The thickening reduces the size of the pumping chamber and obstructs blood flow. It also prevents the heart from properly relaxing between beats and so filling with blood. Eventually, this limits the pumping action. Hypertrophic cardiomyopathy is a rare disease, occurring in no more than 0.2 percent of the U.S. population. It can affect men and women of all ages.
Symptoms can appear in childhood or adulthood.
Restrictive cardiomyopathy is rare in the United States. In this disease the walls of the ventricles stiffen and lose their flexibility due to infiltration by abnormal tissue. As a result, the heart cannot fill adequately with blood and eventually loses its ability to pump properly. Restrictive cardiomyopathy typically results from another disease, which occurs elsewhere in the body. Dilated cardiomyopathy can be present for several years without causing significant symptoms With time, however, the enlarged heart gradually weakens.