Safety and Performance of a System Specifically Designed for Selective Site Pacing FRANCESCO ZANON, M.D.,* CARLA SVETLICH, M.D.,† ERALDO OCCHETTA, M.D.,‡ DOMENICO CATANZARITI, M.D.,§ FRANCESCO CANT ` U, M.D.,¶ LUIGI PADELETTI, M.D.,** MASSIMO SANTINI, M.D.,†† GAETANO SENATORE, M.D.,‡‡ JENNIFER COMISSO, M.S.,§§ ANNAMARIA VARBARO, M.S.,§§ ALESSANDRA DENARO, M.S.,§§ and ANTONIO SAGONE, M.D.¶¶ From the *Ospedale Santa Maria della Misericordia, Rovigo, Italy; †Osp. della Versilia—Lido di Camaiore, Italy; ‡A.O. Maggiore della Carita’, Novara, Italy; §P.O. S. Maria del carmine—Rovereto, Italy; ¶Ospedali Riuniti—Bergamo, Italy; **A.O. Careggi—Firenze, Italy; ††A.C.O. S.Filippo Neri—Roma, Italy; ‡‡P.O. Riunito—Ciri` e, Italy; §§Medtronic Italia, Roma, Italy; and ¶¶Ospedale Sacco—Milano, Italy Introduction: In the right ventricle, selective site pacing (SSP) has been shown to avoid detrimental hemodynamic effects induced by right ventricular apical pacing and, in the right atrium, to prevent the onset of atrial fibrillation and to slow down disease progression. The purpose of our multicenter observational study was to describe the use of a transvenous 4-French catheter-delivered lead for SSP in the clinical practice of a large number of centers. Methods: We enrolled 574 patients in whom an implantable device was indicated. In all patients, SSP was achieved by using the Select Secure System TM (Medtronic Inc., Minneapolis, MN, USA). Results: In 570 patients, the lead was successfully implanted. In 125 patients, atrial SSP was performed: in 75 (60%) the lead was placed in the interatrial septum, in 31 (25%) in the coronary sinus ostium, and in 19 (15%) in the Bachman bundle. Ventricular SSP was undertaken in 138 patients: in 105 (76%) the high septal right ventricular outflow tract (RVOT) position was paced, in seven (5%) the high free-wall RVOT, in 25 (18%) the low septal RVOT, and in one (1%) the low free-wall RVOT. In the remaining 307 patients, the His zone was paced: in 87 (28%) patients, direct His-bundle pacing and in 220 (72%) patients para-hisian pacing was achieved. Adequate pacing parameters and a lead-related complication rate of 2.6% were recorded during a follow-up of 20 ± 10 months. Conclusions: Our results demonstrated that many sites, in the right atrium, in the right ventricle, and in His-bundle region, can be paced using the Select Secure System TM . (PACE 2011; 34:339–347) Pacing, atrium, ventricle, His bundle Introduction Owing to the relatively easy lead placement and proven stability and reliability, the right atrial appendage (RAA) and right ventricular apex (RVA) have become the standard sites for pacemaker lead implantation. However, many experimental studies and large clinical trials have shown that the abnormal conduction of ventricu- lar paced depolarization may lead to impaired car- diac function, arrhythmias, increased morbidity, and even mortality. 1–8 Similarly the RAA pacing Conflict of interest disclosure: J. Comisso, A. Varbaro and A. Denaro are employees of Medtronic, Inc. No other conflict of interest exists. Address for reprints: Francesco Zanon, M.D., Division of Cardiology, Ospedale “Santa Maria della Misericordia”, Viale Tre Martiri, 140, 45100 Rovigo, Italy. Fax: +39 0425 393597; e-mail: franc.zanon@iol.it Received November 16, 2009; revised May 24, 2010; accepted August 25, 2010. doi: 10.1111/j.1540-8159.2010.02951.x results in intraatrial dyssynchrony, as reflected by prolonged P-wave duration, with potentially important implications for atrial arrhythmias and for atrial hemodynamic function. 9,10 The proven detrimental effects of standard pacing have prompted the search for alternative sites. 11,12 However, stylet-delivered pacing leads have not been specifically designed for selective site pacing (SSP), potentially making more challenging their effective placement at sites different from RAA and RVA. Therefore, new lead models and specific tools have been proposed as an alternative method to satisfy the clinical demand for effective SSP. 13 The aim of our multicenter prospective observational study was to describe the use of the Select Secure System (Medtronic Inc., Minneapolis, MN, USA) in clinical practice of a large number of South European centers, reporting data about safety and electrical performances of this system while achieving SSP in the right atrium, right ventricle, and His-bundle area in a large population. C 2010, The Authors. Journal compilation C 2010 Wiley Periodicals, Inc. PACE, Vol. 34 March 2011 339