title: Three-Dimensional Cardiac Mapping Characterizes Ventricular Contractile Patterns during Cardiac Resynchronization Therapy Implant: A Feasibility Study.
abstract: BACKGROUND
  Electroanatomic mapping systems track the position of electrodes in the heart. We assessed the feasibility of characterizing left ventricular (LV) performance during cardiac resynchronization therapy (CRT) implant utilizing an electroanatomic mapping system to track the motion of CRT lead electrodes, thus deriving ventricular contractility surrogates.
  
  
  METHODS
  During CRT implant, atrial, right ventricular (RV), and LV leads were connected to the EnSite NavX™ mapping system (St. Jude Medical Inc., St. Paul, MN, USA). The relative displacement of electrodes was averaged over 10 cardiac cycles during RV, LV, and biventricular (BiV) pacing in DOO mode. Three contractility surrogates indicative of ventricular performance were extracted from the RV-LV distance waveform: systolic slope (SS), time to peak systolic contraction (TPSC), and fractional shortening (FS).
  
  
  RESULTS
  In the 20 patients included, there were detectable differences in each of the three contractility surrogates responding to the different pacing configurations. Median SS varied 42%, median TPSC varied 35%, and median FS varied 19% across RV, LV, and BiV pacing interventions. The RV-LV distance waveform showed subtle sensitivity to varying pacing timing cycles when measured in a subset of patients. For all pacing configurations, RV-LV distance waveforms were stable during 2-minute recordings.
  
  
  CONCLUSIONS
  Tracking the motion of CRT pacing electrodes with a mapping system to derive contractility surrogates during implant is feasible.
authors.affiliation: Aurora Cardiovascular Services, Aurora Sinai/Aurora St. Luke's Medical Centers, University of Wisconsin School of Medicine and Public Health, Milwaukee, Wisconsin.
authors.forename: Imran K
authors.initials: IK
authors.lastname: Niazi
authors.affiliation: Kerckhoff-Klinik, Bad Nauheim, Germany.
authors.forename: Johannes
authors.initials: J
authors.lastname: Sperzel
authors.affiliation: Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Edwin Kevin
authors.initials: EK
authors.lastname: Heist
authors.affiliation: St. Jude Medical, Sylmar, California.
authors.forename: Stuart P
authors.initials: SP
authors.lastname: Rosenberg
authors.affiliation: St. Jude Medical, Sylmar, California.
authors.forename: Kyungmoo
authors.initials: K
authors.lastname: Ryu
authors.affiliation: St. Jude Medical, Sylmar, California.
authors.forename: Michael
authors.initials: M
authors.lastname: Yang
authors.affiliation: Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Andre
authors.initials: A
authors.lastname: D'Avila
authors.affiliation: Massachusetts General Hospital, Boston, Massachusetts.
authors.forename: Jagmeet P
authors.initials: JP
authors.lastname: Singh
mesh_terms: D000368:Aged; D018780:Body Surface Potential Mapping / Q000379:methods*; D058409:Cardiac Resynchronization Therapy Devices; D005240:Feasibility Studies; D005260:Female; D006333:Heart Failure / Q000150:complications / Q000175:diagnosis* / Q000517:prevention & control*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019919:Prosthesis Implantation / Q000379:methods; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D025321:Surgery, Computer-Assisted / Q000379:methods; D016896:Treatment Outcome; D018487:Ventricular Dysfunction, Left / Q000175:diagnosis* / Q000209:etiology / Q000517:prevention & control*
keywords: cardiac resynchronization therapy; contractility; dyssynchrony; electroanatomic mapping; heart failure