title: Acute electrical and hemodynamic effects of multisite left ventricular pacing for cardiac resynchronization therapy in the dyssynchronous canine heart.
abstract: BACKGROUND
  Multisite left ventricular (multi-LV) epicardial pacing has been proposed as an alternative to conventional single-site LV (single-LV) pacing to increase the efficacy of cardiac resynchronization therapy.
  
  
  OBJECTIVE
  To compare the effects of multi-LV versus single-LV pacing in dogs with left bundle branch block (LBBB).
  
  
  METHODS
  Studies were performed in 9 anaesthetized dogs with chronic LBBB using 7 LV epicardial electrodes. Each electrode was tested alone and in combination with 1, 2, 3, and 6 other electrodes, the sequence of which was chosen on the basis of practical real-time electrical mapping to determine the site of the latest activation. LV total activation time (LVTAT) and dispersion of repolarization (DRep) were measured by using approximately 100 electrodes around the ventricles. LV contractility was assessed as the maximum derivative of left ventricular pressure (LVdP/dtmax ).
  
  
  RESULTS
  Single-LV pacing provided, on average, a -4.0% ± 9.3% change in LVTAT and 0.2% ± 13.7% change in DRep. Multi-LV pacing markedly decreased both LVTAT and DRep in a stepwise fashion to reach -41.3% ± 5% (P < .001 for overall comparison) and -14.2% ± 19.5% (P < .02 for overall comparison) in the septuple-LV pacing configuration, respectively. Single-LV pacing provided a mean increase of 10.7% ± 7.7% in LVdP/dtmax. LVdP/dtmax incrementally increased by the addition of pacing electrodes to 16.4% ± 8.7% (P < .001 for overall comparison). High response to single-LV pacing could not be improved further during multi-LV pacing.
  
  
  CONCLUSIONS
  Compared with single-LV pacing, multi-LV pacing can considerably reduce both LVTAT and DRep in dogs with LBBB, but the improvement in contractility is limited to conditions where single-LV pacing provides suboptimal improvement. Further studies are warranted to determine whether these acute effects translate in antiarrhythmic properties and better long-term outcomes.
authors.affiliation: Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands; Hôpital de Haut-Lévêque, CHU de Bordeaux, Pessac, France; L'Institut de Rythmologie et modélisation Cardiaque, Université de Bordeaux Segalen, Bordeaux, France. Electronic address: sylvain.ploux@free.fr.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Ploux
authors.affiliation: Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
authors.forename: Marc
authors.initials: M
authors.lastname: Strik
authors.affiliation: Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
authors.forename: Arne
authors.initials: A
authors.lastname: van Hunnik
authors.affiliation: Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
authors.forename: Lars
authors.initials: L
authors.lastname: van Middendorp
authors.affiliation: Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
authors.forename: Marion
authors.initials: M
authors.lastname: Kuiper
authors.affiliation: Department of Physiology, Cardiovascular Research Institute Maastricht, Maastricht University, Maastricht, The Netherlands.
authors.forename: Frits W
authors.initials: FW
authors.lastname: Prinzen
mesh_terms: D000818:Animals; D018780:Body Surface Potential Mapping; D002037:Bundle-Branch Block / Q000503:physiopathology / Q000628:therapy*; D058406:Cardiac Resynchronization Therapy / Q000379:methods*; D004195:Disease Models, Animal; D004285:Dogs; D006352:Heart Ventricles / Q000503:physiopathology*; D006439:Hemodynamics / Q000502:physiology*; D017725:Ventricular Pressure
keywords: Biventricular pacing; CRT; Cardiac mapping; Cardiac resynchronization therapy; DRep; Heart failure; LBBB; LV; LVTAT; LVdP/dt(max); Left bundle branch block; Multisite left ventricular pacing; RV; cardiac resynchronization therapy; dispersion of repolarization; left bundle branch block; left ventricular; left ventricular total activation time; maximum derivative of left ventricular pressure; multi-LV; multisite left ventricular; right ventricular; single-LV; single-site left ventricular