title: Acute adverse effects of fine particulate air pollution on ventricular repolarization.
abstract: BACKGROUND
  The mechanisms for the relationship between particulate pollution and cardiac disease are not fully understood.
  
  
  OBJECTIVE
  We examined the effects and time course of exposure to fine particulate matter < or = 2.5 microm in aerodynamic diameter (PM(2.5)) on ventricular repolarization of 106 nonsmoking adults who were living in communities in central Pennsylvania.
  
  
  METHODS
  The 24-hr beat-to-beat electrocardiogram (ECG) data were obtained using a high-resolution 12-lead Holter system. After visually identifying and removing artifacts and arrhythmic beats, we summarized normal beat-to-beat QTs from each 30-min segment as heart rate (HR)-corrected QT measures: QT prolongation index (QTI), Bazett's HR-corrected QT (QTcB), and Fridericia's HR-corrected QT (QTcF). A personal PM(2.5) monitor was used to measure individual-level real-time PM(2.5) exposures for 24 hr. We averaged these data and used 30-min time-specific average PM(2.5) exposures.
  
  
  RESULTS
  The mean age of the participants was 56 +/- 8 years, with 41% male and 74% white. The means +/- SDs for QTI, QTcB, and QTcF were 111 +/- 6.6, 438 +/- 23 msec, and 422 +/- 22 msec, respectively; and for PM(2.5), the mean +/- SD was 14 +/- 22 microg/m3. We used distributed lag models under a framework of linear mixed-effects models to assess the autocorrelation-corrected regression coefficients (beta) between 30-min PM(2.5) and the HR-corrected QT measures. Most of the adverse ventricular repolarization effects from PM(2.5) exposure occurred within 3-4 hr. The multivariable adjusted beta (SE, p-value) due to a 10-microg/m3 increase in lag 7 PM(2.5) on QTI, QTcB, and QTcF were 0.08 (0.04, p < 0.05), 0.22 (0.08, p < 0.01), and 0.09 (0.05, p < 0.05), respectively.
  
  
  CONCLUSIONS
  Our results suggest a significant adverse effect of PM(2.5) on ventricular repolarization. The time course of the effect is within 3-4 hr of elevated PM(2.5).
authors.affiliation: Department of Public Health Sciences, Penn State University College of Medicine, Hershey, Pennsylvania 17033, USA. dliao@psu.edu
authors.forename: Duanping
authors.initials: D
authors.lastname: Liao
authors.forename: Michele L
authors.initials: ML
authors.lastname: Shaffer
authors.forename: Sol
authors.initials: S
authors.lastname: Rodriguez-Colon
authors.forename: Fan
authors.initials: F
authors.lastname: He
authors.forename: Xian
authors.initials: X
authors.lastname: Li
authors.forename: Deborah L
authors.initials: DL
authors.lastname: Wolbrette
authors.forename: Jeff
authors.initials: J
authors.lastname: Yanosky
authors.forename: Wayne E
authors.initials: WE
authors.lastname: Cascio
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000633:toxicity*; D015716:Electrocardiography, Ambulatory; D005260:Female; D006329:Heart Conduction System / Q000187:drug effects*; D006801:Humans; D016014:Linear Models; D008297:Male; D008875:Middle Aged; D010316:Particle Size; D052638:Particulate Matter / Q000633:toxicity*; D010414:Pennsylvania; D013997:Time Factors; D016276:Ventricular Function / Q000187:drug effects*
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter