title: Dynamicity of the J-wave in idiopathic ventricular fibrillation with a special reference to pause-dependent augmentation of the J-wave.
abstract: OBJECTIVE
  This study evaluated the pause-dependency of the J-wave to characterize this phenomenon in idiopathic ventricular fibrillation (VF).
  
  
  BACKGROUND
  The J-wave can be found in apparently healthy subjects and in patients at risk for sudden cardiac death, and risk stratification is therefore needed.
  
  
  METHODS
  Forty patients with J-wave-associated idiopathic VF were studied for J waves with special reference concerning pause-dependent augmentation. J waves were defined as those ≥0.1 mV above the isoelectric line and were compared with 76 non-VF patients of comparable age and sex.
  
  
  RESULTS
  The J-wave was larger in patients with idiopathic VF than in the controls: 0.360 ± 0.181 mV versus 0.192 ± 0.064 mV (p = 0.0011). J waves were augmented during storms of VF (n = 9 [22.5%]), which was controlled by isoproterenol; they disappeared within weeks in 5 patients. In addition, sudden prolongation of the R-R interval was observed in 27 patients induced by benign arrhythmia, and 15 patients (55.6%) demonstrated pause-dependent augmentation (from 0.391 ± 0.126 mV to 0.549 ± 0.220 mV; p < 0.0001). In the other 12 experimental subjects and in the 76 control subjects, J waves remained unchanged. Pause-dependent augmentation of J waves was detected in 55.6% (sensitivity) but was specific (100%) in the patients with idiopathic VF with high positive (100%) and negative (86.4%) predictive values.
  
  
  CONCLUSIONS
  Pause-dependent augmentation of J waves was confirmed in about one-half of the patients with idiopathic VF after sudden R-R prolongation. Such dynamicity of J waves was specific to idiopathic VF and may be used for risk stratification.
authors.affiliation: Niigata University Graduate School of Medical and Dental Science, Niigata, Japan. aizaways@med.niigata-u.ac.jp
authors.forename: Yoshifusa
authors.initials: Y
authors.lastname: Aizawa
authors.forename: Akinori
authors.initials: A
authors.lastname: Sato
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Watanabe
authors.forename: Masaomi
authors.initials: M
authors.lastname: Chinushi
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Furushima
authors.forename: Minoru
authors.initials: M
authors.lastname: Horie
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Kaneko
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Imaizumi
authors.forename: Kimie
authors.initials: K
authors.lastname: Okubo
authors.forename: Ichiro
authors.initials: I
authors.lastname: Watanabe
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Shinozaki
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Aizawa
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fukuda
authors.forename: Kunitake
authors.initials: K
authors.lastname: Joo
authors.forename: Michel
authors.initials: M
authors.lastname: Haissaguerre
mesh_terms: D000318:Adrenergic beta-Agonists / Q000627:therapeutic use; D000328:Adult; D016757:Death, Sudden, Cardiac / Q000453:epidemiology* / Q000517:prevention & control; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007545:Isoproterenol / Q000627:therapeutic use*; D007564:Japan / Q000453:epidemiology; D008297:Male; D011237:Predictive Value of Tests; D011379:Prognosis; D012189:Retrospective Studies; D012307:Risk Factors; D015996:Survival Rate / Q000639:trends; D014693:Ventricular Fibrillation / Q000188:drug therapy / Q000401:mortality / Q000503:physiopathology*
chemical_list: D000318:Adrenergic beta-Agonists; D007545:Isoproterenol