[On the time of cardiac aneurysm formation following acute myocardial infarction].

It has been said that ventricular aneurysm is formed in the relatively late stage after the onset of acute myocardial infarction. We examined the time of its formation using digital subtraction angiography (DSA) performed immediately after infarction and at various intervals thereafter. We also examined correlations between aneurysm formation and the degree of rest after infarction, blood pressures, sites of infarction and coronary angiographic findings. The subjects consisted of 35 hospitalized patients with acute myocardial infarction. They were examined by DSA immediately, and one week and one month after their admissions. DSA was performed in the 30 degree right anterior oblique projection, and cardiac aneurysms were diagnosed by the presence of regional protrusion or of dyskinesis of the left ventricular wall on left ventriculography. The results were as follows: Cardiac aneurysms were noted in eight men and four women. The mean age was 69.2 +/- 8.1 years. Infarctions were located in the anteroseptal region (nine patients), in the broad anterior wall (two patients) and in the inferior wall (one patient). The average onset-to-admission interval was 5.6 hours in the aneurysm group, and eight hours in the aneurysm-free group. Cardiac aneurysms were demonstrated by DSA immediately after hospital admission in all 12 patients in the aneurysm group and the size did not increase appreciably with time. The peak CPK was significantly higher in the aneurysm group (3,163) than in the aneurysm-free group (1,655), but there was no group-related difference in risk factors, hypertension, the duration of rest after infarction, or coronary angiographic manifestations. Cardiac aneurysm has been considered as a late complication of myocardial infarction. Many investigators have reported that its formation begins one to four weeks after the onset of infarction with gradual protrusion. In the present study, however, the formation of aneurysms was complete at very early stages after the onset of the myocardial infarction and often encountered in patients with relatively extensive infarction.