Seven children with idiopathic PVT ranging in age from one day to 18 yr, have been observed during the past three years. The presenting complaints and frequency of paroxysms varied greatly. Three patients presented with syncope; four were asymptomatic. Lidocaine was effective in terminatingcute symptomatic attacks; procaine amide and propranolol were effective in long-term control of the arrhythmia. Monitoring of the dynamic ECG was invaluable in establishing the diagnosis, characterizing the arrhythmia, and evaluating the effects of activity and therapy.