Echoventriculography in acute myocardial infarction. III. Clinical correlations and implication of the noninfarcted myocardium.

Echoventriculography permits detection of regional abnormalities of left ventricular wall motion in acute myocardial infarction. Overall and regional performance of the left ventricle was related to the prognosis and clinical severity of acute transmural myocardial infarction in 30 patients. Although values for left ventricular size, ejection fraction and modified mean circumferential fiber shortening velocity were all abnormal (P less than 0.005), they did not differ among 8 patients with uncomplicated infarction, 12 with moderate left ventricular failure and 10 with pulmonary edema or shock. In contrast, magnitude of the summed wall motion amplitudes from seven standards regions around the left ventricle decreased in parallel with ejection fraction (P less than 0.001) and with clinical severity of infarction (r = -0.79, P less than 0.001). Function of the healthy myocardium with hypercontractile in 40 percent of patients, but this occurred only in patients with uncomplicated or moderately severe infarction. In patients with severe pump failure the "uninvolved" myocardium did not manifest a hypercontractile or even normal response despite infusion of catecholamines (-21 percent; r = -0.76, P less than 0.001). Four nonsurviving patients had the poorest ventricular function (as low as 10 percent of normal) as assessed by several segmental echocardiographic performance indexes. Performance of the noninfarcted myocardium therefore seems to have a role in deterioration of left ventricular pump function in acute myocardial infarction