Left ventricular volume in thrombolysed patients with acute anterior myocardial infarction: the effect of captopril and xamoterol

We measured left ventricular volume in 70 asymptomatic patients after first Q-wave anterior myocardial infarction in order to determine whether ventricular dilatation occurs and whether there is evidence for its attenuation or prevention by treatment with captopril or xamoterol — PRevention Of VEntricular Dilatation?: the PROVED? study. 77% of patients received thrombolytic treatment. Patients were randomised a mean of 11 days after infarction to receive either captopril 25 mg three times daily, xamoterol 200 mg twice daily or matching placebo. After 6 months of treatment, 6 patients from the placebo group (n = 24), 1 from the captopril group (n = 23) and 3 from the xamoterol group (n = 23) had been withdrawn from the study because of clinical complications. Left ventricular volume was measured using magnetic resonance imaging, before randomisation and after 6 months of treatment. Changes in left ventricular end-diastolic and end-systolic volume after 6 months of treatment were defined prospectively as the primary end-points. Mean initial end-diastolic volume index was 85 (S.D. 19) ml/m2, mean end-systolic volume index was 45 (S.D. 18) ml/m2, and mean ejection fraction was 48 (S.D. 11)% for the whole group. There was no significant change in left ventricular volume index in the placebo or either treatment group after 6 months of treatment. Only minimal left ventricular dilatation was evident at 11 days. No further increase in left ventricular volume occurred after six months and there was no additional benefit from treatment with either captopril or xamoterol. This finding is important because it shows that patients with uncomplicated anterior myocardial infarction who have received thrombolytic treatment may not be at as great a risk of ventricular dilatation as previously thought, and so may not need long term treatment designed to attenuate ventricular dilatation.