Take the blood flow in the heart for example. A complex geometry, with the myocardium2 that is actively deformed and arteries, veins, and valves that become passively deformed. This complex system determines the blood motion. The flow of the blood causes stress on surfaces and structures – like heart valve prostheses. Especially the left ventricle, which is the strong pump in our heart that transports the oxygen-rich blood through the entire body, has a lot to endure, possibly leading to cardiovascular problems in some cases.