What is Valve Disease?
Healthy heart valves assure blood will flow smoothly through the heart in one direction. When a valve fails to close completely, blood is allowed to flow in the reverse direction. This is called regurgitation or insufficiency. Valves can also be narrowed by deposits of calcium; this is called stenosis.
Like any pump, if the valves fail the pump must work harder to do its job. Since the heart is a muscle, it can enlarge to compensate for the diseased valve but only up to a point before permanent damage and heart failure set in.