Cardiomyopathy
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| Opened left ventricle of heart shows a thickened, dilated left ventricle with subendocardial fibrosis manifested as increased whiteness of endocardium {Autopsy findings}. Image courtesy of Professor Peter Anderson DVM PhD and published with permission © PEIR, University of Alabama at Birmingham, Department of Pathology |
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Cardiomyopathy Microchapters |
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Diagnosis |
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Treatment |
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Guidelines |
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2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy |
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Case Studies |
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Cardiomyopathy On the Web |
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American Roentgen Ray Society Images of Cardiomyopathy |
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Cafer Zorkun, M.D., Ph.D. [2], Raviteja Guddeti, M.B.B.S. [3]
Synonyms and keywords: Myocardiopathy; cardiac muscle disease; heart muscle disease.
Overview
Historical Perspective
- In 1980, the World Health Organization (WHO) defined cardiomyopathies as "heart muscle diseases of unknown cause" to distinguish cardiomyopathy from cardiac dysfunction due to known cardiovascular causes such as hypertension, ischemic heart disease, or valvular disease. In clinical practice, however, 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)
●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:
1- Primary cardiomyopathies (predominantly involving the heart): The primary cardiomyopathies are subdivided into those which are genetic, mixed (predominantly nongenetic; less commonly genetic), or acquired. A- The genetic cardiomyopathies include HCM, ARVC/D, left ventricular noncompaction, PRKAG2 and Danon glycogen storage diseases, conduction defects, mitochondrial myopathies, and ion channel disorders. B- The mixed cardiomyopathies include DCM and RCM. C- The acquired cardiomyopathies include myocarditis, stress-induced (takotsubo), peripartum and tachycardia-induced.
2- 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.
Classification
- In clinical practice, cardiomyopathy can be classified into two main groups based on the main etiology: ischemic versus non-ischemic.
- Moreover, cardiomyopathy has been also classified into two main groups, based on the presence of systolic and/or diastolic function: Heart failure with reduced ejection fraction (HFrEF) versus heart failure with preserved ejection fraction (HFpEF). Most experts agree that ejection fraction of less than 40 should be classified as HFrEF; on the other hand, those patients with EF of more than 40 should be classified as HFpEF.
- Classification of HF severity — The history, including assessment of New York Heart Association (NYHA) functional class, and physical examination in conjunction with the diagnostic tests reviewed below should both establish the primary cause of the HF and provide a reasonable estimate of its severity.
- The classification system that is most commonly used is the NYHA classification: which classifies patients into 4 categories based on their functional limitation:
●Class I – Patients with heart disease without resulting limitation of physical activity. Ordinary physical activity does not cause HF symptoms such as fatigue or dyspnea.
●Class II – Patients with heart disease resulting in slight limitation of physical activity. Symptoms of HF develop with ordinary activity but there are no symptoms at rest.
●Class III – Patients with heart disease resulting in marked limitation of physical activity. Symptoms of HF develop with less than ordinary physical activity but there are no symptoms at rest.
●Class IV – Patients with heart disease resulting in inability to carry on any physical activity without discomfort. Symptoms of HF may occur even at rest.
- Another commonly-used classification of the stages of HF, as outlined by the American College of Cardiology Foundation/American Heart Association guidelines:
●Stage A – At high risk for HF but without structural heart disease or symptoms of HF.
●Stage B – Structural heart disease but without signs or symptoms of HF. This stage includes patients in NYHA functional class I with no prior or current symptoms or signs of HF.
●Stage C – Structural heart disease with prior or current symptoms of HF. This stage includes patients in any NYHA functional class (including class I with prior symptoms).
●Stage D – Refractory HF requiring specialized interventions. This stage includes patients in NYHA functional class IV with refractory HF.
Pathophysiology
- Different causes of cardiomyopathies result in abnormal myocardial function and structure, leading to the development of clinical heart failure symptoms, early or later in life, based on the cause, genetic expression and penetrance, and presence of environmental factors.
- Dilated cardiomyopathy (DCM) is characterized by dilation and impaired contraction of one or both ventricles [14]. The dilation often becomes severe and is invariably accompanied by an increase in total cardiac mass. Affected patients have impaired systolic function and clinical presentation is usually with features of heart failure (HF).
Causes
Differentiating Cardiomyopathy from other Diseases
- It is important to differentiate hypertrophic cardiomyopathy from other causes of myocardial hypertrophy, including athlete heart.
Epidemiology and Demographics
Risk Factors
Natural History, Complications and Prognosis
Diagnosis
History and Symptoms | Physical Examination | Laboratory Findings | Electrocardiogram | Chest X Ray | CT | MRI | Echocardiography | Other Imaging Findings | Other Diagnostic Studies
Treatment
Medical Therapy | Surgery | Primary Prevention | Secondary Prevention | Cost-Effectiveness of Therapy | Future or Investigational Therapies
Case Studies
de:Kardiomyopathie nl:Cardiomyopathie no:Kardiomyopati simple:Cardiomyopathy sr:Кардиомиопатија sv:Hjärtmuskelsjukdom