Radiofrequency Ablation Safe With Mechanical Mitral Valve Prostheses

July 26, 2011

NEW YORK (Reuters Health) Jul 25 - Radiofrequency ablation (RFA) of atrial fibrillation is safe and often effective in patients with mechanical mitral valve prostheses.

Its safety has been a concern in these patients. Damage to the prosthetic valve or entrapment of the ablation catheter in the prosthesis would require open-heart surgery.

But when Dr. Walid I. Saliba from Ohio's Cleveland Clinic and colleagues compared RFA outcomes in 81 patients with mechanical mitral valves and 162 age- and sex-matched controls, the rate of procedure-related complications was similar in the two groups. And no one suffered prosthetic valve damage or catheter entrapment.

As reported in the August 2nd Journal of the American College of Cardiology, all four pulmonary veins were successfully isolated in every case. Superior vena cava potentials were found and ablated more commonly in controls (84.7% vs. 64.2%), whereas ablation in the coronary sinus was needed more often in patients with prosthetic valves (24.7% vs. 14.2%).

During 12 to 24 months of follow-up, the prosthetic valve group did have a higher rate of atrial fibrillation recurrence (49.4% vs. 27.8%; p=0.0006) and more repeat ablations per person (mean, 1.4 vs. 1.2).

At last follow-up, 56 of 81 mitral valve replacement patients (69.1%) were free of arrhythmias and off antiarrhythmic drugs, 11 (13.6%) had their arrhythmia controlled with drugs that had previously failed, and 14 (17.3%) had drug-resistant AF being managed with rate control.

"Radiofrequency ablation is feasible and safe but technically challenging in patients with mitral valve prostheses," the researchers conclude.

"It was possible to restore sinus rhythm off antiarrhythmic drugs in a substantial proportion of patients with mitral valve replacement referred for AF ablation," they add, "but it seems that the ablation procedure needs to be further refined. In particular, ablation strategies with a focus on the atrial substrate, extra-pulmonary vein triggers, and concomitant flutters may help to improve ablation outcomes."

SOURCE: http://bit.ly/pBPCqZ

J Am Coll Cardiol 2011;58:596-602.

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