Radiofrequency catheter ablation of atrial tachycardias related to myocardial scar or incision

Objectives Intra-atrial re-entrant tachycardias (lARTs) are common late after heart surgery. Conventional mapping and ablation is relatively difficult because of the complicated anatomy and multiple potential re-entry loops. In this study we aimed to evaluate the electrophysiological characteristics and radiofrequency catheter ablation of atrial tachycardia (AT) induced by myocardial scar or incision. Methods In 6 patients (three male and three female, aged 33.3±11.8 years) who had AT related to myocardial scar or incision, electrophysiological study and radiofrequency catheter ablation (RFCA) were performed. Earliest activation combined with entrain-ment mapping was adopted to determine a critical isthmus. Results Re-entry related to the lateral atriotomy scar was inducible in 5 of 6 patients. With entrainment mapping, the PPI (post-pacing interval)-TCL (tachycardia cycle length) difference was <30 ms when pacing at the inferior margins of the right lateral atriotomy scar. Among them, 3 patients had successful linear ablation between scar area to inferior vena cava, and 2 patients between scar area to tricuspid annulus. Re-entry involving an ASD patch was demonstrated in 1 of 6 patients. PPI-TCL differences <30 ms were observed 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 AT related to incision was observed during follow-up except for the failed patient. Conclusion Under conventional electrophysiological mapping, adopting linear ablation from scar area to anatomic barrier, successful ablation can be obtained in patients with IRATs related to myocardial scar or incision.