EFFECTS OF BEPRIDIL ON SILENT-MYOCARDIAL-ISCHEMIA AND EICOSANOID METABOLISM IN CHRONIC - STABLE ANGINA-PECTORIS AFTER HEALING OF MYOCARDIAL-INFARCTION

To investigate the effects of bepridil on silent myocardial ischemia a nd on eicosanoid metabolism, 10 patients with chronic stable angina un derwent exercise treadmill testing and 48-hour ambulatory electrocardi ographic monitoring both before and after 4 weeks of bepridil administ ration (150 mg/day). pasting venous levels of thromboxane B-2, 6 keto- prostaglandin F-1 alpha, and ,were measured by radioimmunoassay leukot riene C assay. Bepridil decreased heart rate responses to daily activi ties during ambulatory monitoring, and significantly (p <0.05) reduced the median frequency and duration of silent myocardial ischemic episo des (from 5.5 to 0 events/48 hours and from 86 to 0 minutes/48 hours r espec tively). Bepridil significantly decreased the blood pressure hea rt rate product at peak exercise and significantly prolonged the mean exercise tolerance time (from 456.6 to 527.0 second). Bepridil also si gnificantly decreased the plasma levels of thromboxane B-2 and leukotr iene C-4 at rest. These results suggest that bepridil may reduce silen t myocardial ischemic episodes either by the reduction of cardiac oxyg en demand during daily activities and exercise stress, or by controlli ng coronary and systemic vasomotor tone. The drug also has a salutary effect on eicosanoid metabolism, to which its efficacy on silent myoca rdial ischemic episodes may be related.