Recent Advances in Lesion Formation for Catheter Ablation of Atrial Fibrillation.

Abstract

Despite advances in ablation technology, many patients experience recurrent atrial fibrillation (AF) after radiofrequency ablation. Although estimates vary, the overall 1-year drug-free success for AF ablation is estimated at 40% to 60% for a single procedure and 70% for multiple procedures.1 The cornerstone of conventional AF ablation is pulmonary vein isolation (PVI), and in clinical practice, the most common PVI technique involves creating circular radiofrequency lesions in a point-by-point fashion around the PV ostia/antra.2 However, conventional radiofrequency ablation can be difficult and time-consuming, has less than outstanding efficacy, and can be associated with potentially serious complications, such as steam pops, perforation, tamponade, and thrombus formation, which can lead to thromboembolic events. Given the limitations of conventional radiofrequency ablation, there has been ongoing development of new technologies to facilitate the safety and efficacy of lesion formation and durability. This review will summarize several recent advancements in catheter technology for AF ablation aimed at improving lesion formation (Figure 1). Figure 1. Summary of recent innovations in lesion formation. In radiofrequency ablation, the contact force (CF) between the ablation electrode and the atrial wall is a major determinant of lesion size and durability.3,4 Insufficient CF can result in inadequate lesion formation and higher rates of PV reconnection.5 However, excessive CF can result in complications, such as perforation.6 Therefore, monitoring CF would be expected to maximize ablation efficacy and improve safety. Until recent years, CF has been monitored indirectly using a combination of visual observation of catheter tip motion, tactile feedback, local electrogram attenuation, impedance monitoring, and in some laboratories, intracardiac echocardiogaphy. Although widely used, these methods are a poor surrogate for CF.4,7,8 Recently, ablation catheters that can directly measure CF have become available in the United States. A spring-coupled catheter (SmartTouch) was …