Radiofrequency catheter ablation of ventricular arrhythmias in patients with hypertrophic cardiomyopathy: safety and feasibility Pasquale Santangeli,* §§¶ Luigi Di Biase, MD,* †‡ Dhanunjay Lakkireddy, MD, § J. David Burkhardt, MD,* Jayasree Pillarisetti, MD, § Yoav Michowitz, MD, ¶ Javier E. Sanchez, MD,* Rodney Horton, MD,* † Prasant Mohanty, MBBS, MPH,* G. Joseph Gallinghouse, MD,* Antonio Dello Russo, MD,  Michela Casella, MD,  Gemma Pelargonio, MD,  Pietro Santarelli, MD,  Atul Verma, MD, # Calambur Narasimhan, MD,** Kalyanam Shivkumar, MD, ¶ Andrea Natale, MD, FACC, FHRS* †## From the *Texas Cardiac Arrhythmia Institute at St. David Medical Center and † Department of Biomedical Engineering, University of Texas, Austin, Texas, ‡ Department of Cardiology, University of Foggia, Foggia, Italy, § University of Kansas, Kansas City, Kansas, §§ Catholic University, Rome, Italy. ¶ UCLA Cardiac Arrhythmia Center and Electrophysiology Programs, Los Angeles, California,  Catholic University, Rome, Italy, # Southlake Regional Health Center, New Market, Ontario, Canada, **Care Hospital, Andhra Pradesh, India, and ## Stanford University, Palo Alto, California. BACKGROUND Management of ventricular tachycardia (VT) in pa- tients with hypertrophic cardiomyopathy (HCM) is challenging. OBJECTIVE The purpose of this study is to assess the value of radiofrequency catheter ablation (RFCA) for the treatment of the VTs in the setting of HCM. METHODS Twenty-two patients (18 with ICD) with HCM and multiple episodes of VTs resistant to medical therapy underwent RFCA with an open irrigation catheter. Epicardial access was obtained if required. All patients were followed for at least 1 year after RFCA. RESULTS Mean age was 50.4  15.3, and mean ejection fraction was 34.3%  9.8%. RFCA was performed endocardially in all patients, while epicardial radiofrequency applications were needed in 13 patients. A previous endocardial ablation was un- successful in six patients. At 20  9 months of follow-up, elimi- nation of VTs reached 73%. No major complication was observed during and after the procedures in all patients. CONCLUSION Catheter ablation of VTs in patients with hyper- trophic cardiomyopathy refractory to medical therapy is safe, feasible, and successful in eliminating VT. Epicardial VT map- ping and ablation should be considered as an important access option for the treatment of these patients to increase the success rate. KEYWORDS Hypertrophic cardiomyopathy; Ventricular tachycar- dia; Catheter ablation; Outcomes ABBREVIATIONS ECG = electrocardiogram; EF = ejection frac- tion; HCM = hypertrophic cardiomyopathy; ICD = implantable cardioverter-defibrillator; ICE = intracardiac echocardiography; LV = left ventricle, ventricular; NYHA = New York Heart Associ- ation; RF = radiofrequency; RFCA = radiofrequency catheter ab- lation; RV = right ventricle, ventricular; SD = standard devia- tion; VT = ventricular tachycardia (Heart Rhythm 2010;7:1036 –1042) © 2010 Heart Rhythm Society. All rights reserved. Hypertrophic cardiomyopathy (HCM) is a genetic dis- ease of the sarcomere characterized by abnormal left ven- tricular (LV) hypertrophy with myocyte disarray. 1 Sudden and unexpected death is the most devastating consequence of HCM, occurring in up to 6% of patients, 1 with ventricular tachycardia (VT) being the principal etiologic mecha- nism. 2,3 The arrhythmogenic substrate responsible for VT occurrence in HCM has not been completely defined, al- though slow and distorted conduction due to cardiac myo- cyte disarray and fibrosis 4,5 may play a pivotal role in the genesis of reentrant VTs. The management of VTs in the setting of HCM is currently confined to antiarrhythmic drug therapy, with lim- ited efficacy, 3,6,7 and to implantable cardioverter-defibrillator (ICD) therapy for high-risk patients, 3,8 such as those with hemodynamically unstable VTs. A few previous reports have suggested that radiofrequency catheter ablation (RFCA) may be a suitable treatment strategy for selected HCM patients with Pasquale Santangeli and Luigi Di Biase contributed equally to the study and to the drafting of the manuscript and should both be considered as first authors. Preliminary results of this manuscript were presented by Dr. Luigi Di Biase at the 2009 American Heart Association annual meeting, which was held in Orlando, Florida. Address reprint requests and correspon- dence: Andrea Natale, M.D., F.A.C.C., F.H.R.S., Executive Medical Di- rector of the Texas Cardiac Arrhythmia Institute, at St. David’s Medical Center, 1015 East 32d Street, Suite 516, Austin, Texas 78705. E-mail address: dr.natale@gmail.com. (Received March 25, 2010; accepted May 15, 2010.) 1547-5271/$ -see front matter © 2010 Heart Rhythm Society. All rights reserved. doi:10.1016/j.hrthm.2010.05.022