Hypertrophic cardiomyopathy | |
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Other names | Asymmetric septal hypertrophy; idiopathic hypertrophic subaortic stenosis;[1] hypertrophic obstructive cardiomyopathy (HOCM) |
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Specialty | Cardiology |
Symptoms | Feeling tired, leg swelling, shortness of breath, chest pain, fainting[2] |
Complications | Heart failure, irregular heartbeat, sudden cardiac death[3][4] |
Causes | Genetics, Fabry disease, Friedreich's ataxia, certain medications[5][6] |
Diagnostic method | Electrocardiogram, echocardiogram, stress testing, genetic testing[7] |
Differential diagnosis | Hypertensive heart disease, aortic stenosis, athlete's heart[5] |
Treatment | Medications, implantable cardiac defibrillator, surgery[7] |
Medication | Beta blockers, verapamil, disopyramide[8] |
Prognosis | Less than 1% per year risk of death (with treatment)[9] |
Frequency | Up to 1 in 200 people[8] |
Hypertrophic cardiomyopathy (HCM, or HOCM when obstructive) is a condition in which muscle tissues of the heart become thickened without an obvious cause.[8] The parts of the heart most commonly affected are the interventricular septum and the ventricles.[10] This results in the heart being less able to pump blood effectively and also may cause electrical conduction problems.[3] Specifically, within the bundle branches that conduct impulses through the interventricular septum and into the Purkinje fibers, as these are responsible for the depolarization of contractile cells of both ventricles.[11]
People who have HCM may have a range of symptoms. People may be asymptomatic, or may have fatigue, leg swelling, and shortness of breath.[2] It may also result in chest pain or fainting.[2] Symptoms may be worse when the person is dehydrated.[10] Complications may include heart failure, an irregular heartbeat, and sudden cardiac death.[3][4]
HCM is most commonly inherited[6] in an autosomal dominant pattern.[10] It is often due to mutations in certain genes involved with making heart muscle proteins.[6] Other inherited causes of left ventricular hypertrophy may include Fabry disease, Friedreich's ataxia, and certain medications such as tacrolimus.[5] Other considerations for causes of enlarged heart are athlete's heart and hypertension (high blood pressure).[10] Making the diagnosis of HCM often involves a family history or pedigree, an electrocardiogram, echocardiogram, and stress testing.[7] Genetic testing may also be done.[7] HCM can be distinguished from other inherited causes of cardiomyopathy by its autosomal dominant pattern, whereas Fabry disease is X-linked, and Friedreich's ataxia is inherited in an autosomal recessive pattern.[10]
Treatment may depend on symptoms and other risk factors. Medications may include the use of beta blockers, verapamil or disopyramide.[8] An implantable cardiac defibrillator may be recommended in those with certain types of irregular heartbeat.[7] Surgery, in the form of a septal myectomy or heart transplant, may be done in those who do not improve with other measures.[7] With treatment, the risk of death from the disease is less than one percent per year.[9]
HCM affects up to one in 200 people.[8] People of all ages may be affected.[12] The first modern description of the disease was by Donald Teare in 1958.[13][14]