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Catheter Ablation of Chronic AFib

The procedure was safe and effective in highly selected patients with symptomatic chronic atrial fibrillation.

Catheter ablation of atrial fibrillation (AF), a procedure now widely performed in major electrophysiology laboratories, has been studied most carefully in patients with paroxysmal AF. In this study, researchers randomized 146 patients with symptomatic, drug-refractory chronic AF to circumferential pulmonary-vein catheter ablation or control treatment. Patients were a select group: Their maximum age was 70 (mean, 57); all had left-atrial diameters 5.5 cm and LV ejection fractions (LVEFs) 30%; and only 8% had structural heart disease.

Both groups started amiodarone (200 mg daily) 6 weeks before the ablation group underwent their procedures. The ablation group continued the amiodarone for 3 months postablation and were permitted one cardioversion if needed. Controls underwent cardioversion after the initial 6 weeks of amiodarone, and they continued the amiodarone for 3 months with a second cardioversion permitted if needed. Both groups discontinued amiodarone after 3 months. For 1 year after randomization, patients recorded their rhythms with event monitors 5 times per week and when symptoms occurred.

Of the 77 patients in the ablation group, 25 (32%) underwent repeat ablation (20 for recurrent AF, 5 for atrial flutter). Of the 69 controls, 53 (77%) elected to undergo circumferential ablation for recurrent AF and only 3 (4%) converted to sinus rhythm without any drug therapy. In an intention-to-treat analysis, significantly more patients randomized to ablation than to control treatment were in sinus rhythm at 1 year (74% vs. 58%).

Patients who remained in sinus rhythm after ablation had a significant mean increase in LVEF, decrease in left-atrial size, and decline in AF symptom score. No complications occurred.

Comment: This well-designed trial provides strong evidence that catheter ablation is safe and effective for chronic AF. However, we must bear in mind that (1) these were highly selected patients with chronic AF; (2) this was not a trial designed to compare amiodarone with catheter ablation, but to define the safety and success of catheter ablation; (3) 32% of ablated patients required a second procedure (the success rate with a single procedure is roughly 50%); and (4) although complications did not occur in this trial, catheter ablation of AF does come with risks for stroke, cardiac tamponade, pulmonary-vein stenosis, and esophageal perforation. Nonetheless, catheter ablation of chronic AF appears here to stay.

— Hugh Calkins, MD

Published in Journal Watch Cardiology March 23, 2006

Citation(s):

Oral H et al. Circumferential pulmonary-vein ablation for chronic atrial fibrillation. N Engl J Med 2006 Mar 2; 354:934-41.

• Medline abstract (Free)

Wood MA and Ellenbogen KA. Catheter ablation of chronic atrial fibrillation — The gap between promise and practice. N Engl J Med 2006 Mar 2; 354:967-9.

• Medline abstract (Free)

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