Air pollution from breathing particulate matter (that is, tiny particles suspended in the air) can cause irregular heart rhythms (arrhythmias) in healthy teenagers, according to new research published today in the Journal of the American Heart Association. open access and peer-reviewed. of the American Heart Association.
Although the negative cardiovascular effects of air pollution in adults have already been established, this study is the first to assess the impact of air pollution on adolescents in the general population.
Although irregular heart rhythms are relatively rare, they can lead to sudden cardiac death in healthy teenagers and young adults. Our findings linking air pollution to irregular heart rhythms suggest that particulate matter may contribute to the risk of sudden cardiac death among young people. Since cardiovascular conditions in childhood and adolescence can carry over into adulthood and affect the risk of major cardiovascular disease later in life, the identification of modifiable risk factors for cardiac arrhythmia that can cause cardiac death among teenagers should be of great public interest.”
Fan He, Ph.D., lead study author and instructor of public health sciences at Penn State College of Medicine in Hershey, Pennsylvania
The study examined the impact of breathing fine particles on the heart rate of teenagers. Fine particles (PM2.5) are less than 2.5 microns in size and can easily be inhaled into the lungs and even enter the bloodstream. Particles smaller than 2.5 microns are usually related to fuel combustion, such as particles from car exhaust or forest fires. Once inhaled, the pollutants irritate the lungs and blood vessels around the heart, and previous research has suggested that over time, the pollutants increase the disease process in the arteries.
The researchers looked at the impact of breathing particulate pollution on two types of irregular heart rhythms characterized by premature contraction of the heart muscle, often described as a “skipped heartbeat”. In premature atrial contractions (APCs), the heartbeat originates in the atria (upper chambers of the heart). This usually causes no symptoms or harm, but frequent and premature atrial contractions have been linked to an increased risk of atrial fibrillation: a severe form of arrhythmia in which the upper chambers quiver instead of beating effectively , thus increasing the risk of blood clots and stroke. Premature ventricular contractions (PVCs) occur when the heartbeat comes from one of the ventricles (lower chambers of the heart). These also increase the risk of heart attack, stroke, heart failure or sudden cardiac death.
If premature contractions do not cause symptoms, they are not treated. However, if they occur often and cause a frequent feeling of skipped heartbeats, fast heartbeats, or palpitations, treatment with medications, implantable devices, or procedures may be advised.
Researchers analyzed health data from 322 adolescents (mean age 17 years; 56% male; 79% non-Hispanic white adolescents) living in central Pennsylvania who participated in a follow-up assessment in the Penn State study Child Cohort. This study, conducted between 2002 and 2006, initially recruited children between the ages of 6 and 12. The data analyzed in this study reviewed the results of the follow-up assessment almost 7.5 years later (2010-2013). This group of children were free of major cardiovascular disease and were considered to be at low risk for irregular heart rhythms. In the follow-up study, researchers simultaneously measured exposure to fine particles in the air each teen breathed (using a device called a nephelometer) over 24 hours and ECG traces of each teen’s heart rate using a small portable device called a Holter monitor. .
The average concentration of PM2.5 measured in the study was about 17 micrograms of particulate matter per cubic meter of air (µg/m3) per day, which is well below the air quality standard based on the health of 35 µg/m3 established by the US Environmental Protection Agency (EPA).
The study found:
- 79% of participants had at least one irregular heart rhythm during the 24-hour study period. Of this group, 40% had atrial premature contractions only, 12% had ventricular premature contractions only, and 48% had both.
- A 5% increase in the number of premature ventricular contractions was observed within two hours of exposure for each 10 µg/m3 increase in PM2.5.
- No association was found between particle concentration and number of premature atrial contractions.
“It is alarming that we were able to observe such a significant impact of air pollution on cardiac arrhythmias when air quality was maintained within the health standards set by the EPA. It may suggest that adolescents living in highly polluted areas such as inner cities they are at even higher risk,” he said.
The results were consistent with data previously obtained in adults using similar methods by these researchers and others, although the increase in premature ventricular contractions was even greater in the adults. According to the study authors, reducing the risk of irregular heart rhythms in teenagers may reduce the risk of developing heart disease as adults.
“Our study found that air pollution increases the risk of cardiovascular disease and sudden cardiac death, even among healthy teenagers,” he said. “Protective measures, such as wearing masks and avoiding vigorous physical activity, may be warranted on days when particle concentrations are high, particularly during the morning rush hour.”
The most effective way to reduce everyone’s exposure to air pollution is to support stronger air quality regulations at the national level, said American Heart Association volunteer expert Robert D. Brook, MD, FAHA, professor of medicine at Wayne State University in Detroit. Brook has co-authored several American Heart Association scientific statements on air pollution.
“PM2.5 levels have fallen dramatically since the 1970s-1980s due to regulations that have been indisputably linked to improved health effects and life expectancy,” Brook said. “In a recent AHA scientific statement, Personal Protective Actions Against Air Pollution Exposure, strategies and activities or behavior changes that can reduce exposure to pollution, such as air cleaners laptops, face masks, respirators and exercise during off-peak hours. However, there have been no studies showing that these measures can prevent adverse clinical health effects such as heart attacks.”
According to a 2020 American Heart Association policy statement citing a global study, ambient air pollution is widely recognized as a major contributor to cardiovascular disease and death. In 2017, exposure to particulate air pollution was estimated to be associated with more than 7 million premature deaths and the loss of 147 million healthy life years worldwide. The Association recommends further development of evidence-based policy approaches, continued investment in research, and greater innovation and transformational partnerships to reduce the cardiovascular burden of ambient air pollutants in the US.
“The most interesting and significant aspect of this study is clearly that the results were found in healthy young adolescents,” Brook said. “The study adds support to concerns that even healthy young people are immune to adverse cardiovascular responses to PM2.5 and exposure levels within the 24-hour national ambient air quality standards set by EPA. It’s plausible that the findings help explain that. the potential reason for the timing of arrhythmias and even sudden death in some susceptible young people.”
Dr. He and his colleagues are currently evaluating the impact of air pollution on other markers of cardiac electrical activity.
This study was limited in not being able to analyze the impact of air pollution on different subtypes of premature ventricular contractions, which may help cardiologists better understand how pollution affects heart function. The results of this study in adolescents may not be generalizable to younger children.
Source:
American Heart Association
Journal reference:
He, F., et al. (2022) Acute impact of fine particulate air pollution on cardiac arrhythmias in a population-based adolescent sample: the Penn State Children’s Cohort. Journal of the American Heart Association. doi.org/10.1161/JAHA.122.026370.