title: Optimal strength and number of shocks at upper limit of vulnerability testing required to predict high defibrillation threshold without inducing ventricular fibrillation.
abstract: BACKGROUND
  The upper limit of vulnerability (ULV) closely correlates with the defibrillation threshold (DFT). The aim of this study was to establish the optimal protocol for using the ULV test to predict high DFT (>20 J) without inducing ventricular fibrillation (VF).
  
  
  RESULTS
  The 10-J and 15-J ULV test with 3 coupling intervals (-20, 0, and +20 ms to the peak of T-wave) and the DFT test were performed in 96 patients receiving implantable cardioverter defibrillator. ULV ≤ 10 J was confirmed in 47 (49%). ULV ≤ 15 J was confirmed in 70 (77%) of 91 patients (15-J ULV test could not be done in 5). The sensitivity and negative predictive value of both ULV >10 J and >15 J for predicting high DFT were 100%. The specificity and positive predictive value of ULV >15 J were higher than those for ULV >10 J (85% vs. 55%, 43% vs. 22%, respectively). The rate of VF inducibility for confirming ULV ≤ 15 J was lower than that for ULV ≤ 10 J (23% vs. 51%, P<0.0001). On analysis of single 15-J ULV test only at the peak of T-wave, VF was not induced in 79 of 91 patients, but 4 of these had high DFT.
  
  
  CONCLUSIONS
  The 15-J ULV test with 3 coupling intervals could correctly identify high-DFT patients and reduce the necessity for VF induction at defibrillator implantation.
authors.affiliation: Division of Cardiovascular Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine.
authors.forename: Kaoru
authors.initials: K
authors.lastname: Takami
authors.forename: Akihiro
authors.initials: A
authors.lastname: Yoshida
authors.forename: Koji
authors.initials: K
authors.lastname: Fukuzawa
authors.forename: Asumi
authors.initials: A
authors.lastname: Takei
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Kiuchi
authors.forename: Gaku
authors.initials: G
authors.lastname: Kanda
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Kumagai
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Takami
authors.forename: Satoko
authors.initials: S
authors.lastname: Torii-Tanaka
authors.forename: Mitsuaki
authors.initials: M
authors.lastname: Itoh
authors.forename: Kimitake
authors.initials: K
authors.lastname: Imamura
authors.forename: Ryudo
authors.initials: R
authors.lastname: Fujiwara
authors.forename: Atsushi
authors.initials: A
authors.lastname: Suzuki
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Nakanishi
authors.forename: Soichiro
authors.initials: S
authors.lastname: Yamashita
authors.forename: Akinori
authors.initials: A
authors.lastname: Matsumoto
authors.forename: Ken-ichi
authors.initials: K
authors.lastname: Hirata
mesh_terms: D000368:Aged; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000009:adverse effects / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D014693:Ventricular Fibrillation / Q000503:physiopathology* / Q000517:prevention & control*