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FINE PARTICLE EXPOSURE IS ASSOCIATED WITH ALTERED VENTRICULAR REPOLARIZATION
Citation:
NEAS, L. M., A. SCHNEIDER, M. C. HERBST, R. W. WILLIAMS, A. HINDERLITER, W. CASCIO, D. GRAFF, A. PETERS, AND R. DEVLIN. FINE PARTICLE EXPOSURE IS ASSOCIATED WITH ALTERED VENTRICULAR REPOLARIZATION. Presented at American Thoracic Society International Conference, San Francisco, NC, May 19 - 23, 2007.
Description:
Exposure to fine airborne particulate matter (PM2.5) has previously been associated with cardiac events, especially in older people with cardiovascular disease and in diabetics. This study examined the cardiac effects of short-term exposures to ambient PM2.5 in a prospective panel of 22 adults with diabetes in Chapel Hill, NC, from November, 2004 through December, 2005. Each subject was studied for four consecutive days. PM2.5 and meteorological data were measured daily on the clinic rooftop. Cardiac function was examined with 24-hour ambulatory ECG monitors and analyzed with models adjusting for season, weekday, meteorology, and a random subject effect. Results are presented for an increase of 10µg/m³ PM2.5 as percent changes of mean with a 95% confidence interval. For the entire cohort, T-wave amplitude decreased in association with PM2.5 during the first 24 hours (-6.2% [-11.1%; -1.3%]). For the 13 subjects not on beta blockers, PM2.5 during the first 24 hours was associated with decreased T-wave amplitude ( 7.1% [-13.3%; -0.9%]). The 8 subjects on beta blockers showed no association of T wave amplitude with PM2.5. These changes in left ventricular repolarization coincided with changes in endothelial function, but preceded increases in circulating inflammatory markers by 48 hours. These findings suggest that exposure to high levels of PM2.5 may alter ventricular repolarization and increase myocardial vulnerability to arrhythmias.
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