Within the entire 190,115-person sample group, atrial fibrillation was the most common arrhythmia, affecting 50.6% of the people included in the study; supraventricular tachycardia was next, with 24.8%; followed by premature beats, at 21.9% and atrial flutter at 2.8%. Not all of the conditions were affected by the pollutants equally.
Of the six pollutants, nitrogen dioxide was the most damaging, increasing the odds of all four types of arrhythmia. Incidents of atrial flutter increased 11.4% on days when nitrogen dioxide levels were high; for ventricular tachycardia it was 8.9%, followed by premature beats at 3.7% and atrial fibrillation at 3.4%.
As might be expected, geography and season played a role in who was getting arrhythmia from exposure to air pollution. The greatest incidence was in the heavily industrial south; dirty air was most common in the fall and winter—when more coal is being burned for heating. As for the exact mechanism that causes the six pollutants to lead to arrhythmia, the researchers admit they are not certain. Among the possibilities they list are some impact on the electrical activity of the heart; systemic inflammation; and general impairment of the autonomic nervous system, which regulates not just heart rate, but blood pressure, respiration, digestion, and more.
“Although the mechanisms are not fully understood,” the researchers wrote, “the association between air pollution and acute onset of arrhythmia we observed is biologically plausible. Our findings … highlight the necessity of more stringent air pollution control, as well as prompt responses for susceptible populations during episodes of air pollution.” That’s good advice for China—and the rest of the fossil fuel-burning world as well.