For patients undergoing atrial fibrillation (AF) ablation, preprocedural thrombus screening with intracardiac echocardiography (ICE) is noninferior to the standard transoesophageal echocardiography (TEE) for preventing thromboembolic events, according to findings from a recent randomised trial.¹ The study, known as the ICE vs TEE Study (NCT05466266), also found that ICE offered benefits in procedural safety, patient comfort, and workflow efficiency.
This multicentre, randomised, controlled, noninferiority trial was conducted across 10 hospitals in China between August 2022 and July 2023. The study enrolled 1,810 adults with AF scheduled for catheter ablation who were receiving uninterrupted oral anticoagulation. Participants were randomised 1:1 to undergo preprocedural thrombus screening with either ICE (n=906) or TEE (n=904).
The primary endpoint was the incidence of periprocedural thromboembolic events, defined as stroke, transient ischaemic attack (TIA), or systemic embolism, within 30 days post-ablation. Secondary endpoints included the rate of thrombus detection, procedural safety outcomes like major bleeding, procedural efficiency metrics, and patient-reported outcomes such as comfort and anxiety.
The primary endpoint occurred in 4 of 906 patients (0.4%) in the ICE group and 5 of 904 patients (0.6%) in the TEE group. The absolute risk difference was –0.11%, which met the prespecified criteria for noninferiority (p for noninferiority=0.01).¹
Thrombus detection rates were similar between the groups (2.0% with ICE vs 1.5% with TEE; p=0.48). However, ICE identified more thrombi located outside the left atrial appendage (LAA) compared to TEE (0.6% vs 0%; p<0.001).
Regarding safety, major bleeding related to transseptal puncture was significantly lower in the ICE group than in the TEE group (0.2% vs 1.2%; relative risk 0.18; 95% CI 0.04–0.81; p=0.03). The ICE group also experienced significantly shorter mean fluoroscopy times (4.2 vs 9.3 minutes; p<0.001) and preprocedural waiting times (14.4 vs 23.6 hours; p<0.001). Patients in the ICE arm reported significantly less procedural pain and lower levels of anxiety and depression.
These findings suggest that while TEE is the current standard for thrombus screening before AF ablation, ICE presents a safe and effective alternative. The study highlights that anticoagulation alone may not eliminate thrombus risk, reinforcing the need for preprocedural imaging.² The investigators concluded, “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.”¹
This study was funded by Biosense Webster and Noncommunicable Chronic Diseases–National Science and Technology Major Project (2024ZD0521906).
References
1. Hu X, Jiang W, Wang X, et al. Intracardiac vs Transesophageal Echocardiography in Atrial Fibrillation Ablation: A Randomized Clinical Trial. JAMA Cardiol. 2025. https://doi.org/10.1001/jamacardio.2025.3687
2. Lurie A, Wang J, Hinnegan KJ, et al. Prevalence of left atrial thrombus in anticoagulated patients with atrial fibrillation. J Am Coll Cardiol. 2021;77:2875–86. https://doi.org/10.1016/j.jacc.2021.04.036
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