Clinical Assessment of Thromboembolic Risk in Patients Undergoing Elective Electrical Cardioversion with or Without...

Background and Objectives: Elective electrical cardioversion (eECV) in patients with atrial fibrillation (AF) or atrial flutter is associated with a low risk of thromboembolic events (TEs) when adequate anticoagulation is provided. However, the role of routine transesophageal echocardiography (TEE) prior to eECV remains uncertain. This study aimed to assess thromboembolic outcomes in patients undergoing eECV with or without TEE guidance in a real-world clinical setting. Methods: A single-center, combined retrospective-prospective observational study including 296 adequately anticoagulated patients with AF or atrial flutter scheduled for eECV was conducted. The retrospective cohort (n = 220) underwent eECV without routine TEE, while the prospective cohort (n = 85) underwent TEE prior to eECV. The primary outcome was the occurrence of thromboembolic events (ischemic stroke or systemic embolism) within 30 days after eECV. Arrhythmia recurrence at 30 days was assessed as a secondary, exploratory outcome. Results: Among patients undergoing eECV, thromboembolic events were rare. In the retrospective cohort, 3/220 patients (1.36%) experienced a TE, whereas no events were observed in the prospective cohort (0/76). Due to the low number of events, the study was underpowered to detect meaningful differences between strategies (RR 2.44; 95% CI 0.13-46.7; p = 0.55). TEE identified left atrial appendage thrombus in 9/85 screened patients (10.6%), who were subsequently excluded from cardioversion. Arrhythmia recurrence at one month was more frequent in the prospective cohort (19.7% vs. 7.3%), likely reflecting differences in baseline clinical characteristics. Conclusions: Thromboembolic events after eECV in adequately anticoagulated patients were infrequent in this real-world cohort. While the study design limits direct comparison between strategies, the results indicate that a conventional anticoagulation-based approach without routine TEE is associated with a low risk of thromboembolic events in most patients. At the same time, the detection of left atrial appendage thrombus in a subset of patients underscores the importance of individualized risk assessment and supports the selective use of TEE in higher-risk clinical settings.