Comparative effects of oral acebutolol and propranolol at rest and during exercise in ischemic heart disease: Double-blind placebo crossover study utilizing radionuclide ventriculography

Acebutolol is a new investigational β-antagonist which has intrinsic sympathomimetic and cardioselective properties. In this study its effects on the ischemic consequences following supine bicycle exercise were compared to those of propranolol in 16 patients with chronic stable coronary artery disease (CAD) using a double-blind placebo crossover protocol and equilibrium radionuclide ventriculography. In eight patients (group I), the left ventricular ejection fraction (LVEF) at peak exercise fell under control conditions. During chronic acebutolol therapy (400 mg thrice daily), the exercise-induced LVEF (means ± 1 SD) was significantly higher (37.1 ± 15.5% versus 42.2 ± 14.3%; p < 0.05). The corresponding values during placebo and during propranolol (80 mg thrice daily) were 39.2 ± 12.3% versus 43.4 ± 14.8% (p = 0.07). In eight patients (group II) in whom supine bicycle exercise produced increases in LVEF, both acebutolol (58.8 ± 5.4% versus 53.8 ± 4.4%) and propranolol (57.8 ± 5.7% versus 54.1 ± 4.9%) attenuated the increases. In neither group was the resting LVEF reduced by acebutolol or propranolol. The data show that acebutolol and propranolol are approximately equipotent in minimizing the radionuclide left ventriculographic manifestations of myocardial ischemia induced by supine bicycle exercise.