Abstract
A 6-year-old asymptomatic boy without structural heart disease was revealed by a school-based heart disease screening to have isolated premature ventricular contractions (PVCs). After confirming the disappearance of PVCs by exercise stress test, he was followed up once a year. Three years after the initial diagnosis, he experienced palpitations and dimmed vision but without syncope. At 11 years of age, he was diagnosed with repetitive and sustained ventricular monomorphic tachycardia. On admission, he had fever due to an upper respiratory tract infection. His palpitations were severe, and his 12-lead electrocardiogram showed polymorphic ventricular tachycardia of right ventricular origin. After continuous infusion of an ultra-short-acting beta blocker, his ventricular tachycardia improved to maximal bigeminal premature contractions. Electrophysiological examination was performed under general anesthesia. This showed that tachycardia arose from the posterior free wall of right ventricular outflow tract. To target the initial PVC, radiofrequency ablation was successfully performed with an irrigated ablation catheter. Observation over 18 months following ablation showed no recurrence of ventricular tachycardia and symptoms. Although PVCs that originate from the right ventricular outflow tract in children with normal structural hearts usually carry a good prognosis, there are rare cases that involve polymorphic ventricular tachycardia with symptoms. In the follow-up of children with PVCs identified in school heart screenings, we must pay attention to the manifestation of symptoms for earlier detection of malignant arrhythmias.
