Prevalence of left atrial diverticula and accessory appendages and origins of the sinoatrial nodal artery in patients with atrial fibrillation

Background: Considering the importance of knowledge about anatomical variations in the left atrium (LA) and its nearby structures for clinical decision-making and the lack of pertinent studies on Iranian patients, this study was conducted to determine the prevalence of LA diverticula and accessory appendages and the origins of the sinoatrial (SA) nodal artery in patients with atrial fibrillation. Methods: In this observational cross-sectional study, 45 consecutive patients with atrial fibrillation undergoing preprocedural computed tomography angiography were enrolled. The prevalence rates of LA diverticula and accessory appendages and the origins of the SA nodal artery were determined and compared according to the patients' age and gender. Results: The origin of the SA nodal artery was R1 (medial to right auricle) in 30 patients (66.7%), L1 (medial to left auricle) in 11 patients (24.4%), and both R1 and L1 in 1 patient. The origin in the remaining 3 subjects was L2 (posterior to auricle), L3 (posterior to left atrium), and R2 (posterior to right atrium). The prevalence rates of LA diverticula and accessory appendages were 48.9% and 17.8%, respectively. Diverticula were seen in 34.8% and 63.6% of the patients younger and older than 50 years, respectively (P = 0.050). Also, accessory appendages were present in 30.4% and 4.5% of the patients younger and older than 50 years, respectively (P = 0.047). There was no significant association for age (P > 0.05). Conclusions: The findings of the present study show that the main supplying artery of the SA nodal artery was R1 from the right coronary artery. The prevalence rates of LA diverticula and accessory appendages were higher than those reported previously.