title: Beneficial effect of Bradycardia Tachycardia Response (BTR) algorithm on VT detection in the presence of rate smoothing.
abstract: BACKGROUND
  Rate smoothing algorithms, while known to help prevent ventricular tachyarrhythmias in some patients, have been shown to result in underdetection of ventricular tachycardia (VT) due to interaction between bradycardia pacing and tachycardia detection parameters. A new algorithm named Bradycardia Tachycardia Response (BTR) has been developed in order to prevent rate smoothing-induced underdetection. The efficacy of BTR is not known. The aim of this study was to assess the effectiveness of BTR in preventing VT underdetection due to rate smoothing.
  
  
  RESULTS
  Two ICD models (TELIGEN and VITALITY AVT, Boston Scientific, St. Paul, MN, USA) bearing identical rate smoothing algorithms were connected to a VT simulator. Devices were programmed similarly except for the BTR feature that exists in TELIGEN only. The detection performance of both devices was tested using varying combinations of AV delay, rate smoothing down, and upper rate limit and compared between the two models. VT underdetection (delay or nondetection) occurred during pacing in 62% of the VT episodes with VITALITY AVT. In TELIGEN, all simulated VT episodes were detected appropriately as soon as their rates exceeded the programmed VT detection rate. Detection tended to be affected by higher upper rate, longer AV delays, and more aggressive rate smoothing.
  
  
  CONCLUSIONS
  The BTR algorithm effectively counteracts VT detection delay caused by the interaction of rate smoothing with VT detection parameters, thus enabling safe use of the rate smoothing feature.
authors.affiliation: Leviev Heart Center, Sheba Medical Center and Tel Aviv University, Tel Hashomer, Israel.
authors.forename: Savvas
authors.initials: S
authors.lastname: Nikolidakis
authors.forename: David
authors.initials: D
authors.lastname: Luria
authors.forename: Jessica Shayovich
authors.initials: JS
authors.lastname: Weisemberg
authors.forename: Nechemya
authors.initials: N
authors.lastname: Tanami
authors.forename: David Bar
authors.initials: DB
authors.lastname: Lev
authors.forename: Osnat
authors.initials: O
authors.lastname: Gurevitz
authors.forename: Raed Abu
authors.initials: RA
authors.lastname: Sham'a
authors.forename: Michael
authors.initials: M
authors.lastname: Eldar
authors.forename: Paul
authors.initials: P
authors.lastname: Friedman
authors.forename: Michael
authors.initials: M
authors.lastname: Glikson
mesh_terms: D000465:Algorithms; D001919:Bradycardia / Q000175:diagnosis* / Q000628:therapy*; D002304:Cardiac Pacing, Artificial / Q000379:methods*; D003198:Computer Simulation; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D006801:Humans; D008955:Models, Cardiovascular; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000628:therapy; D013813:Therapy, Computer-Assisted / Q000379:methods*