Hypertrophic cardiomyopathy is a disease of the myocardium (the muscle of the heart) in which a portion of the myocardium is hypertrophied (thickened) without any obvious cause. It is perhaps most well known as a leading cause of sudden cardiac death in young athletes. The occurrence of hypertrophic cardiomyopathy is a significant cause of sudden unexpected cardiac death in any age group and as a cause of disabling cardiac symptoms. Younger people are likely to have a more severe form of hypertrophic cardiomyopathy HCM is frequently asymptomatic until sudden cardiac death, and for this reason some suggest routinely screening certain populations for this disease.
A cardiomyopathy is a primary disease that affects the muscle of the heart. With hypertrophic cardiomyopathy (HCM), the sarcomeres (contractile elements) in the heart replicate causing heart muscle cells to increase in size, which results in the thickening of the heart muscle. In addition, the normal alignment of muscle cells is disrupted, a phenomenon known as myocardial disarray. HCM also causes disruptions of the electrical functions of the heart. HCM is most commonly due to a mutation in one of 9 sarcomeric genes that results in a mutated protein in the sarcomere, the primary component of the myocyte (the muscle cell of the heart).
While most literature so far focuses on European, American, and Japanese populations, HCM appears in all racial groups. The prevalence of HCM is about 0.2% to 0.5% of the general population.Myosin heavy chain mutations are associated with development of familial hypertrophic cardiomyopathy.
Hypertrophic cardiomyopathy Signs and symptoms
The clinical course of HCM is variable. Many patients are asymptomatic or mildly symptomatic. The symptoms of HCM include dyspnea (shortness of breath), chest pain (sometimes known as angina), uncomfortable awareness of the heart beat (palpitations), lightheadedness, fatigue, fainting (called syncope) and sudden cardiac death. Dyspnea is largely due to increased stiffness of the left ventricle, which impairs filling of the ventricles and leads to elevated pressure in the left ventricle and left atrium. Symptoms are not closely related to the presence or severity of an outflow tract gradient. Often, symptoms mimic those of congestive heart failure (esp. activity intolerance & dyspnea), but treatment is very different. To treat with diuretics (a mainstay of CHF treatment) will exacerbate symptoms in hypertrophic cardiomyopathy by decreasing ventricular volume and increasing outflow resistance.
Risk factors for sudden death in individuals with HCM include a young age at first diagnosis (age Hypertrophic Cardiomyopathy Association Helps Draft Bill to Prevent Sudden Cardiac Arrest (SCA) in Children and Teens Undiagnosed Silent Killer Causes Thousands of Deaths Every Year Last year, a fortuitous meeting between Lisa Salberg, founder and CEO of the Hypertrophic Cardiomyopathy Association (HCMA), and Congressman Frank Pallone, Jr. (Dem., N.J.) was instrumental in the drafting of the Cardiomyopathy Health Education, Awareness, Risk Assessment, and Training in the Schools (HEARTs) Act, a bill which Pallone introduced to Congress today.
Calling awareness to sudden cardiac arrest is one of the cornerstones of the HCMA, the national resource for patients who have Hypertrophic Cardiomyopathy (HCM), the most common genetic heart disease. HCM, which results in a thickening of the heart muscle, is the leading cause of Sudden Cardiac Arrest (SCA) in children and young adults.