Cardiomyopathy is a group of primary diseases of the heart muscle. Early on there may be few or no symptoms. As the disease worsens,

shortness of breath Shortness of breath (SOB), known as dyspnea (in AmE) or dyspnoea (in BrE), is an uncomfortable feeling of not being able to breathe well enough. The American Thoracic Society defines it as "a subjective experience of breathing discomfort that con ...

, feeling tired, and swelling of the legs may occur, due to the onset of

heart failure Heart failure (HF), also known as congestive heart failure (CHF), is a syndrome caused by an impairment in the heart's ability to Cardiac cycle, fill with and pump blood. Although symptoms vary based on which side of the heart is affected, HF ...

. An irregular heart beat and fainting may occur. Those affected are at an increased risk of sudden cardiac death. As of 2013, cardiomyopathies are defined as "disorders characterized by morphologically and functionally abnormal myocardium in the absence of any other disease that is sufficient, by itself, to cause the observed phenotype." Types of cardiomyopathy include hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular dysplasia, and Takotsubo cardiomyopathy (broken heart syndrome). In hypertrophic cardiomyopathy the heart muscle enlarges and thickens. In dilated cardiomyopathy the ventricles enlarge and weaken. In restrictive cardiomyopathy the ventricle stiffens. In many cases, the cause cannot be determined. Hypertrophic cardiomyopathy is usually inherited, whereas dilated cardiomyopathy is inherited in about one third of cases. Dilated cardiomyopathy may also result from

alcohol Alcohol may refer to: Common uses * Alcohol (chemistry), a class of compounds * Ethanol, one of several alcohols, commonly known as alcohol in everyday life ** Alcohol (drug), intoxicant found in alcoholic beverages ** Alcoholic beverage, an alco ...

, heavy metals,

coronary artery disease Coronary artery disease (CAD), also called coronary heart disease (CHD), or ischemic heart disease (IHD), is a type of cardiovascular disease, heart disease involving Ischemia, the reduction of blood flow to the cardiac muscle due to a build-up ...

cocaine Cocaine is a tropane alkaloid and central nervous system stimulant, derived primarily from the leaves of two South American coca plants, ''Erythroxylum coca'' and ''Erythroxylum novogranatense, E. novogranatense'', which are cultivated a ...

use, and viral infections. Restrictive cardiomyopathy may be caused by amyloidosis, hemochromatosis, and some cancer treatments. Broken heart syndrome is caused by extreme emotional or physical stress. Treatment depends on the type of cardiomyopathy and the severity of symptoms. Treatments may include lifestyle changes, medications, or surgery. Surgery may include a ventricular assist device or heart transplant. In 2015 cardiomyopathy and myocarditis affected 2.5 million people. Hypertrophic cardiomyopathy affects about 1 in 500 people while dilated cardiomyopathy affects 1 in 2,500. They resulted in 354,000 deaths up from 294,000 in 1990. Arrhythmogenic right ventricular dysplasia is more common in young people.

Signs and symptoms

The presentation of cardiomyopathy is: * Shortness of breath or trouble breathing, especially with physical exertion * Fatigue * Swelling in the ankles, feet, legs, abdomen and veins in the neck * Dizziness * Lightheadedness * Fainting during physical activity * Arrhythmias (abnormal heartbeats) * Chest pain, especially after physical exertion or heavy meals * Heart murmurs (unusual sounds associated with heartbeats)

Causes

Cardiomyopathies can be of genetic (familial) or non-genetic (acquired) origin. Genetic cardiomyopathies usually are caused by

sarcomere A sarcomere (Greek σάρξ ''sarx'' "flesh", μέρος ''meros'' "part") is the smallest functional unit of striated muscle tissue. It is the repeating unit between two Z-lines. Skeletal striated muscle, Skeletal muscles are composed of tubular ...

cytoskeletal The cytoskeleton is a complex, dynamic network of interlinking protein filaments present in the cytoplasm of all Cell (biology), cells, including those of bacteria and archaea. In eukaryotes, it extends from the cell nucleus to the cell membrane ...

diseases, neuromuscular disorders, inborn errors of metabolism, malformation syndromes and sometimes are unidentified. Non-genetic cardiomyopathies can have definitive causes such as viral infections, myocarditis and others. Cardiomyopathies are either confined to the heart or are part of a generalized systemic disorder, both often leading to cardiovascular death or progressive heart failure-related disability. Other diseases that cause heart muscle dysfunction are excluded, such as

hypertension Hypertension, also known as high blood pressure, is a Chronic condition, long-term Disease, medical condition in which the blood pressure in the artery, arteries is persistently elevated. High blood pressure usually does not cause symptoms i ...

, or abnormalities of the heart valves. Often, the underlying cause remains unknown, but in many cases the cause may be identifiable. Alcoholism, for example, has been identified as a cause of dilated cardiomyopathy, as has drug toxicity, and certain infections (including

Hepatitis C Hepatitis C is an infectious disease caused by the hepatitis C virus (HCV) that primarily affects the liver; it is a type of viral hepatitis. During the initial infection period, people often have mild or no symptoms. Early symptoms can include ...

). Untreated

celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine. Patients develop intolerance to gluten, which is present in foods such as wheat, rye, spel ...

can cause cardiomyopathies, which can completely reverse with a timely diagnosis. In addition to acquired causes, molecular biology and genetics have given rise to the recognition of various genetic causes. A more clinical categorization of cardiomyopathy as 'hypertrophied', 'dilated', or 'restrictive', has become difficult to maintain because some of the conditions could fulfill more than one of those three categories at any particular stage of their development. The current

American Heart Association The American Heart Association (AHA) is a nonprofit organization in the United States that funds cardiovascular medical research, educates consumers on healthy living and fosters appropriate Heart, cardiac care in an effort to reduce disability ...

(AHA) definition divides cardiomyopathies into primary, which affect the heart alone, and secondary, which are the result of illness affecting other parts of the body. These categories are further broken down into subgroups which incorporate new genetic and molecular biology knowledge.

Mechanism

The pathophysiology of cardiomyopathies is better understood at the cellular level with advances in molecular techniques. Mutant proteins can disturb cardiac function in the contractile apparatus (or mechanosensitive complexes). Cardiomyocyte alterations and their persistent responses at the cellular level cause changes that are correlated with sudden cardiac death and other cardiac problems. Cardiomyopathies are generally varied individually. Different factors can cause cardiomyopathies in adults as well as children. For example, dilated cardiomyopathy in adults is associated with ischemic cardiomyopathy, hypertension, valvular diseases, and genetics. In children, neuromuscular diseases such as Becker muscular dystrophy or X-linked genetic disorder, are directly linked with cardiomyopathies.

Diagnosis

175 px, Normal sinus rhythm on EKG Among the diagnostic procedures done to determine a cardiomyopathy are: * Physical exam * Family history *

Blood test A blood test is a medical laboratory, laboratory analysis performed on a blood sample that is usually extracted from a vein in the arm using a hypodermic needle, or via fingerprick. Multiple tests for specific blood components, such as a glucose ...

* ECG * Echocardiogram * Stress test *

Genetic testing Genetic testing, also known as DNA testing, is used to identify changes in DNA sequence or chromosome structure. Genetic testing can also include measuring the results of genetic changes, such as RNA analysis as an output of gene expression, or ...

Classification

Cardiomyopathies can be classified using different criteria: * Primary/intrinsic cardiomyopathies ** Congenital *** Hypertrophic cardiomyopathy (HCM) *** Arrhythmogenic right ventricular cardiomyopathy (ARVC) *** Left ventricular noncompaction *** Ion Channelopathies like the Long QT syndrome and the very rare Short QT syndrome *** Catecholaminergic polymorphic ventricular tachycardia ** Mixed *** Dilated cardiomyopathy (DCM) *** Restrictive cardiomyopathy (RCM) *** Brugada syndrome ** Acquired *** Stress cardiomyopathy *** Myocarditis,

inflammation Inflammation (from ) is part of the biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or irritants. The five cardinal signs are heat, pain, redness, swelling, and loss of function (Latin ''calor'', '' ...

of and injury to heart tissue due in part to its infiltration by

lymphocytes A lymphocyte is a type of white blood cell (leukocyte) in the immune system of most vertebrates. Lymphocytes include T cells (for cell-mediated and cytotoxic adaptive immunity), B cells (for humoral, antibody-driven adaptive immunity), and ...

and

monocytes Monocytes are a type of leukocyte or white blood cell. They are the largest type of leukocyte in blood and can differentiate into macrophages and monocyte-derived dendritic cells. As a part of the vertebrate innate immune system monocytes also i ...

*** Eosinophilic myocarditis,

of and injury to heart tissue due in part to its infiltration by eosinophils *** Ischemic cardiomyopathy (''not formally included in the classification, due to ischemic cardiomyopathy being a direct result of another cardiac problem'') * Secondary/extrinsic cardiomyopathies ** Metabolic/storage *** Fabry's disease *** Hemochromatosis ** Endomyocardial *** Endomyocardial fibrosis *** Hypereosinophilic syndrome ** Endocrine ***

Diabetes mellitus Diabetes mellitus, commonly known as diabetes, is a group of common endocrine diseases characterized by sustained hyperglycemia, high blood sugar levels. Diabetes is due to either the pancreas not producing enough of the hormone insulin, or th ...

***

Hyperthyroidism Hyperthyroidism is a endocrine disease in which the thyroid gland produces excessive amounts of thyroid hormones. Thyrotoxicosis is a condition that occurs due to elevated levels of thyroid hormones of any cause and therefore includes hyperth ...

***

Acromegaly Acromegaly is a disorder that results in excess growth of certain parts of the human body. It is caused by excess growth hormone (GH) after the growth plates have closed. The initial symptom is typically enlargement of the hands and feet. There ...

** Cardiofacial *** Noonan syndrome ** Neuromuscular ***

Muscular dystrophy Muscular dystrophies (MD) are a genetically and clinically heterogeneous group of rare neuromuscular diseases that cause progressive weakness and breakdown of skeletal muscles over time. The disorders differ as to which muscles are primarily affe ...

***

Friedreich's ataxia Friedreich's ataxia (FRDA) is a rare, inherited, autosomal recessive neurodegenerative disorder that primarily affects the nervous system, causing progressive damage to the spinal cord, peripheral nerves, and cerebellum, leading to impaired ...

** Other *** Obesity-associated cardiomyopathy

Treatment

Treatment may include suggestion of lifestyle changes to better manage the condition. Treatment depends on the type of cardiomyopathy and condition of disease, but may include medication (conservative treatment) or iatrogenic/implanted pacemakers for slow heart rates, defibrillators for those prone to fatal heart rhythms, ventricular assist devices (VADs) for severe heart failure, or catheter ablation for recurring dysrhythmias that cannot be eliminated by medication or mechanical cardioversion. The goal of treatment is often symptom relief, and some patients may eventually require a heart transplant. Acoramidis (Attruby) was approved for medical use in the United States in November 2024, to treat adults with cardiomyopathy of wild-type or variant (hereditary) transthyretin-mediated amyloidosis (ATTR-CM) to reduce death and hospitalization related to heart problems.

References

External links

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