Air pollution may spur irregular heart rhythms in teens: study

Breathing in tiny particles of air pollution may trigger irregular heart rhythms in otherwise healthy teenagers and increase their risk of sudden cardiac death, a new study has found.

The study, published in the Journal of the American Heart Association on Wednesday, investigated the impact of inhaling fine particulate matter — also known as PM 2.5 — on heart rhythms of adolescents.

Such particles, which are smaller than 2.5 microns in diameter, are key pollutants in wildfire smoke and in vehicle exhaust and can irritate the lungs and blood vessels of the heart.

“While relatively rare, irregular heart rhythms can lead to sudden cardiac death in otherwise healthy adolescents and young adults,” lead author Fan He, an instructor in public health sciences at the Penn State College of Medicine said in a statement.  

“Our findings linking air pollution to irregular heart rhythms suggest that particulate matter may contribute to the risk of sudden cardiac death among youth,” He added.

While the negative impacts of air pollution on adult cardiovascular health have already been determined, this latest study is the first to explore the effects on teenagers in the general population, according to the authors.

The researchers analyzed the impact of inhaling particulate matter pollution on two types of arrhythmias — irregular heart rhythms — characterized by the premature contraction in the heart muscle. This phenomenon, they explained, is also known as a “skipped heartbeat.”

In premature atrial contractions, the heartbeat originates from the atria, or the heart’s top chambers. While such contractions usually cause no symptoms, their frequent occurrence has been linked to an increased risk of atrial fibrillation — a severe form of arrhythmia in which the atria fail to beat effectively and raise the risk of blood clots and stroke, the scientists noted.

Premature ventricular contractions — when the heartbeat originates from one of the heart’s lower chambers, the ventricles — also raise the risk of later heat attack, stroke, heart failure or sudden cardiac death, according to the authors. 

When premature contractions cause no symptoms, they are not treated, but when they lead to a frequently skipped heartbeat, doctors may suggest implantable devices or other others, the scientists said.

The researchers analyzed health data for 322 adolescents living in central Pennsylvania in a 2010-2013 follow-up evaluation to a 2002-2006 Penn State Child Cohort study, in which the children were originally ages 6 to 12 years old.

The children were all free of major cardiovascular conditions and were considered at low risk for irregular heart rhythms, according to the study.

As part of the follow-up, the scientists measured exposure to fine particulate matter in the air each teen breathed for 24 hours, while tracking their heart rhythms via a small wearable device.

The average PM 2.5 concentration measured in the study was about 17 micrograms of particulate matter per cubic meter of air — well below the Environmental Protection Agency’s standard of 35 micrograms per cubic meter, according to the study.

Nonetheless, the researchers found that 79 percent of the participants had at least one irregular heart rhythm during the 24-hour study period. Of that group, 40 percent had only premature atrial contractions, 12 percent had only premature ventricular contractions and 48 percent had both.

The scientists observed a 5-percent increase in the number of premature ventricular contractions within two hours of exposure for each increase of 10 micrograms of PM 2.5 per cubic meter of air.

“It is alarming that we were able to observe such a significant impact of air pollution on cardiac arrhythmias when the air quality remained well within the health-based standards established by the EPA,” He said.

Protective measures, such as wearing masks, may be warranted with air pollution concentrations are especially high, according to the scientists, who also called for stronger air quality regulations on a national level.  

“It may suggest that adolescents who live in highly polluted areas such as inner cities are at even higher risk,” He added.