Radiofrequency ablation of atrial tachycardia in patients with repaired atrial septal defect

ObjectiveTo evaluate the electrophysiological characteristics and radiofrequency catheter ablation of atrial tachycardia (AT) in patients with repaired atrial septal defects (ASD).MethodsIn 76 consecutive patients with AT who underwent the electrophysiological study and radiofrequency catheter ablation (RFCA). 4 patients (one male and three female aged 35.5 ± 11.5 years) had AT-related myocardial scar or incision. Earliest activation combined with entrainment mapping was adopted to determine a critical isthmus.ResultsRe-entry related to the lateral atriotomy scar was inducible in 3 of 4 patients. With entrainment mapping, the PPI-TCL difference was <30 ms when pacing at the inferior margins of the right lateral atriotomy scar. Among them, 2 patients had successful linear ablation between scar area to inferior vena cava, and 1 patient between scar areas to tricuspid annulus. Re-entry involving an ASD patch was demonstrated in 1 of 4 patients. PPI-TCL differences <30 ms were found when entraining tachycardia at sites near the septal patch. But linear ablation failed in terminating AT. There was no complication during procedure. No recurrence of incision-related AT was found during follow-up except for the failed patient.ConclusionUnder conventional electrophysiological mapping, adopting linear ablation from scar area to anatomic barrier, successful ablation also can be obtained in patients with IRAT related to myocardial scar or incision.