The effect of ambient air pollutants on cardiac arrhythmia hospital admissions in Ireland

Abstract Aim Exposure to poor ambient air quality and cardiovascular disease (CVD) has been investigated in numerous studies; whether ambient air pollutants are a cause of development of CVD, however, remains unclear. This study aimed to examine the relationship between COVID-19 transport restrictions and hospital admissions due to CVD specifically cardiac arrhythmias in Dublin city and county for 2020. Methods Admission data were collected from the Hospital In-patient Enquiry (HIPE). Daily count of hospital admissions within Dublin city and county addresses with primary diagnosis of cardiac arrythmias was performed. Daily concentration of particulate matter (PM2.5 and PM10) and nitrogen dioxide (NO2) were obtained from the Environmental Protection Agency (EPA). Atmospheric data was obtained from Met Éireann. The data from 2018 - 2019 were compared with the period of transport restrictions (starting March 2020). Results During the period of transport restrictions, there was a significant reduction daily concentration of NO2 from 12.6 µg/m3 to 9.3 µg/m3 (p < 0.001) and PM2.5 from 9.0 µg/m3 to 7.74 µg/m3 (p = 0.004), and there was significant decrease in cardiac arrythmias admission. Among the 3,760 patient episodes included in this study, the mean age at admission was 64.98 years, and 60.9 were male (n = 2,292). Conclusions This study using routinely gathered data, highlighted that the transported restrictions introduced to mitigate against COVID-19 lead to reductions in ambient air pollutants, and improvements in ambient air quality. Established relationships between ambient air pollutants and cardiac arrythmias would indicate that these improvements in ambient air quality contributed to the reduction in cardiac arrythmia-related hospitalisations. It also highlighted the unexpected co-benefits of the COVID-19 transport restrictions, reinforce the need for more robust transport policies that can mitigate for ambient air pollution. Key messages • Reduced NO2 and PM2.5 levels, leading to fewer cardiac arrhythmia hospital admissions in Dublin. • Improved air quality from COVID-19 restrictions reduced cardiac arrhythmia hospitalisations, highlighting the need for robust transport policies.