Coronary insufficiency and beta-blockade.

Beta-blocking drugs were specifically introduced for the treatment of exercise-induced angina pectoris. Their therapeutic utility in this specific presentation of coronary insufficiency is undoubted. However, since they were introduced, evolution of the pathological, haemodynamic, and electrophysiological understanding of the disease syndrome has undergone considerable reappraisal, in no small measure owing to the physiological tool that these drugs have furnished. Their influence on the various aspects of the syndrome of exercise-induced ischaemic myocardial pain is widely known. The physiological conflict posed by unopposed blockade of one sympathetic outflow pathway remains the source of many of their clinical disadvantages. Many important questions directly related to their therapeutic use remain unanswered. The potential benefits and hazards of their long-term administration in patients with advanced coronary heart disease remains to be established.