Association of Long-term Air Pollution With Ventricular Conduction and Repolarization Abnormalities

Background: Short-term exposure to air pollution may affect ventricular repolarization, but there is limited information on how long-term exposures might affect the surface ventricular electrocardiographic (ECG) abnormalities associated with cardiovascular events. We carried out a study to determine whether long-term air pollution exposure is associated with abnormalities of ventricular repolarization and conduction in adults without known cardiovascular disease. Methods: A total of 4783 participants free of clinical cardiovascular disease in the Multi-Ethnic Study of Atherosclerosis underwent 12-lead ECG examinations, cardiac-computed tomography, and calcium scoring, as well as estimation of air pollution exposure using a finely resolved spatiotemporal model to determine long-term average individual exposure to fine particulate matter (PM 2.5 ) and proximity to major roadways. We assessed ventricular electrical abnormalities including presence of QT prolongation (Rautaharju QTrr criteria) and intraventricular conduction delay (QRS duration >120 milliseconds). We used logistic regression to determine the adjusted relationship between air pollution exposures and ECG abnormalities. Results: A 10-μg/m 3 increase in estimated residential PM 2.5 was associated with an increased odds of prevalent QT prolongation (adjusted odds ratio [OR] = 1.6 [95% confidence interval (CI) = 1.2—2.2]) and intraventricular conduction delay (1.7 [1.0—2.6]), independent of coronary-artery calcium score. Living near major roadways was not associated with ventricular electrical abnormalities. No evidence of effect modification by traditional risk factors or study site was observed. Conclusions: This study demonstrates an association between long-term exposure to air pollution and ventricular repolarization and conduction abnormalities in adults without clinical cardiovascular disease, independent of subclinical coronary arterial calcification.