Abstract 17851: The Electroanatomic Mechanisms of Atrial Tachycardia in Patients With Tetralogy of Fallot and Double Outlet Right Ventricles
Background: Atrial tachycardias (AT) are common after palliation or repair of congenital heart disease (CHD). The electroanatomic mechanism of AT in post-operative Tetralogy of Fallot (TOF) and double outlet right ventricle (DORV) pts has not been fully explored.
Methods: Retrospective analysis of TOF or DORV pts studied in the electrophysiology (EP) lab from January 1997 – March 2010. Sustained ATs were mapped using the CARTO system (Biosense Webster).
Results: Sixty pts were identified with 80 EP studies performed and 126 ATs identified. Median age at definitive surgical repair was 8 yrs (range 0.1–28 yrs). The first EP study for AT occurred at a median age of 35 yrs (2–58 yrs). Forty-five percent of pts had both cavotricuspid isthmus (CTI) dependent and non-dependent intra-atrial reentrant tachycardias (IART), 25% had only CTI dependent IART and 18% had only CTI non-dependent IART. In total, 95 IART circuits were identified, 5 in a figure-of-8 pattern. There were 12 focal atrial reentrant tachycardias, 4 ectopic atrial tachycardias and 15 presentations of atrial fibrillation (AF). The CTI was the critical area for ablation in the majority of pts (Figure 1). Along with the lateral right atrial (RA) wall, the two made up 85% of IART circuits. Of the catheters leading to an acutely successful ablation, 29 (34%) were standard catheters and 41 (48%) were irrigated catheters (with the latter used more frequently later in the study period). Excluding AF, the acute success rate for ablation was 89% (94% for CTI-dependent circuits, 85% for non-CTI). Of the 58 ablated pts, 20 had additional ablation attempts, 17 within 3 yrs of their first ablation.
Conclusion: The CTI and lateral RA wall are critical corridors of conduction in 85% of IART circuits in TOF and DORV pts. The acute success rate for AT ablations is high, but a substantial recurrence rate remains. Recurrences may be reduced if both the CTI and lateral RA wall are targeted and blocked, even if the mapped circuit points only to one region.
- © 2010 by American Heart Association, Inc.