Circumferential Pulmonary Vein Ablation for Chronic Atrial Fibrillation - CPVA for Chronic Atrial Fibrillation

Mar 31, 2006
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Date Published:
01/01/2006
Date Updated:
03/31/2006
Original Posted Date:
03/31/2006
References

Description:

The goal of the trial was to evaluate treatment with circumferential pulmonary vein ablation (CPVA) compared with conventional antiarrhythmic medical therapy with amiodarone among patients with chronic atrial fibrillation (AF).

Study Design

Study Design:

Patients Enrolled: 146
Mean Follow Up: 12 months
Mean Patient Age: Mean age 57 years
Female: 9
Mean Ejection Fraction: Mean 55% at baseline

Patient Populations:

Chronic atrial fibrillation present >six months without intervening spontaneous episodes of sinus rhythm and that recurred within one week after cardioversion.

Exclusions:

Age <18 or >70 years, left atrial diameter >55 mm; left ventricular ejection fraction <30%; contraindication to amiodarone therapy or anticoagulation with warfarin; presence of mechanical prosthetic valve; history of cerebrovascular accident; presence of left atrial thrombus on transesophageal echocardiography; prior attempt at catheter or surgical ablation for atrial fibrillation

Primary Endpoints:

Freedom from atrial fibrillation and atrial flutter in the absence of antiarrhythmic-drug therapy one year after ablation in the group that underwent circumferential pulmonary-vein ablation or one year after cardioversion in the control group.

Secondary Endpoints:

Incidence of complications, changes from baseline in the CPVA group in the diameter of the left atrium, left ventricular ejection fraction, and severity of symptoms.

Drug/Procedures Used:

Patients were randomized to three months of amiodarone plus circumferential pulmonary vein ablation at week 6 (n=77) or control, defined as three months of amiodarone therapy plus two cardioversions by week 6 (n=69). An event monitor was to be worn for at least 3 minutes 5 times per week to monitor for asymptomatic atrial fibrillation or atrial flutter, which had to last for >3 seconds to be considered an event.

Principal Findings:

Structural heart disease was present in 6 patients in each group. In the CPVA group, 16% had atrial fibrillation terminated during the procedure, with the remaining 84% requiring administration of ibutilide or transthoracic cardioversion for termination. In the control group, 96% of patients required transthoracic cardioversion for termination. Cavotricuspid isthmus ablation was performed in 71% of the CPVA group for atrial flutter. In the CPVA group, repeat ablation was performed in 32% of patients due to recurrent AF or atrial flutter. In the control group, 77% of patients received CPVA by one year.

The primary endpoint of freedom from recurrent atrial fibrillation or flutter without antiarrhythmic therapy at one year occurred in 74% of the CPVA group and 58% of the control group (p=0.05).

Data on diameter of the left atrium, LV ejection fraction, and symptom severity score at 12 months were not reported by treatment group but rather by the occurrence of recurrent AF, and only in the CPVA group. The left atrium was smaller at 12 months compared with baseline among patients without recurrent AF (40 mm vs 45 mm, p<0.001), with no difference among patients with recurrent AF. Ejection fraction was higher at 12 months compared with baseline among patients without recurrent AF (62% vs 55%, p<0.001), with no difference among patients with recurrent AF. Likewise, the improvement in symptom severity score from baseline was higher in patients without recurrent AF vs with AF (10 vs 5, p=0.002).

Interpretation:

Among patients with chronic atrial fibrillation, treatment with circumferential pulmonary vein ablation was associated with a higher rate of freedom from recurrent atrial fibrillation or flutter without antiarrhythmic therapy at one year compared with conventional antiarrhythmic medical therapy with amiodarone and cardioversion.

Catheter ablation is used in the setting of symptomatic paroxysmal atrial fibrillation when antiarrhythmic medical therapy has failed. The present study extends these findings to the setting of chronic atrial fibrillation, although there are several limitations of the study. First, the study evaluated CPAV in a very select group of patients, notably age younger than 70 years and few with structural heart disease, and the applicability to the broad chronic AF population is limited. Additionally, a large proportion of patients required a repeat ablation procedure. Given the high event rate for recurrent AF by one year, it is pressumed that a large percentage of these episodes were asymptomatic although these data were not reported. Finally, it is unknown how CPAV for chronic AF would compare with surgical therapy.

References:

Oral H, et al. Circumferential Pulmonary-Vein Ablation for Chronic Atrial Fibrillation. N Engl J Med 2006;354:934-41.

Keywords: Pulmonary Veins, Electric Countershock, Catheter Ablation, Atrial Flutter, Sulfonamides


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