Role of cardioselectivity and intrinsic sympathomimetic activity in beta-blocking drugs in cardiovascular disease

Abstract

The significance of ancillary properties of β blockers continues to be the focus of considerable clinical investigation. β 1-selective blocking agents, such as acebutolol, inhibit cardiac β 1 receptors, but have less influence on bronchial and vascular β 2 receptors. Certain β 1-selective blocking drugs, including acebutolol, have intrinsic sympathomimetic activity (ISA), also termed partial agonist activity. This property produces slight cardiac stimulation, which can be blocked by propranolol. Drugs with mild or moderate ISA have proven to be as clinically effective as β blockers lacking this property. Additionally, drugs with ISA possess potential therapeutic benefits, particularly for patients with coronary artery disease. The hemodynamic influences of cardioselectivity and ISA on left ventricular function, heart rate, cardiac output, left-sided heart filling pressure and myocardial oxygen consumption in patients with coronary artery disease are now clearly defined.