A large study of 322 Chinese cities has found that long-term exposure to air pollution is associated with an increased risk of arrhythmia, or irregular heartbeat. The study, which evaluated hourly exposure to air pollution and the sudden onset of symptoms of arrhythmia using data from 2025 hospitals in the Chinese cities, found that acute exposure to ambient air pollution was associated with an increased risk of symptomatic arrhythmia. The risks occurred during the first several hours after exposure and could persist for up to 24 hours. The exposure-response relationships between six pollutants and four subtypes of arrhythmias were approximately linear without discernable thresholds of concentrations.
The study included 1,90,115 patients with acute onset of symptomatic arrhythmia, including atrial fibrillation, atrial flutter, premature beats, and supraventricular tachycardia. Exposure to ambient air pollution was most strongly associated with atrial flutter and supraventricular tachycardia, followed by atrial fibrillation and premature beats. Among six pollutants, nitrogen dioxide (NO2) had the strongest association with all four types of arrhythmias, and the greater the exposure, the stronger the association, the researchers found.
While the exact mechanisms are not yet fully understood, the association between air pollution and acute onset of arrhythmia is biologically plausible, the authors said. Some evidence has indicated that air pollution alters cardiac electrophysiological activities by inducing oxidative stress and systemic inflammation, affecting multiple membrane channels, as well as impairing autonomic nervous function.
The researchers noted that the association was immediate and underscores the need to protect at-risk people during heavy air pollution. The study adds to evidence of adverse cardiovascular effects of air pollution, highlighting the importance of further reducing exposure to air pollution and of prompt protection of susceptible populations worldwide. Atrial fibrillation and atrial flutter affect an estimated 59.7 million people globally. Air pollution is a modifiable risk factor for heart disease, but the evidence linking it with arrhythmia has been inconsistent, the researchers said.