Early treatment of patients with myocardial infarction and left ventricular dysfunction was performed in 90 patients aiming at influencing left ventricular remodelling. After twelve months of treatment with 25 mg captopril t.i.d. left ventricular ejection fraction was improved by 10% in comparison to a treatment with 40 mg of frusemide or placebo (p = 0.001). Late treatment of the patients not treated with captopril resulted in partial reversal of left ventricular dilatation, while withdrawal of captopril therapy in stable patients with ejection fractions over 30% and without clinical signs of congestive heart failure did not result in deterioration of left ventricular function. These results give a sound rationale for the earlier use of ACE-inhibitors in the treatment of congestive heart failure and left ventricular dysfunction.