Ablation During Mitral Valve Surgery for Continuous Atrial Fibrillation - Ablation During Mitral Valve Surgery for Continuous Atrial Fibrillation

Description:

The goal of the trial was to evaluate the efficacy of left atrial radiofrequency ablation (RFA) during mitral valve surgery compared with mitral valve surgery alone among patients with continuous atrial fibrillation.

Study Design

Study Design:

Patients Screened: 101
Patients Enrolled: 97
Mean Follow Up: 12 months
Mean Patient Age: Mean age 67 years
Female: 43

Patient Populations:

Patients requiring mitral valve surgery and who also had a history of continuous atrial fibrillation, defined as the presence of uninterrupted atrial fibrillation for at least 6 months that showed no evidence of spontaneous reversibility to sinus rhythm and was not possible to revert with medications or direct current cardioversion.

Exclusions:

Sick sinus syndrome, uncontrolled hyperthyroidism, permanent pacemaker, or previous cardiac surgery

Primary Endpoints:

Presence of sinus rhythm at 12 months

Secondary Endpoints:

Patient functional status and exercise capacity assessed by shuttle-walk test, left atrial contractility, and left atrial and left ventricular dimension and function and plasma levels of B-type natriuretic peptide.

Drug/Procedures Used:

Patients were randomized to mitral valve surgery alone (n=48) or mitral valve surgery plus RFA of the left atrium (n=49). Patients were blinded to treatment assignment. Radiofrequency lesions were created endocardially with a handheld monopolar, 7-electrode probe and radiofrequency waves were delivered for 120 seconds to achieve transmural lesions.

Principal Findings:

Mean duration of atrial fibrillation was 57 months in the RFA group and 46.7 months in the surgery alone group. The large majority of patients had mitral regurgitation (84%), with moderate or severe tricuspid regurgitation in 24.5% of the RFA group and 29.2% of the surgery alone group. Baseline shuttle-walk distance was 281 m and 253 m, respectively. Mitral valve replacement was performed in 23% and 29% of patients, respectively.

At 12 month follow-up, the primary endpoint of presence of sinus rhythm occurred significantly more frequently in the RFA group compared with the surgery alone group (44.4% vs 4.5%, p<0.001), a finding observed as early as hospital discharge (53.3% vs 4.5%, p<0.001). Change from baseline to 12 months in shuttle-walk distance was 78 m in the RFA group and 49 m in the surgery alone group (p=0.13). New York Heart Association class did not differ between groups at 12 months (1.2 vs 1.3, p=0.34). Reduction in BNP level from baseline to 12 months was greater in the RFA group (-76 fmol/ml vs -30 fmol/ml, p=0.02). Ejection fraction at 12 months was higher in the RFA group, 59% vs 54.2%, p=0.004). There was no difference in operative or post-operative complications.

Interpretation:

Among patients with continuous atrial fibrillation, treatment with left atrial radiofrequency ablation (RFA) during mitral valve surgery was associated with higher rates of sinus rhythm at 12 months compared with mitral valve surgery alone.

In addition to the improvement in sinus rhythm, which was observed as early as hospital discharge, there were improvements in other efficacy parameters including LV function, BNP, and functional parameters. No excess operative complications or mortality were observed in the RFA group compared with mitral valve surgery alone. In another small randomized trial (n=30), biatrial RFA was associated with higher rates of sinus rhythm at 6 and 12 months. Given the promising findings in the present study, larger multicenter trials are warranted to further validate these findings.

References:

Doukas G, et al. Left Atrial Radiofrequency Ablation During Mitral Valve Surgery for Continuous Atrial Fibrillation. JAMA. 2005;294:2323-2329.

Clinical Topics: Arrhythmias and Clinical EP, Valvular Heart Disease, Implantable Devices, EP Basic Science, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Mitral Regurgitation

Keywords: Tricuspid Valve Insufficiency, Mitral Valve Insufficiency, Heart Conduction System, Electric Countershock, Catheter Ablation


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