Cardiomyopathy

Cardiomyopathy
Classification and external resources

Opened left ventricle of heart shows a thickened, dilated left ventricle with subendocardial fibrosis manifested as increased whiteness of endocardium.
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]

Contents

Extrinsic cardiomyopathies

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]

Ischemic cardiomyopathy

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.

Cardiomyopathy due to systemic diseases

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.

Intrinsic cardiomyopathies

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:

Signs and symptoms

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

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.

Famous cases

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.

Genetic Causes

Genetic causes of cardiomyopathy[10]
Phenotype Inheritance pattern Chromosomal locus Gene Protein Skeletal myopathy
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

References

  1. Kasper, Denis L. et al. (2005). Harrison's Principles of Internal Medicine, 16th edn. McGraw-Hill. ISBN 0-07-139140-1. 
  2. 2.0 2.1 2.2 Richardson, P. et al.; McKenna, W; Bristow, M; Maisch, B; Mautner, B; O'Connell, J; Olsen, E; Thiene, G et al. (1996). "Report of the 1995 World Health Organization/International Society and Federation of Cardiology Task Force on the Definition and Classification of cardiomyopathies". Circulation 93 (5): 841–2. PMID 8598070.  (Full text)
  3. Salazar-Schettino PM, Perera R, Ruiz-Hernandez AL, et al. (2009). "Chagas disease as a cause of symptomatic chronic myocardopathy in mexican children". Pediatr Infect Dis J 28 (11): 1011–3. doi:10.1097/INF.0b013e3181ad8425. PMID 19859016. 
  4. Sánchez-Guillén Mdel C, López-Colombo A, Ordóñez-Toquero G, et al. (2006). "Clinical forms of Trypanosoma cruzi infected individuals in the chronic phase of Chagas disease in Puebla, Mexico". Mem Inst Oswaldo Cruz 101 (7): 733–40. PMID 17160280. 
  5. doi:10.1093/eurheartj/ehm342
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  6. doi:10.1161/CIRCULATIONAHA.106.174287
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  7. Cardiomyopathy Association. "About cardiomyopathy". http://www.cardiomyopathy.org/html/about_cardio.htm. Retrieved 2006-09-28. 
  8. Donald G. Barceloux; Donald Barceloux (1999). "Cobalt". Clinical Toxicology 37 (2): 201–216. doi:10.1081/CLT-100102420. 
  9. "Cherepanov's death still a mystery:". The Sports Network. 2008-10-15. http://www.tsn.ca/nhl/story/?id=252684. 
  10. Towbin, JA; Bowles NE (January 2002). "The failing heart". Nature 415 (6868): 227–233. doi:10.1038/415227a. PMID 11805847. 

External links