Study Shows Air Pollution Also Affects Cardiac System

According to an article published in the Aug. 26 issue of the Journal of the American College of Cardiology , air pollution has both short- and long-term toxic effects that injure the heart and blood vessels, increase rates of hospitalization for cardiac illness, and can even cause death.

"We used to think air pollution was a problem that primarily affects the lungs. We now know it is also bad for the heart," said Robert A. Kloner, M.D., Ph.D., director of research at the Heart Institute of the Good Samaritan Hospital, and a professor of medicine at the Keck School of Medicine, University of Southern California, both in Los Angeles.

When pollutants are inhaled, they trigger an increase in "reactive oxygen species"—superoxiding molecules that damage cells, cause inflammation in the lungs, and spark the cascade of harmful effects in the heart and cardiovascular system. Recent research suggests that ultrafine air pollutants, such as those coming from car exhaust, may pass into the blood stream and damage the heart and blood vessels directly. Hearts directly exposed to ultrafine air pollutants show an immediate decrease in both coronary blood flow and the heart's pumping function, as well as a tendency to develop arrhythmias, according to studies conducted at the Heart Institute.

"There doesn't have to be an environmental catastrophe for air pollution to cause injury," said Boris Z. Simkhovich, M.D., Ph.D, a senior research associate at the Heart Institute of the Good Samaritan Hospital, and an assistant professor of research medicine at the Keck School of Medicine, University of Southern California. "We're talking about very modest increases. Air pollution can be dangerous at levels that are within the accepted air quality standards."

Studies in both humans and animals have shown that exposure to air pollution can affect heart rate, blood pressure, blood vessel function, blood clotting, and heart rate variability (a factor in developing heart rhythm disturbances), and speed the progression of atherosclerosis.

The elderly and patients who have already been diagnosed with heart disease or diabetes (which damages the blood vessels) are particularly vulnerable to the cardiovascular effects of air pollution.

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