In what proportion of children with heart failure has Enalapril been shown to be safe and effective?
In children with heart failure evidence of the effect of enalapril is empirical. Enalapril was clinically safe and effective in 50% to 80% of for children with cardiac failure secondary to congenital heart malformations before and after cardiac surgery,  impaired ventricular function , valvar regurgitation,  congestive cardiomyopathy,  , arterial hypertension, life-threatening arrhythmias coexisting with circulatory insufficiency.   
ACE inhibitors have shown a transient beneficial effect on heart failure due to anticancer drugs and possibly a beneficial effect in muscular dystrophy-associated cardiomyopathy, which deserves further studies.