Heparin, aspirin with dipyridamol or 5% dextrose were administered to 266 patients admitted to the coronary unit with unstable angina. All patients were concurrently treated with isosorbide dinitrate, a beta-blocker and nifedipine. The number of patients who developed an acute myocardial infarction (IM) during the subsequent 72 hours was comparable in all three groups. However, in the heparin treated group only 3.2% patients developed Q IM, as compared with 20% patients treated with aspirin and dipyridamol (p = 0.005) and with 19% in the control group (p = 0.006). The magnitude of the IM was evaluated according to the highest serum value of creatine phosphokinase. In the heparin treated group its value was 810.5 +/- 538 i.u./l which was significantly less than in the aspirin + dipyridamol group where it was 1229 +/- 829 i.u./l (p = 0.048) and in the control group where it was 1417 +/- 919 i.u./l (p = 0.009). The authors defined the group of patients with a high risk of development of IM who had protracted anginous pain longer than 45 mins. with ST segment depression deeper than 1 mm on the ECG on admission. 55% of these patients developed an infarction in the course of the subsequent 72 hours.

Keywords: Angina, Unstable /drug therapy/; Aspirin /administration & dosage/; Dipyridamole /administration & dosage/; Drug Therapy, Combination; Electrocardiography; Female; Heparin /therapeutic use/; Humans; Male; Middle Aged; Myocardial Infarction /prevention & control/