title: Pacing with capture verification in candidates for resynchronisation therapy: a feasibility study.
abstract: BACKGROUND
  Devices for cardiac resynchronisation therapy (CRT) deliver energy into 3 output channels. Such a burden can significantly reduce device longevity. Autocapture has been shown to improve pacemaker longevity and safety of right ventricular pacing in clinical studies. The aim of this study was to investigate the application of Autocapture during biventricular pacing (BIV) to decrease the energy cost of CRT.
  
  
  METHODS
  During implantation of BIV devices, an acute study was performed to test the hypothesis that the evoked response (ER) elicited by each delivered stimulus is correctly detected and measured either on the right ventricular (RV) channel during BIV pacing with the left ventricular (LV) channel pacing first, or in the LV channel with the RV channel pacing first. A reliable measurement of ER is the critical requirement for the correct performance of Autocapture.
  
  
  RESULTS
  ER amplitude in the right ventricle during BIV pacing was not significantly decreased compared with RV pacing in the VVI mode (16.36+/-5.27 mV vs 17.09+/-6.12 mV). ER amplitude in the left ventricle during BIV pacing was not significantly decreased compared with LV pacing in the VVI mode (12.4+/-8.95 mV vs 12.25+/-8.97 mV). Three patients in atrial fibrillation had a DDDR pacemaker with the LV lead connected to the atrial port, and received BIV pacing with Autocapture turned on in the RV channel. Autocapture performance in the long term, as assessed by the trend of RV threshold over 20+/-8 months, showed that LV depolarisation was never sensed as an ER on the RV channel.
  
  
  CONCLUSIONS
  Our observations support the feasibility and safety of capture verification during BIV pacing on the ventricular channel paced secondly, which could increase the longevity of CRT devices, and decrease the costs of this new therapy for heart failure patients.
authors.affiliation: Institute of Cardiology, University of Bologna, Via Massarenti 9, 40138 Bologna, Italy. mbiffi@orsola-malpighi.med.unibo.it
authors.forename: Mauro
authors.initials: M
authors.lastname: Biffi
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Boriani
authors.forename: Matteo
authors.initials: M
authors.lastname: Bertini
authors.forename: Paolo
authors.initials: P
authors.lastname: Silvestri
authors.forename: Cristian
authors.initials: C
authors.lastname: Martignani
authors.forename: Angelo
authors.initials: A
authors.lastname: Branzi
mesh_terms: D000465:Algorithms; D001281:Atrial Fibrillation; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004562:Electrocardiography; D004567:Electrodes, Implanted; D005071:Evoked Potentials; D005240:Feasibility Studies; D006333:Heart Failure / Q000628:therapy*; D006801:Humans; D010138:Pacemaker, Artificial; D016277:Ventricular Function, Left; D016278:Ventricular Function, Right