title: Ventricular arrhythmia discriminator programming and the impact on the incidence of inappropriate therapy in patients with implantable cardiac defibrillators.
abstract: BACKGROUND
  The incidence of inappropriate therapy from implantable cardioverter defibrillators (ICDs) has been reduced by programming ventricular arrhythmia discriminators (VAD) on at the time of implant.
  
  
  OBJECTIVE
  To determine which VAD is most effective in preventing inappropriate therapy.
  
  
  RESULTS
  Dual chamber ICD (n=48) or cardiac resynchronization therapy defibrillator (CRT-D) (n=55) implantation was performed in 103 patients (M=94, F=9). Patients were followed prospectively for therapy events (shock or anti-tachycardia pacing) for a mean 362+/-289 days. Events were correlated with clinical characteristics and VAD programming. Of the 103 pts followed, 11 received inappropriate therapy (IT), 15 received appropriate therapy (AT), and 77 received no therapy (NT). In the AT and IT groups, a total of 207 events (ATP=171, shock=36) were observed. A total of sixty-four electrograms (EGMs) were analyzed. Programming VADs "ON" versus "OFF" reduced the incidence of IT events compared to those receiving AT or NT events (p<.01), with a trend in fewer patients receiving IT (31.3% "ON" vs 55.6% "OFF", p = 0.131). Programming atrial fibrillation (AF) detection ON resulted in fewer patients receiving IT compared to those receiving AT or NT (3.6% vs 19%, p<.05). Furthermore, programming AF or AFL algorithms "ON", resulted in overall fewer episodes of IT therapy (p<.01).
  
  
  CONCLUSIONS
  AF or AFL discriminators significantly reduced the incidence of IT, and were predominantly responsible for the benefits from VAD programming observed in this study. Activating these features as part of routine ICD or CRT-D programming may provide a simple and effective alternative to the use of more complex and multiple VAD strategies.
authors.affiliation: UCSD Medical Center, and the Veterans Administration Medical Center, San Diego, CA, USA.
authors.forename: Uma N
authors.initials: UN
authors.lastname: Srivatsa
authors.forename: Bobbi L
authors.initials: BL
authors.lastname: Hoppe
authors.forename: Sanjiv
authors.initials: S
authors.lastname: Narayan
authors.forename: Gregory K
authors.initials: GK
authors.lastname: Feld
authors.forename: Ulrika
authors.initials: U
authors.lastname: Birgersdotter-Green