title: A pitfall in using far-field bipolar electrograms in arrhythmia discrimination in a patient with an implantable cardioverter defibrillator.
abstract: Analysis of stored electrograms from bipolar far-field electrodes is considered to be useful in differentiating supraventricular from ventricular arrhythmias. A case of inappropriate ICD shocks for sinus tachycardia is presented whereby successive shocks caused marked widening of the ventricular electrograms. Analysis of these stored electrograms, recorded from far-field bipolar electrodes, gave the false impression of ventricular tachycardia. The widening was due to the current of injury effects, probably a consequence of the large amount of intervening myocardium between the bipoles. While analyzing recordings from far-field bipolar electrodes is generally useful, it is not always reliable, for changes in electrogram morphology, relative to baseline rhythm, may result from other factors like current of injury.
authors.affiliation: Department of Medicine, Mount Sinai Medical Center, New York, New York, USA.
authors.forename: H M
authors.initials: HM
authors.lastname: Nayak
authors.forename: L
authors.initials: L
authors.lastname: Tsao
authors.forename: F
authors.initials: F
authors.lastname: Santoni-Rugiu
authors.forename: J A
authors.initials: JA
authors.lastname: Gomes
authors.forename: D
authors.initials: D
authors.lastname: Mehta
mesh_terms: D000328:Adult; D017147:Defibrillators, Implantable / Q000009:adverse effects; D003937:Diagnosis, Differential; D004562:Electrocardiography / Q000379:methods*; D004582:Electronics, Medical; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D013616:Tachycardia, Sinus / Q000175:diagnosis* / Q000503:physiopathology / Q000628:therapy; D017180:Tachycardia, Ventricular / Q000175:diagnosis*