Complex fractionated atrial electrograms related to left atrial wall thickness.

INTRODUCTION: The mechanism of complex fractionated atrial electrogram (CFAE) in patients with atrial fibrillation (AF) remains controversial. This study investigated the relationship between CFAE and left atrial (LA) wall thickness. METHODS AND RESULTS: LA muscular wall thickness (excluding fat) was measured by cardiac computed tomography in 31 patients with AF (12 paroxysmal, 19 persistent) prior to catheter ablation procedures. Measurements were performed at 31 distinct LA locations: 3 at roof, 3 at floor, 9 at anterior wall, 9 at posterior wall, 3 at lateral wall, 3 at septum, and 1 at base of the anterior appendage. The range of LA wall thickness (LAWT) varied widely (average 2.4 ± 0.4 mm, range 1.5-3.1 mm) between patients. In addition, there were significant regional differences in LAWT. Each patient had an average of 7.3 ± 3.5 CFAE sites. The LA wall was thicker at CFAE sites (227 sites, 3.0 ± 1.0 mm) than at non-CFAE sites (734 sites, 2.2 ± 0.9 mm, P < 0.001). In 23 of 31 (74%) patients, the LA wall was thicker at CFAE area than at non-CFAE area. There was no difference in LAWT between sites where CFAE vanished and those where CFAE persisted after pulmonary vein isolation (PVI) among sites with CFAE before PVI. The LAWT > 2.5 mm predicted CFAE with a sensitivity of 70% and a specificity of 70%. CONCLUSION: The LAWT correlates well with CFAE areas, suggesting that one of the mechanisms of CFAE might be related to LAWT.