Effects of nisoldipine in silent myocardial ischemia after healing of acute myocardial infarction

Abstract

Silent myocardial ischemia occurring after acute myocardial infarction is classified as Cohn type II and has a frequency of 20–30% in all patients with acute myocardial infarction. Follow-up data of patients with either silent or anginal ischemia show a poor prognosis. Thus, all ischemic episodes occurring after myocardial infarction should be treated aggressively. Many multicenter studies have evaluated whether drug treatment can improve prognosis or protect from a nonfatal second attack. Calcium antagonists, especially those that increase heart rate, have not been considered as drugs of choice for this purpose, despite the many beneficial effects shown on myocardial tissue in experimental studies. In the study reported here, the effect of nisoldipine on postinfarction silent myocardial ischemia was evaluated by ambulatory left ventricular function monitoring. Ten patients were selected for study who showed silent myocardial ischemia after their first acute infarction. Blood pressure fell significantly (p < 0.05) after 4 weeks of treatment with nisoldipine (5–10 mg/day), but heart rate showed no change at rest. Exercise time improved (p < 0.05), with increased peak double products. During exercise, there was no significant change in enddiastolic volume but there was a marked improvement in end-systolic volume, and at the submaximal point the ejection fraction was significantly (p < 0.05) increased. Ejection fraction at rest also improved. The deterioration in ejection fraction due to dipyridamole was ameliorated by nisoldipine. Ejection fraction and blood pressure improved during the calculation test, and work performance also improved. These results indicate that nisoldipine attenuates silent myocardial ischemia after myocardial infarction, resulting in functional improvement during exercise and the dipyridamole and calculation tests. It is concluded that nisoldipine may be the drug of choice for patients with silent myocardial ischemia after myocardial infarction.