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{{Cardiomyopathy}}
{{Cardiomyopathy}}
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{{CMG}}; {{AE}}  [[User:Lina Ya'qoub|Lina Ya'qoub, MD]] {{MIR}}, {{EdzelCo}}


==Overview==
==Overview==
Cardiomyopathies can generally be categorized into two groups, (based on [[World Health Organization]] guidelines) '''extrinsic cardiomyopathies''' and '''intrinsic cardiomyopathies'''.<ref name="ref2">{{cite journal | last = Richardson | first = P. ''et al'' | title = Report of the 1995 World Health Organization/International Society and Federation of Cardiology Task Force on the Definition and Classification of cardiomyopathies | journal = Circulation | volume = 93 | issue = 5 | pages = 841-2 | date = 1996 | id = PMID 8598070}} ([http://circ.ahajournals.org/cgi/content/full/93/5/841 Full text])</ref>
In clinical practice, the term "cardiomyopathy" had also been applied to diseases of known cardiovascular cause, including ischemic cardiomyopathy and hypertensive cardiomyopathy. As a result, the 1995 WHO/International Society and Federation of Cardiology (ISFC) Task Force on the Definition and Classification of the Cardiomyopathies expanded the classification to include all diseases affecting heart muscle and to take into consideration etiology as well as the dominant pathophysiology. In the 1995 classification, the cardiomyopathies were defined as "diseases of the myocardium associated with cardiac dysfunction." They were classified according to anatomy and physiology into the following types: Dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), restrictive cardiomyopathy (RCM), arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), and unclassified cardiomyopathies. Then, a 2006 AHA scientific statement proposed a contemporary definition and classification of the cardiomyopathies: "Cardiomyopathies are a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction that usually (but not invariably) exhibit inappropriate ventricular hypertrophy or dilation and are due to a variety of causes that frequently are genetic. Cardiomyopathies either are confined to the heart or are a part of generalized systemic disorders, often leading to cardiovascular death or progressive heart failure-related disability." As such, cardiomyopathies are categorized into two groups: Primary cardiomyopathies (predominantly involving the heart) which are subdivided into those which are genetic, mixed (predominantly nongenetic; less commonly genetic), or acquired, and the secondary cardiomyopathies (accompanied by other organ system involvement). Then, in 2008, the ESC working group on myocardial and pericardial diseases presented an update to the WHO/ISFC classification in which cardiomyopathy was defined as: "A myocardial disorder in which the heart muscle is structurally and functionally abnormal in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to explain the observed myocardial abnormality". Despite that, the term "cardiomyopathy" continues to be used in patients with ischemic, hypertensive, valvular and congenital heart diseases. refer to disorders of the heart muscle leading to its abnormal function and/or structure. It can generally be categorized into two groups (based on [[World Health Organization]] guidelines): extrinsic cardiomyopathies and intrinsic cardiomyopathies <ref name="ref2">{{cite journal | last = Richardson | first = P. ''et al'' | title = Report of the 1995 World Health Organization/International Society and Federation of Cardiology Task Force on the Definition and Classification of cardiomyopathies | journal = Circulation | volume = 93 | issue = 5 | pages = 841-2 | date = 1996 | id = PMID 8598070}} ([http://circ.ahajournals.org/cgi/content/full/93/5/841 Full text])</ref>. Cardiomyopathy can be classified from a clinical standpoint, as to whether it is restrictive, dilated, or hypertrophic, and also by whether it is a primary cardiomyopathy or a secondary cardiomyopathy, as a result of another underlying process. In 2013, the MOGE(S) classification for a phenotype-genotype nomenclature of cardiomyopathies was proposed by the World Heart Federation[6]. This classification suggests a nosology that addresses five characteristics of cardiomyopathic disorders: morphofunctional state (M), organ involvement (O), genetic inheritance (G), etiologic annotation (E) and functional state (S) according to ACC/AHA A-D stage and New York Heart Association (NYHA) I-IV functional class.


==Classification==
==Classification==
Cardiomyopathies are myocardial diseases that are independent of:
In clinical practice, the term "cardiomyopathy" had also been applied to diseases of known cardiovascular cause, including ischemic cardiomyopathy and hypertensive cardiomyopathy.
 
