title: Relation between time of symptom onset of ST-segment elevation myocardial infarction and patient baseline characteristics: from the National Cardiovascular Data Registry.
abstract: BACKGROUND
  The presence of a morning excess of ST-segment elevation myocardial infarction (STEMI) has been observed. The relation between patient characteristics and timing of STEMI may provide insight into the biological processes responsible for this phenomenon.
  
  
  OBJECTIVE
  Patient baseline characteristics will vary with timing of STEMI.
  
  
  METHODS
  We performed an analysis using a large national registry of unselected patients with STEMI (N=45,218). Patients were categorized by time of symptom onset: early (6 am-2 pm), late day (2 pm-10 pm), and overnight (10 pm-6 am) then evaluated for variations in characteristics.
  
  
  RESULTS
  A circadian variation in the timing of symptom onset of STEMI was observed (early 41%, late day 32%, and overnight 26%, P<0.001). Circadian variations in factors known to alter timing of events were seen, including lower rates of home β-blocker use, smoking, and diabetes, with early onset of STEMI symptoms. In addition, patients in the 6 am to 2 pm subgroup were more likely older, white race, and male, with higher rates of home aspirin use and lower rates of obesity. Higher rates of coexisting cardiovascular disease, including prior heart failure, 3-vessel coronary artery disease, and depressed left ventricular ejection fraction, were observed in the overnight group. More robust antiplatelet therapy with home clopidogrel use was not associated with a change in the timing of events.
  
  
  CONCLUSIONS
  A morning excess of STEMI continues to exist and represents a potential target for preventative strategies. Patient baseline characteristics vary with the onset of STEMI and may reflect a physiologic relationship between these factors and the timing of events.
authors.affiliation: Cardiology Division, The University of Texas Southwestern Medical School, Dallas, Texas 75390, USA. owen@mogabgab.com
authors.forename: Owen
authors.initials: O
authors.lastname: Mogabgab
authors.forename: Stephen D
authors.initials: SD
authors.lastname: Wiviott
authors.forename: Elliot M
authors.initials: EM
authors.lastname: Antman
authors.forename: Joanne M
authors.initials: JM
authors.lastname: Foody
authors.forename: Tracy Y
authors.initials: TY
authors.lastname: Wang
authors.forename: Marc S
authors.initials: MS
authors.lastname: Sabatine
authors.forename: Christopher P
authors.initials: CP
authors.lastname: Cannon
authors.forename: Shuang
authors.initials: S
authors.lastname: Li
authors.forename: Robert P
authors.initials: RP
authors.lastname: Giugliano
mesh_terms: D000319:Adrenergic beta-Antagonists / Q000627:therapeutic use; D017677:Age Distribution; D000368:Aged; D057911:Angiotensin Receptor Antagonists / Q000627:therapeutic use; D001241:Aspirin / Q000627:therapeutic use; D002318:Cardiovascular Diseases / Q000453:epidemiology; D003920:Diabetes Mellitus / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000453:epidemiology* / Q000628:therapy; D009204:Myocardial Revascularization / Q000706:statistics & numerical data; D009765:Obesity / Q000453:epidemiology; D062645:Percutaneous Coronary Intervention / Q000706:statistics & numerical data; D010975:Platelet Aggregation Inhibitors / Q000627:therapeutic use; D044469:Racial Groups; D012042:Registries; D012307:Risk Factors; D017678:Sex Distribution; D012907:Smoking / Q000453:epidemiology; D013318:Stroke Volume; D015912:Thrombolytic Therapy / Q000706:statistics & numerical data; D013997:Time Factors; D014481:United States / Q000453:epidemiology
chemical_list: D000319:Adrenergic beta-Antagonists; D057911:Angiotensin Receptor Antagonists; D010975:Platelet Aggregation Inhibitors; D001241:Aspirin