Real-time 3-dimensional transesophageal echocardiography during left atrial radiofrequency catheter ablation for atrial fibrillation.

Left atrial radiofrequency catheter ablation has been recognized as an important treatment option for drugrefractory symptomatic atrial fibrillation.1 Recent consensus on technique favors catheter ablation directed to the left atrium near the pulmonary vein (PV) ostium to achieve PV isolation.2 However, ablation in the region of the ligament of Marshall (LOM) to achieve electrical isolation of the left PVs can be difficult because of variable catheter stability. The superior extent of the LOM protrudes into the body of the left atrium between the anterior region of the left PV antrum and the left atrial appendage (Figure 1A). Inadvertent misdirection of ablative lesions anterior to the LOM in the region of the left atrial appendage increases the risk of cardiac perforation and does not contribute to successful PV isolation, and misdirection of ablative lesions posteriorly into the left PV or posterior left PV antrum can result in PV stenosis or fatal esophageal injury,2 respectively. Thus, circumferential isolation of the left PVs via precise delivery of ablative lesions outside the PV ostium, including the region of the LOM ridge, would be expected to enhance procedural safety and efficacy.3 More specifically, enhanced imaging technologies like 3-dimensional (3D) echocardiography, if able to image the ablation catheter and endocardium in real time, would be expected to minimize procedural complications such as PV stenosis, esophageal injury, and cardiac perforation. Although these complications are rare, occurring at rates 1% when contemporary techniques are used,1 they can be serious or fatal. Intracardiac echocardiography and advanced mapping systems have been used to guide ablation lesion delivery in this and other regions.1 Electroanatomic mapping systems in particular can display a non–real-time 3D rendering of the left atrial endocardial surface1; however, accurate representation of the region of the LOM can be difficult to achieve. We report here on the use of real-time 3D transesophageal echocardiography (RT 3D TEE) to image catheter tip placement and tissue contact to guide left atrial catheter ablation at the LOM. Left atrial catheter ablation was performed in a 53-year-old man with paroxysmal, drug-refractory, symptomatic atrial