Does exercise-induced ST-segment depression predict benefit of medical intervention in patients recovering from acute myocardial infarction? The Danish Study Group on Verapamil in Myocardial Infarction.

Abstract

The present study tested the hypothesis that the increased risk in patients with exercise-provoked ST-segment depression recovering from acute myocardial infarction could by abolished by anti-ischaemic medical intervention. Prior to discharge a symptom-limited exercise test was carried out. Patients were then double-blindly randomized to treatment with either verapamil 120 mg t.i.d. or placebo, and observed for up to 18 months (mean 17 months). End-point was first major event; i.e. non-fatal reinfarction or death. Two-hundred-and-ninety-eight patients were included. Forty-four patients with and 111 without exercise-induced ischaemia were randomized to verapamil and 39 and 104 respectively, to placebo. The overall number of events was 12.5%. In patients without ST-segment depression, 12.5% in the placebo group (hazard = 1) and 12.6% in the verapamil group (hazard = 1.13) had an event (NS). In patients with ST-segment depression 15.4% in the placebo group (hazard = 1.20) and 9.1% in the verapamil group (hazard = 0.85) had an event (NS). The latter reduction (41%) supports the hypothesis that patients with ST-segment depression, i.e. residual myocardial ischaemia, are those who benefit from anti-ischaemic intervention after myocardial infarction.