Abstract: Objective To investigate the anatomical and morphological characteristics and volume of left atrial appendage(LAA) in the patients with atrial fibrillation evaluated by multi-slice spiral computed tomography (MSCT), and to investigate the relationship with age. Methods A total of 92 patients with paroxysmal atrial fibrillation treated in our hospital from August 2019 to August 2021 were continuously enrolled. All the patients underwent MSCT and three-dimensional volume reconstruction before operation. The anatomical and morphological characteristics and corrected volume of LAA under MSCT were observed, and the relationship between LAA and age was analyzed. Results The LAA of 92 patients with atrial fibrillation showed abundant comb muscles and muscle trabeculae, lobulated surface and irregular shape. Among them, chicken wing type LAA accounted for 60.9%, and the average volume after LAA correction was 6.7±4.8 mL/m². With the increase of average volume after LAA correction, the proportion of non-chicken wing LAA increased. The proportion of LAA corrected mean volume ≥6.7 mL/m² in the elderly patients aged ≥65 years old was significantly higher than that in the patients aged <65 years old. Pearson correlation analysis showed that the average volume after LAA correction was significantly positively correlated with age in the patients with atrial fibrillation (r=0.429, P=0.009). In addition, the proportion of non-chicken wing LAA increased with age. Univariate and binary Logistic regression analysis showed that age, duration of atrial fibrillation and LAA corrected mean volume were the independent influencing factors for the occurrence of non-chicken wing LAA. Conclusions The distribution of non-chicken wing LAA was positively correlated with age. The influence of age should be fully considered when using non-chicken wing LAA to evaluate the risk factors of stroke in patients with atrial fibrillation.

Key words: atrial fibrillation, left atrial appendage, form, corrected volume, age