Dilated cardiomyopathy can be caused by pregnancy, drugs, including alcohol, some infections including HIV, and perhaps by multiple heart attacks over time. The dilated heart from any of these causes is unable to pump as effectively as a normal heart, resulting eventually incongestive heart failure. The main symptoms of this are shortness of breath and fatigue. Cases due to pregnancy can resolve after the birth of the baby, and cases due to alcohol or drugs may resolve if one stops using these substances. However, many other cases progress to increasing heart failure and possible sudden death.
Dilated cardiomyopathy is a major cause of heart transplantation.
Hypertrophic cardiomyopathy is thought in most cases to be due to an inherited genetic trait and an abnormal gene coding for a component of heart muscle has recently been identified in people with this form of the disease. In this form of the disease, the heart muscle becomes extremely thickened, interfering with the heart's ability to pump blood. Symptoms may include fainting, chest pain, palpitations, shortness of breath and fatigue. Medical treatment with beta blockers is often effective, as is surgery to remove some of the thickened muscle tissue. In restrictive cardiomyopathies, another type of tissue or substance is deposited in and around the heart muscle fibers, preventing the heart from filling adequately with blood, and then from pumping it out strongly.