My mother has hypertrophic cardiomyopathy. what is it in a nutshell?

Significant disease: Hypertrophic cardiomyopathy is a condition in which the heart muscle becomes thick, and obstruction to outflow may occur. Arrhythmias may occur as well. It is commonly inherited, first degree relatives should be screened. Patients may have severe symptoms, or no symptoms at all. It is a common cause of death in young athletes who seemed completely healthy.