title: Circadian variation of plaque rupture in acute myocardial infarction.
abstract: Studies have reported a circadian variation in the onset of acute myocardial infarction (AMI). Pathologic studies have revealed that plaque rupture is 1 of the major causes of AMI, but none of these has looked specifically at the circadian variation of plaque rupture. The aim of this study was to use intravascular ultrasound (IVUS) to investigate the circadian variation of plaque rupture in AMI. This study included 174 consecutive patients with AMI who underwent preinterventional IVUS. All patients were assigned to either a rupture group or a nonrupture group according to the preinterventional IVUS. In the 81 patients (47%) in the rupture group, the frequency of the onset of AMI increased significantly in the period from 6 A.M. to 12 P.M. compared with all other time periods (p <0.05). The clinical features of AMI in the rupture group were characterized as occurring significantly more at rest (67% vs 31%, p <0.01) and after significantly less preinfarction angina (22% vs 57%, p <0.01) compared with the nonrupture group. A different circadian variation was identified in the nonrupture group, characterized as a significant nocturnal nadir (12 to 6 A.M. compared with all other periods, p <0.05). The circadian variation of AMI is the result of a morning increase in incidence of plaque rupture.
authors.affiliation: Baba Memorial Hospital, Sakai, Japan. m4497147@msic.med.osaka-cu.ac.jp
authors.forename: Atsushi
authors.initials: A
authors.lastname: Tanaka
authors.forename: Takahiko
authors.initials: T
authors.lastname: Kawarabayashi
authors.forename: Daiju
authors.initials: D
authors.lastname: Fukuda
authors.forename: Yoshiharu
authors.initials: Y
authors.lastname: Nishibori
authors.forename: Tsunemori
authors.initials: T
authors.lastname: Sakamoto
authors.forename: Yukio
authors.initials: Y
authors.lastname: Nishida
authors.forename: Kenei
authors.initials: K
authors.lastname: Shimada
authors.forename: Junichi
authors.initials: J
authors.lastname: Yoshikawa
mesh_terms: D000368:Aged; D002940:Circadian Rhythm; D003324:Coronary Artery Disease / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000503:physiopathology*; D003331:Coronary Vessels / Q000473:pathology; D005260:Female; D006801:Humans; D015994:Incidence; D007564:Japan / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000000981:diagnostic imaging / Q000453:epidemiology / Q000503:physiopathology*; D012307:Risk Factors; D012422:Rupture, Spontaneous; D014463:Ultrasonography