[Myocardial infarction beyond the 48 first hours: treatment with calcium channel antagonists].

Calcium channel blocking agents prevent calcium entering cardiac and smooth muscle cells. With reduction of the blood pressure, heart rate and myocardial contractility, they reduce myocardial oxygen demand. By relieving spasm and coronary constriction, and dilating the collateral coronary vessels, they improve perfusion of the ischemic zones. The results in experimental infarction are contradictory: the reduction in the infarct size and ischaemia is not constant. In the Myocardial Infarction Study, a trial of lidoflazine in 1792 subjects followed up for an average of 5 years, there was no significant difference between the mortality rates of the two groups. In the Danish Verapamil Infarction Trial I, which included 436 subjects receiving 360 mg/day of verapamil or placebo, the 6 months mortality was less (NS) in the verapamil group (12.8%) than in the placebo group (13.9%) as was the reinfarction rate (7.8% versus 9.2%; NS). In the DAVIT II trial of 1775 subjects, treatment was introduced 9 +/- 2.7 days after admission. Mortality was lower (NS) in the verapamil group (11.1%) than in the placebo group (13.8%) and the recurrences were less common (p = 0.04) in the treatment group (11.0%) than with placebo (13.2%). The Secondary Prevention Reinfarction Israeli Nifedipine Trial is a comparison of Nifedipine 30 mg/day and placebo introduced 7-21 days after infarction in 2276 subjects. After 10 months, the mortality and reinfarction rate were similar in both groups, as in the SPRINT II trial (60 mg/day of nifedipine or placebo) at 6 months. In the Multicenter Diltiazem Postinfarction Trial of 2466 patients, Diltiazem 240 mg/day or placebo was administered 3 to 15 days after infarction.(ABSTRACT TRUNCATED AT 250 WORDS)