Endogenous digoxin-like factor in acute myocardial infarction.

OBJECTIVES

The aim of the study was to test the hypotheses that the concentrations of endogenous digoxin-like factor (EDLF) are (i) increased in the initial period after acute myocardial infarction (AMI) and (ii) may contribute to the genesis of ventricular arrhythmias.

DESIGN

Consecutive sample study.

SETTING

An 800-bed city teaching hospital, primary hospitalized care centre.

SUBJECTS

Fifty-four consecutive patients of both sexes with a first transmural AMI, 16 male patients with unstable angina pectoris and eight healthy subjects.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Time-course of the changes of plasma concentrations of EDLF (DELFIA digoxin fluoroimmunoassay) in patients during days 1-14 after uncomplicated AMI and AMI complicated with ventricular fibrillation and congestive heart failure.

RESULTS

Plasma concentrations of EDLF in patients on the 1st day after AMI were increased (1.25 +/- 0.26 ng ml-1 digoxin equivalents, P < 0.025) as compared with both healthy controls (0.34 +/- 0.06 ng ml-1) and patients with unstable angina pectoris (0.40 +/- 0.08 ng ml-1). On the 1st day after AMI the plasma levels of EDLF in seven patients with primary ventricular fibrillation were higher (2.54 +/- 0.67 ng ml-1, P < 0.05) than in 47 patients without ventricular fibrillation (1.05 +/- 0.27 ng ml-1). 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-1, P < 0.01) than in 40 patients with AMI without congestive heart failure (1.51 +/- 0.32 ng ml-1). Starting from the 2nd day of AMI, plasma EDLF decreased to the level of the control values (0.35 +/- 0.04 ng ml-1) and did not change during a 2-week period of observation.

CONCLUSIONS

The results show an increase of plasma EDLF during the 1st day after AMI, and that higher plasma EDLF may be associated with the development of ventricular arrhythmias.