Clinical impact of incidental findings on pre-ablation cardiac computed tomography in patients undergoing atrial fibrillation ablation

Background Cardiac computed tomography (CT) before catheter ablation for atrial fibrillation (AF) is widely performed to characterise pulmonary vein (PV) anatomy and exclude left atrial appendage (LAA) thrombus. Recent ESC guidelines and EHRA/EACVI consensus documents support pre-ablation cardiac imaging for thrombus exclusion in selected high-risk groups and describe CT as a first-line option for non-invasive LAA assessment. Although its extended field of view may capture additional findings beyond the primary procedural indication, their prevalence and clinical consequences remain poorly defined. Purpose To quantify the prevalence of additional findings on pre-ablation cardiac CT and to assess their impact on further investigation, treatment, and the ablation pathway. Methods We retrospectively reviewed formal radiology reports from 320 consecutive patients undergoing pre-ablation cardiac CT at a single university hospital between October 2023 and May 2025. Findings were classified as previously known versus newly detected, and as clinically significant if they prompted further investigation or treatment, or if they altered ablation timing or intra-procedural strategy. We captured both incidental extracardiac and cardiac findings, alongside procedure-relevant findings such as LAA thrombus and PV variants, as these can influence downstream management and the ablation pathway. Results The mean age was 66.6 ± 10.0 years (range 23–87), and 234 patients (70.2%) were male. At least one abnormal finding was reported in 295 patients (92.2%). Newly detected findings occurred in 190 (59.3%), while 135 (42.1%) had pre-existing known abnormalities; these categories were not mutually exclusive. Further diagnostic investigation was triggered in 23 patients (7.2%) and treatment was required in 10 (3.1%). Ablation timing was altered in 13 (4.1%), mainly to prioritise the management of suspected malignancy or vascular pathology. Procedural strategy was modified in 34 (10.6%), most frequently due to PV anatomical variants including accessory PVs (n=12) and left common ostium (n=8). The most common indications for additional investigation were suspected lung malignancy (n=5), pancreatic lesions (n=4), LAA thrombus (n=3), and adrenal lesions (n=2). Conclusions Pre-ablation cardiac CT frequently identifies findings beyond its primary procedural indication. Approximately one in twelve patients required further investigation, one in twenty-two required treatment, and one in twenty-three experienced a change in ablation timing. Systematic review and reporting of the full CT field of view, supported by clear referral pathways, may improve patient safety and optimise clinical outcomes.