This is an example Mitral Valve Scaffold for educational purposes. This one-way valve sits between the atria and the ventricles in the heart. I've included two versions with differing tolerances for printing, where Valve 2 is more realistic and Valve 1 might be easier for you to print. Best printed in flexible TPU or ninjaflex for realism.

Mitral valve replacement is performed when the vale becomes too tight (mitral valve stenosis) for blood to flow into the left ventricle, or too loose (mitral valve regurgitation) in which case blood can leak back into the left atrium and back into the lung.

www.en.wikipedia.org/wiki/Mitral_valve_replacement