Haemodynamic advantages of combined alpha-blockade and beta-blockade over beta-blockade alone in patients with coronary heart disease.

The acute haemodynamic effects of beta-blockade with propranolol and combined alpha-blockade and beta-blockade with labetalol were compared in a randomised study in 12 patients with coronary artery disease proved by angiography. Propranolol induced significantly greater depression of left ventricular function both at rest and during exercise than labetalol. This difference was probably attributable to the vasodilator activity of labetalol and the associated reduction in afterload offsetting the haemodynamic disadvantages of blockade of cardiac beta-adrenoceptors alone. The haemodynamic advantages of combined alpha-blockade and beta-blockade over beta-blockade alone may thus have therapeutic implications for the use of these treatments in patients with coronary heart disease.