As a result, the 1995 WHO/International Society and Federation of Cardiology (ISFC) Task Force on the Definition and Classification of the Cardiomyopathies expanded the classification to include all diseases affecting heart muscle and to take into consideration etiology as well as the dominant pathophysiology. In the 1995 classification, the cardiomyopathies were defined as "diseases of the myocardium associated with cardiac dysfunction."
 
The cardiomyopathies were classified according to anatomy and physiology into the following types:
 
* Dilated cardiomyopathy (DCM)
* Hypertrophic cardiomyopathy (HCM)
* Restrictive cardiomyopathy (RCM)
* Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D)
* Unclassified cardiomyopathies
 
Then, a 2006 AHA scientific statement proposed a contemporary definition and classification of the cardiomyopathies: "Cardiomyopathies are a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction that usually (but not invariably) exhibit inappropriate ventricular hypertrophy or dilation and are due to a variety of causes that frequently are genetic. Cardiomyopathies either are confined to the heart or are a part of generalized systemic disorders, often leading to cardiovascular death or progressive heart failure-related disability."
 
As such, cardiomyopathies are categorized into two groups:
 
* Primary cardiomyopathies (predominantly involving the heart) which are subdivided into those which are genetic, mixed (predominantly nongenetic; less commonly genetic), or acquired
 
** The genetic cardiomyopathies include:
*** HCM
*** ARVC/D
*** Left ventricular noncompaction
*** PRKAG2
*** Danon glycogen storage diseases
*** Conduction defects
*** Mitochondrial myopathies
*** Ion channel disorders
** The mixed cardiomyopathies include:
*** DCM
*** RCM
** The acquired cardiomyopathies include:
*** Myocarditis
*** Stress-induced (takotsubo)
*** Peripartum and tachycardia-induced
* Secondary cardiomyopathies (accompanied by other organ system involvement)
 
Regarding the pathophysiology classification, cardiomyopathies are myocardial diseases that are independent of:
 
* [[Congenital Heart Disease]]
* [[Congenital Heart Disease]]
* [[Pericardial Disease]]
* [[Pericardial Disease]]
* [[Pulmonary hypertension]] / [[hypertension|Systemic hypertension]]
* [[Pulmonary hypertension]] / [[hypertension|systemic hypertension]]
* [[Valvular heart disease]]
* [[Valvular heart disease]]
* Ischemic cardiac disease


===Extrinsic cardiomyopathies===  
===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'':<ref name="ref2" />
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'':<ref name="ref2" />


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*[[Ischemic]] cardiomyopathy
*[[Ischemic]] cardiomyopathy
*[[Hypertensive]] cardiomyopathy
*[[Hypertensive]] cardiomyopathy
*Nutritional Diseases
*Nutritional diseases
*Systemic metabolic disease
*Systemic metabolic disease
*Valvular cardiomyopathy
*Valvular cardiomyopathy


====Ischemic cardiomyopathy====
====Ischemic Cardiomyopathy====
[[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 scar tissue ([[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 [[heart failure|failure]], and this failure is the functional result of an ischemic cardiomyopathy.
[[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 other 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 scar tissue ([[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 [[heart failure|failure]], and this failure is the functional result of an ischemic cardiomyopathy.


====Cardiomyopathy due to systemic diseases====
====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.
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 dystrophy|muscular dystrophies]].


===Intrinsic cardiomyopathies===
===Intrinsic Cardiomyopathies===
An intrinsic cardiomyopathy is weakness in the muscle of the heart that is not due to an identifiable external cause.  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 are a mixed-bag of disease states, each with their own causes.
An intrinsic cardiomyopathy is weakness in the muscle of the heart that is not due to an identifiable external cause.  To make a diagnosis of an intrinsic cardiomyopathy, significant coronary artery disease should be ruled out (amongst other causes of extrinsic cardiomyopathy).  The term intrinsic cardiomyopathy does not describe the specific [[etiology]] of weakened heart muscle.  The intrinsic cardiomyopathies are a mixed-bag of disease states, each with their own causes.


Intrinsic cardiomyopathy has a number of causes including [[medication|drug]] and [[ethanol|alcohol]] toxicity, certain [[infection]]s (including [[Hepatitis C]]), and various [[genetics|genetic]] and [[idiopathic]] (i.e., unknown) causes.
Intrinsic cardiomyopathy has a number of causes including [[medication|drug]] and [[ethanol|alcohol]] toxicity, certain [[infection]]s (including [[Hepatitis C]]), and various [[genetics|genetic]] and [[idiopathic]] (i.e., unknown) causes.
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* [[Noncompaction cardiomyopathy]] has been recognized as a separate type since the 1980s. The term refers to a cardiomyopathy where the left ventricle wall has failed to grow properly from birth and has a spongy appearance when viewed during an echocardiogram.
* [[Noncompaction cardiomyopathy]] has been recognized as a separate type since the 1980s. The term refers to a cardiomyopathy where the left ventricle wall has failed to grow properly from birth and has a spongy appearance when viewed during an echocardiogram.


===Alternate Detailed Classification Schemes===
==Alternate Detailed Classification Schemes==


There are other more detailed classification schemes with a more complete Differential diagnosis as shown below:
There are other more detailed classification schemes with a more complete differential diagnosis as shown below:
==== Clinical Classification ====
=== Clinical Classification ===
* '''DILATED (D)''':  
* '''DILATED (D)''':  
*:* Left and/or right ventricular enlargement
*:* Left and/or right ventricular enlargement
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*:* Emboli
*:* Emboli
* '''RESTRICTIVE (R)''':  
* '''RESTRICTIVE (R)''':  
*:* Endomyocardial scarring or myocardial infiltration resulting in restriction to left and/or right ventricular filling.
*:* Endomyocardial scarring or myocardial infiltration resulting in restriction to left and/or right ventricular filling. This entity is more common in the tropics.
* '''HYPERTROPHIC (H)''':  
* '''HYPERTROPHIC (H)''':  
*:* Disproportionate [[left ventricular hypertrophy]]  
*:* Disproportionate [[left ventricular hypertrophy]]  
*:*:* Typically involving septum more than free wall  
*:*:* Typically involving septum more than free wall  
*:*:* With or without an intraventricular systolic pressure gradient  
*:*:* With or without an intraventricular systolic pressure gradient  
*:*:*:* Usually of a nondilated left ventricular cavity
*:*:*:* Usually of a nondilated left ventricular cavity: the left ventricular cavity is either normal or reduced.
==== PRIMARY MYOCARDIAL INVOLVEMENT ====
=== Primary Myocardial Involvement ===
* Idiopathic (D,R,H)
* Idiopathic (D,R,H)
* Hereditary (D,R,H)
* Hereditary (D,R,H)
*:* Up to 20% of dilated cardiomyopathy
*:* Up to 20% of dilated cardiomyopathy
*:* [[Dominant]], [[recessive]], and [[x-linked]]
*:* [[Dominant]], [[recessive]], and [[x-linked]]
* Eosinophilic Endomyocardial Disease (R)
* Eosinophilic endomyocardial disease (R)
* [[Endomyocardial Fibrosis]] (R)
* [[Endomyocardial fibrosis]] (R)
==== SECONDARY MYOCARDIAL INVOLVEMENT ====
=== Secondary Myocardial Involvement ===
* Sensitivity and toxic reactions  ([[Dilated cardiomyopathy]])
* Sensitivity and toxic reactions  ([[dilated cardiomyopathy]])
*:* [[Alcohol]]
*:* [[Alcohol]]
*:* [[Cocaine]]
*:* [[Cocaine]]
*:* [[Radiation]]
*:* [[Radiation]]
*:* [[Doxorubicin]]
*:* [[Doxorubicin]]
* Metabolic ([[Dilated cardiomyopathy]])
* Metabolic ([[dilated cardiomyopathy]])
*:* [[Selenium]] Deficiency
*:* [[Selenium]] deficiency
*:* [[Hypophosphatemia]]
*:* [[Hypophosphatemia]]
*:* [[Hypocalcemia]]
*:* [[Hypocalcemia]]
*:* [[Thyroid Disease]]
*:* [[Thyroid disease]]
* Infectious ([[Dilated cardiomyopathy]])
* Infectious ([[Dilated cardiomyopathy]])
*:* [[Myocarditis|Viral Myocarditis]]
*:* [[Myocarditis|Viral myocarditis]]
*:* [[Myocarditis|Bacterial Myocarditis]]
*:* [[Myocarditis|Bacterial myocarditis]]
*:* [[Myocarditis|Fungal Myocarditis]]
*:* [[Myocarditis|Fungal myocarditis]]
*:* [[Myocarditis|Protozoal Myocarditis]]
*:* [[Myocarditis|Protozoal myocarditis]]
*:* [[Myocarditis|Metazoal Myocarditis]]
*:* [[Myocarditis|Metazoal myocarditis]]
*:* [[Myocarditis|Spirochetal Myocarditis]]
*:* [[Myocarditis|Spirochetal myocarditis]]
*:* [[Myocarditis|Rickettsial Myocarditis]]
*:* [[Myocarditis|Rickettsial myocarditis]]
* Familial Storage Disease ([[Dilated cardiomyopathy]], [[Restrictive cardiomyopathy]])
* Familial Storage Disease ([[dilated cardiomyopathy]], [[restrictive cardiomyopathy]])
*:* [[Glycogen Storage Disease]]
*:* [[Glycogen storage disease]]
*:* [[Mucopolysaccharidoses]]
*:* [[Mucopolysaccharidoses]]
*:* [[Hemochromatosis]]
*:* [[Hemochromatosis]]
*:* [[Fabry’s Disease]]
*:* [[Fabry’s disease]]
* Connective Tissue Disorders ([[Dilated cardiomyopathy]])
* Connective Tissue Disorders ([[dilated cardiomyopathy]])
*:* [[Systemic Lupus Erythematosus]]
*:* [[Systemic lupus erythematosus]]
*:* [[Polyarteritis Nodosa]]
*:* [[Polyarteritis nodosa]]
*:* [[Rheumatoid Arthritis]]
*:* [[Rheumatoid arthritis]]
*:* [[Progressive Systemic Sclerosis]]
*:* [[Progressive systemic sclerosis]]
*:* [[Dermatomyositis]]
*:* [[Dermatomyositis]]
* Infiltrative and Granulomatous ([[Restrictive cardiomyopathy]], [[Dilated cardiomyopathy]])
* Infiltrative and Granulomatous ([[restrictive cardiomyopathy]], [[dilated cardiomyopathy]])
*:* [[Amyloidosis]]
*:* [[Amyloidosis]]
*:* [[Sarcoidosis]]
*:* [[Sarcoidosis]]
*:* [[Malignancy]]
*:* [[Malignancy]]
* Neuromuscular ([[Dilated cardiomyopathy]])
* Neuromuscular ([[dilated cardiomyopathy]])
*:* [[Muscular Dystrophy]]
*:* [[Muscular dystrophy]]
*:* [[Myotonic Dystrophy]]
*:* [[Myotonic dystrophy]]
*:* [[Friedreich’s Ataxia]] ([[Hypertrophic cardiomyopathy]], [[Dilated cardiomyopathy]])
*:* Friedreich’s ataxia ([[hypertrophic cardiomyopathy]], [[dilated cardiomyopathy]])
* Other (Dilated cardiomyopathy)
* Other (dilated cardiomyopathy)
*:* [[Beta thallasemia cardiomyopathy]]
*:* Beta thallasemia cardiomyopathy
*:* Uncontrolled [[Tachycardia]] ([[Tachycardia induced cardiomyopathy]])
*:* Uncontrolled [[tachycardia]] ([[tachycardia induced cardiomyopathy]])
*:* [[Right Ventricular Dysplasia]]
*:* Right ventricular dysplasia
* [[Peripartum Heart Disease]] ([[Dilated cardiomyopathy]])
* [[Peripartum heart disease]] ([[dilated cardiomyopathy]]): which occurs in the last month of pregnancy, up to 6 months after delivery.


