Comparison of intracardiac echocardiography and transesophageal echocardiography for imaging of the right and left atrial appendages

Background Transesophageal echocardiography (TEE) is the standard for diagnosis of atrial thrombi and is performed before ablation of atrial arrhythmias. Intracardiac echocardiography (ICE) is routinely used during these procedures and may provide an alternative imaging modality. Objective The purpose of this study was to compare TEE and ICE for right atrial appendage (RAA) and left atrial appendage (LAA) anatomy and thrombus. Methods This prospective blinded study enrolled 71 patients with atrial arrhythmias who presented for ablation. TEE and ICE were performed simultaneously to assess the RAA and LAA for thrombi, spontaneous echo contrast, and dimensions. ICE images were acquired sequentially from the right atrium, right ventricular outflow tract, and the pulmonary artery. Results Imaging of the RAA and LAA was achieved in all 71 patients using ICE but in only in 69 patients using TEE because of inability to intubate the esophagus. A total of 4 thrombi were diagnosed (3 LAA, 1 RAA). All were detected by ICE but only 1 by TEE. Diagnostic imaging of the LAA was achieved in 71 patients (100%) with ICE and in 62 patients (87.3%) with TEE (P <.002). Spontaneous echo contrast was more commonly diagnosed with ICE (P <.01). There was strong correlation between TEE and ICE for length (r = 0.71), width (r = 0.94), and area (r = 0.88) of the LAA. Image quality with ICE was highest from the pulmonary artery and lowest from the right atrium. Conclusion ICE imaging is a viable alternative to TEE for visualization of the LAA and RAA during catheter ablation procedures.