Effect of nipradilol on silent myocardial ischemia, plasma beta- endorphin, and bradykinin in chronic stable angina

Abstract

Hypothesis: This study was undertaken to investigate the effect of nipradilol on the total ischemic burden and on plasma levels of beta- endorphin and bradykinin. Methods: Sixteen patients with chronic stable angina were subjected to exercise treadmill testing and 24-h ambulatory electrocardiogram (ECG). Results: Nipradilol significantly decreased both mean heart rate and mean pressure rate product at submaximal and maximal exercise. It significantly improved exercise-induced maximal ST-segment depression from -2.7 ± 0.5 mm to -1.3 ± 0.6 mm (p<0.05) and reduced the number of leads with significant ST-segment depression (4.0 ± 1.2 vs. 2.0 ± 1.8, p<0.05). Silent ischemic episodes recorded in 24-h ambulatory ECG were significantly decreased by nipradilol administration, concomitantly with a decrement of mean heart rate and observed maximal heart rate. Patients with exercise-induced silent myocardial ischemia showed significantly increased plasma levels of beta-endorphin during both the placebo and nipradilol phases of the study. However, during the nipradilol phase, bradykinin did not change significantly at rest and at peak exercise. Conclusion: Nipradilol effectively controls exercise-induced myocardial ischemia and silent myocardial ischemic episodes, and does not influence the response of plasma levels of beta-endorphin to exercise stress testing in patients with exercise-induced silent myocardial ischemia.