Antifibrillatory effects of alpha 1-adrenoceptor blocking drugs in experimental coronary artery occlusion and reperfusion.

The myocardium of animals and man possesses alpha 1-adrenoceptors in addition to beta-adrenoceptors. Ischemia increases sympathetic tone, and ventricular arrhythmias can occur by beta- and alpha 1-adrenoceptor stimulation. I believe that alpha 1-adrenoceptor blocking drugs have antifibrillatory effects and will review the data that support this condition. The effect of alpha 1-adrenoceptor blocking drugs on the incidence of ventricular fibrillation in acute coronary artery occlusion and (or) reperfusion has been determined in 24 studies in conscious and anesthetized dogs and rats, anesthetized cats and pigs, and rat and guinea-pig isolated hearts. The drugs reduced the incidence of fibrillation from 35 to 24% in coronary occlusion and from 61 to 29% in reperfusion.