Association of a Left Atrial Diverticulum with Adverse Events During Catheter Ablation for Atrial Fibrillation

Abstract

Background/Objectives: Left atrial diverticula (LADs) have been reported to potentially be associated with arrhythmic substrates, thromboembolic events, and complications during catheter ablation for atrial fibrillation (AF), but their clinical significance remains unclear. This study aimed to assess the prevalence, location, and potential relationship with complications during AF catheter ablation using preoperative CT. Methods: This study included 595 consecutive patients undergoing AF catheter ablation at Keio University Hospital from April 2021 to February 2024. Preoperative ECG-gated cardiac MDCT scans were analyzed to assess the presence and location of the LAD. Intraoperative adverse events were documented, and the association between the LAD and mechanical complications, such as a cardiac perforation and tamponade, was evaluated. Results: A total of 595 patients undergoing catheter ablation for AF or atrial tachycardia (AT) were included, with 210 (35.3%) found to have an LAD. No significant differences in age, sex, body mass index, or arrhythmia type were observed between patients with or without an LAD. LADs were most commonly located in the anterior region of the right superior pulmonary vein (53.4% of cases), followed by the anterior region of the left superior pulmonary vein (15% of cases). Perioperative complications occurred in 12 cases (2.0%), with 7 in the LAD group and 5 in the non-LAD group. Mechanical complications were observed exclusively in the LAD group (n = 4), with three of the cases associated with LADs. In all cases, LADs were present in the anterior region of the right superior pulmonary vein and were caused by the accidental insertion of an angiographic catheter into the LAD during pulmonary venography before insertion of the ablation catheter into the left atrium. However, all cases were hemodynamically stable, and the procedures were completed as planned. Conclusions: LADs are a more common anatomical structure than generally recognized and may be associated with mechanical complications during AF catheter ablation. Identifying the presence of an LAD on preoperative CT is crucial for predicting potential risks.

Keywords: atrial fibrillation; atrial tachycardia; cardiac computed tomography; catheter ablation; complications; left atrial diverticulum.

Figure 1

Locations and frequencies of LADs. This figure shows the distribution of LADs in the left atrium in 595 cases. The left side of the figure represents the medial left atrium, and the top represents the superior aspect. The most common location was the anterosuperior aspect of the septum, on the anterior side of the right superior pulmonary vein, followed by the anterior side of the left superior pulmonary vein. LAD, left atrial diverticulum; RSPV, right superior pulmonary vein; RIPV, right inferior pulmonary vein; LSPV, left superior pulmonary vein; LIPV, left inferior pulmonary vein.

Figure 2

Three patients with LAD-related complications. In all three cases, extravasation was observed during pulmonary vein angiography using an angioburman catheter. In all cases, an LAD was found on the anterior side of the right superior pulmonary vein, the common site of the LAD. The catheter had inadvertently entered the diverticulum during contrast injection immediately after transitioning from angiography of the left pulmonary vein to that of the right pulmonary vein. The red arrow indicates the left atrial diverticulum on the CT image, the yellow arrow points to the extravasation of contrast observed in the fluoroscopic image, and the red dashed line represents the roof line of the left atrium. LA, left atrium; LAD, left atrial diverticulum.