Abstract 3312: Electrophysiologic Characteristics of Atrial Tachyarrhythmias in Patients with Tetralogy of Fallot and Pulmonic Stenosis: Importance of Cavotricuspid Isthmus Ablation
Background: Atrial Tachyarrhythmias (AT) are a leading cause of morbidity in adult congenital heart disease patients with Tetralogy of Fallot (TOF) and pulmonic stenosis (PS), two lesions which often result in residual pulmonic regurgitation and right ventricular overload. Data regarding the characteristics of such arrhythmias are sparse. We report the underlying electrophysiologic (EP) mechanisms of AT in adult patients with TOF and PS who presented to our center with symptomatic AT.
Methods: We reviewed the records of 1200 patients followed at the Columbia Adult Congenital Heart Disease Center between 01/2000 – 09/2005 in order to identify patients with repaired TOF or PS and symptomatic AT other than atrial fibrillation who underwent EP evaluation.
Results: Relevant clinical data and follow-up were obtained in 158 /1200 patients with the diagnosis of TOF or PS. A total of 11/158 patients had symptomatic AT (7 male, 4 female; TOF=9, PS=2) and underwent 17 separate EP procedures for 13 distinct ATs. Of the 11 patients with symptomatic AT, 10 patients underwent percutaneous ablation of the arrhythmias (mean number of ablations= 1.6/patient). The EP mechanisms for the AT in patients were: (A) Isthmus-dependent, counterclockwise atrial flutter (n=8 patients; mean CL= 346 ms, range= 231 ms – 675 ms); (B) Scar-related macroreentrant atrial arrhythmia (n=2 patients; mean CL= 425 ms, range= 260 ms – 506 ms); (C) Accelerated junctional rhythm (n=1 patient; CL= 350 ms). The number of patients requiring post-procedure medical therapy was: amiodarone (n=2); beta- or calcium-blockers (n=5); digoxin (n=3). After a mean post-ablation follow-up of 14.5 months, all 11 patients were free of subsequent AT.
Conclusions: Adult congenital heart disease patients with TOF and PS manifest a variety of mechanisms for symptomatic AT. However, the majority of these arrhythmias are isthmus-dependent atrial flutters with variable cycle lengths. A treatment strategy based on percutaneous ablation of isthmus-dependent and scar-related AT can successfully treat existing arrhythmias and maintain freedom from subsequent AT.