Location of acutely successful radiofrequency catheter ablation of intraatrial reentrant tachycardia in patients with congenital heart disease

Intraatrial reentrant tachycardia (IART) is common after surgery for congen ital heart disease (CHD). Radiofrequency (RF) catheter ablation of IART tar gets anatomic areas critical to the maintenance of the arrhythmia circuit, areas that have not been well defined in this patient population. The purpo se of this study was to determine the anatomic areas critical to IART circu its, defined by activation mapping and confirmed by an acutely successful R F ablation at the site. A total of 110 RF ablation procedures in 88 patient s (median age 23.4 years, range 0.1 to 62.7) with CHD were reviewed. Patien ts were grouped according to surgical intervention: Mustard/Senning (n = 15 ), other biventricular repaired CHD (n = 24), Fontan (n = 43), and palliate d CHD (n = 6). In first-time ablation procedures, greater than or equal to1 IART circuits were acutely terminated in 80% of Mustard/Senning, 71% of re paired CHD, and 72% of Fontan (p = NS). The palliated CHD group underwent 1 of 6 successful procedures (17%), and this patient was excluded. The locat ions of acutely successful RF applications in Mustard/Senning patients (n = 14 sites) were at the tricuspid valve isthmus (57%) and at the lateral rig ht atrial wall (43%). In patients with repaired CHD (n = 18 sites), success ful RF sites were at the isthmus (67%) and the lateral (22%) and anterior ( 11%) right atria. In the Fontan group (n = 40 sites), successful RF sites i ncluded the lateral right atrial wall (53%), the anterior right atrium (25% ), the isthmus area (15%), and the atrial septum (7%). Location of success was statistically different for the Fontan group (p = .002). In conclusion, the tricuspid valve isthmus is a critical area for ablation of IART during the Mustard/Senning procedure and in patients with repaired CHD. IART circ uits in Fontan patients are anatomically distinct, with the lateral right a trial wall being the more common area for successful RF applications. This information may guide RF and/or surgical ablation procedures in patients wi th CHD and IART. (C)2000 by Excerpta Medica, Inc.