Association between particulate matter air pollution and subclinical myocardial fibrosis in structurally normal hearts: a CMR-based study

AIMS: The impact of particulate matter (PM) exposure on early myocardial remodelling remains incompletely understood. Cardiac magnetic resonance (CMR) mapping provides sensitive markers of diffuse myocardial fibrosis and inflammation that may reveal subclinical injury. METHODS AND RESULTS: Patients with structurally normal hearts and no late-gadolinium-enhancement on CMR from May 2020 to November 2024 were included. Long-term exposure to PM2.5 and PM10 was derived from the nearest European-Environment-Agency monitoring stations. Associations between PM and CMR parameters were tested with multivariable linear and logistic regression adjusted for demographic, clinical, socioeconomic factors, and inflammatory markers. Two-hundred-thirty-one patients (45 ± 21 years; 53% males; mean annual PM2.5 and PM10 exposure of 28.6 ± 14.8 µg/m3 and 56.0 ± 35.3 µg/m3) were included. After adjustment, exposure to PM2.5 (β & 0.034%; 95% CI 0.005-0.063; P & 0.023) and PM10 (β & 0.021 per 1 µg/m3; 95% CI 0.009-0.032; P & 0.001) were associated with higher synthetic-extracellular volume (ECV), whereas only PM2.5 was associated with higher native T1 (β & 0.317 ms per 1 µg/m3; 95% CI 0.07-0.564; P & 0.012). No associations were observed with other CMR parameters, including T2 mapping. By multivariable logistic regression, PM2.5, but not PM10, was associated with increased native T1 and synthetic-ECV. The association between PM and mapping was most pronounced in males and patients ≥50 years, and no mediation effect of inflammatory markers was found. CONCLUSION: In individuals with structurally normal hearts, chronic exposure to PM2.5 and PM10 was associated with higher synthetic-ECV values, suggesting early diffuse myocardial fibrosis related to air pollution.