Hypertrophic cardiomyopathy (HCM) is a condition in which a portion of the heart becomes thickened without an obvious cause. This results in the heart being less able to pump blood effectively.Symptoms vary from none to feeling tired, leg swelling, and shortness of breath. It may also result in chest pain or fainting.Complications include heart failure, an irregular heartbeat, and sudden cardiac death.
HCM is most commonly inherited from a person's parents.It is often due to mutations in certain genes involved with making heart muscle proteins. Other causes may include Fabry disease, Friedreich's ataxia, and certain medications such as tacrolimus.It is a type of cardiomyopathy, a group of diseases that primarily affects the heart muscle. Diagnosis often involves an electrocardiogram, echocardiogram, and stress testing.Genetic testing may also be done.
Treatment may include the use of beta blockers, diuretics, or disopyramide.An implantable cardiac defibrillator may be recommended in those with certain types of irregular heartbeat.Surgery, in the form of a septal myectomy or heart transplant, may be done in those who do not improve with other measures.With treatment, the risk of death from the disease is less than one percent per year.
The clinical course of HCM is variable. Many people with HCM are asymptomatic or mildly symptomatic, and many of those carrying disease genes for HCM do not have clinically detectable disease.The symptoms and signs of HCM include shortness of breath due to stiffening and decreased blood filling of the ventricles, exertional chest pain (sometimes known as angina) due to reduced blood flow to the coronary arteries, uncomfortable awareness of the heart beat (palpitations), as well as disruption of the electrical system running through the abnormal heart muscle.
Dyspnea is largely due to increased stiffness of the left ventricle (LV), which impairs filling of the ventricles, but also leads to elevated pressure in the left ventricle and left atrium, causing back pressure and interstitial congestion in the lungs. 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 and dyspnea), but treatment of each is different. Beta blockers are used in both cases, but treatment with diuretics, a mainstay of CHF treatment, will exacerbate symptoms in hypertrophic obstructive cardiomyopathy by decreasing ventricular preload volume and thereby increasing outflow resistance (less blood to push aside the thickened obstructing tissue).
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