Hypertrophic cardiomyopathy (HCM) is a form of heart disease that involves thickening (hypertrophy) of the heart muscle. When the walls get too thick, the heart muscle functions inefficiently, causing some patients to have obstruction to blood flow from the heart. HCM is also associated with abnormal heart rhythms, which can sometimes be life threatening.
The term “cardiomyopathy” indicates that the increase in muscle thickness is related to a disease of the muscle itself and is not caused by other conditions that are known to make the heart muscle thicken because it is forced to work harder. The thickened heart muscle of HCM is also stiffer than normal and thus does not relax easily to fill with blood between each heartbeat.
- HCM is the most common genetic disease of the heart (prevalence: 1 in 500).
- HCM is the most common cause of sudden cardiac death in young people and athletes.
- HCM is most commonly diagnosed in the second or third decade of life, but may be diagnosed at any age.
Hypertrophic cardiomyopathy is usually inherited, but in many cases, there is no obvious family history of the condition. If left untreated, HCM can lead to irregular heart rhythms (cardiac arrhythmias) and heart failure.
HCM can sometimes be described as a “hidden disease” because people who have it may not always have symptoms. And when HCM symptoms do appear, they may be difficult to recognize because they are similar to other health conditions such as asthma, anxiety, hypertension, or coronary artery disease. Even though HCM can be difficult to pin down, there are common symptoms. Treatment strategies for HCM have made very important advances in the last two decades.