Angiotensin convertase inhibitor (Enalapril) was used in 51 children aged 4 days 
up to 18 years (mean 4.3 +/- 5.5, years). As many as 27 subjects were newborns 
(4) and infants (23). The patients suffered from circulatory insufficiency due 
to congestive cardiomyopathy (13 cases). 6 treated subjects suffered from 
circulatory insufficiency due to congenital heart malformations before cardiac 
surgery and 22 after it (including complex malformations operated according to 
Fontan method). 10 children were treated because of arterial hypertension. 4 
subjects suffered form life-threatening arrhythmias coexisting with circulatory 
insufficiency. (These subjects were already mentioned among the patients 
suffering from circulatory insufficiency). Enalapril (mainly as a drug named 
Benalapril) was used in the mean dose of 0.21 mg/kg of body mass daily. 4 
patients (8%) died during treatment but their deaths can not be related to 
angiotensin convertase inhibitor therapy. In the other children (82%) the 
beneficial influence of angiotensin convertase inhibitor use was found 
(improvement in comparison with the state before convertase inhibitor 
introduction). In 10% of subjects enalapril did not show any significant 
therapeutic effect. According to authors' opinion enalapril use is exceptionally 
profitable in the subjects surgically treated for complex heart malformations 
(Fontan operation). The beneficial effect was also found in majority of children 
suffering from congestive cardiomyopathy. Convertase inhibitor was always 
successfully used as the unique antihypertensive drug in children suffering from 
arterial hypertension. In the other cases treatment was combined (mainly with 
digitalis). This combination seems to be exceptionally useful in children 
suffering from congestive cardiomyopathy. Only in 1 case unserious side effect 
was found (persistent cough).