Evaluation of methods of measurement and estimation of left ventricular function after acute myocardial infarction.

Using multiple gated cardiac blood pool imaging and single-plane ventriculography from cardiac catheterization, 2 independent measures of left ventricular (LV) ejection fraction (EF) were determined in each of 21 patients. Patients were seen 2 to 6 weeks after their first acute myocardial infarction and were free of electrocardiographic evidence of conduction abnormalities and left or right ventricular hypertrophy. Differences between the 2 measures of LVEF were examined and then compared with the extent of myocardial necrosis estimated from the standard 12-lead electrocardiogram using the complete 54-criteria/32-point Selvester QRS scoring system. Regression analysis yielded an r value of 0.81 (SEE = 8.05) for the overall relation between the 2 measures of LVEF. Correlation coefficients of -0.70, -0.66 and -0.72 were obtained for the relations of radionuclide LVEF, catheterization LVEF and the mean of these 2 determinations, respectively, compared with QRS score. A QRS score 4 or less achieved 100% specificity and that of 8 or less 100% sensitivity for predicting an LVEF greater than 40%. Thus, the Selvester QRS scoring system may be of value in identifying patients with or without markedly impaired LVEF. This risk stratification may be important in reaching optimal postinfarction therapeutic decisions.