title: Circadian variation in the onset of unstable angina and non-Q-wave acute myocardial infarction (the TIMI III Registry and TIMI IIIB).
abstract: Circadian variation has been demonstrated in several types of acute cardiovascular disease, including acute myocardial infarction (AMI), sudden cardiac death, silent ambulatory ischemia, and thrombotic stroke. In contrast, no diurnal variation was observed in 1 study of non-Q-wave AMI, and limited data are available for unstable angina. To assess whether circadian variation is present in unstable angina and non-Q-wave AMI, we examined the time of onset of ischemic pain in 7,731 patients who were prospectively identified in the Thrombolysis in Myocardial Ischemia (TIMI) III Registry, 3,318 of whom were enrolled in the prospective study, and in 1,473 patients enrolled in the TIMI IIIB trial. A circadian variation in the onset of pain was observed, with an increase in the number of patients experiencing the onset of pain in the morning hours between 6 A.M. and 12 noon (p <0.001). This circadian variation was observed both in patients with unstable angina and in those with evolving non-Q-wave AMI. A similar circadian pattern was observed in all subgroups tested. These findings were confirmed in the TIMI IIIB trial and complement previous studies suggesting that circadian variation exists in the onset of the full spectrum of myocardial ischemic syndromes.
authors.affiliation: Cardiovascular Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02115, USA.
authors.forename: C P
authors.initials: CP
authors.lastname: Cannon
authors.forename: C H
authors.initials: CH
authors.lastname: McCabe
authors.forename: P H
authors.initials: PH
authors.lastname: Stone
authors.forename: M
authors.initials: M
authors.lastname: Schactman
authors.forename: B
authors.initials: B
authors.lastname: Thompson
authors.forename: P
authors.initials: P
authors.lastname: Theroux
authors.forename: R S
authors.initials: RS
authors.lastname: Gibson
authors.forename: T
authors.initials: T
authors.lastname: Feldman
authors.forename: N S
authors.initials: NS
authors.lastname: Kleiman
authors.forename: G H
authors.initials: GH
authors.lastname: Tofler
authors.forename: J E
authors.initials: JE
authors.lastname: Muller
authors.forename: B R
authors.initials: BR
authors.lastname: Chaitman
authors.forename: E
authors.initials: E
authors.lastname: Braunwald
mesh_terms: D000368:Aged; D000789:Angina, Unstable / Q000503:physiopathology*; D002940:Circadian Rhythm; D004562:Electrocardiography; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000503:physiopathology*; D011446:Prospective Studies; D012042:Registries; D015912:Thrombolytic Therapy