Cardiomyopathy | |
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Classification and external resources | |
Opened left ventricle of heart shows a thickened, dilated left ventricle with subendocardial fibrosis manifested as increased whiteness of endocardium. |
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ICD-10 | I42.0 |
ICD-9 | 425.4 |
DiseasesDB | 2137 |
MedlinePlus | 001105 |
MeSH | D009202 |
Cardiomyopathy, which literally means "heart muscle disease," is the deterioration of the function of the myocardium (i.e., the actual heart muscle) for any reason. People with cardiomyopathy are often at risk of arrhythmia or sudden cardiac death or both.[1]
Cardiomyopathies can be categorized as extrinsic or intrinsic.[2]
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These are cardiomyopathies where the primary pathology is outside the myocardium itself. Most cardiomyopathies are extrinsic, because by far the most common cause of a cardiomyopathy is ischemia. The World Health Organization calls these specific cardiomyopathies:[2]
Commonly used term "ischemic cardiomyopathy," referring to myocardial ischemia and infarction, is not supported by current cardiomyopathies classification schemes[5][6].
Ischemic cardiomyopathy is a weakness in the muscle of the heart due to inadequate oxygen delivery to the myocardium with coronary artery disease being the most common cause. Anemia and sleep apnea are relatively common conditions that can contribute to ischemic myocardium and hyperthyroidism can cause a 'relative' ischemia secondary to high output heart failure. Individuals with ischemic cardiomyopathy typically have a history of myocardial infarction (heart attack), although longstanding ischemia can cause enough damage to the myocardium to precipitate a clinically significant cardiomyopathy even in the absence of myocardial infarction. In a typical presentation, the area of the heart affected by a myocardial infarction will initially become necrotic as it dies, and will then be replaced by myocardial scarring (fibrosis). This fibrotic tissue is akinetic; it is no longer muscle and cannot contribute to the heart's function as a pump. If the akinetic region of the heart is substantial enough, the affected side of the heart (i.e. the left or right side) will go into failure, and this failure is the functional result of an ischemic cardiomyopathy.
In some individuals, severe emotional stress may lead to "takotsubo cardiomyopathy", a specific cardiomyopathy which has a particular aetiology.
Many diseases can result in cardiomyopathy. These include diseases like hemochromatosis, (an abnormal accumulation of iron in the liver and other organs), amyloidosis (an abnormal accumulation of the amyloid protein), diabetes, hyperthyroidism, lysosomal storage diseases and the muscular dystrophies.
Some current chemotheraphy drugs can also be the cause. However, this is only likely in 2-3% of patients.
An intrinsic cardiomyopathy is defined as weakness in the muscle of the heart that is not due to an identifiable external cause. This definition was used to categorize previously idiopathic cardiomyopathies although specific external causes have since been identified for many. For example, alcoholism has been identified as a cause for some forms of dilated cardiomyopathy.
To make a diagnosis of an intrinsic cardiomyopathy, significant coronary artery disease should be ruled out (amongst other things). The term intrinsic cardiomyopathy does not describe the specific etiology of weakened heart muscle. The intrinsic cardiomyopathies consist of a variety of disease states, each with their own causes.
Many intrinsic cardiomyopathies now have identifiable external causes including drug and alcohol toxicity, certain infections (including Hepatitis C), and various genetic and idiopathic (i.e., unknown) causes.
Intrinsic cardiomyopathies are generally classified into four types,[2][7] but additional types are also recognized:
Symptoms and signs may mimic those of almost any form of heart disease. Chest pain is common. Mild myocarditis or cardiomyopathy is frequently asymptomatic; severe cases are associated with heart failure, arrhythmias, and systemic embolization. Manifestations of the underlying disease (e.g., Chagas' disease) may be prominent. Most patients with biopsy-proven myocarditis report a recent viral prodrome preceding cardiovascular symptoms.
ECG abnormalities are often present, although the changes are frequently nonspecific. A pattern characteristic of left ventricular hypertrophy may be present. Flat or inverted T waves are most common, often with low-voltage QRS complexes. Intraventricular conduction defects and bundle branch block, especially left bundle branch block, are also common. An echocardiogram is useful to detect wall motion abnormalities or a pericardial effusion. Chest radiographs can be normal or can show evidence of congestive heart failure with pulmonary edema or cardiomegaly.
