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 ≤ 2.5 μm in aerodynamic diameter (PM2.5) 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 PM2.5 monitor was used to measure individual-level real-time PM2.5 exposures for 24 hr. We averaged these data and used 30-min time-specific average PM2.5 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 PM2.5, the mean ± SD was 14 ± 22 μg/m3. We used distributed lag models under a framework of linear mixed-effects models to assess the autocorrelation-corrected regression coefficients (β) between 30-min PM2.5 and the HR-corrected QT measures. Most of the adverse ventricular repolarization effects from PM2.5 exposure occurred within 3–4 hr. The multivariable adjusted β (SE, p-value) due to a 10-μg/m3 increase in lag 7 PM2.5 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 PM2.5 on ventricular repolarization. The time course of the effect is within 3–4 hr of elevated PM2.5