title: Biventricular paced QRS predictors of left ventricular lead locations in relation to mortality in cardiac resynchronization therapy.
abstract: BACKGROUND
  Left ventricular (LV) lead location during cardiac resynchronization therapy (CRT) has influenced mortality and heart failure events; however the biventricular paced QRS morphology has not been established as a predictor of LV lead location or mortality.
  
  
  METHODS
  We evaluated the biventricular paced QRS morphology in 306 patients undergoing CRT in relation to specific anatomic locations. A logistic regression model and Kaplan-Meier survival estimates were used to determine predictors of LV lead location and survival.
  
  
  RESULTS
  The mean age was 68±13years. Predictors of LV lead location from anterior, lateral, and posterior segments were: absence of R in V1, QS in aVL; and R in aVL, respectively. Absence of an R in II, III, or aVF predicted an inferior site. A QS in V4-V6 differentiated apical from basal sites (p=0.01). LV pacing from sites along the middle cardiac vein revealed a higher mortality (34%), than lateral sites (20%, p=0.02).
  
  
  CONCLUSIONS
  Biventricular paced QRS criteria were predictive of LV lead locations. The proposed algorithm enhanced the predictive accuracy of these criteria. LV pacing sites along the middle cardiac vein were associated with increased mortality.
authors.affiliation: Division of Cardiology, Electrophysiology Section, Drexel University College of Medicine, Philadelphia, PA, USA. Electronic address: john.fontaine@drexelmed.edu.
authors.forename: John M
authors.initials: JM
authors.lastname: Fontaine
authors.affiliation: Division of Cardiology, Electrophysiology Section, Drexel University College of Medicine, Philadelphia, PA, USA.
authors.forename: Ashwani
authors.initials: A
authors.lastname: Gupta
authors.affiliation: Division of Cardiology, Electrophysiology Section, Drexel University College of Medicine, Philadelphia, PA, USA.
authors.forename: Sona M
authors.initials: SM
authors.lastname: Franklin
authors.affiliation: Division of Cardiology, Electrophysiology Section, Drexel University College of Medicine, Philadelphia, PA, USA.
authors.forename: Christina U
authors.initials: CU
authors.lastname: Kang
authors.affiliation: Division of Cardiology, Electrophysiology Section, Drexel University College of Medicine, Philadelphia, PA, USA.
authors.forename: Latrisha A
authors.initials: LA
authors.lastname: Whigham
mesh_terms: D000368:Aged; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000401:mortality / Q000503:physiopathology; D058406:Cardiac Resynchronization Therapy / Q000009:adverse effects / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices / Q000009:adverse effects; D004562:Electrocardiography; D004567:Electrodes, Implanted / Q000009:adverse effects; D005260:Female; D006333:Heart Failure / Q000401:mortality* / Q000628:therapy*; D006801:Humans; D008297:Male; D015996:Survival Rate; D016896:Treatment Outcome; D016277:Ventricular Function, Left
keywords: Biventricular pacing; Cardiac resynchronization therapy; Congestive heart failure; Electrocardiogram; Implantable defibrillator