- The four valves of the heart include the tricuspid, pulmonary, mitral and aortic valves.
- Some people are born with defective heart valves. Some individuals' heart valves become defective as a result of infection, with age, or for other reasons.
- A properly functioning heart valve should open and close fully. Stenosis occurs when a valve is narrowed and doesn't open fully; regurgitation occurs when the valve doesn't close fully and allows blood to leak back through.
- Mitral valve prolapse is one of the most common heart valve conditions, which may not cause symptoms and doesn't require treatment in every individual who has it. A common condition affecting babies is a bicuspid aortic valve, in which the aortic valve doesn't develop normally and has two leaflets rather than three.
- Some people may need to have their heart valves replaced. There are mechanical valves, which are man-made, and also biological valves, which may come from human donors, cows or pigs.
