There are four valves within the heart that regulate the flow of blood between the heart’s four chambers. The two valves on the left side of the heart direct oxygen-rich blood while the two valves on the right side handle oxygen-poor blood.

The heart valves are made up of either two or three flaps (cusps) that swing open to allow blood to flow through and close tightly to prevent blood leakage. The valves are synchronized to open and shut in the same rhythm as the systolic (contraction) and diastolic (relaxation) phases of the cardiac cycle. It is this opening and shutting of the valves that make the characteristic “lub-dub” sound of the heartbeat.

There are a number of conditions that can affect the structure and function of the valves in the heart.