Arsenic and Heart Arrhythmia
Joel D. Schwartz, Ph.D.,
Harvard School of Public Health
NIEHS Grants P30ES000002, R01ES014663 and R01ES015172
The consumption of arsenic-contaminated drinking water is a known risk-factor for skin and bladder cancer and is associated with other diseases including diabetes and cardiovascular diseases. Now, researchers at the University of North Carolina at Chapel Hill report that low-level exposure to arsenic is associated with a prolongation of the Q-T portion of the heart rhythm.
Long Q-T syndrome (LQTS) is a disorder of the heart's conduction system. The disorder affects the recharging of the heart after each heartbeat. Congenital LQTS is a rare disorder that is usually inherited. In other cases, LQTS can be caused by certain medicines, including arsenic trioxide, which is a highly effective treatment for promyelocytic leukemia. LQTS can lead to an abnormal heart rhythm, fainting, or even sudden death.
The researchers performed a cross-sectional analysis of elderly men from the Normative Aging Study. The study included 226 participants and analyzed toe nail clippings for arsenic content, which is a recognized biomarker for arsenic ingestion. Electrocardiograms were conducted on all study participants. Most of the participants lived in the Boston region and obtained their water from the Massachusetts Water Resources Authority. The arsenic concentration of this water resource is generally less than 1 microgram per liter, far below the current EPA standard of 10 micrograms per liter.
The study participants’ use of calcium channel blockers was also determined. Previous research suggested that the use of these drugs could ameliorate arsenic trioxide-induced Q-T prolongation seen during treatment of acute promyelocytic leukemia. In the current study, there was no evidence of an effect of medication use on Q-T interval. The results of this study provide new information to guide efforts to reduce the arrhythmic effects of arsenic exposure.
Citation: Mordukhovich I, Wright RO, Amarasiriwardena C, Baja E, Baccarelli A, Suh H, Sparrow D, Bokonas P, Schwartz J. Association between low-level environmental arsenic exposure and QT interval duration in a general population study. Am J Epdemiol. 2009 Sep 15;170(6):739-46.
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