Intravenous beta-blockade in coronary heart disease: is cardioselectivity or intrinsic sympathomimetic activity hemodynamically useful?

Beta-blocking drugs are increasingly prescribed in coronary heart disease, but controversy surrounds the hemodynamic relevance of their ancillary pharmacologic properties--cardioselectivity and intrinsic sympathomimetic activity. We therefore compared the effects of four intravenous beta-adrenoreceptor antagonists with different ancillary properties on left ventricular function in 24 patients with coronary heart disease. All four drugs depressed the relation between left ventricular filling pressure and cardiac output at rest and during exercise. However, practolol and oxprenolol, which have intrinsic sympathomimetic activity, induced significantly less depression of left ventricular function than either propranolol or metoprolol, which do not have this activity. Cardioselectivity, a property of both practolol and metoprolol, had no discernible hemodynamic advantage. Beta-blocking drugs that have intrinsic sympathomimetic activity appear to be more effective in maintaining cardiac function than drugs without this property, when given intravenously to patients with coronary heart disease.