Effect of early treatment with nifedipine in suspected acute myocardial infarction

In this single centre prospective, double blind study, 98 patients with suspected acute myocardial infarction (AMI) were randomized, within six hours, to nifedipine 10 mg (46 patients) or placebo (52 patients) both administered sublingually. The delay time from onset of chest pain to treatment was 3.33±0.2 hours (mean±SEM) and 3.28±0.18 hours for the nifedipine and placebo treated groups, respectively. Treatment was continued orally for 3 days. AMI was confirmed in 28 patients given nifedipine and 23 patients given placebo. Infarct sizing by CK-MB isoenzyme release was possible, for technical reasons, in only 23 patients nifedipine and 17 patients on placebo. CK-M B isoenzyme release was 710±104IUI−1 and 655±118IUI−1 for the nifedipine and placebo treated groups respectively (P>0.05). In the acute coronary insufficiency (ACI) group—18 patients given nifedipine and 29 patients given placebo—there was no significant difference in duration of admission, urgent cardiac readmission or progression to AMI within one month. Study withdrawal occurred in 15.3%—8 nifedipine and 7 placebo. Overall, one month mortality was 10.2% with 5 deaths in both the nifedipine and placebo treated groups. Early treatment with nifedipine did not reduce enzymatically determined infarct size or one month mortality in patients with AMI, or reduce one month morbidity or mortality in patients with ACI.