Cardiomyopathy means abnormal heart muscle. There are various types of cardiomyopathy. Sometimes the condition appears suddenly, so it is called acute. In other cases, the condition has been present for many years or even since birth (congenital) and therefore is termed chronic. Often it can be difficult to determine how long the cardiomyopathy has been present, as sometimes it is not diagnosed until it leads to heart failure.
There are three main types of non-inflammatory cardiomyopathy:
Hypertrophic cardiomyopathy is a disease that causes abnormal thickening (hypertrophy) of the heart muscle. The muscle can be thickened in such a way that it obstructs blood flow out of the heart (hypertrophic obstructive cardiomyopathy or HOCM). In many cases of hypertrophic cardiomyopathy, there is a genetic cause, so that if one member of the family is diagnosed with it other biological family members should also be evaluated. The importance of diagnosing this condition is that it can cause sudden, life-threatening rhythm abnormalities that may be associated with strenuous exercise. Therefore, people with this abnormality are often restricted from competitive sports or strenuous activity and are treated with medications known as beta blockers. There is no definitive cure for hypertrophic cardiomyopathy, though surgeries or other procedures are sometimes performed to remove muscle that is causing obstruction. Heart transplantation may be required if symptoms cannot be controlled.
Restrictive cardiomyopathy is when the heart muscle cannot relax normally between heartbeats, so blood cannot easily get into the ventricles that pump it throughout the body. When blood cannot get into the ventricles it backs up, first into the atria, causing them to enlarge (increasing the risk of rhythm abnormalities and clot formation). The blood then backs up into other places such as the lungs (with left ventricular restriction) or more commonly into the body, causing swelling of the extremities or liver enlargement. It may also back up into other organs, preventing them from functioning normally. There is no medical treatment for restrictive cardiomyopathy other than controlling the symptoms. Heart transplantation is frequently required as the only effective treatment.
Dilated cardiomyopathy is the most common type of cardiomyopathy and has many causes. It can be the result of a genetic abnormality, congenital heart defect, damage from medicines such as chemotherapy, damage from drug use (such as alcohol or cocaine), damage from a prior infection or inflammation (myocarditis), damage from prior heart attacks or coronary artery abnormalities, and more. In the case of dilated cardiomyopathy, the heart is usually greatly enlarged and does not pump very well because the muscle is weakened. The extent of this weakness may vary. Symptoms also vary and depend on how well or how poorly the heart functions and the presence of congestive heart failure.