Background Scar-related Intra-atrial re-entrant tachycardias (IARTs) located at lateral wall of right atrium are common late after cardiac surgery in which right lateral atriotomy was performed, and also occurred in some patients without prior atriotomy. Conventional mapping and ablation is relatively difficult because of the complicated anatomy and multiple potential re-entry loops.
Objective The study aims to investigate a new method of strategic linear ablation to isolation of scar area from right lateral wall for successful ablation of scar-related atrial tachycardia originating at lateral wall of right atrium.
Methods Four patients had AT related to myocardial scar or incision located at lateral wall of right atrium underwent the electrophysiological study and RF catheter ablation. Earliest activation combined with entrainment mapping was adopted to determine a critical isthmus. Scar area isolation from right lateral wall was performed by linear ablation along cavotricuspid isthmus, from the scar to crista terminalis and to the inferior vena cava (IVC), from the scar to the tricuspid annulus.
Results Fifteen IARTs was induced in all of four patients. Four of 15 atrial tachycardias (ATs) were intra-scar reentry AT, three typical atrial flutter (AFL), two double loop reentry tachycardia (DLR) around superior vena cava (SVC) and inferior vena cava (IVC) respectively, four upper loop reentry tachycardia (ULR) around SVC, two lower loop reentry tachycardia (LLR) around IVC. The reentry loops of all ATs were related with scar area. The mean tachycardia cycle length was 268.1±49.5 ms. In all patients, linear ablations along cavotricuspid isthmus, from scar area to crista terminalis and to IVC, were performed. Linear ablation from scar area to tricuspid annulus was performed in one patient. Isolation of scar area from right lateral wall was achieved in all patients. All tachycardias, including scar-related AT and typical AFL were ablated successfully. There was no complication during procedure. No recurrences of AT was observed during follow-up.
Conclusion Under conventional electrophysiological mapping, linear ablations from scar area to anatomic barrier and/or isolation of scar area from right lateral wall, could be successfully abolish IARTs and all potential circuits with reentry around or related to the scar.