Left atrial diverticula in patients undergoing atrial fibrillation ablation: morphologic analysis and clinical impact.

Introduction: Left atrial diverticula (LAD) have been reported to be (1) at risk for intracavitary thrombosis and cardiac perforation during ablation and (2) sites of extrapulmonary vein foci. In atrial fibrillation (AF) ablation, their presence might undermine procedure safety and efficacy. This observational study evaluates the morphology and clinical impact of LAD in patients undergoing AF ablation.

Methods And Results: Consecutive patients undergoing computed tomography scan (Aquilion 64, Toshiba, Otawara, Japan) and AF ablation with imaging integration (CARTO 3 Merge, Biosense Webster, CA, USA) in our center were included. Morphologic analysis was performed by 2 independent radiologists. Ablation was obtained by irrigated radiofrequency energy (Navistar Thermocool or Thermocool SF, Biosense Webster). Out of 212 patients, 58 (27.3%) had LAD; 74.4% of LAD were located in the anterosuperomedial left atrium. In patients with and without LAD, the prevalence of prior cerebrovascular events was similarly low. The rate of major periprocedure complications did not differ significantly: 1.7% versus 2.6% (P = 1) in patients with and without LAD, respectively. However, 1 case of cardiac perforation occurred during ablation in a diverticulum. During follow-up, survival free from arrhythmia recurrences was comparable in the 2 groups.

Conclusion: LAD are present in about one-fourth of patients undergoing AF ablation and, in general, they have no impact on its safety and efficacy. However, occasionally, radiofrequency energy delivery in a LAD can cause tissue overheating and perforation.