Hypertrophic cardiomyopathy (HCM) is a condition in which the heart muscle becomes thick. Often, one part of the heart is thicker than the other parts.
The thickening can make it harder for blood to leave the heart, forcing the heart to work harder to pump blood. It also can make it harder for the heart to relax and fill with blood.
HCM is most often passed down in families. It is thought to result from defects in the genes that control heart muscle growth.
Younger people are likely to have a more severe form of HCM. However, the condition is seen in people of all ages.
Some people with the condition may have no symptoms. They may first find out they have the problem during a routine medical exam.
In many young adults, the first symptom of HCM is sudden collapse and possible death. This can be caused by highly abnormal heart rhythms. It may also be due to a blockage that prevents the outflow of blood from the heart to the rest of the body.
Common symptoms include:
- Chest pain
- Fainting, especially during exercise
- Lightheadedness, especially with or after activity or exercise
- Heart beating fast or irregularly
- Shortness of breath with activity or after lying down