Hypertrophic cardiomyopathy (HCM) is a genetically inherited disease affecting the heart. It causes thickening of heart muscle, especially the chamber responsible for pumping blood out of the heart, the left ventricle. This condition can cause patients to experience symptoms of chest pain, shortness of breath, fatigue, and heart beat palpitations. Researchers believe the disease may be caused by abnormalities in the genes responsible for producing proteins of the heart muscle.