title: Successful reduction of a high defibrillation threshold by a combined implantation of a subcutaneous array and azygos vein lead.
abstract: A 72-year-old man with nonischemic cardiomyopathy was referred because his implantable cardioverter defibrillator had failed to terminate spontaneous ventricular fibrillation (VF). Defibrillation threshold (DFT) testing confirmed that 830-V shocks failed to defibrillate VF despite optimization of the biphasic waveform and reversal of shock polarity. The placement of a new right ventricular lead and the addition of a subcutaneous array failed to defibrillate VF at 830 V. The combination of a subcutaneous array and azygos vein coil successfully defibrillated VF. The mechanism for successful DFT reduction was likely greater current supplied to the posterior basal left ventricle by the azygos vein lead.
authors.affiliation: Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, Alabama 35294-0019, USA. takumi-y@fb4.so-net.ne.jp
authors.forename: Takumi
authors.initials: T
authors.lastname: Yamada
authors.forename: Peter G
authors.initials: PG
authors.lastname: Robertson
authors.forename: H Thomas
authors.initials: HT
authors.lastname: McElderry
authors.forename: Harish
authors.initials: H
authors.lastname: Doppalapudi
authors.forename: Vance J
authors.initials: VJ
authors.lastname: Plumb
authors.forename: G Neal
authors.initials: GN
authors.lastname: Kay
mesh_terms: D000368:Aged; D001401:Azygos Vein / Q000601:surgery*; D017147:Defibrillators, Implantable; D004056:Differential Threshold; D004554:Electric Countershock / Q000295:instrumentation* / Q000379:methods*; D004567:Electrodes, Implanted; D006801:Humans; D008297:Male; D019919:Prosthesis Implantation / Q000379:methods; D014693:Ventricular Fibrillation / Q000517:prevention & control*