In a single-blind, placebo-controlled, crossover trial versus diltiazem, we evaluated the influence of gallopamil on cardiovascular responses evoked by bicycle exercise. Twelve patients with chronic stable angina were enrolled. After a 5 days placebo run-in period, patients were randomly assigned either to gallopamil (50 mg thrice daily) or diltiazem (60 mg thrice daily) for 10 days. Then, patients were changed to the alternative drug. After placebo, and at the end of each subsequent period, all subjects underwent right heart catheterization by means of a Swan-Ganz thermodilution catheter. Hemodynamics were determined in 3 ways: supine, standing and during a multistage exercise test. RESULTS anginal attacks were reduced to a similar degree by gallopamil (2.1 +/- 1/week versus 5.8 +/- 2.8/week during placebo, p less than 0.01) and diltiazem (2.0 +/- 0.8/week versus 5.8 +/- 2.8/week during placebo, P less than 0.01). At rest, gallopamil caused a significant decrease in heart rate and a slight fall in systemic vascular resistance. Cardiac index rose during exercise and was higher with respect to placebo at peak exercise (6.7 vs 5.6 l/min/m2, P less than 0.05). As a consequence, stroke volume index and stroke work index both increased at maximum workload (P less than 0.05). Compared to placebo, exercise time was significantly improved by gallopamil (+50%, P less than 0.02) and diltiazem (+38%, P less than 0.05). Likewise, time to onset of ST-segment depression was prolonged by 70% with gallopamil (P less than 0.01) and by 64% with diltiazem (P less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)