Reduction in heart rate variability with traffic and air pollution in patients with coronary artery disease

Environ Health Perspect. 2010 Mar;118(3):324-30. doi: 10.1289/ehp.0901003. Epub 2009 Nov 18.


Introduction: Ambient particulate pollution and traffic have been linked to myocardial infarction and cardiac death risk. Possible mechanisms include autonomic cardiac dysfunction.

Methods: In a repeated-measures study of 46 patients 43-75 years of age, we investigated associations of central-site ambient particulate pollution, including black carbon (BC) (a marker for regional and local traffic), and report of traffic exposure with changes in half-hourly averaged heart rate variability (HRV), a marker of autonomic function measured by 24-hr Holter electrocardiogram monitoring. Each patient was observed up to four times within 1 year after a percutaneous intervention for myocardial infarction, acute coronary syndrome without infarction, or stable coronary artery disease (4,955 half-hour observations). For each half-hour period, diary data defined whether the patient was home or not home, or in traffic.

Results: A decrease in high frequency (HF; an HRV marker of vagal tone) of 16.4% [95% confidence interval (CI), 20.7 to 11.8%] was associated with an interquartile range of 0.3-microg/m3 increase in prior 5-day averaged ambient BC. Decreases in HF were independently associated both with the previous 2-hr averaged BC (10.4%; 95% CI, 15.4 to 5.2%) and with being in traffic in the previous 2 hr (38.5%; 95% CI, 57.4 to 11.1%). We also observed independent responses for particulate air matter with aerodynamic diameter < or = 2.5 microm and for gases (ozone or nitrogen dioxide).

Conclusion: After hospitalization for coronary artery disease, both particulate pollution and being in traffic, a marker of stress and pollution, were associated with decreased HRV.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Air Pollutants / toxicity*
  • Boston
  • Carbon / toxicity
  • Coronary Artery Disease / physiopathology*
  • Electrocardiography, Ambulatory
  • Female
  • Heart Rate / drug effects*
  • Heart Rate / physiology
  • Humans
  • Male
  • Middle Aged
  • Motor Vehicles*
  • Myocardial Infarction / physiopathology
  • Particle Size
  • Particulate Matter / toxicity*
  • Time Factors


  • Air Pollutants
  • Particulate Matter
  • Carbon