A heart valve normally allows blood to flow in only one direction through the heart.
Heart valves have to withstand a lot of pressure.
Over time, they may start to leak or become stiff and not open fully, making the heart less efficient.
People affected may become breathless, and without treatment, will eventually die.
Doctors can operate and replace faulty heart valves.
[b]Mechanical Valves[/b] are made of materials such as titanium and polymers.
They last a very long time.
However, with a mechanical valve, you have to take medicine for the rest of your life to prevent your blood clotting around it.
[b]Biological Valves[/b] are based on valves taken from animals such as pigs or cattle, or even human donors.
These work extremely well and the patient doesn't need an medication.
However, they only last about 12 to 15 years.
In most cases, heart valve replacement is an open heart operation.
This means that the surgeon opens your chest and heart to remove the damaged valve.
The new [b]artificial (prosthetic) valve[/b] is then sewn into place.
However, in some cases, the valve can be replaced without opening the chest.