title: Time distribution of the onset of chest pain in subjects with acute ST-elevation myocardial infarction: an eight-year, single-center study in China.
abstract: OBJECTIVE
  The objective of this study was to explore the time distribution patterns of the onset of chest pain in subjects with acute ST-elevation myocardial infarction in a Chinese population.
  
  
  METHODS
  A total of 1467 patients with acute ST-elevation myocardial infarction were enrolled from 2003 to 2010. The hourly, daily, monthly, seasonal and day-of-week fluctuations in the prevalence of acute ST-elevation myocardial infarction were analyzed.
  
  
  RESULTS
  A peak was found between the morning hours of 07:31 and 08:30. A second peak was observed between 14:31 and 15:30, and a third peak was found between 23:31 and 00:30 (p<0.001). The monthly maximum was recorded in November and the minimum was in April (p<0.001). The number of daily cases was greatest in autumn and lowest in the spring (p = 0.001). Day-of-the-week variations of ST-elevation acute myocardial infarction were not found, except in patients more than 75-years-old.
  
  
  CONCLUSIONS
  Periodic variations in the frequency of ST-elevation acute myocardial infarction in Chinese patients showed significant differences with regard to diurnal, monthly and seasonal patterns. The exact mechanisms underlying these circadian variations require further study.
authors.affiliation: Department of Cardiovascular Medicine, First Affiliated Hospital of Nanjing Medical University, Nanjing, Jiangsu Province, China. enzhijia@yahoo.cn
authors.forename: En-Zhi
authors.initials: EZ
authors.lastname: Jia
authors.forename: Zhen-Xia
authors.initials: ZX
authors.lastname: Xu
authors.forename: Hong-Zhou
authors.initials: HZ
authors.lastname: Cai
authors.forename: Chang-Yan
authors.initials: CY
authors.lastname: Guo
authors.forename: Li
authors.initials: L
authors.lastname: Li
authors.forename: Tie-Bing
authors.initials: TB
authors.lastname: Zhu
authors.forename: Lian-Sheng
authors.initials: LS
authors.lastname: Wang
authors.forename: Ke-Jiang
authors.initials: KJ
authors.lastname: Cao
authors.forename: Wen-Zhu
authors.initials: WZ
authors.lastname: Ma
authors.forename: Zhi-Jian
authors.initials: ZJ
authors.lastname: Yang
mesh_terms: D000367:Age Factors; D015992:Body Mass Index; D002637:Chest Pain / Q000453:epidemiology* / Q000209:etiology / Q000473:pathology*; D002681:China / Q000453:epidemiology; D005260:Female; D006801:Humans; D016015:Logistic Models; D008297:Male; D009203:Myocardial Infarction / Q000150:complications / Q000453:epidemiology* / Q000503:physiopathology*; D015995:Prevalence; D011446:Prospective Studies; D012307:Risk Factors; D012621:Seasons; D012737:Sex Factors; D013997:Time Factors