==References==
==References==
{{Reflist|2}}
{{Reflist|2}}
{{WH}}
{{Sisakian H. Cardiomyopathies: Evolution of pathogenesis concepts and potential for new therapies. World J Cardiol. 2014;6(6):478-94.}}{{WH}}
{{WS}}
{{WS}}
[[Category:Best pages]]
[[Category:Cardiology]]
[[Category:Genetic Disease]]
[[Category:Up-To-Date]]
[[Category:Up-To-Date cardiology]]
[[Category:Disease]]

Latest revision as of 03:24, 27 October 2023

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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Lina Ya'qoub, MD Mahshid Mir, M.D. [2], Edzel Lorraine Co, DMD, MD[3]

Overview

In clinical practice, the term "cardiomyopathy" had also been applied to diseases of known cardiovascular cause, including ischemic cardiomyopathy and hypertensive cardiomyopathy. As a result, the 1995 WHO/International Society and Federation of Cardiology (ISFC) Task Force on the Definition and Classification of the Cardiomyopathies expanded the classification to include all diseases affecting heart muscle and to take into consideration etiology as well as the dominant pathophysiology. In the 1995 classification, the cardiomyopathies were defined as "diseases of the myocardium associated with cardiac dysfunction." They were classified according to anatomy and physiology into the following types: Dilated cardiomyopathy (DCM), hypertrophic cardiomyopathy (HCM), restrictive cardiomyopathy (RCM), arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D), and unclassified cardiomyopathies. Then, a 2006 AHA scientific statement proposed a contemporary definition and classification of the cardiomyopathies: "Cardiomyopathies are a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction that usually (but not invariably) exhibit inappropriate ventricular hypertrophy or dilation and are due to a variety of causes that frequently are genetic. Cardiomyopathies either are confined to the heart or are a part of generalized systemic disorders, often leading to cardiovascular death or progressive heart failure-related disability." As such, cardiomyopathies are categorized into two groups: Primary cardiomyopathies (predominantly involving the heart) which are subdivided into those which are genetic, mixed (predominantly nongenetic; less commonly genetic), or acquired, and the secondary cardiomyopathies (accompanied by other organ system involvement). Then, in 2008, the ESC working group on myocardial and pericardial diseases presented an update to the WHO/ISFC classification in which cardiomyopathy was defined as: "A myocardial disorder in which the heart muscle is structurally and functionally abnormal in the absence of coronary artery disease, hypertension, valvular disease and congenital heart disease sufficient to explain the observed myocardial abnormality". Despite that, the term "cardiomyopathy" continues to be used in patients with ischemic, hypertensive, valvular and congenital heart diseases. refer to disorders of the heart muscle leading to its abnormal function and/or structure. It can generally be categorized into two groups (based on World Health Organization guidelines): extrinsic cardiomyopathies and intrinsic cardiomyopathies [1]. Cardiomyopathy can be classified from a clinical standpoint, as to whether it is restrictive, dilated, or hypertrophic, and also by whether it is a primary cardiomyopathy or a secondary cardiomyopathy, as a result of another underlying process. In 2013, the MOGE(S) classification for a phenotype-genotype nomenclature of cardiomyopathies was proposed by the World Heart Federation[6]. This classification suggests a nosology that addresses five characteristics of cardiomyopathic disorders: morphofunctional state (M), organ involvement (O), genetic inheritance (G), etiologic annotation (E) and functional state (S) according to ACC/AHA A-D stage and New York Heart Association (NYHA) I-IV functional class.

Classification

In clinical practice, the term "cardiomyopathy" had also been applied to diseases of known cardiovascular cause, including ischemic cardiomyopathy and hypertensive cardiomyopathy.

As a result, the 1995 WHO/International Society and Federation of Cardiology (ISFC) Task Force on the Definition and Classification of the Cardiomyopathies expanded the classification to include all diseases affecting heart muscle and to take into consideration etiology as well as the dominant pathophysiology. In the 1995 classification, the cardiomyopathies were defined as "diseases of the myocardium associated with cardiac dysfunction."

The cardiomyopathies were classified according to anatomy and physiology into the following types:

  • Dilated cardiomyopathy (DCM)
  • Hypertrophic cardiomyopathy (HCM)
  • Restrictive cardiomyopathy (RCM)
  • Arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D)
  • Unclassified cardiomyopathies

Then, a 2006 AHA scientific statement proposed a contemporary definition and classification of the cardiomyopathies: "Cardiomyopathies are a heterogeneous group of diseases of the myocardium associated with mechanical and/or electrical dysfunction that usually (but not invariably) exhibit inappropriate ventricular hypertrophy or dilation and are due to a variety of causes that frequently are genetic. Cardiomyopathies either are confined to the heart or are a part of generalized systemic disorders, often leading to cardiovascular death or progressive heart failure-related disability."

