Effect of f-adrenergic blockade on beat-to-beat response to Valsalva manoeuvrel

Abstract

In a double-blind crossover study, 8 patients with angina and with angiographically documented coronary artery disease received two weeks apart 5 successive doses of 4 mg tolamolol (20 mg) and .5 successive doses of 2 mg propranolol (Io mg) administered intravenously within 25 minutes. After 20 mg tolamolol, a significant decrease occurred in heart rate (N4%), in aortic systolic pressure (4%), in left ventricular systolic pressure (4%), in left ventricular dp/pt (25%), in cardiac index (i8%), in stroke index (6%), in systolic ejection rate (rx%), and in left ventricular work (24%), and a significant increase in left ventricular end-diastolic pressure (39%) and in systemic vascular resistance (I7%). After Io mg propranolol, a significant decrease occurred in heart rate (I3%), in aortic systolic pressure (3%), in left ventricular systolic pressure (3%), in left ventricular dp/dt (28%), in cardiac index (22%), in stroke index (io%), in systolic ejection rate (i6%), and in left ventricular work (27%), and a significant increase in left ventricular end-diastolic pressure (47%) and in systemic vascular resistance (25%). No significant difference in haemodynamics was observed between these equipotent doses of intravenous tolamolol andpropranolol except that tolamolol caused a significantly smaller increase in systemic vascular resistance.