- Full (HTML) - Full (PDF) - Related EHP Articles - PubMed:Related Articles - PubMed:Citation - Cited in PMC - Purchase This Issue

Judy L. Mumford,¹ Kegong Wu,² Yajuan Xia,² Richard Kwok,³ Zhihui Yang,⁴ James Foster,⁵ and William E. Sanders Jr.^6,7

¹U.S. Environmental Protection Agency, National Health and Environmental Effects Research Laboratory, Research Triangle Park, North Carolina, USA; ²Inner Mongolia Center for Endemic Disease Control and Research, Huhhot, Inner Mongolia, China; ³RTI International, Research Triangle Park, North Carolina, USA; ⁴Ba Men Anti-Epidemic Station, Lin He, Inner Mongolia, China; ⁵Wake Heart Associates, Raleigh, North Carolina, USA; ⁶Department of Medicine, and ⁷Center for Environmental Medicine, Asthma and Lung Biology, University of North Carolina, Chapel Hill, North Carolina, USA

Abstract
Background: Chronic arsenic exposure is associated with cardiovascular abnormalities. Prolongation of the QT (time between initial deflection of QRS complex to the end of T wave) interval and profound repolarization changes on electrocardiogram (ECG) have been reported in patients with acute promyelocytic leukemia treated with arsenic trioxide. This acquired form of long QT syndrome can result in life-threatening arrhythmias.

Objective: The objective of this study was to assess the cardiac effects of arsenic by investigating QT interval alterations in a human population chronically exposed to arsenic.

Methods: Residents in Ba Men, Inner Mongolia, have been chronically exposed to arsenic via consumption of water from artesian wells. A total of 313 Ba Men residents with the mean arsenic exposure of 15 years were divided into three arsenic exposure groups: low (≤ 21 µg/L) , medium (100–300 µg/L) , and high (430–690 µg/L) . ECGs were obtained on all study subjects. The normal range for QTc (corrected QT) interval is 0.33–0.44 sec, and QTc ≥ 0.45 sec was considered to be prolonged.

Results: The prevalence rates of QT prolongation and water arsenic concentrations showed a dose-dependent relationship (p = 0.001) . The prevalence rates of QTc prolongation were 3.9, 11.1, 20.6% for low, medium, and high arsenic exposure, respectively. QTc prolongation was also associated with sex (p < 0.0001) but not age (p = 0.486) or smoking (p = 0.1018) . Females were more susceptible to QT prolongation than males.

Conclusions: We found significant association between chronic arsenic exposure and QT interval prolongation in a human population. QT interval may potentially be useful in the detection of early cardiac arsenic toxicity.

Key words: arsenic, cardiac repolarization, cardiovascular effects, drinking water, nail, QT prolongation. Environ Health Perspect 115:690–694 (2007) . doi:10.1289/ehp.9686 available via http://dx.doi.org/ [Online 14 February 2007]

Address correspondence to J.L. Mumford, MD 58C, U.S. Environmental Protection Agency, Research Triangle Park, NC 27711 USA. Telephone: (919) 966-0651. Fax: (919) 966-0655. Email: mumford.judy@epa.gov

We thank I.I.H. Chen for his technical advice in preparing this manuscript, X.C. Le of the University of Alberta for analyzing water samples, S. Lassell of North Carolina State University for analyzing nail samples, Y. Li of RTI International for excellent assistance in statistical analysis, and also all the participating members of Inner Mongolia Center for Endemic Disease Control and Research and Ba Men Anti-epidemic Station.

This research has been reviewed by the U.S. EPA and approved for publication. Approval does not signify that the contents reflect views of the agency or endorse the trade names mentioned.

This study was conducted and funded by the U.S. EPA, partially funded by Cooperative Agreement R82952201 with the University of North Carolina at Chapel Hill, Center for Environmental Medicine, Asthma and Lung Biology ; and Cooperative Agreement R82808401, Inner Mongolia Center for Endemic Disease Control and Research.

The authors declare they have no competing financial interests.

Received 6 September 2006 ; accepted 14 February 2007.