As such, cardiomyopathies are categorized into two groups:

  • Primary cardiomyopathies (predominantly involving the heart) which are subdivided into those which are genetic, mixed (predominantly nongenetic; less commonly genetic), or acquired
    • The genetic cardiomyopathies include:
      • HCM
      • ARVC/D
      • Left ventricular noncompaction
      • PRKAG2
      • Danon glycogen storage diseases
      • Conduction defects
      • Mitochondrial myopathies
      • Ion channel disorders
    • The mixed cardiomyopathies include:
      • DCM
      • RCM
    • The acquired cardiomyopathies include:
      • Myocarditis
      • Stress-induced (takotsubo)
      • Peripartum and tachycardia-induced
  • Secondary cardiomyopathies (accompanied by other organ system involvement)

Regarding the pathophysiology classification, cardiomyopathies are myocardial diseases that are independent of:

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:[1]

Ischemic Cardiomyopathy

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 other 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 scar tissue (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.

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.

Intrinsic Cardiomyopathies

An intrinsic cardiomyopathy is weakness in the muscle of the heart that is not due to an identifiable external cause. To make a diagnosis of an intrinsic cardiomyopathy, significant coronary artery disease should be ruled out (amongst other causes of extrinsic cardiomyopathy). The term intrinsic cardiomyopathy does not describe the specific etiology of weakened heart muscle. The intrinsic cardiomyopathies are a mixed-bag of disease states, each with their own causes.

Intrinsic cardiomyopathy has a number of 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,[1][2] but additional types are also recognized:

  • Dilated cardiomyopathy (DCM), the most common form, and one of the leading indications for heart transplantation. In DCM the heart (especially the left ventricle) is enlarged and the pumping function is diminished. Approximately 40% of cases are familial, but the genetics are poorly understood compared with HCM. In some cases it manifests as peripartum cardiomyopathy, and in other cases it may be associated with alcoholism.
  • Hypertrophic cardiomyopathy (HCM or HOCM), a genetic disorder caused by various mutations in genes encoding sarcomeric proteins. In HCM the heart muscle is thickened, which can obstruct blood flow and prevent the heart from functioning properly.
  • Arrhythmogenic right ventricular cardiomyopathy (ARVC) arises from an electrical disturbance of the heart in which heart muscle is replaced by fibrous scar tissue. The right ventricle is generally most affected.
  • Restrictive cardiomyopathy (RCM) is an uncommon cardiomyopathy. The walls of the ventricles are stiff, but may not be thickened, and resist the normal filling of the heart with blood. A rare form of restrictive cardiomyopathy is the obliterative cardiomyopathy, seen in the hypereosinophilic syndrome. In this type of cardiomyopathy, the myocardium in the apices of the left and right ventricles becomes thickened and fibrotic, causing a decrease in the volumes of the ventricles and a type of restrictive cardiomyopathy.
  • Noncompaction cardiomyopathy has been recognized as a separate type since the 1980s. The term refers to a cardiomyopathy where the left ventricle wall has failed to grow properly from birth and has a spongy appearance when viewed during an echocardiogram.

Alternate Detailed Classification Schemes

There are other more detailed classification schemes with a more complete differential diagnosis as shown below:

Clinical Classification

  • DILATED (D):
  • RESTRICTIVE (R):
    • Endomyocardial scarring or myocardial infiltration resulting in restriction to left and/or right ventricular filling. This entity is more common in the tropics.
  • HYPERTROPHIC (H):
    • Disproportionate left ventricular hypertrophy
      • Typically involving septum more than free wall
      • With or without an intraventricular systolic pressure gradient
        • Usually of a nondilated left ventricular cavity: the left ventricular cavity is either normal or reduced.

Primary Myocardial Involvement

Secondary Myocardial Involvement

References

  1. 1.0 1.1 1.2 Richardson, P.; 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)
  2. Cardiomyopathy Association. "About cardiomyopathy". September 28, 2006

Template:Sisakian H. Cardiomyopathies: Evolution of pathogenesis concepts and potential for new therapies. World J Cardiol. 2014;6(6):478-94.Template:WH Template:WS