Quantitative MRI assessment of left ventricular filling: associations with left atrial and pulmonary artery...

Left ventricular diastolic dysfunction is associated with left atrial remodeling and alterations of the pulmonary circulation. However, whether these interconnected changes across the cardiopulmonary axis can be simultaneously characterized using a non-dedicated whole-body MRI examination in individuals free of overt cardiovascular disease remains unclear.

339 subjects (mean age 56.4 years; 43.4% female) without overt cardiovascular disease were included. Linear regression models, adjusted for age, sex, and cardiovascular risk factors, explored the association of Left ventricle (LV) filling rates with left atrium (LA) size and function, and mean pulmonary artery (MPA).

Average maximal LA was 19.6 cm², minimal LA 11.8 cm², area-based LA function 39.8%, non-electrocardiogram-synchronized LA size 16.8 cm², LV early filling rate 227.1 mL/s, late filling rate 238.4 mL/s, and MPA diameter 2.67 cm. Higher early and late LV filling rates were associated with larger maximal LA size across all models (β = 2.30; β = 1.00), minimal LA size (β = 1.41; β = 0.77), and non-electrocardiogram-synchronized LA size (β = 1.86; β = 0.90, all p < 0.001, fully adjusted model). Higher early LV filling rates, but not higher late LV filling rates, were associated with larger MPA diameter across all models (β = 0.06, p = 0.03, fully adjusted model).

In individuals free of overt cardiovascular disease, MRI-derived LV filling dynamics were associated with structural alterations of the left atrium and pulmonary vasculature, suggesting that changes across the cardiopulmonary axis may already be detectable by whole-body MRI before clinical disease becomes apparent.