title: Examining the relationship between triggering activities and the circadian distribution of acute aortic dissection.
abstract: OBJECTIVE
  There are limited data examining triggering activities and circadian distribution at the onset of acute aortic dissection (AAD) in the context of diagnostic and anatomical classification. The aim of this study was to further investigate this relationship between triggering activities and circadian distribution at the onset of AAD according to diagnostic and anatomic classification.
  
  
  METHODS
  A total of 166 patients with AAD admitted to Kyungpook National University Hospital between July 2001 and June 2009 were included. To assess the influence of diagnostic and anatomical classification, we categorized the patients into intramural hematoma (IMH) group (n=67)/non-IMH group (n=99) and Stanford type A (AAD-A, n=94)/type B (AAD-B, n=72). To evaluate circadian distribution, the day was divided into four 6-hour periods: night (00-06 hours), morning (06-12 hours), afternoon (12-18 hours), and evening (18-00 hours).
  
  
  RESULTS
  Most (72%) AAD episodes were related to physical (53%) and mental activities (19%), with about one-third occurring during the afternoon, and only 12% occurring at night. No differences in triggering activities or circadian distribution were observed among the groups. Waking hours including morning, afternoon, and evening correlated with triggering activities (p=0.003). These relationships were observed for the non-IMH (p=0.008) and AAD-B (p=0.003) cases. The remaining categories had similar relationships, but did not reach statistical significance.
  
  
  CONCLUSIONS
  Our findings suggest differences in the relationship between triggering activities and the circadian distribution of the onset of AAD according to diagnostic and anatomical classification.
authors.affiliation: Department of Internal Medicine, Kyungpook National University Hospital, Daegu, Korea.
authors.forename: Hyeon Min
authors.initials: HM
authors.lastname: Ryu
authors.forename: Ju Hwan
authors.initials: JH
authors.lastname: Lee
authors.forename: Yong Seop
authors.initials: YS
authors.lastname: Kwon
authors.forename: Sun Hee
authors.initials: SH
authors.lastname: Park
authors.forename: Sang Hyuk
authors.initials: SH
authors.lastname: Lee
authors.forename: Myung Hwan
authors.initials: MH
authors.lastname: Bae
authors.forename: Jang Hoon
authors.initials: JH
authors.lastname: Lee
authors.forename: Dong Heon
authors.initials: DH
authors.lastname: Yang
authors.forename: Hun Sik
authors.initials: HS
authors.lastname: Park
authors.forename: Yongkeun
authors.initials: Y
authors.lastname: Cho
authors.forename: Shung Chull
authors.initials: SC
authors.lastname: Chae
authors.forename: Jae-Eun
authors.initials: JE
authors.lastname: Jun
authors.forename: Wee-Hyun
authors.initials: WH
authors.lastname: Park