title: Particulate air pollution as a risk factor for ST-segment depression in patients with coronary artery disease.
abstract: BACKGROUND
  The association of particulate matter (PM) with cardiovascular morbidity and mortality is well documented. PM-induced ischemia is considered a potential mechanism linking PM to adverse cardiovascular outcomes.
  
  
  RESULTS
  In a repeated-measures study including 5979 observations on 48 patients 43 to 75 years of age, we investigated associations of ambient pollution with ST-segment level changes averaged over half-hour periods measured in the modified V(5) position by 24-hour Holter ECG monitoring. Each patient was observed up to 4 times within 1 year after a percutaneous intervention for myocardial infarction, acute coronary syndrome without infarction, or stable coronary artery disease without acute coronary syndrome. Elevation in fine particles (PM(2.5)) and black carbon levels predicted depression of half-hour-averaged ST-segment levels. An interquartile increase in the previous 24-hour mean black carbon level was associated with a 1.50-fold increased risk of ST-segment depression > or =0.1 mm (95% CI, 1.19 to 1.89) and a -0.031-mm (95% CI, -0.042 to -0.019) decrease in half-hour-averaged ST-segment level (continuous outcome). Effects were greatest within the first month after hospitalization and for patients with myocardial infarction during hospitalization or with diabetes.
  
  
  CONCLUSIONS
  ST-segment depression is associated with increased exposure to PM(2.5) and black carbon in cardiac patients. The risk of pollution-associated ST-segment depression may be greatest in those with myocardial injury in the first month after the cardiac event.
authors.affiliation: Exposure, Epidemiology, and Risk Program, Department of Environmental Health, Harvard School of Public Health, Boston, MA 02215, USA.
authors.forename: Kai Jen
authors.initials: KJ
authors.lastname: Chuang
authors.forename: Brent A
authors.initials: BA
authors.lastname: Coull
authors.forename: Antonella
authors.initials: A
authors.lastname: Zanobetti
authors.forename: Helen
authors.initials: H
authors.lastname: Suh
authors.forename: Joel
authors.initials: J
authors.lastname: Schwartz
authors.forename: Peter H
authors.initials: PH
authors.lastname: Stone
authors.forename: Augusto
authors.initials: A
authors.lastname: Litonjua
authors.forename: Frank E
authors.initials: FE
authors.lastname: Speizer
authors.forename: Diane R
authors.initials: DR
authors.lastname: Gold
mesh_terms: D054058:Acute Coronary Syndrome / Q000175:diagnosis / Q000453:epidemiology; D000328:Adult; D000368:Aged; D000393:Air Pollutants / Q000009:adverse effects; D003324:Coronary Artery Disease / Q000175:diagnosis* / Q000453:epidemiology*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006760:Hospitalization; D006801:Humans; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000175:diagnosis / Q000453:epidemiology; D017202:Myocardial Ischemia / Q000175:diagnosis / Q000453:epidemiology; D052638:Particulate Matter / Q000009:adverse effects*; D012307:Risk Factors
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter
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