[Alpha receptor blocking and cardial insufficiency]

Alpha receptor blocking drugs like Phentolamine, Phenoxybenzamine and Prazosin are potent vasodilators for the treatment of severe left ventricular failure refractory to treatment with digitalis and diuretics. 11 patients with congestive heart failure showed significant clinical and haemodynamic improvement after 4-week administration of 9 mg Prazosin/day. The cardiothoracic ratio was reduced significantly. Haemodynamically a marked decrease of peripheral vascular resistance, an increase of cardiac output, stroke volume and stroke work was noted. Heart rate and plasma catecholamines (dopamine, adrenaline, noradrenaline) showed no significant change. It is concluded that Prazosin exerts a beneficial effect in severe congestive heart failure after 4 week treatment without significant counterregulation to the vasodilatation.