1153 Mapping of Intraatrial Reentrant Tachycardias by Remote Magnetic Navigation in Patients with d-Transposition of the Great Arteries After Mustard or Senning Procedure JINJIN WU, M.D., ANDREAS PFLAUMER, M.D., ISABEL DEISENHOFER, M.D., EKREM ¨ UCER, M.D., JOHN HESS, M.D., BERNHARD ZRENNER, M.D., and GABRIELE HESSLING, M.D. From the Deutsches Herzzentrum M ¨ unchen and 1. Medizinische Klinik, Klinikum rechts der Isar, Technische Universit¨ at M ¨ unchen, Munich, Germany Remote Magnetic Mapping After Mustard/Senning Procedure. Introduction: Mapping of intraatrial reentrant tachycardia (IART) still presents a challenge in complex congenital heart disease. The goal of this work was to present our initial experience with remote magnetic navigation (RMN) for mapping of IART in four patients after the atrial switch procedure (Mustard n = 1, Senning n = 3) for d-transposition of the great arteries. Methods: Three-dimensional (3D) mapping of the systemic venous atrium and the pulmonary venous atrium (PVA) was performed using RMN (Niobe) in conjunction with 3D mapping (CartoRMT). The maps were fused with a CT-based 3D anatomy. Results: All patients had cavotricuspid isthmus-dependent IART with a mean atrial cycle length of 305 ms. Mapping of both atria (PVA retrogradely by passing the aortic and tricuspid valve) was feasi- ble and safe. The procedure time for IART mapping ranged from 210 to 320 minutes with a mean of 251 minutes. The fluoroscopy time for IART mapping ranged from 15.8 to 45.0 minutes (mean 31.6 min- utes) for patients, and ranged from 12.3 to 24.3 minutes with a mean of 19.5 minutes for physicians. No procedural complications occurred. Conclusion: Precise mapping of IART in the complex anatomical structures after an atrial switch pro- cedure was feasible and safe using RMN. The maneuverability of the catheter was possible even with a retrograde access crossing two valves. Further reduction of procedural and fluoroscopy times for both patients and physicians seems possible (J Cardiovasc Electrophysiol, Vol. 19, pp. 1153-1159, November 2008) transposition of great vessels, intraatrial reentrant tachycardias, remote magnetic navigation, mapping, catheter ablation Introduction Mustard 1 and Senning 2 were the first to use an atrial baf- fle construction in patients with d-transposition of the great arteries (d-TGA) that directs venous blood from the superior (SVC) and inferior vena cava (IVC) to the mitral valve and the left ventricle and pulmonary venous blood to the tricuspid valve and the right ventricle (RV) (“atrial switch procedure”) (Fig. 1A, B). Many patients who underwent these operations have now survived into adulthood. Late cardiac arrhythmias, especially intraatrial reentrant tachycardias (IART), occur in up to 30% of this population during long-term follow-up and seem to represent a significant factor for long-term morbidity and mortality. 3,4 This manuscript was processed by a guest editor. Dr. Pflaumer received compensation for participating in a speaker’s bureau at Stereotaxis Satellite Symposium in Pedirhythm 2007, Istanbul. Address for correspondence: Jinjin Wu, M.D., Deutsches Herzzentrum M¨ unchen, Lazarettstr. 36, 80636 M¨ unchen, Germany. Fax: +49-89-1218- 4593; E-mail: wu@dhm.mhn.de Manuscript received 6 March 2008; Revised manuscript received 14 April 2008; Accepted for publication 29 April 2008. doi: 10.1111/j.1540-8167.2008.01231.x Since the initial experience with mapping and catheter ablation of IART, 5,6 different mapping techniques, such as noncontact mapping 7 and electroanatomic mapping, 8 have been introduced to facilitate the procedure and to improve ablation success. Remote magnetic navigation (RMN) is a new technique for steering a soft and flexible catheter by the use of an ex- ternal magnetic field. 9 RMN has been used for mapping and ablation of supraventricular reentrant tachycardia, 10-12 atrial fibrillation, 13 and ventricular tachycardia. 14 As the RMN catheter offers stable contact with the myocardial wall with- out the risk of perforation, it might be especially suited for ac- cessing difficult anatomy as in postsurgical congenital heart disease. This is the first report using the RMN system for IART mapping in patients following the Mustard or Senning procedure. Methods Patients Four patients (2 males, 2 females; age 23–40 years) had undergone an atrial switch procedure at the age of 1– 4 years. The Mustard procedure had been performed in one patient, the Senning procedure in two patients, and in one pa- tient the original Mustard operation had been converted to a Senning procedure because of pulmonary venous ob- struction. All patients were admitted with a 12-lead