ObjectiveTo analyze the correlation between the gray value of epicardial fat and the prognosis of patients with atrial fibrillation (AF) treated by thoracoscopic radiofrequency ablation.MethodsThe clinical data of 97 patients, including 75 males and 22 females with an average age of 57.8±9.4 years, who underwent thoracoscopic radiofrequency ablation in Fuwai Hospital from 2017 to 2018 were analyzed retrospectively. The left atrial fat volume and average gray scale were calculated by left atrial enhanced CT. According to the average gray scale of left atrial fat tissue, the patients were divided into three groups: a high gray scale group, a medium gray scale group and a low gray scale group. The patients were followed up at 3, 6 and 12 months after operation. The end point of follow-up was the recovery rate of sinus rhythm. Survival analysis was used to analyze the correlation between CT features of epicardial fat enhancement and prognosis.ResultsAfter adjustment of body mass index, body surface area, gender and left atrial end diastolic diameter, regression analysis showed that the fat gray of left atrial enhanced CT was correlated with the type of AF (OR=0.30, 95%CI 0.12-0.79, P=0.014). Cox regression analysis showed that the fat gray value of left atrial CT predicted the recurrence of AF after thoracoscopic radiofrequency ablation (OR=0.92, 95%CI 0.85-0.99). The Kaplan-Meier curve showed significant difference in the long-term recurrence rate of AF among the three groups (P=0.011). The lower left atrial fat enhanced CT gray scale was, the higher long-term recurrence rate of AF was.ConclusionThe gray value of left atrial fat enhanced CT can effectively predict the recurrence of AF after radiofrequency ablation in thoracoscopic surgery.