Left ventricular function in acute myocardial infarction: assessment by nuclear angiography

Left ventricular function was assessed in 38 patients two to six days after acute myocardial infarction using nuclear angiocardiography and the following parameters were measured: Left ventricular end-diastolic (LVEDV) and end-systolic volumes (LVESV), ejection fraction (LVEF), indices of left ventricular filling and emptying, right ventricular ejection fraction and ejection rate. Their clinical significance was assessed by their relationship to the patients site and size of infarction, functional capacity, morbidity and mortality. The most sensitive indices of depressed left ventricular function were the EF and ESV. Thus, function was preserved in patients with a small inferior infarction (LVEF = 0.57 +/- 0.07, LVESV = 69 +/- 14 ml) and in Killip Class I (LVEF = 0.48 +/- 0.13, LVESV = 80 +/- 20 ml). Function was disturbed most in patients with extensive anterior infarction (LVEF = 0.18 +/- 0.12, LVESV = 131 +/- 46 ml), Killip Class IV (LVEF = 0.13 +/- 0.07, LVESV = 160 +/- 35 ml), cardiogenic shock (LVEF = 0.14 +/- 0.07, LVESV = 160 +/- 35 ml), pulmonary edema (LVEF = 0.11 +/- 0.06, LVESV = 166 +/- 25 ml) and pulmonary capillary wedge pressure greater than 20 mm Hg (LVEF = 0.14 +/- 0.07, LVESV = 160 +/- 33 ml). Previous infarction was associated with LV dilatation and a greater LVEDV. A lower ejection fraction signified a large infarct and poor left ventricular function. If the ejection fraction was less than 0.15, the patients were unlikely to leave the hospital alive, or if less than 0.25, they were left with poor residual ventricular function and either had significant cardiac failure or high late mortality. Nuclear angiocardiography was a simple method of predicting the clinical pattern and prognosis in each patient and emphasized the importance of limiting infarct size in acute myocardial infarction.