Medical therapy of angina pectoris.

The pathophysiology of angina pectoris is best understood as an imbalance between oxygen supply and demand. The primary determinants of myocardial oxygen demand are heart rate, arterial pressure, heart size, myocardial contractility, and myocardial mass. The medical therapy of angina pectoris is directed toward reducing myocardial oxygen demand by reducing the workload of the heart and the specific determinants listed. The most common medications used in the treatment of angina pectoris are nitroglycerin and propranolol. Nitroglycerin reduces myocardial oxygen demand primarily by reducing heart size and arterial pressure. Propranolol reduces oxygen demand primarily by reducing heart rate. Medical therapy is generally effective in controlling the symptoms of angina pectoris in 80% or more of the patients and allows them to lead useful and productive lives.