title: Circadian and seasonal variations of ventricular tachyarrhythmias in patients with early repolarization syndrome and Brugada syndrome: analysis of patients with implantable cardioverter defibrillator.
abstract: BACKGROUND
  The circadian and seasonal patterns of ventricular tachyarrhythmia (VTA) in patients with early repolarization syndrome (ERS) have not been determined. We compared the timing of VTAs in patients with ERS and Brugada syndrome (BS).
  
  
  RESULTS
  We enrolled patients with ERS (n = 14) and BS (n = 53) who underwent implantable cardioverter defibrillator (ICD) implantation. The timing of VTAs, including cardiac arrest and appropriate shocks, was determined. During follow up of 6.4 ± 3.6 years in the ERS group and 5.0 ± 3.3 years in the BS group, 5 of 14 (36%) ERS and 10 of 53 (19%) BS patients experienced appropriate shocks (P = 0.37). Cardiac arrest showed a trend of nocturnal distribution peaking from midnight to early morning (P = 0.14 in ERS, P = 0.16 in BS). Circadian distribution of appropriate shocks showed a significant nocturnal peak in patients with ERS (P < 0.0001) but a trend toward a nocturnal peak in patients with BS (P = 0.08). There were no seasonal differences in cardiac arrest in patients with ERS and BS. However, patients with ERS showed a seasonal peak in appropriate shocks from spring to summer (P < 0.0001). There was no significant seasonal peak in patients with BS. The timing of VTAs (cardiac arrest plus appropriate shock) showed significant nocturnal distributions in patients with ERS and BS (P < 0.01, respectively). A significant clustering of VTAs was noted from spring to summer (P < 0.01) in patients with ERS, but not in patients with BS (P = 0.42).
  
  
  CONCLUSIONS
  Incidence of VTAs showed marked circadian variations with night-time peaks in patients with ERS and BS.
authors.affiliation: Asan Medical Center, University of Ulsan, Seoul, Korea.
authors.forename: Sung-Hwan
authors.initials: SH
authors.lastname: Kim
authors.forename: Gi-Byoung
authors.initials: GB
authors.lastname: Nam
authors.forename: Seunghee
authors.initials: S
authors.lastname: Baek
authors.forename: Hyung Oh
authors.initials: HO
authors.lastname: Choi
authors.forename: Ki Hun
authors.initials: KH
authors.lastname: Kim
authors.forename: Kee-Joon
authors.initials: KJ
authors.lastname: Choi
authors.forename: Boyoung
authors.initials: B
authors.lastname: Joung
authors.forename: Hui-Nam
authors.initials: HN
authors.lastname: Pak
authors.forename: Moon-Hyoung
authors.initials: MH
authors.lastname: Lee
authors.forename: Sung Soon
authors.initials: SS
authors.lastname: Kim
authors.forename: Seung-Jung
authors.initials: SJ
authors.lastname: Park
authors.forename: Young Keun
authors.initials: YK
authors.lastname: On
authors.forename: June Soo
authors.initials: JS
authors.lastname: Kim
authors.forename: Il-Young
authors.initials: IY
authors.lastname: Oh
authors.forename: Eue-Keun
authors.initials: EK
authors.lastname: Choi
authors.forename: Seil
authors.initials: S
authors.lastname: Oh
authors.forename: Yun-Shik
authors.initials: YS
authors.lastname: Choi
authors.forename: Jong Il
authors.initials: JI
authors.lastname: Choi
authors.forename: Sang Weon
authors.initials: SW
authors.lastname: Park
authors.forename: Young-Hoon
authors.initials: YH
authors.lastname: Kim
authors.forename: Man Young
authors.initials: MY
authors.lastname: Lee
authors.forename: Hong Euy
authors.initials: HE
authors.lastname: Lim
authors.forename: Young-Soo
authors.initials: YS
authors.lastname: Lee
authors.forename: Yongkeun
authors.initials: Y
authors.lastname: Cho
authors.forename: Jun
authors.initials: J
authors.lastname: Kim
authors.forename: Dong-Il
authors.initials: DI
authors.lastname: Lee
authors.forename: Dae Kyoung
authors.initials: DK
authors.lastname: Cho
authors.forename: You-Ho
authors.initials: YH
authors.lastname: Kim
mesh_terms: D000328:Adult; D001145:Arrhythmias, Cardiac / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D053840:Brugada Syndrome / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D016009:Chi-Square Distribution; D002940:Circadian Rhythm; D016757:Death, Sudden, Cardiac / Q000517:prevention & control*; D017147:Defibrillators, Implantable; D004554:Electric Countershock / Q000009:adverse effects / Q000295:instrumentation*; D004562:Electrocardiography; D022062:Electrophysiologic Techniques, Cardiac; D004868:Equipment Failure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D056910:Republic of Korea; D012189:Retrospective Studies; D012621:Seasons; D017180:Tachycardia, Ventricular / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D016896:Treatment Outcome; D014693:Ventricular Fibrillation / Q000175:diagnosis / Q000503:physiopathology / Q000628:therapy*