Catheter ablation of complex atrial tachyarrhythmias in adult patients with cor triatriatum.

Purpose: Reports concerning clinical characteristics of cor triatriatum and approaches for catheter ablation of complex atrial tachyarrhythmias remain limited. Here, we describe successful catheter ablation treatments for complex atrial tachyarrhythmias in patients with cor triatriatum and address the clinical caveats.

Methods: Demographic characteristics, electrophysiologic findings, and ablation results in four patients with cor triatriatum were described.

Results: Catheter ablation was performed in four patients with cor triatriatum (three sinister and one dexter) and complex atrial arrhythmias (three with persistent atrial fibrillation (AF) and one with atypical left atrial flutter). A transseptal puncture was selectively directed into the accessory compartment containing the pulmonary veins. A comprehensive preview involving transthoracic echocardiography, transesophageal echocardiography, and computed tomography of the pulmonary veins was critical for proper positioning of ablation catheters. The pulmonary veins remain the major triggers or initiators for AF, and four pulmonary vein isolation procedures were sufficient to achieve successful results with negative inducibility test in the patients with AF. Heterogeneous conduction and complex fractionated signals were observed on the fibromuscular membrane. Atypical flutter was terminated during ablation over the connection between membrane and left atrial roof. The procedure was successfully performed on all patients without complications. No acute recurrences of atrial tachyarrhythmias were observed in any of the patients during short-term follow-up.

Conclusions: Catheter ablation is a feasible and efficient therapeutic strategy for treating complex atrial tachyarrhythmias in patients with cor triatriatum. Atrial remodeling due to anatomical obstruction or heterogeneous conduction of the fibromuscular membrane may serve as an arrhythmic substrate.