title: Electrocardiogram-based algorithm to predict the left ventricular lead position in recipients of cardiac resynchronization systems.
abstract: BACKGROUND
  Biventricular pacing is associated with various electrocardiographic patterns depending on the position of the left ventricular (LV) lead. We aimed to develop an electrocardiogram-based algorithm to predict the position of the LV lead.
  
  
  METHODS
  The algorithm was developed in 100 consecutive recipients of cardiac resynchronization therapy (CRT) systems. QRS axis, morphology, and polarity were analyzed with a view to define the specific electrocardiographic characteristics associated with the various LV lead positions. The algorithm was prospectively validated in 50 consecutive CRT device recipients.
  
  
  RESULTS
  The first analysis of the algorithm was the QRS morphology in V(1). A positive R wave in V(1) suggested LV lateral or posterior wall stimulation. A QS pattern was specific of anterior LV leads. In the presence of an R wave in V(1), V(6) was analyzed to distinguish between an inferior and anterior LV lead. Inferior leads were never associated with a positive V(6). To differentiate between lateral and posterior positions, we analyzed the pattern in V(2). Lateral leads were associated with an R morphology in V(1) and a negative V(2). Posterior leads were associated with an R morphology in V(1) and V(2). The algorithm allowed a reliable distinction between an inferior or anterior and a lateral or posterior lead position in 90% of patients. Inferior, anterior, lateral, and posterior positions were reliably distinguished in 80% of patients.
  
  
  CONCLUSIONS
  This algorithm predicted the position of the LV lead with a high sensitivity and predictive value.
authors.affiliation: University Victor Segalen, Bordeaux, and Hospital Haut Leveque, Pessac, France.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Ploux
authors.forename: Pierre
authors.initials: P
authors.lastname: Bordachar
authors.forename: Antoine
authors.initials: A
authors.lastname: Deplagne
authors.forename: Bilel
authors.initials: B
authors.lastname: Mokrani
authors.forename: Sylvain
authors.initials: S
authors.lastname: Reuter
authors.forename: Julien
authors.initials: J
authors.lastname: Laborderie
authors.forename: Stephane
authors.initials: S
authors.lastname: Garrigue
authors.forename: Nicolas
authors.initials: N
authors.lastname: Delarche
authors.forename: Pierre
authors.initials: P
authors.lastname: Jais
authors.forename: Michel
authors.initials: M
authors.lastname: Haissaguerre
authors.forename: Jacques
authors.initials: J
authors.lastname: Clementy
mesh_terms: D000368:Aged; D000465:Algorithms; D018780:Body Surface Potential Mapping / Q000379:methods*; D002304:Cardiac Pacing, Artificial / Q000379:methods; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D004562:Electrocardiography / Q000379:methods*; D004567:Electrodes, Implanted; D005260:Female; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D013813:Therapy, Computer-Assisted / Q000379:methods; D016277:Ventricular Function, Left