Rhythm-'a-line-ment' during catheter ablation of chronic atrial fibrillation: the role of left atrial linear lesions

Although recommended by the current guidelines for the treatment of atrial fibrillation (AF),1,2 catheter ablation of long-standing persistent AF (herein referred to as chronic AF) still remains a challenge for the interventional electrophysiologist. Initial attempts at a successful treatment of chronic AF have concentrated on different lesion sets. In the past, we have learned that pulmonary vein (PV) isolation alone, irrespective of its extension in terms of isolated atrial tissue around the PVs, is not sufficient to achieve a considerable success rate and, therefore, is restricted to a very selected cohort of chronic AF patients.3,4 Thus, additional arrhythmogenic processes beyond the PVs have become evident in the pathophysiology of chronic AF. Based on the concept of the ‘multiple wavelet’ hypothesis and in an effort to replicate the results of the surgical treatment of AF, linear lesions were applied to the left atrium, alone or in addition to PV isolation. However, with bidirectionally blocked lines at the left atrial roof and the mitral isthmus,4 or even with complete electrical isolation of the posterior left atrium including the PVs,5 the success rates range between 60 and 70%. Since a significant number of patients did not benefit from a standardized lesion set, the new concept rather to tailor the ablation approach to the patients' individual chronic AF processes has been implemented by Haissaguerre and co-workers.6 This concept was based on the observation that chronic AF could occasionally be terminated by ablation. Thus, using the combination of different strategies, … *Corresponding author. Tel: +49 40 428034120, Fax: +49 40 428034125, Email: willems{at}uke.uni-hamburg.de