RESUMEN
Multiple, short runs of repetitive ventricular premature beats are present in 5 adolescents. These premature beats are continually present, uniform, long and variably coupled and occasionally fuse with sinus beats. This pattern is constant over several years and is associated with generally healthy individuals and otherwise normal hearts. Four of the subjects are completely asymptomatic without syncope or palpitations. The 5th case was asymptomatic for 2 yr until she died suddenly during sleep. Autopsy revealed a pathology of the specialized conduction system in the region of the AV junction. The distinctive pattern and characteristics of this arrhythmia suggest a congenital etiology and a mechanism different from other forms of ventricular ectopia. The single incident of sudden death indicates that this disorder is not benign.