title: Implanted defibrillators in trouble: initial device misclassification leads to correct diagnosis-a case series.
abstract: OBJECTIVE
  Supraventricular tachycardia, mistakenly diagnosed as ventricular tachycardia, may lead to inappropriate ICD therapy. Inappropriate ICD therapy associates with increased morbidity and mortality. A reduction of inappropriate therapy is therefore desired.
  
  
  RESULTS
  We present three different cases that beautifully illustrate the diagnostic possibilities of stored electrograms. Initial differential diagnoses in all three patients included ventricular tachycardia, focal atrial tachycardia, atrio-ventricular re-entry tachycardia, and atrio-ventricular nodal re-entry tachycardia. The first case was diagnosed as atrio-ventricular nodal re-entry tachycardia. In the second case, atrio-ventricular re-entry tachycardia was revealed. Ectopic atrial tachycardia was the reason for inappropriate therapy in the third patient.
  
  
  CONCLUSIONS
  Thorough analysis of stored electrograms yielded correct diagnosis in all cases, which subsequently was confirmed by electrophysiological study.
authors.forename: Andreas
authors.initials: A
authors.lastname: Müssigbrodt
authors.forename: Helge
authors.initials: H
authors.lastname: Knopp
authors.forename: Timm
authors.initials: T
authors.lastname: Seewöster
authors.forename: Sebastian
authors.initials: S
authors.lastname: Hilbert
authors.forename: Johannes
authors.initials: J
authors.lastname: Lucas
authors.forename: Kerstin
authors.initials: K
authors.lastname: Nowotnick
authors.forename: Borislav
authors.initials: B
authors.lastname: Dinov
authors.forename: Gerhard
authors.initials: G
authors.lastname: Hindricks
authors.forename: Arash
authors.initials: A
authors.lastname: Arya
authors.forename: Sergio
authors.initials: S
authors.lastname: Richter
mesh_terms: D000328:Adult; D017147:Defibrillators, Implantable; D003937:Diagnosis, Differential; D003951:Diagnostic Errors / Q000517:prevention & control*; D004562:Electrocardiography / Q000379:methods*; D006801:Humans; D008297:Male; D008875:Middle Aged; D013617:Tachycardia, Supraventricular / Q000175:diagnosis* / Q000517:prevention & control*; D017180:Tachycardia, Ventricular / Q000175:diagnosis* / Q000517:prevention & control*
keywords: Antitachycardia pacing; Atrioventricular nodal re-entry tachycardia; Atrioventricular re-entry tachycardia; Ectopic atrial tachycardia; Electrogram; Implantable cardioverter defibrillator; Inapproriate therapy; Supraventricular tachycardia