Catheter Ablation of Atrial Fibrillation

Atrial fibrillation (AF) is the mostcommon sustained cardiac ar-rhythmia and is associated with signif-icant morbidity and cost.1 AF is seen across a wide spectrum of patients, from lone AF without structural heart disease, to the postoperative setting, to patients with significant left ventricu-lar dysfunction and advanced heart failure. AF is clinically classified as paroxysmal (7 days), persistent (7 days or requiring intervention to re-store sinus rhythm), longstanding per-sistent (1 year), or permanent, when restoration of sinus rhythm is no lon-ger pursued.2 The presence of AF is associated with increased mortality, and treatment of patients requires symptom relief and prevention of thromboembolism. Opti-mal antithrombotic therapy is deter-mined on the basis of stroke risk as predicted by the CHADS2 scoring sys-tem (a system that awards 1 point each for congestive heart failure, hyperten-sion, age 75 years, and diabetes mel-litus and 2 points for prior stroke or transient ischemic attack).3,4 More re-cently, a modified scoring system, CHA2DS-VASC2, has been shown to improve risk prediction for patients previously thought to be at low risk for thromboembolic events.5 Large-scale randomized trials have not shown mortality reduction with a rhythm control strategy compared with a rate control strategy6; however, many patients continue to have symptoms despite adequate rate control. For these patients, 3 therapeutic options are available for AF: (1) Antiarrhythmic drug therapy, (2) catheter ablation, and (3) surgical intervention (Maze proce-dure). Antiarrhythmic drug therapy has limited efficacy (40%–60%) and im-portant side effects and has been shown to be less effective than catheter ablation in multiple comparative stud-ies.7 In this Clinician Update, we illus-trate current ablation strategies used to treat paroxysmal and persistent AF in the electrophysiology laboratory.