Intracardiac vs Transesophageal Echocardiography in Atrial Fibrillation Ablation: A Randomized Clinical Trial.

Importance: Transesophageal echocardiography (TEE) is the standard imaging modality for thrombus screening prior to atrial fibrillation (AF) ablation but carries procedural risks. Intracardiac echocardiography (ICE) is an alternative that may offer comparable safety with procedural advantages. Objective: To determine whether ICE is noninferior to TEE in preventing periprocedural thromboembolic events in AF ablation. Design, Setting, and Participants: This multicenter randomized clinical trial was conducted at 10 hospitals in China from August 2022 to July 2023, with a 30-day follow-up, enrolling adults with AF scheduled for catheter ablation who met predefined eligibility criteria. Data analysis was performed from August 2023 to December 2023. Interventions: Thrombus screening with ICE or TEE prior to ablation. Main Outcomes and Measures: The primary end point was the incidence of periprocedural thromboembolic events (stroke, transient ischemic attack, or systemic embolism). Secondary end points included thrombus detection, procedural safety and efficiency, and patient-reported comfort. Results: A total of 1810 patients (mean [SD] age, 64.3 [9.4] years; 868 women [48.0%]; 887 patients [49.0%] with paroxysmal AF) were randomized to ICE (n = 906) or TEE (n = 904). Thromboembolic events occurred in 4 of 906 patients undergoing ICE (0.4%) and 5 of 904 patients undergoing TEE (0.6%) (risk difference, -0.11%; Farrington-Manning 95% CI, -0.84% to 0.62%; P for noninferiority = .01). Thrombus was detected in 2.0% vs 1.5% (relative risk [RR], 1.29; 95% CI, 0.64-2.61; P = .48) with ICE vs TEE, respectively, with more non-left atrial appendage thrombi in ICE (0.6% vs 0%; P < .001). Major bleeding related to transseptal puncture was lower with ICE (0.2% vs 1.2%; RR, 0.18; 95% CI, 0.04-0.81; P = .03). ICE reduced mean (SD) fluoroscopy time (4.2 [1.5] vs 9.3 [3.0] minutes; P < .001), preprocedural waiting time (14.4 [8.0] vs 23.6 [10.5] hours; P < .001), and anxiety or depression prevalence (24.6% vs 37.5%; RR, 0.66; 95% CI, 0.56-0.76; P < .001). Conclusions and Relevance: In this multicenter randomized clinical trial, ICE was noninferior to TEE for preventing thromboembolic complications in AF ablation and offered additional advantages in safety, efficiency, and patient comfort, supporting its use as a viable alternative in clinical practice. Trial Registration: ClinicalTrial.gov Identifier: NCT05466266.