By Ashley Starkweather, B.S. and Asher Kimchi M.D.

Milan, Italy – A recent study shows that patients who suffer from atrial fibrillation and have prosthetic mitral valve replacements can undergo transcatheter ablation with positive results. The study, published by Christopher C. Lang, MB, CHB, et. al., from San Raffaele University Hospital in Milan, Italy, in the March 15, 2005 issue of the Journal of the American College of Cardiology, looked at twenty-six patients with mitral valve prostheses (MVP) who underwent circumferential pulmonary vein ablation for atrial fibrillation (AF) and compared their outcomes to a control group of fifty-two patients who underwent ablation for AF and did not have prosthetic mitral valves. The study concluded that this procedure is both feasible in this population of patients. 

Patients with prosthetic mitral valves represent an important subgroup of AF patients for whom appropriate nonpharmacologic therapy has yet to be established. A possible risk in this group could be prosthetic valvular damage when performing transcatheter ablation procedures. This study sought to determine the risks and benefits for these patients when performing circumferential pulmonary vein ablation (CPVA) for the treatment of AF. 

Between July 2001 and July 2003, twenty-six patients with mechanical mitral valves were identified and enrolled in the study and underwent CPVA. For each of these patients, two control subjects were matched based on left atrial diameter, chronic or paroxysmal AF, duration of symptoms, age, gender, history of hypertension, and impaired left ventricular function. All MVP patients and controls were resistant to at least two anti-arrhythmic drugs. Follow-up was performed for twelve months and Holter recordings were performed for all patients at 3, 6, and 12 months. 

There were no significant differences between the groups in regards to age, duration of AF, LA diameter, gender, LV hypertrophy or LV impairment. There was a trend towards longer procedure time in the MVP group, however, this trend was not significant. Fluoroscopy times were significantly increased in this group (35.3 +/- 21min versus 20.9 +/- 15 min in controls), which signifies an increased exposure to radiation.  

At the end of follow-up, 73 percent of MVP patients were in sinus rhythm, compared to 75 percent in the controls. Atrial tachycardia occurred in six (23 percent) of MVP patients, requiring repeat ablation in three, and one control patient (2 percent) which resolved without intervention. Some complications did occur in the MVP groups, including one transient ischemic attack and one femoral pseudoaneurysm. No complications occurred in the control group. 

The results of this study suggest that CPVA is feasible in AF patients with MVP, with similar risks and outcomes to those of AF patients without MVP. Complication rates were higher, however, in MVP patients as well as radiation exposure and post-ablation atrial tachycardia. 

Co-authors: Vincenzo Santinelli MD, Giuseppe Augello MD, Amedeo Ferro MD, Filippo Gugliotta BEng, Simone Gulletta MD, Gabriele Vicedomini MD, Cézar Mesas MD, Gabriele Paglino MD, Simone Sala MD, Nicoleta Sora MD, Patrizio Mazzone MD, Francesco Manguso MD, PhD and Carlo Pappone MD, PhD