Effects of heparin treatment on collateral development and regional myocardial function in acute myocardial infarction.

To define the effects of heparin treatment during the acute stage of the first anterior myocardial infarction on coronary collateral development and regional myocardial function, we evaluated angiographically the extent of a collateral visualization (collateral index: 0-3) to the completely obstructed infarct-related coronary artery and regional wall motion in 18 patients during convalescence after infarction. The patients were divided into two groups depending on the presence (group I) or absence (group II) of heparin treatment (170 to 220 IU/kg per day) during the acute phase of infarction. The collateral index was significantly higher in group I (1.5 +/- 0.9) than in group II (0.4 +/- 0.4; p less than 0.05). The left ventricular ejection fraction tended to be greater in group I than in group II (49 +/- 12% vs 38 +/- 16%), and there was a significant difference in regional wall motion of the infarct area that was evaluated by the percentage of segment shortening between the two groups (group I:7.4 +/- 9.2%, group II:-0.8 +/- 4.5%, p less than 0.05). These findings indicate that heparin treatment for patients with acute myocardial infarction is worthwhile in terms of the preservation of left ventricular function as a result collateral development.