Effects of oxprenolol versus propranolol on myocardial performance and myocardial O2 consumption in hypertensive patients

Abstract

The purpose of the study was to compare the effects of oxprenolol, a beta-adrenergic blocking agent with intrinsic sympathomimetic activity, to propranolol, a beta-blocker without intrinsic sympathomimetic activity, on myocardial performance and myocardial O2 consumption (MVO2). Myocardial performance was reflected by the systolic time intervals (STI) and MVO2 by the triple product of heart rate X left ventricular ejection time X systolic blood pressure (HR X LVET X SBP). The trial, a double-blind cross-over study, included 32 hypertensive patients, 17 males and 15 females, with a mean age of 50.9 years. The patients were divided into two groups: group A - 16 patients who were treated with effective antihypertensive doses of oxprenolol and diuretics (Esidrex K) for the first 8 weeks (period I) and with similar doses of propranolol and diuretics for the following 8 weeks (period II); Group B - the same number of patients who received the same drugs in the reverse order. All patients were examined during both periods at 2- and 3-week intervals, blood pressure and heart rate were recorded, and patients were provided with the appropriate study medication. At the end of periods I and II, myocardial function was assessed on the basis of STI, and MVO2 was evaluated on the basis of the triple product of HR X LVET X SBP. Four measurements of STI and MVO2 were carried out for each patient at the end of periods I and II: prior to intake of medication and 1 1/2, 3 and 4 1/2 h after intake of medication.(ABSTRACT TRUNCATED AT 250 WORDS)