Congestive heart failure and ejection fraction in acute myocardial infarction

Left ventricular ejection fraction (EF) was determined by means of radionuclide ventriculography (RNV) in 477 patients 8-12 days after an acute myocardial infarction (AMI). EF was correlated to infarct size and clinical and radiological parameters of congestive heart failure (CHF). The 138 patients (29%) who had signs of CHF had a mean (+/- SD) EF of 35 +/- 14% and a relative heart volume of 597 +/- 112 ml/m2 compared to 51 +/- 14% and 487 +/- 88 ml/m2 among those without CHF. The 52 patients who also had radiological signs of CHF had a mean EF of 27 +/- 12% versus 35 +/- 14% among those with clinical signs and symptoms of CHF. Presence of CHF was positively correlated to the size of AMI and to the reduction of EF. CHF was seen with increasing frequency from 16% in small to 46% in large first infarctions. Patients with reinfarctions showed the same correlation between these parameters, however, with subsequently more depressed EF values and more frequent presence of CHF due to previous myocardial damage. CHF was seldom (8%) observed in patients with EF greater than 50%. In contrast, 67% of the patients with EF less than 35% had CHF. Thus patients with an EF less than 35% represent a high risk group with regard to development of CHF and should be followed closely. It is suggested that radionuclide measurement of EF adds important clinical information in patients with diagnostic uncertainty of CHF.