title: The relationship between pacing site and induction or termination of sustained monomorphic ventricular tachycardia by antitachycardia pacing.
abstract: BACKGROUND
  With the development of left ventricular pacing for cardiac resynchronization, there is an interest in the possibility of improving ventricular antitachycardia pacing (ATP) efficacy by pacing from the LV electrode(s).
  
  
  OBJECTIVE
  This study assessed the efficacy of pacing delivered from the left coronary vein (LCV) compared to that delivered from the right ventricular apex (RVA) upon ventricular tachycardia (VT) induction and termination.
  
  
  METHODS
  Sixty patients undergoing provocative ventricular electrophysiology (EP) studies in three centers were enrolled. Multipolar EP catheters were placed in the atrium, the RVA, and LCV. VT induction was attempted from the RVA and LCV in random order. Upon detection of monomorphic VT, burst ATP for up to 10 pulses at 88% VT cycle length was delivered from the RVA or LCV, in a random order, and crossed over when possible. Identical VT morphologies were reinduced to allow paired comparison of RVA versus LCV ATP.
  
  
  RESULTS
  Data from 55 patients were analyzed. Thirty-four morphologically distinct monomorphic VT types were induced in 22 patients. ATP succeeded in 18 (55%) and VTs in 13 patients. RVA ATP terminated 15 of 23 (65%) VTs, and LCV ATP terminated 10 of 23 (43%) VTs (P = 0.14). ATP delivered ipsilateral to the earliest activation site required 5.0 + or - 2.6 pulses to terminate compared to 4.8 + or - 1.7 pulses when delivered from the contralateral site (P = 0.90). Paired comparison was possible for 13 VT morphologies in 11 patients. Paired RVA and LCV ATP efficacy was identical (54%vs 54%, P = 1.0).
  
  
  CONCLUSIONS
  ATP delivered from a LCV lead offers no efficacy advantage over pacing from the RVA.
authors.affiliation: University Hospital, London, Ontario, Canada.
authors.forename: Raymond
authors.initials: R
authors.lastname: Yee
authors.forename: Ulrika
authors.initials: U
authors.lastname: Birgersdotter-Green
authors.forename: Paul
authors.initials: P
authors.lastname: Belk
authors.forename: Troy
authors.initials: T
authors.lastname: Jackson
authors.forename: Jill
authors.initials: J
authors.lastname: Christensen
authors.forename: Mark S
authors.initials: MS
authors.lastname: Wathen
mesh_terms: D002304:Cardiac Pacing, Artificial / Q000379:methods*; D004566:Electrodes; D005260:Female; D006352:Heart Ventricles; D006801:Humans; D008297:Male; D008875:Middle Aged; D017180:Tachycardia, Ventricular / Q000209:etiology* / Q000503:physiopathology / Q000628:therapy*