Haemodynamic and electrocardiographic effects of practolol during upright exercise in coronary heart disease

Abstract

The effects of practolol (400 mg orally) on haemodynamic and electrocardiographic data have been studied at rest and during several levels of submaximal upright exercise in six patients with coronary heart disease. After practolol, the heart rate, aortic pressure, cardiac output, pressure-time index, and mean systolic ejection rate were reduced, while mean pulmonary arterial pressure was increased; stroke work was unchanged. Practolol appears to depress left ventricular function and to decrease myocardial contractility. At submaximal levels of exercise, the magnitude of the ST segment depression is decreased after practolol and its relationship to the pressure time index is modified. After beta blockade, angina pectoris occurs either at a lesser degree of myocardial ischaemia, as suggested by less depression of the ST segment, or the magnitude of the ST segment depression is no longer a reliable sign of myocardial ischaemia.