title: Impaired detection of ventricular tachyarrhythmias by a rate-smoothing algorithm in dual-chamber implantable defibrillators: intradevice interactions.
abstract: BACKGROUND
  Rate smoothing is an algorithm initially designed to prevent rapid changes in pacemaker rates. In this study, we sought to determine the potential of the rate-smoothing mechanism in preventing detection of ventricular tachyarrhythmias.
  
  
  RESULTS
  Clinical testing of rate smoothing was performed at the time of defibrillator arrhythmia induction in 16 patients with implantable defibrillators during 65 episodes of ventricular tachyarrhythmias. We also performed simulator-based testing to assess detection of ventricular tachycardia between 170 and 220 beats/min with systematic sequential change of rate-smoothing percent, AV delay, and maximal rate. During clinical testing of 54 ventricular fibrillation/polymorphic ventricular tachyarrhythmia episodes, there were no cases of nondetection and 3 episodes (5%) of minimally delayed detection. Of 10 monomorphic ventricular tachyarrhythmias, 6 had either delayed (2 cases) or absent (4 cases) detection. During simulator testing, complex interrelationships were demonstrated in AV delay, upper rate, and rate-smoothing percent in determining the severity of the effect on detection. Generally, long AV delay, higher upper rate, and smaller (more aggressive) rate smoothing were associated with increased risk of ventricular tachyarrhythmia underdetection. Importantly, use of parameters that impaired detection was always accompanied by a programmer warning message.
  
  
  CONCLUSIONS
  Rate smoothing may result in delay or failure of ventricular tachycardia detection. It is important to consider warning messages when programming rate smoothing and to test for appropriate detection when rate smoothing is used despite warning messages.
authors.affiliation: Sheba Medical Center and Tel Aviv University, Tel Hashomer, Israel.
authors.forename: Michael
authors.initials: M
authors.lastname: Glikson
authors.forename: Amy L
authors.initials: AL
authors.lastname: Beeman
authors.forename: David M
authors.initials: DM
authors.lastname: Luria
authors.forename: David L
authors.initials: DL
authors.lastname: Hayes
authors.forename: Paul A
authors.initials: PA
authors.lastname: Friedman
mesh_terms: D000465:Algorithms; D016477:Artifacts; D003198:Computer Simulation; D017147:Defibrillators, Implantable / Q000009:adverse effects* / Q000592:standards; D019544:Equipment Failure Analysis / Q000295:instrumentation / Q000379:methods; D005188:False Negative Reactions; D006339:Heart Rate; D006801:Humans; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012986:Software Validation; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000209:etiology*