What is Hypertrophic cardiomyopathy?

Hypertrophic cardiomyopathy (HCM) is the commonest type of cardiomyopathy (heart muscle disease), characterized by unexplained thickening of the heart muscle, mainly at the left heart. It is caused by changes (mutation) in certain cardiac genes. So, the children of the patients would have a 50% chance of inheriting the abnormal gene. The expression of the disease is usually during adolescence and young adulthood. About half of the HCM patients have no significant symptoms, hence some patients only get diagnosed past middle age.

The common complaints are shortness of breath and chest discomfort, usually during physical activities. Uncommonly fainting or near fainting may occur. In a very small group of patients, there is elevated risk of sudden cardiac death.

The condition is usually suspected from an abnormal ECG. It is diagnosed by detecting abnormal thickening of heart muscle, usually through ultrasound of the heart (echocardiogram) or cardiac MRI. In about a third of the patients the scan may also show left heart facing resistance when pumping blood out (left ventricular outflow tract (LVOT) obstruction), with an even higher proportion of patients having this problem during physical activities. Genetic testing should also be considered after proper genetic counseling.

There are no specific medications to cure HCM. Most patients are expected to have a normal lifespan. Management is mainly to improve symptoms and treat/prevent complications, which mainly are heart failure, abnormal heart rhythm and, very rarely, sudden cardiac death.

Most patients do not require any specific treatment. Management strategy would involve lifestyle modifications, and medications in some. A small minority of patients may need device implantation to prevent sudden death. When medications do not work well, cardiac surgery may be necessary to improve symptoms due to LVOT obstruction.