Stenosis. The valve opening is narrow and does not open completely, which may be caused by growths, scars, or abnormal deposits on the heart valves.
Atresia. The valve does not form, so there is no opening for blood to pass from one chamber to another.
Regurgitation. Also referred to as Insufficiency. The valve does not close completely, so blood can leak back through the valve into the heart chamber.

Aortic valve stenosis is a narrowing of the aortic valve in the heart that causes it to open incompletely. This reduces the blood flow to the different parts of the body.

Pulmonary valve stenosis. In Pulmonary Valve Stenosis the pulmonary (Pulmonic) valve of the heart is narrowed. This narrowing of the valve slows the flow of blood from the right side of the heart to the lungs, thus, the heart must pump harder to push the blood through the narrowed opening.

Pulmonary valve atresia is a defect in which a solid sheet of tissue forms in place of the pulmonary valve. This prevents blood in the right side of the heart from traveling normally to the lungs to pick up oxygen.

Tricuspid valve atresia is a defect in which a solid sheet of tissue forms in place of the tricuspid valve. Without the tricuspid valve, blood entering the right atrium cannot travel normally to the right ventricle and then to the lungs to pick up oxygen.

Ebstein's anomaly is a defect in which the tricuspid valve is both displaced and abnormally formed. The valve leaks and allows blood to flow back into the right atrium instead of flowing into the lungs.