title: Anodal capture in cardiac resynchronization therapy implications for device programming.
abstract: BACKGROUND
  Right ventricular (RV) anodal capture (AC) has been reported in cardiac resynchronization therapy (CRT), when left ventricular (LV) pacing uses pseudobipolar (LV tip to RV proximal electrode) configuration. The aim of the study was to analyze the prevalence of AC and its implications for device programming.
  
  
  RESULTS
  When AC occurred, the resulting QRS morphology was evaluated with the following pacing modes: (1) LV tip pacing plus RV AC, (2) Biventricular (BiV) pacing (i.e., both LV and RV tip pacing), and (3) BiV pacing plus RV AC. Several interventricular pacing (VV) intervals from 50 ms of LV preactivation to 30 ms of RV preactivation were tested in modes 2 and 3. From 38 consecutive patients, AC was achieved in 14 (in 74% of the pacemakers and in none of the defibrillators). LV tip pacing plus RV AC obtained narrower QRS than BiV pacing at all VV intervals in seven of the patients with AC (50%). When BiV pacing is combined with RV AC, it produced a ventricular depolarization through two wave fronts (one from the LV tip and the second from either the ring or the tip of the RV lead depending on the VV interval programmed).
  
  
  CONCLUSIONS
  AC obtained the narrowest QRS of all tested pacing modes in a significant proportion of patients undergoing CRT. Though the stimulus was delivered from three sites (BiV pacing plus RV AC mode), only two wave fronts of ventricular activation were seen by ECG.
authors.affiliation: Thorax Institute, Hospital Clínic, University of Barcelona, and Institut de Investigació, Biomèdica August Pi i Sunyer (IDIBAPS), Catalonia, Spain. dtambore@clinic.ub.es
authors.forename: David
authors.initials: D
authors.lastname: Tamborero
authors.forename: Lluis
authors.initials: L
authors.lastname: Mont
authors.forename: Roberto
authors.initials: R
authors.lastname: Alanis
authors.forename: Antonio
authors.initials: A
authors.lastname: Berruezo
authors.forename: Jose Maria
authors.initials: JM
authors.lastname: Tolosana
authors.forename: Marta
authors.initials: M
authors.lastname: Sitges
authors.forename: Barbara
authors.initials: B
authors.lastname: Vidal
authors.forename: Josep
authors.initials: J
authors.lastname: Brugada
mesh_terms: D000368:Aged; D016477:Artifacts; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004562:Electrocardiography / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D019544:Equipment Failure Analysis; D005260:Female; D006801:Humans; D008297:Male; D010138:Pacemaker, Artificial; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000628:therapy*; D013813:Therapy, Computer-Assisted / Q000379:methods*; D016896:Treatment Outcome