Cardiomyopathy

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Cardiomyopathy
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

Cardiomyopathy Microchapters
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Patient Information
Overview
Historical Perspective
Classification
Pathophysiology
Causes
Differentiating Cardiomyopathy from other Diseases
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
Guidelines
2023 ESC Guideline Recommendations
2020 AHA/ACC Guideline for the Diagnosis and Treatment of Patients With Hypertrophic Cardiomyopathy
Case Studies
Case #1
Cardiomyopathy On the Web
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Most cited articles
Review articles
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American Roentgen Ray Society Images of Cardiomyopathy All Images X-rays Echo & Ultrasound CT Images MRI
Ongoing Trials at Clinical Trials.gov
US National Guidelines Clearinghouse
NICE Guidance
FDA on Cardiomyopathy
CDC on Cardiomyopathy
Cardiomyopathy in the news
Blogs on Cardiomyopathy
Directions to Hospitals Treating Cardiomyopathy
Risk calculators and risk factors for 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.

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.

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.

Differentiating Cardiomyopathy from other Diseases

• It is important to differentiate hypertrophic cardiomyopathy from other causes of myocardial hypertrophy, including athlete heart.

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

Case #1