title: A stepwise electrocardiographic algorithm for differentiation of mid-septal vs. apical right ventricular lead positioning: the SPICE ECG substudy.
abstract: OBJECTIVE
  Right ventricular (RV) septum is a non-apical site targeted during lead implantation. Electrocardiographic (ECG) recognition of mid-septal lead location is challenging. The aim of the study is to determine ECG correlates of RV mid-septal pacing.
  
  
  RESULTS
  The present study is a pre-specified analysis of a prospective, multicenter study, which randomized recipients of an implantable cardioverter defibrillator to an apical vs. mid-septal RV lead positioning. Following implantation, a 12-lead ECG was recorded during intrinsic rhythm and RV pacing. In total, 227 patients, 121 in the apical group (76.9% males, 67.1 ± 11.3 years) and 106 in the mid-septal group (82.1% males, age 64.7 ± 12.7 years) were included. Apically as compared with septally paced patients had significantly longer paced QRS duration (177.0 ± 25.0 vs. 170.4 ± 21.7, respectively, P = 0.03) and significantly more leftward paced QRS axis (-71.6 ± 33.3° vs. 9.4 ± 86.5°, respectively, P < 0.001). A significantly higher proportion of patients in the mid-septal as compared with the apical group displayed predominantly positive QRS in lead V6 (62.3 vs. 4.1%, P < 0.001), predominantly positive QRS in any of the inferior leads (53.8 vs. 4.1%, P < 0.001), and a QR pattern in lead aVL (53.3 vs. 3.3%, P < 0.001). These ECG correlates were incorporated in a stepwise algorithm with total sensitivity of 87% and specificity of 90% for the identification of a mid-septal lead location.
  
  
  CONCLUSIONS
  A mid-septal lead location may be identified using a simple stepwise algorithm, based on the presence of positive QRS in lead V6, positive QRS in any of the inferior leads, and a QR pattern in lead aVL.
authors.affiliation: Department of Cardiology, Henry Dunant Hospital, 107 Mesogion Avenue, Athens 115 26, Greece andrikop@hotmail.com.
authors.forename: George
authors.initials: G
authors.lastname: Andrikopoulos
authors.affiliation: Department of Cardiology, Henry Dunant Hospital, 107 Mesogion Avenue, Athens 115 26, Greece.
authors.forename: Stylianos
authors.initials: S
authors.lastname: Tzeis
authors.affiliation: Department of Cardiology and Angiology I, Heart Centre Freiburg University, Freiburg, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Asbach
authors.affiliation: Deutsches Herzzentrum München, Klinik für Herz- und Kreislauferkrankungen, Abteilung für Elektrophysiologie, Faculty of Medicine, Technische Universität München, Munich, Germany.
authors.forename: Verena
authors.initials: V
authors.lastname: Semmler
authors.affiliation: Deutsches Herzzentrum München, Klinik für Herz- und Kreislauferkrankungen, Abteilung für Elektrophysiologie, Faculty of Medicine, Technische Universität München, Munich, Germany.
authors.forename: Carsten
authors.initials: C
authors.lastname: Lennerz
authors.affiliation: Ostalbklinikum, Abteilung für Innere Medizin II, Aalen, Germany.
authors.forename: Ulrich
authors.initials: U
authors.lastname: Solzbach
authors.affiliation: Deutsches Herzzentrum München, Klinik für Herz- und Kreislauferkrankungen, Abteilung für Elektrophysiologie, Faculty of Medicine, Technische Universität München, Munich, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Grebmer
authors.affiliation: Klinikum Lüdenscheid, Abteilung für Innere Medizin III, Lüdenscheid, Germany Berufsgenossenschaftliches Universitätsklinikum Bergmannsheil, Medizinische Klinik II, Ruhr Universität Bochum, Bochum, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Kloppe
authors.affiliation: Universitätsklinikum Leipzig, Abteilung für Kardiologie und Angiologie, Leipzig, Germany.
authors.forename: Norbert
authors.initials: N
authors.lastname: Klein
authors.affiliation: Department of Cardiology, Henry Dunant Hospital, 107 Mesogion Avenue, Athens 115 26, Greece.
authors.forename: Socratis
authors.initials: S
authors.lastname: Pastromas
authors.affiliation: Department of Cardiology and Angiology I, Heart Centre Freiburg University, Freiburg, Germany.
authors.forename: Jürgen
authors.initials: J
authors.lastname: Biermann
authors.affiliation: Deutsches Herzzentrum München, Klinik für Herz- und Kreislauferkrankungen, Abteilung für Elektrophysiologie, Faculty of Medicine, Technische Universität München, Munich, Germany.
authors.forename: Christof
authors.initials: C
authors.lastname: Kolb
mesh_terms: D000368:Aged; D000465:Algorithms; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D004567:Electrodes, Implanted; D005260:Female; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D019919:Prosthesis Implantation / Q000379:methods*; D054088:Ventricular Septum
keywords: Algorithm; Apical; Electrocardiogram; Pacing; Septal