title: Periodic variation and its effect on management and prognosis of Korean patients with acute myocardial infarction.
abstract: BACKGROUND
  The characteristics of the periodic variation in acute myocardial infarction (AMI) and the subsequent effect on management and prognosis have not been fully investigated in a large number of Asian populations.
  
  
  RESULTS
  From a prospective, observational multicenter online registry, 4,573 patients diagnosed as AMI in Korea from January to December 2006 were included. The highest incidence of AMI was between 8 a.m. and noon. The number of cases was highest in the winter and lowest in the autumn (13.6 vs 11.4 patients per day, P<0.001). Patients with symptom onset during working hours had a shorter time to first medical contact (203+/-288 min) compared with out-of-hours onset (230+/-288 min, P=0.003). In patients who underwent primary angioplasty, out-of hours symptom onset was associated with a greater time delay in both the patient's and the medical facility's response (door-to-balloon time out-of hours vs working hours: 101+/-54 min vs 84+/-44 min, P<0.001). In patients with ST-segment elevation myocardial infarction, symptoms to first medical contact showed a significant relationship to in-hospital mortality (for every 10 min of symptoms to first medical contact, odds ratio 1.006, 95% confidence interval 1.001-1.012, P=0.018)
  
  
  CONCLUSIONS
  Circadian and periodic variation in AMI exists in Korean patients, which resulted in different patient behavior, hospital management and outcomes.
authors.affiliation: Division of Cardiology, Department of Internal Medicine, College of Medicine, Seoul National University, Seoul, Korea.
authors.forename: Hyo Eun
authors.initials: HE
authors.lastname: Park
authors.forename: Bon-Kwon
authors.initials: BK
authors.lastname: Koo
authors.forename: Wonjae
authors.initials: W
authors.lastname: Lee
authors.forename: Youngjin
authors.initials: Y
authors.lastname: Cho
authors.forename: Jin Sik
authors.initials: JS
authors.lastname: Park
authors.forename: Ji-Yong
authors.initials: JY
authors.lastname: Choi
authors.forename: Myung-Ho
authors.initials: MH
authors.lastname: Jeong
authors.forename: Jong Hyun
authors.initials: JH
authors.lastname: Kim
authors.forename: Shung Chull
authors.initials: SC
authors.lastname: Chae
authors.forename: Young Jo
authors.initials: YJ
authors.lastname: Kim
authors.forename: Chang-Wook
authors.initials: CW
authors.lastname: Nam
authors.forename: Jae-Hwan
authors.initials: JH
authors.lastname: Lee
authors.forename: Dong Hoon
authors.initials: DH
authors.lastname: Choi
authors.forename: Taek Jong
authors.initials: TJ
authors.lastname: Hong
authors.forename: Jei Keon
authors.initials: JK
authors.lastname: Chae
authors.forename: Jae Young
authors.initials: JY
authors.lastname: Rhew
authors.forename: Kee Sik
authors.initials: KS
authors.lastname: Kim
authors.forename: Hyo-Soo
authors.initials: HS
authors.lastname: Kim
authors.forename: Byung-Hee
authors.initials: BH
authors.lastname: Oh
authors.forename: Young Bae
authors.initials: YB
authors.lastname: Park
mesh_terms: D000368:Aged; D044466:Asian People; D002940:Circadian Rhythm; D005260:Female; D017052:Hospital Mortality; D006801:Humans; D015994:Incidence; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000401:mortality* / Q000628:therapy; D011446:Prospective Studies; D012042:Registries; D056910:Republic of Korea / Q000453:epidemiology; D012621:Seasons; D013997:Time Factors