Chronic inflammation contributes to cardiac fibrosis, and systemic IL-16 levels are specifically elevated in HFpEF patients (compared with HF with reduced ejection fraction [HFrEF] and controls), with a significant association between serum IL-16 and indices of LV diastolic dysfunction (LAVI, E/E’, and DWS) [42]. Here, IL16 is linked to hydrops fetalis.