title: Circadian pattern of fibrillatory events in non-Brugada-type idiopathic ventricular fibrillation with a focus on J waves.
abstract: BACKGROUND
  The circadian pattern of ventricular fibrillation (VF) episodes in patients with idiopathic ventricular fibrillation (IVF) is poorly understood.
  
  
  OBJECTIVE
  The purpose of this study was to assess the circadian pattern of VF occurrence in patients with IVF.
  
  
  METHODS
  Excluding Brugada syndrome and other primary electrical diseases, the circadian pattern of VF occurrence was determined in 64 patients with IVF. The clinical and electrocardiographic characteristics were compared among patients with nocturnal (midnight to 6:00 AM) VF and nonnocturnal VF in relation to J waves. A J wave was defined as either notching or a slur at the QRS terminal >0.1 mV above the isoelectric line in contiguous leads.
  
  
  RESULTS
  The overall distribution pattern of VF occurrence showed 2 peaks at approximately 6:00 AM and around 8:00 PM. Nocturnal VF was observed in 20 patients (31.3%), and J waves were present in 14 of these 20 individuals (70.0%), whereas J waves were less frequent in the 44 nonnocturnal patients with VF: 16 (36.4%) (P = .0117). Among patients with J waves, nocturnal VF was observed in 46.7% with a peak at approximately 4:00 AM. Nocturnal VF was less common in patients without J waves, occurring in only 17.6% (P = .0124). Both the type and location of J waves and the pattern of the ST segment were similar between the nocturnal and nonnocturnal VF groups. J waves were associated with a VF storm and long-term arrhythmia recurrence.
  
  
  CONCLUSIONS
  In IVF, the presence of J waves may characterize a higher nocturnal incidence of VF and a higher acute and chronic risk of recurrence.
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan. Electronic address: yoshiyaaizawa-circ@umin.ac.jp.
authors.forename: Yoshiyasu
authors.initials: Y
authors.lastname: Aizawa
authors.affiliation: Department of Cardiology, Tachikawa General Hospital, Niigata, Japan.
authors.forename: Masahito
authors.initials: M
authors.lastname: Sato
authors.affiliation: Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Shiga, Japan.
authors.forename: Seiko
authors.initials: S
authors.lastname: Ohno
authors.affiliation: Department of Cardiovascular and Respiratory Medicine, Shiga University of Medical Science, Shiga, Japan.
authors.forename: Minoru
authors.initials: M
authors.lastname: Horie
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Seiji
authors.initials: S
authors.lastname: Takatsuki
authors.affiliation: Department of Cardiology, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Keiichi
authors.initials: K
authors.lastname: Fukuda
authors.affiliation: Graduate School of Health Sciences, Niigata University School of Medicine, Niigata, Japan.
authors.forename: Masaomi
authors.initials: M
authors.lastname: Chinushi
authors.affiliation: Department of Cardiology, Nagano Red Cross Hospital, Nagano, Japan.
authors.forename: Tatsuya
authors.initials: T
authors.lastname: Usui
authors.affiliation: Cardiovascular Division, Faculty of Medicine, University of Tsukuba, Ibaraki, Japan.
authors.forename: Kazutaka
authors.initials: K
authors.lastname: Aonuma
authors.affiliation: Department of Cardiology, Niigata City Hospital, Niigata, Japan.
authors.forename: Yukio
authors.initials: Y
authors.lastname: Hosaka
authors.affiliation: HôpitalCardiologique du Haut-Lévêque, Bordeaux-Pessac, France.
authors.forename: Michel
authors.initials: M
authors.lastname: Haissaguerre
authors.affiliation: Department of Cardiology, Tachikawa General Hospital, Niigata, Japan.
authors.forename: Yoshifusa
authors.initials: Y
authors.lastname: Aizawa
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D000889:Anti-Arrhythmia Agents / Q000627:therapeutic use; D053840:Brugada Syndrome; D002940:Circadian Rhythm; D015331:Cohort Studies; D016001:Confidence Intervals; D016757:Death, Sudden, Cardiac / Q000453:epidemiology; D018450:Disease Progression; D004562:Electrocardiography; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012008:Recurrence; D018570:Risk Assessment; D015996:Survival Rate; D013997:Time Factors; D014693:Ventricular Fibrillation / Q000175:diagnosis* / Q000188:drug therapy / Q000401:mortality*
chemical_list: D000889:Anti-Arrhythmia Agents
keywords: Circadian rhythm; Idiopathic ventricular fibrillation; J waves; Sudden cardiac death; Ventricular fibrillation