CORRESPONDENCE: LETTER TO THE EDITOR
Reply
Carlo Pappone, MD, FACC* and
Vincenzo Santinelli, MD
* San Raffaele University Hospital, Department of Cardiology, Electrophysiology and Cardiac Pacing Unit, via Olgettina 60, Milan 20132, Italy (Email: pappone.carlo{at}hsr.it).
We are thankful for the comments made by Dr. Shanmugam as we can further emphasize major points already addressed in the Methods and Discussion sections of our original study (1). Most of all, our goal was to establish for the first time the safety and feasibility of transcatheter ablation of atrial fibrillation (AF) in a very challenging group of patients with mitral valve prosthesis (MVP). We even performed a live satellite broadcast of such a procedure at the last Boston Atrial Fibrillation Symposium on January 14, 2005, in a patient with MVP and chronic AF, where we were able to cardiovert and maintain her into sinus rhythm from the end of the ablation until now.
In our study (1), patients with MVP had both paroxysmal AF (14 patients) and chronic AF (13 patients). Extreme end of the atrial disease was not merely based on the type of AF but on the fact that AF was highly symptomatic and refractory to at least two antiarrhythmic drugs in patients with very enlarged left atrium (55 mm). Also, the 73% (75% in the control group) maintenance rate of sinus rhythm was achieved by percutaneous transcatheter ablation in this selected group of patients. It is not rare to see AF occurrence within the first month following the ablation procedure owing to tissue inflammation, and this does not generally influence the outcomes. Some patients did not have additional lines done in the left atrium as we were in the process of assessing the benefit of these lines, as already mentioned in the original report (1). This was not due to variation in anatomic mapping. Furthermore, 81% of patients in both groups had additional lines performed along the mitral isthmus and in the posterior wall; 12% of the MVP group (vs. 13% of the control group) had only the mitral isthmus line done (again, as we were investigating the benefit of additional lines; data now published [2]), allowing us to compare outcomes in both groups. Postablation left atrial tachycardia occurred in six patients of the MVP group (one in the control group), probably to incomplete block along the mitral isthmus line because of the risks and inability of getting close to the mitral prothesis, as we mentioned in the Discussion section of our original study (1). However, surgical scarring in the MVP group, combined with eventual incomplete block, could very well facilitate complex macro-reentrant arrhythmias. Finally, in our Conclusions section, we acknowledge the fact that AF ablation should ideally be performed at the time of MV replacement when feasible.
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References
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1. Lang CC, Santinelli V, Augello G, et al. Transcatheter radiofrequency ablation of atrial fibrillation in patients with mitral valve prostheses and enlarged atria: safety, feasibility, and efficacy J Am Coll Cardiol 2005;45:868-872.[Abstract/Free Full Text]
2. Pappone C, Manguso F, Vicedomini G, et al. Prevention of iatrogenic atrial tachycardia after ablation of atrial fibrillation: a prospective randomized study comparing circumferential pulmonary vein ablation with a modified approach Circulation 2004;110:3036-3042.[Abstract/Free Full Text]
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