title: Use of the AutoCapture Pacing System with implantable defibrillator leads.
abstract: BACKGROUND
  Previous studies using various bipolar pacemaker leads have shown that the AutoCapture (AC) Pacing System is able to verify ventricular capture and regulate pacing output, increasing patient safety with respect to unexpected threshold changes and potentially prolonging device longevity. An increasing number of patients with implantable cardioverter defibrillators (ICDs) require ventricular pacing that contributes to a shortening of longevity of these systems. This prospective study tested the compatibility of the AC system with bipolar ICD leads.
  
  
  METHODS
  The AC algorithm was evaluated prior to ICD testing in 30 ICD recipients. A single coil, active fixation, true bipolar ventricular lead was implanted in 21 patients, and a dual coil, passive fixation, integrated bipolar ventricular lead was implanted in 9 patients. A ventricular evoked response sensitivity test and an AC threshold test were performed using a pacemaker with the ventricular AC algorithm.
  
  
  RESULTS
  AC was recommended in 22/30 (73.3%) of implants, including 20/21 (95.2%) with the single coil and 2/9 (22.2%) with the dual coil lead. Mean polarization was lower (1.23 +/- 0.95 mV vs 3.70 +/- 2.33 mV, P = 0.013) while the mean evoked response was higher (18.04 +/- 8.29 mV vs 10.13 +/- 4.22 mV, P = 0.002) with the single coil leads.
  
  
  CONCLUSIONS
  Automatic threshold tracking using the AC is compatible with ICD leads. Leads with lower polarization and greater evoked response are more likely to result in recommendation of AC use. Use of this system offers the potential for increasing ICD generator longevity and improving patient safety in response to late unexpected threshold increases.
authors.affiliation: New England Medical Center, Boston, MA, USA.
authors.forename: John P
authors.initials: JP
authors.lastname: Marenco
authors.forename: Ruth Ann
authors.initials: RA
authors.lastname: Greenfield
authors.forename: Ali
authors.initials: A
authors.lastname: Massumi
authors.forename: Zaffer A
authors.initials: ZA
authors.lastname: Syed
authors.forename: Timothy
authors.initials: T
authors.lastname: Mcintyre
authors.forename: Michael
authors.initials: M
authors.lastname: Hardage
authors.forename: Mark S
authors.initials: MS
authors.lastname: Link
authors.forename: Munther K
authors.initials: MK
authors.lastname: Homoud
authors.forename: Mark
authors.initials: M
authors.lastname: Estes
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Wang
mesh_terms: D000368:Aged; D000465:Algorithms; D002304:Cardiac Pacing, Artificial; D017147:Defibrillators, Implantable; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies