Background and aim: To assess the prevalence of incidental extracardiac findings in patients who underwent cardiac CT for the evaluation of left atrial (LA) anatomy before atrial fibrillation (AF) catheter ablation. We also aimed to determine the independent predictors of relevant extracardiac alterations. Patients and methods: We studied consecutive patients who underwent cardiac CT with a 256-slice scanner for the visualization of LA anatomy before AF ablation. Prevalence of clinically significant and not significant extracardiac findings were recorded. Moreover, we determined the variables associated with relevant extracardiac alterations with uni- and multivariate logistic regression analyses. Results: In total, 1,952 consecutive patients who underwent cardiac CT examination between 2010 and 2020 were included in our study (mean age 61.2 +- 10.6 years; 66.2% male). Incidental extracardiac findings were detected in 820 (42.0%; 95%CI 5 0.40-0.44%) patients, while clinically significant alterations were reported in 416 (21.3%; 95%CI 5 20.0-23.2%) patients. When analyzing the predictors of clinically relevant alterations, age (OR 5 1.04; 95%CI 5 1.03-1.05), male sex (OR 5 1.39; 95%CI 5 1.121.73), chest pain (OR 5 1.46; 95%CI 5 1.09-1.93), hypertension (OR 5 1.42; 95%CI 5 1.12-1.81), heart failure (OR 5 1.68; 95%CI 5 1.09-2.53), obstructive CAD (OR 5 1.56; 95%CI 5 1.16-2.09) and prior stroke/TIA (OR 5 1.56; 95%CI 5 1.04-2.30) showed association with clinically significant incidental findings in the univariate analysis (all P < 0.05). In the multivariate analysis, age (OR 5 1.04; 95%CI 5 1.02-1.06; P < 0.001) proved to be the only significant predictor of clinically relevant extracardiac finding. Conclusion: Cardiac CT performed before AF ablation is not only helpful in understanding LA anatomy, but might also identify clinically significant pathologies. These incidental findings might have further diagnostic or therapeutic consequences.  Kulcsszavak: incidental findings, tomography, x-ray computed