Treatment depends on the type of cardiomyopathy, but may include medication, implanted pacemakers, defibrillators, or ventricular assist devices (LVADs), or ablation. The goal of treatment is often symptom relief, and some patients may eventually require a heart transplant. Treatment of cardiomyopathy (and other heart diseases) using alternative methods such as stem cell therapy is commercially available but is not supported by convincing evidence.
In 1966, the addition of cobalt compounds to stabilize beer foam in Canada led to cardiomyopathy, which came to be known as beer drinker's cardiomyopathy.[8]
Dave Williams of Drowning Pool died of cardiomyopathy in 2002.
Dr. Robert Atkins, inventor of "The Atkins Diet" suffered from cardiomyopathy in the years before his death from a fall.
Alexei Cherepanov, 19 year old professional ice hockey player, died of cardiomyopathy during an ice hockey game in 2008.[9]
Andy Hallett, a 33 year old actor from the television series Angel, died of congestive heart failure in 2009, brought on by a cardiomyopathy from a tooth infection five years earlier.
Michael James Hegstrand aka Road Warrior Hawk an American professional wrestler.
Slash, guitarist for Guns N Roses, survived cardiomyopathy .
Reggie Lewis, captain and all-star of the Boston Celtics, died from hypertrophic cardiomyopathy at age 27.
Marc-Vivien Foé, Cameroonian international professional football (soccer) player, collapsed and died of hypertrophic obstructive cardiomyopathy (HOCM) aged 28 during a FIFA Confederations Cup Match on 26 June 2003.
Cuttino Mobley, a retired NBA player who last played for the LA Clippers, was forced to retire after being diagnosed with hypertrophic cardiomyopathy in late 2008.
Hank Gathers, a college basketball star recruit who played for Loyola Marymount University, collapsed during a free throw attempt against UCSB and later again against the University of Portland. The second time he never got up and was pronounced dead on arrival.
Nick Carter of the Backstreet Boys was diagnosed with cardiomyopathy after suffering chest pains.
Katie Gallagher, who placed second on the TV reality show Survivor: Palau, was diagnosed with viral cardiomyopathy several years later.
The Amazing Jonathan was diagnosed with "a serious heart condition" in March 2007. The performer's website identified the condition as cardiomyopathy and went on to assert that, due to a combination of weight loss and blood thinners, he was doing well and did not intend to retire.
Phenotype | Inheritance pattern | Chromosomal locus | Gene | Protein | Skeletal myopathy |
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Dilated cardiomyopathy | X-linked | Xp21 | dystrophin | Dystrophin | Duchenne / Becker muscular dystrophy |
X-linked | Xq28 | G4.5 | Tafazzin | Barth syndrome | |
Autosomal dominant | 15q14 | actin | Actin | Nemaline myopathy | |
2q35 | desmin | Desmin | Desmin myopathy | ||
5q33 | δ-sarcoglycan | δ-sarcoglycan | Limb girdle muscular dystrophy 2F | ||
1q32 | Troponin T | Troponin T | |||
14q11 | β-myosin heavy chain | β-myosin heavy chain | |||
15q2 | α-tropomyosin | α-tropomyosin | Nemaline myopathy | ||
Midna | Mitochondrial respiratory chain | Mitochondrial respiratory chain | Mitochondrial myopathy | ||
Dilated cardiomyopathy with conduction disease | Autosomal dominant | 1q21 | lamin A/C | Lamin A/C | Emery-Dreifuss muscular dystrophy |
Hypertrophic cardiomyopathy | Autosomal dominant | 14q11 | β-myosin heavy chain | β-myosin heavy chain | |
14q11 | β-myosin heavy chain | β-myosin heavey chain | |||
1q32 | Troponin T | Troponin T | |||
12q23 | Troponin T | Troponin T | |||
15q2 | α-tropomyosin | α-tropomyosin | Nemaline myopathy | ||
11q11 | myosin-binding protein C | myosin-binding protein C | |||
3p21 | myosin essential light chain | myosin essential light chain | |||
3p21 | myosin regulatory light chain | myosin regulatory light chain | |||
2p31 | titin | Titin | |||
Hypertrophic cardiomyopathy with Wolf-Parkinson-White syndrome | 7q3 | AMPK | AMPK | ||
MIDINA | Mitochondrial respiratory chain | Mitochondrial respiratory chain | Mitochondrial myopathy | ||
Left ventricular noncompaction | X-linked | Xq28 | G4.5 | Tafazzin | Barth syndrome |
Autosomal dominant | 18q12 | α-dystrobrevin | α-Dystrobrevin | Muscular dystrophy |
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