title: Implantable cardioverter defibrillator electrogram adjudication for device registries: methodology and observations from ALTITUDE.
abstract: BACKGROUND
  The increasing use of remote monitoring with the associated large retrievable databases provides a unique opportunity to analyze observations on implantable cardioverter-defibrillator (ICD) therapies. Adjudication of a large number of stored ICD electrograms (EGMs) presents a unique challenge. The ALTITUDE study group was designed to use the LATITUDE remote monitoring system to evaluate ICD patient outcomes across the United States.
  
  
  RESULTS
  Of 81,081 patients on remote monitoring, a random sample of 2,000 patients having 5,279 shock episodes was selected. The ALTITUDE EGM review committee was comprised of seven electrophysiologists from four institutions. An online EGM adjudication system was designed. Episodes were classified as appropriate (70% of shock episodes) or inappropriate ICD therapies (30%). Light's Kappa was used to assess agreement. Interobserver and intraobserver Kappa scores for dual-chamber ICDs were 0.84 (0.71-0.91) and 0.89 (0.82-0.95), consistent with substantial agreement. Interobserver and intraobserver Kappa scores for single-chamber ICDs were 0.61 (0.54-0.67) and 0.69 (0.59-0.79). The rhythm categories of "nonsustained arrhythmia" and "polymorphic and monomorphic ventricular tachycardia" resulted in the greatest degree of discordant adjudication between reviewers.
  
  
  CONCLUSIONS
  This method of adjudication of a large volume of stored EGM data prior to device therapies will allow new observations in regards to device performance and has the potential to improve device programming and design. There was substantial interreviewer agreement for rhythm classification. Agreement was greater for dual-chamber compared to single-chamber devices, indicating the atrial lead adds diagnostic value in rhythm interpretation.
authors: Mayo Clinic, Rochester, Minnesota 55905, USA. powell.brian@mayo.edu
authors: Brian D
authors: BD
authors: Powell
authors: Yong-Mei
authors: YM
authors: Cha
authors: Samuel J
authors: SJ
authors: Asirvatham
authors: David A
authors: DA
authors: Cesario
authors: Michael
authors: M
authors: Cao
authors: Paul W
authors: PW
authors: Jones
authors: Milan
authors: M
authors: Seth
authors: Leslie A
authors: LA
authors: Saxon
authors: F Roosevelt
authors: FR
authors: Gilliam
mesh_terms: D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000628:therapy; D017147:Defibrillators, Implantable; D022062:Electrophysiologic Techniques, Cardiac; D006801:Humans; D008991:Monitoring, Physiologic / Q000379:methods*; D012042:Registries; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000628:therapy; D016896:Treatment Outcome