, underwent a right heart catheterization with Seldinger's percutaneous approach and brachial or radial artery percutaneous catheterization. Haemodynamic variables were recorded in the supine position after catheterization in baseline conditions at rest, after a warming-up period of 6 min, before and after a first and second exercise test with stepwise increments of 25 W per 3 min. Before the second exercise test, either placebo or diltiazem (25 mg) was injected intravenously in 3 min. In comparison with placebo, diltiazern significantly reduced resting blood pressure (P<0.001) and systemic vascular resistance (P<0001) and increased cardiac index (P<0.01); during exercise it also reduced the mean pulmonary arterial pressure (P<005), pulmonary wedge pressure (P<0.05), total pulmonary resistance (P<0.02), and increased the stroke volume (P<005). The present study demonstrated that intravenous diltiazem did not induce a significant rise in cardiac index but reduced the afterload and slightly reduced the preload. Diltiazem also reduced myocardial oxygen consumption and decreased blood pressure, mean right atrial pressure and slightly decreased the heart rate. [ABSTRACT FROM PUBLISHER]