LEFT-VENTRICULAR VOLUMES, EJECTION FRACTION, AND PLASMA PROATRIAL NATRIURETIC FACTOR-(1-98) AFTER WITHDRAWAL OF ENALAPRIL TREATMENT INITIATED EARLY AFTER MYOCARDIAL-INFARCTION

Objectives-To assess whether the reduction in left ventricular dilatat ion after acute myocardial infarction obtained by early administration of angiotensin converting enzyme inhibitors depends on continuous tre atment. Design-Prospective observational and cross sectional study of withdrawal of randomised treatment with enalapril or placebo. Patients -106 patients on 6 months trial treatment after an acute myocardial in farction. Main outcome measures-Left ventricular volumes and ejection fraction as assessed by echocardiography and circulating proatrial nat riuretic factor (1-98) before and 4-6 weeks after withdrawal of treatm ent. Results-There were no significant changes (mean (SD)) in left ven tricular systolic (0 . 7 (4 . 7) ml/m(2)) and diastolic (0 . 4 (6 . 6) ml/m(2)) volume indices, ejection fraction (-0 . 9 (6)%), and proatri al natriuretic factor (172 (992)pmol/l) after withdrawal of enalapril. The significantly lower left ventricular volumes observed with 6 mont hs of enalapril therapy after acute myocardial infarction, as compared with placebo, were maintained 6 weeks after drug withdrawal. Conclusi on-The results show that the benefit of 6 months of enalapril treatmen t initiated early after myocardial infarction is maintained for at lea st 6 weeks after drug withdrawal, suggesting that the treatment effect on left ventricular structure is not reversed by changes in loading c onditions caused by subsequent drug withdrawal.