[Endogenous digoxin-like factor in myocardial infarction]

The main aim of the study was to test the hypotheses that (a) concentrations of endogenous digoxin-like factor (EDLF) are increased in the initial period after acute myocardial infarction (AMI) and (b) may contribute to the onset of ventricular arrhythmias. 54 patients of both sexes with a first transmural AMI were included in a retrospective study. Plasma concentrations of EDLF were measured repeatedly during days 1-14 after AMI using DELFIA digoxin fluoroimmunoassay. 16 male patients with unstable angina pectoris and suspected AMI as well as 8 healthy subjects of both sexes served as controls. Plasma concentrations of EDLF in patients during the first day of AMI were increased (1.25 + (-)0.26 ng/ml, digoxin equivalents, p < 0.05) as compared with both healthy controls (0.34 + (-)0.08 ng/ml) and patients with unstable angina pectoris (0.4 + (-)0.06 ng/ml). First day after AMI plasma levels of EDLF in 7 patients with primary ventricular fibrillation were higher (2.54 + (-)0.67 ng/ml, p < 0.03) than in 47 patients without ventricular fibrillation (1.05 + (-)0.27 ng/ml). In 14 patients with AMI and congestive heart failure (class III, Killip) plasma concentrations of EDLF were significantly lower (0.32 + (-)0.09 ng/ml, p < 0.03) than in 40 patients with AMI without congestive heart failure (1.51 + (-)0.32 ng/ml). Starting from the second day of AMI plasma EDLF decreased to the level of control and did not change during two weeks of observation. These results, being in agreement with our previous experimental data, show an increase of plasma EDLF after AMI and suggest that EDLF may be involved in myocardial ischemia-induced arrhythmogenesis and participate in pathogenesis of congestive heart failure after AMI.