Radiofrequency catheter ablation of supraventricular tachycardia substrates after mustard and senning operations for d-transposition of the great arteries

OBJECTIVES The purpose of this study was to determine the efficacy and risk s of radiofrequency ablation of various forms of supraventricular tachycard ia after Mustard and Senning operations for d-transposition of the great ar teries. BACKGROUND In this patient group, the reported success rate of catheter abl ation of intraatrial reentry tachycardia is about 70% with a negligible com plication rate. There are no reports of the use of radiofrequency ablation to treat other types of supraventricular tachycardia. METHODS Standard diagnostic criteria were used to determine supraventricula r tachycardia type. Appropriate sites for attempted ablation included 1) in traatrial reentry tachycardia: presence of concealed entrainment with a pos tpacing interval similar to tachycardia cycle length; 2) focal atrial tachy cardia: a P-A interval less than or equal to-20 ms; and 3) typical variety of atrioventricular (AV) node reentry tachycardia: combined electrographic and radiographic features. RESULTS Nine Mustard and two Senning patients underwent 13 studies to succe ssfully ablate all supraventricular tachycardia substrates in eight (73%) p atients. Eight of eleven (73%) patients having intraatrial reentry tachycar dia, 3/3 having typical AV node reentry tachycardia, and 2/2 having focal a trial reentry tachycardia were successfully ablated. Among five patients ha ving intraatrial reentry tachycardia (IART) and not having ventriculoatrial (V-A) conduction, two suffered high-grade AV block when ablation of the sy stemic venous portion of the medial tricuspid valve/inferior vena cava isth mus was attempted. CONCLUSIONS Radiofrequency catheter ablation can be effectively and safely performed for certain supraventricular tachycardia types in addition to int raatrial reentry. A novel catheter course is required for slow pathway modi fication. High-grade AV block is a potential risk of lesions placed in the systemic venous medial isthmus. (J Am Coll Cardiol 2000;35:428-41) (C) 2000 by the American College of Cardiology.