Comparative effects of diltiazem,propranolol, and placebo on exercise performance using radionuclide ventriculography in patients with symptomatic coronary artery disease: Results of a double-blind,randomized, crossover study

The effects of oral diltiazem (120 mg), propranolol (100 mg), and placebo on exercise performance and left ventricular function were compared before and during symptom-limited supine bicycle exercise by means of multigated radionuclide ventriculography in 12 patients with documented, symptomatic coronary artery disease; a double-blind, randomized crossover protocol was used. Diltiazem increased ejection fraction (EF) at submaximal exercise (+7.0 absolute percentage points, p < 0.02) and maximal exercise (+8.1 percentage points, p < 0.01). Exercise EF was increased by 13.6 percentage points (p < 0.02) in patients with decreased ventricular function (resting EF <50%). Propranolol had no effect on exercise EF at any stage, even when patients with EF <50% were excluded. The increase in total exercise time was significant after diltiazem (+27%, p < 0.01) but not after propranolol (+16%, p = NS). As expected, propranolol decreased both resting (?9 bpm, p < 0.01) and exercise heart rates (?27 bpm, p < 0.001), whereas diltiazem had no significant effect. Propranolol decreased resting diastolic blood pressure (?8 mm Hg, p < 0.02), exercise systolic (?27 mm Hg, p < 0.001) and diastolic (?9 mm Hg, p < 0.01) blood pressures, and rest (p < 0.01) and exercise (p < 0.001) double product. Diltiazem decreased resting systolic blood pressure (?9 mm Hg, p < 0.01) and both resting (?8 mm Hg, p < 0.001) and exercise (?9 mm Hg, p < 0.01) diastolic blood pressures. Diltiazem decreased double product at submaximal (p < 0.005) but not maximal exercise. Angina limited exercise in four patients after diltiazem compared to eight and seven patients after placebo and propranolol respectively (p < 0.05). Thus, diltiazem improved exercise performance with the use of radionuclide ventriculography during symptom-limited supine bicycle ergometry to a greater extent than did propranolol or placebo, and this effect was most apparent in those with decreased left ventricular function.