Incessant reciprocating tachycardia (IRT) was diagnosed in 10 children aged 0-11 years (mean 2.5 years), followed-up for an average of 11 years (range 4-22 years). 8 children were treated for an average period of 2.8 years (range 0.5-6 years) with the association of amiodarone and digitoxine. All children were treated initially or secondarily with verapamil and/or betablockers with digitoxine for an average of 4.6 years (range 1-9 years). The true frequency of IRT, its tolerance and the age at diagnosis did not indicate the probable required length of treatment with amiodarone, but only the initial response to this drug. Finally, 5 patients were cured and in sinus rhythm, and the other 5 were well controlled, having only occasional bursts of tachycardia. When we compared one group of 5 cases with clinical signs of cardiac failure and radiological cardiomegaly (CTR greater than 0.60) with a second group of 5 cases in which the arrhythmia was better tolerated, surprisingly, the frequency of intreated IRT was not t he factor which influenced its tolerance (198/min vs 194/min). On the other hand, the following differences were observed between the two groups: a younger age at diagnosis in the first group (5 months vs 4.6 years) responsible for the longer follow-up period (14.5 vs 7 years), earlier treatment period with amiodarone (3.6 years compared to 5.5 years) and a longer treatment period with this drug (3.5 vs 2 years). It was only at about the age of 7 that this treatment could be withdrawn or changed with half the children completely cured, and the other half only controlled.(ABSTRACT TRUNCATED AT 250 WORDS)