Epicardially derived fibroblasts preferentially contribute to the parietal leaflets of the atrioventricular valves in the murine heart

► EPDCs do not invade trabecular myocardium until after ED17. ► EPDCs preferentially populate the lateral atrioventricular cushions. ► EPDCs do not significantly contribute to the major atrioventricular cushions. ► EPDCs in valves express characteristic fibroblast markers. ► EPDCs significantly contribute to the VICs of postnatal AV valves.