title: [Right bundle branch block during right ventricular pacing].
abstract: BACKGROUND
  We describe the case of a 78-year-old patient who presented for ablation of a wide complex tachycardia with right bundle branch block (RBBB) morphology. A pacemaker spike at the QRS onset indicated supraventricular tachycardia with AV synchronous ventricular pacemaker activation.
  
  
  METHODS
  Correct positioning of the ventricular lead in the right ventricular apex was confirmed by fluoroscopy and echocardiography, excluding malpositioning of the right ventricular lead.
  
  
  RESULTS
  In the electrophysiological study we diagnosed atrial tachycardia with 1:1 AV stimulation by the pacemaker. The ECG, however, presented negative concordance in the precordial leads. Only after shifting the precordial leads V1 and V2 from the 4th to the 2nd intercostal space were all 12 ECG leads in accordance with the clinical tachycardia.
  
  
  CONCLUSIONS
  Thus, it is suspected that malpositioning of the ECG electrodes generated an apparent RBBB morphology of the clinical tachycardia. Malpositioning of ECG electrodes switches the lead characteristics from horizontal (anterior-posterior) to frontal (cranial-caudal) plane properties. In this situation, the precordial leads V1 and V2 with positive vector in V1 and V2 imitate aVL (V2) and aVR (V1) and can produce an apparent RBBB morphology.
authors.affiliation: Department of Cardiology and Angiology, Klinikum Lüdenscheid Märkische Kliniken GmbH, Paulmannshöherstr. 14, 58515, Lüdenscheid, Deutschland. Harilaos.bogossian@klinikum-luedenscheid.de.|University Witten/Herdecke, Witten, Deutschland. Harilaos.bogossian@klinikum-luedenscheid.de.
authors.forename: Harilaos
authors.initials: H
authors.lastname: Bogossian
authors.affiliation: Department of Cardiology and Angiology, Klinikum Lüdenscheid Märkische Kliniken GmbH, Paulmannshöherstr. 14, 58515, Lüdenscheid, Deutschland.
authors.forename: Fuad
authors.initials: F
authors.lastname: Hasan
authors.affiliation: Division of Electrophysiology, Department of Cardiovascular Medicine, University of Münster, Münster, Deutschland.
authors.forename: Gerrit
authors.initials: G
authors.lastname: Frommeyer
authors.affiliation: Department of Cardiology and Angiology, Klinikum Lüdenscheid Märkische Kliniken GmbH, Paulmannshöherstr. 14, 58515, Lüdenscheid, Deutschland.|University Bochum, Bochum, Deutschland.
authors.forename: Bernd
authors.initials: B
authors.lastname: Lemke
authors.affiliation: Department of Cardiology and Angiology, Klinikum Lüdenscheid Märkische Kliniken GmbH, Paulmannshöherstr. 14, 58515, Lüdenscheid, Deutschland.|University Witten/Herdecke, Witten, Deutschland.
authors.forename: Markus
authors.initials: M
authors.lastname: Zarse
mesh_terms: D000368:Aged; D002037:Bundle-Branch Block / Q000175:diagnosis*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D003951:Diagnostic Errors / Q000517:prevention & control*; D004562:Electrocardiography / Q000379:methods*; D005189:False Positive Reactions; D005260:Female; D006352:Heart Ventricles; D006801:Humans; D013612:Tachycardia, Ectopic Atrial / Q000175:diagnosis*; D016896:Treatment Outcome
keywords: 4th intercostal space; Precordial leads; Right bundle branch block