They may, however, become diseased. Stenosis is a constriction or narrowing of the valve opening. This makes blood flow through the valve difficult. Valve regurgitation occurs when the valves do not shut completely, resulting in part of the blood moving backwards through the valve into the chamber where it came from. These diseases cause extra work for the heart and usually occur in the two left sided heart valves.
Medications can be effective for some patients with heart valve disease.
However, when symptoms such as chest pain, fatigue, and shortness of breath become severe enough to limit the patient's lifestyle, surgery is usually necessary. At times, heart valves can be repaired. Often, however, they must be replaced. Biological valves are usually from a pig, cow, or human cadaver. The major disadvantage is a tendency in certain age groups for the valve to deteriorate, and this may lead to the need for another operation at a later date.