Trial of heparin versus atenolol in prevention of myocardial infarction in intermediate coronary syndrome.

A randomised, double-blind, placebo controlled study of morbidity and mortality was carried out using heparin, atenolol, and a combination of both drugs, in 214 patients with the intermediate coronary syndrome. During the trial period, transmural myocardial infarction developed in 9 (17%) out of 54 patients on placebo, 8 (13%) out of 60 on atenolol, 1 (2%) out of 51 on heparin, and 2 (4%) out of 49 on heparin and atenolol combined (p = 0.024). The improved prognosis in the heparin-treated patients was was maintained at follow-up. All five deaths occurred among patients who did not receive heparin. These results show that intravenous heparin therapy was of benefit in preventing myocardial infarction in patients with the intermediate coronary syndrome.