Safety of the Open-Irrigated Ablation Catheter for Radiofrequency Ablation: Safety Analysis from Six Clinical Studies ALBERT L. WALDO, M.D.,* DAVID J. WILBER, M.D.,† FRANCIS E. MARCHLINSKI, M.D.,‡ WILLIAM G. STEVENSON, M.D.,§ BRENDA AKER, B.S.,¶ LEE MING BOO, PHARM.D.,** and WARREN M. JACKMAN, M.D.†† From the *Department of Medicine, Case Western Reserve University, Cleveland, Ohio; †Department of Medicine, Loyola University Medical Center, Maywood, Illinois; ‡Department of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania; §Department of Medicine, Brigham and Women’s Hospital, Boston, Massachusetts; ¶Clinical Operation and **Medical Affairs, Biosense Webster, Inc., Diamond Bar, California; and ††Heart Rhythm Institute, University of Oklahoma Health Sciences Center, Oklahoma City, Oklahoma Background: The open-irrigated catheter is used most frequently for atrial and ventricular radiofrequency ablation (RFA), and is often considered as the standard by which new ablation systems are compared. But few data have been published concerning its safety. This report provides a comprehensive safety analysis of the use of an open-irrigated catheter for RFA of atrial flutter, ventricular tachycardia, and atrial fibrillation in 1,275 patients in six rigorously monitored, prospective, multicenter studies. Methods: This analysis is of data from six studies conducted as part of both Food and Drug Administration-mandated investigational device exemption studies and postapproval studies. The six studies span a period of more than 10 years. All serious RFA complications and vascular access complications that occurred within seven days postprocedure were included. Results: The number of patients who experienced any acute serious RFA complication in these studies combined was 4.9% (63/1,275). The two earliest studies were conducted when the open-irrigated catheter was first introduced, and accounted for 55.6% of the complications. In the first atrial flutter ablation study, RFA complications decreased by 60% (15.4%–6.2%) after a proctoring program was initiated during the study. For all studies, vascular access complications ranged between from 0.5%–4.7%, and no stroke or transient ischemic attack was reported within 7 days postprocedure. No significant pulmonary vein stenosis was reported from the atrial fibrillation studies. Conclusion: A proctoring program, careful fluid management, and absence of char and coagulum contributed to the safe use of the open-irrigated RFA catheter. (PACE 2012; 35:1081–1089) catheter ablation, radiofrequency, atrial fibrillation, atrial flutter, ventricular tachycardia, open-irrigated ablation catheter Introduction Catheter ablation has become an important clinical tool in the treatment of many cardiac rhythm disorders. In fact, it is often the treatment of choice for arrhythmias such as atrioventricular (AV) nodal reentrant tachycardia, AV reentrant tachycardia and arrhythmias directly related to the Wolff-Parkinson-White Syndrome, atrial Financial Support: All studies are funded by Biosense Webster, Inc. Authors’ Disclosures: All authors report financial interactions with a variety of commercial companies—all disclosures are available upon request. Address for reprints: Albert L. Waldo, M.D., University Hos- pitals Case Medical Center, 11100 Euclid Avenue, Cleveland, OH 44106. Fax: 216 844-7196; e-mail: albert.waldo@case.edu Received February 29, 2012; revised April 30, 2012; accepted May 1, 2012. doi: 10.1111/j.1540-8159.2012.03480.x tachycardia, atrial flutter (AFL), and, increasingly, ventricular tachycardia (VT) and atrial fibrillation (AF). 1,2 Efficacy and safety are always the yin and yang of treatment, and no less so than for radiofrequency (RF) catheter ablation (RFA). Continued development of catheters to improve efficacy and safety of RFA has led to the use of the open-irrigated catheter. Saline irrigation from the catheter cools the electrode-tissue interface, allowing use of higher RF power (greater resistive heating for deeper lesions) while reducing the risk of thrombus formation. Greater heating below the surface may increase the risk of a deep steam pop and cardiac perforation. 3 The open-irrigated catheter’s efficacy in several different arrhythmias has been well documented. 4,5 (AFL data on file.) The open-irrigated catheter was approved by the United States Food and Drug Administration (FDA) nearly 10 years ago, and has become the standard ablation system by which new systems are compared. As a result, a thorough C 2012, The Authors. Journal compilation C 2012 Wiley Periodicals, Inc. PACE, Vol. 35 September 2012 1081