Acute adverse effects of fine particulate air pollution on ventricular repolarization.
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).
Liao
Duanping
D
Department of Public Health Sciences, Penn State University College of Medicine, Hershey, Pennsylvania 17033, USA. dliao@psu.edu
Shaffer
Michele L
ML
Rodriguez-Colon
Sol
S
He
Fan
F
Li
Xian
X
Wolbrette
Deborah L
DL
Yanosky
Jeff
J
Cascio
Wayne E
WE
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*
D000393:Air Pollutants; D052638:Particulate Matter