Feasibility of catheter ablation of mitral annular flutter in patients with prior mitral valve surgery Stavros Mountantonakis, MD, David S. Frankel, MD, Mathew D. Hutchinson, MD, FHRS, Sanjay Dixit, MD, FHRS, Michael Riley, MD, PhD, David J. Callans, MD, FHRS, Fermin Garcia, MD, David Lin, MD, Wendy Tzou, MD, Rupa Bala, MD, Francis E. Marchlinski, MD, FHRS, Edward P. Gerstenfeld, MD From the Section of Cardiac Electrophysiology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania. BACKGROUND Mitral annular flutter (MAF) may occur after abla- tion of atrial fibrillation in patients with prior mitral valve (MV) replacement or repair. Percutaneous catheter ablation may be challenging owing to the presence of surgical scar and a prosthetic MV. OBJECTIVE We examined the feasibility of and outcome after mitral isthmus ablation in patients with prior MV surgery. METHODS Twenty-one consecutive patients (18 males, age 61 10 years) with a history of MV surgery (nine replacement, 12 repair with annuloplasty ring) underwent catheter ablation of clinical (n = 17) or easily inducible (n = 4) MAF (group 1). Patients were matched for age, gender, and ejection fraction, with 21 patients undergoing MAF ablation without prior MV surgery (group 2). Irrigated ablation was delivered endocardially in a linear fashion from the MV to the left inferior and/or to the right superior pulmonary vein and, when required, epicardially inside the coronary sinus. Isolation of all pulmonary veins was also performed. RESULTS There was no difference in termination of tachycardia during ablation (group 1 vs. group 2; 86% vs. 71%; P = .454), achieving mitral isthmus block (71% vs. 71%; P = 1.000), or need for epicardial ablation (43% vs. 62%; P = .354) between groups. No complications occurred in either group. After a mean follow-up of 7  4 months, 15 (71%) patients in group 1 and 14 (67%) in group 2 had no recurrence of atrial arrhythmias. CONCLUSIONS Percutaneous mitral isthmus ablation is feasible and safe in patients with prior MV replacement or repair and has comparable outcomes to patients without prior MV surgery. KEYWORDS Catheter ablation; Mitral annular flutter; Mitral valve surgery; Atrial fibrillation ABBREVIATIONS AF = atrial fibrillation; CS = coronary sinus; CT = computed tomography; INR = international normalized ra- tio; LA = left atrium; LAA = left atrial appendage; MAF = mitral annular flutter; MV = mitral valve (Heart Rhythm 2011;8:809 – 814) © 2011 Heart Rhythm Society. All rights reserved. Introduction Preoperative atrial fibrillation (AF) is common in patients un- dergoing mitral valve (MV) surgery 1 and has been associated with increased incidence of stroke and all-cause mortality. 2 Surgical ablation of AF at the time of MV surgery has become more popular based on evidence that it is associated with low morbidity and mortality 3 and that it decreases the incidence of postoperative thromboembolic events and valve-related com- plications. 4–6 The ablation procedure typically consists of epi- cardial pulmonary vein isolation using radiofrequency energy, amputation of the left atrial appendage (LAA), and linear ablation connecting the isolated pulmonary veins to the mitral annulus. Restoration of sinus rhythm has been achieved in 70%–96% of patients over an average follow-up of 5 years. 7,8 However, gaps in the linear ablation lesions may lead to left atrial flutters after surgery. Management of patients with postoperative atrial flutter after combined AF and MV surgery is challenging. Patients can be quite symptomatic, and the ventricular rate is often difficult to control. Antiarrhythmic medications have lim- ited efficacy in treating these incessant arrhythmias. Mitral annular flutter (MAF) may occur after surgical ablation, and catheter ablation may be technically challenging because of the presence of surgical scar and a prosthetic valve or annuloplasty ring. The MAF recurrence rate after linear ablation of the mitral isthmus without achieving bidirec- tional block is quite high. 9,10 We examined the feasibility and outcome of mitral isthmus ablation in patients with MAF and a history of MV repair or replacement. Methods Study population We studied 21 consecutive patients with a history of MV surgery who were referred to our institution for ablation of symptomatic left atrial flutter, alone or in addition to AF, between 2005 and 2010 (group 1). The diagnosis of MAF was confirmed during electrophysiology study with activa- Address reprint requests and correspondence: Edward P. Gerstenfeld, M.D., 9 Founders Pavilion, 3400 Spruce Street, Philadelphia, Pennsylvania 19104. E-mail address: gerstene@uphs.upenn.edu. (Received November 1, 2010; accepted January 7, 2011.) 1547-5271/$ -see front matter © 2011 Heart Rhythm Society. All rights reserved. doi:10.1016/j.hrthm.2011.01.019