Haemodynamic dose-response effects of intravenous beta-blocking drugs with different ancillary properties in patients with coronary heart disease

Abstract

The haemodynamic dose-response effects of propranolol, practolol, oxprenolol and metoprolol were compared in a randomized single-blind study in 24 patients with stable coronary heart disease. The doses of drugs used gave approximately equal degrees of inhibition of exercise tachycardia. The haemodynamic profile in the control period was stable and similar in each group. All four drugs consistently reduced heart rate and cardiac output and increased pulmonary wedge pressure, but the changes were significantly greater after propranolol and metoprolol than after practolol and oxprenolol. There was no significant difference between the effects of the four drugs on calculated stroke volume. The increase in the calculated systemic vascular resistance was similar after all four drugs. These observations indicate that when administered intravenously to patients with coronary heart disease in equivalent negative chronotropic doses, drugs with intrinsic sympathomimetic activity (e.g. practolol and oxprenolol) resulted in less depression of left ventricular pumping function than drugs without this property. The possession of cardioselectivity (e.g. practolol and metoprolol) did not appear to confer any haemodynamic benefit.