[Catheter ablation for atrial fibrillation]

Atrial fibrillation, the most common cardiac arrhythmia, is frequently disabling and drug-resistant, and can be associated with major complications such as thromboembolic events. Non drug approaches, including surgery and catheter-based ablation, are used to treat the most severely symptomatic patients. These new treatment strategies have drastically improved our knowledge of the pathophysiology of this arrhythmia and, importantly, have shown that atrial fibrillation is curable. Since 1994, two main approaches have been used to modify the substrate responsible for AF maintenance, namely the creation of linear lesions, and ablation of triggers located within the pulmonary veins (about 90% of cases). Most teams worldwide now use approaches centered on PV isolation, which, although imperfect, are sufficiently effective to be offered routinely to selected patients in experienced centers. The importance of PVs in the initiation of AF has been clearly demonstrated, and there is also evidence of a role in AF maintenance. However, the existence of non venous foci or a prominent substrate for AF maintenance limits the success rate to about 70%. We are now using a combination of PV isolation and a linear lesion delivered to the mitral isthmus, from the mitral annulus to the ostium of the left inferior pulmonary vein. This more complex procedure carries a significantly higher success rate, about 82% of patients being cured and drug-free. The main problem is to identify patients requiring mitral isthmus ablation in addition to PV isolation. At present, AF ablation is restricted to symptomatic patients in whom at least two antiarrhythmic drugs have failed, but future technical improvements are likely to broaden the indications of ablation therapy for AF.