Catheter Ablation of Primary Supraventricular Tachycardia Substrate Presenting as Atrial Fibrillation in Adolescents Margaret J. Strieper, DO,* Patrick Frias, MD,* Peter Fischbach, MD,* Lynne Costello, RN, † and Robert M. Campbell, MD* *Children’s Healthcare of Atlanta Sibley Heart Center, Emory University School of Medicine; † Children’s Healthcare of Atlanta, Atlanta, GA, USA ABSTRACT Background. Atrial fibrillation is rarely encountered in children and adolescents, and these cases are usually secondary to myocardial diseases, electrical abnormalities, or scar related in postoperative congenital heart disease patients. Untreated sustained atrial fibrillation may lead to tachycardia-induced cardiomyopathy and/or systemic thromboembolization. Objective. The objective here is to describe our findings in four adolescent patients presenting with recurrent atrial fibrillation. Design. We report here the results of the findings in four patients who presented with recurrent clinical atrial fibrillation. Results. Each of the four underwent electrophysiologic study that revealed a primary reentry or automatic supraven- tricular tachycardia (SVT) substrate, which was able to be treated with radiofrequency ablation. In three of the four cases, elimination of the primary substrate prevented subsequent recurrence of SVT symptoms or documented SVT and/or atrial fibrillation. Conclusion. Children and adolescents presenting with atrial fibrillation warrant an exhaustive search for a treatable primary cause of myocardial or electrical disease. If present, a primary SVT substrate may be successfully ablated to prevent recurrence of atrial fibrillation and any associated complications. Pulmonary vein isolation is rarely indicated in adolescents and should be avoided. Key Words. Pediatrics; Atrial Fibrillation; Catheter Ablation Introduction A trial fibrillation (AF) is the most common rhythm abnormality in adults, but is uncom- mon in children and adolescents. When it is observed in young patients, AF is usually second- ary to myocardial diseases, primary electrical abnormalities, or scar related in postoperative congenital heart disease patients. Untreated AF may lead to tachycardia-induced cardiomyopathy (TIC) and/or systemic thromboembolization. Antiarrhythmic treatment of AF is marginally suc- cessful and several ablative strategies to treat AF have been employed with varying success. 1–3 In 2004, Nanthakumar and associates 4 reported the results of catheter ablation in nine adolescents with symptomatic, lone recurrent AF who failed antiarrhythmic therapy. Irregular, rapidly-firing atrial foci in the pulmonary veins, along the crista terminalis, and/or in the left atrium were successfully ablated using radiofre- quency energy. Two patients with TIC had reso- lution of left ventricular dilatation/dysfunction following successful radiofrequency ablation (RFA). We report here four pediatric patients with structurally normal hearts and normal/non- preexcited resting electrocardiograms who pre- sented with recurrent AF. The AF was found to be the result of a primary supraventricular tachy- cardia (SVT), which was treated with RFA in eliminating the recurrent AF. Methods This study was a retrospective review of patients referred to Children’s Healthcare of Atlanta, Sibley Heart Center for electrophysiologic evalu- ation of recurrent AF with possible attempt at RFA. Resting EKGs in all patients demonstrated 465 © 2010 Copyright the Authors Congenital Heart Disease © 2010 Wiley Periodicals, Inc. Congenit Heart Dis. 2010;5:465–469