Results of a restrictive use of antiarrhythmic drugs in the chronic treatment of atrioventricular reentrant tachycardias in infancy and childhood.

Childhood supraventricular tachycardia (SVT) carries a good prognosis. Thus, treatment should be based on the use of drugs with a low risk of such potentially serious side effects as proarrhythmia, which is well documented for class I and III drugs in children. We studied all pediatric patients with a first manifestation of SVT between 1988 and the end of 1995 who were seen for a follow-up examination, including Holter monitoring, during 1996. The minimum follow-up period was 12 months. Fifty children met study entry criteria. Mean patient age at first presentation was 2 years (median 1 month), with 33 of the patients (66%) having experienced their first episode of tachycardia in their first year of life. Of 39 patients initially treated with either digoxin or a beta blocker, SVT in 29 (75%) responded favorably to this treatment. There were no adverse effects. Of the 10 children whose disease did not respond to these first-line agents, 9 (23% of those treated) required class I or III antiarrhythmic drugs. Thus, first-line antiarrhythmic long-term prophylaxis using drugs with a favorable risk profile, such as digoxin and beta blockers, resulted in successful disease management in a large proportion of unselected children, avoiding the need for chronic use of class I or class III antiarrhythmic drugs.