Of all the different diseases to affect the heart, one of the most frequently encountered is a damaged valve. This can be caused by a variety of things, but one of the most common causes is rheumatic fever. This is especially true of under developed third world countries. The valve tissue becomes scarred, making it too stiff to open and close effectively. This has the effect of allowing blood to leak backwards through the system, a condition often known as a heart murmur. Disease of the heart valves can also lead to such things as angina or palpitations.
However, as well as being quite a common problem, it is often treatable by means of an operation. Nowadays a valve operation is fairly routine, being carried out at many hospitals. Replacement valves fall into two broad categories - natural or man made. Both come in various types, but the natural version can either be made from tissue taken from another part of the patient's body, or even a complete valve from an animal with a similar heart to a human being, such as a pig.
