Cardiomyopathy
Encyclopedia
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. Cardiomyopathy can often go undetected, making it especially dangerous to carriers of the disease.
Although in theory the term "cardiomyopathy" could apply to almost any disease affecting the heart, in practice it is usually reserved for "severe myocardial disease leading to heart failure".
It is also possible to classify cardiomyopathies functionally, as involving dilation, hypertrophy, or restriction.
EKG abnormalities are often present, although the changes are frequently nonspecific. A pattern characteristic of left ventricular hypertrophy may be present. Flat or inverted T wave
s 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.
, defibrillators
, or ventricular assist device
s (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. Due to the severity of the disease, treatment requires the use of numerous chemicals and drugs, which have to be taken for the rest of the patient's life.
Sudden Cardiac Death
Sudden cardiac death is natural death from cardiac causes, heralded by abrupt loss of consciousness within one hour of the onset of acute symptoms. Other forms of sudden death may be noncardiac in origin...
or both. Cardiomyopathy can often go undetected, making it especially dangerous to carriers of the disease.
Although in theory the term "cardiomyopathy" could apply to almost any disease affecting the heart, in practice it is usually reserved for "severe myocardial disease leading to heart failure".
Classification
Cardiomyopathies can be categorized as extrinsic or intrinsic.- An extrinsic cardiomyopathy is a cardiomyopathy where the primary pathologyPathologyPathology is the precise study and diagnosis of disease. The word pathology is from Ancient Greek , pathos, "feeling, suffering"; and , -logia, "the study of". Pathologization, to pathologize, refers to the process of defining a condition or behavior as pathological, e.g. pathological gambling....
is outside the myocardium itself. Most cardiomyopathies are extrinsic, because by far the most common cause of a cardiomyopathy is ischemiaIschemiaIn medicine, ischemia is a restriction in blood supply, generally due to factors in the blood vessels, with resultant damage or dysfunction of tissue. It may also be spelled ischaemia or ischæmia...
. The World Health Organization calls these specific 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 etiologyEtiologyEtiology is the study of causation, or origination. The word is derived from the Greek , aitiologia, "giving a reason for" ....
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 drugMedicationA pharmaceutical drug, also referred to as medicine, medication or medicament, can be loosely defined as any chemical substance intended for use in the medical diagnosis, cure, treatment, or prevention of disease.- Classification :...
and alcoholEthanolEthanol, also called ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a volatile, flammable, colorless liquid. It is a psychoactive drug and one of the oldest recreational drugs. Best known as the type of alcohol found in alcoholic beverages, it is also used in thermometers, as a...
toxicity, certain infectionInfectionAn infection is the colonization of a host organism by parasite species. Infecting parasites seek to use the host's resources to reproduce, often resulting in disease...
s (including Hepatitis CHepatitis CHepatitis C is an infectious disease primarily affecting the liver, caused by the hepatitis C virus . The infection is often asymptomatic, but chronic infection can lead to scarring of the liver and ultimately to cirrhosis, which is generally apparent after many years...
), and various geneticGeneticsGenetics , a discipline of biology, is the science of genes, heredity, and variation in living organisms....
and idiopathicIdiopathicIdiopathic is an adjective used primarily in medicine meaning arising spontaneously or from an obscure or unknown cause. From Greek ἴδιος, idios + πάθος, pathos , it means approximately "a disease of its own kind". It is technically a term from nosology, the classification of disease...
(i.e., unknown) causes.
It is also possible to classify cardiomyopathies functionally, as involving dilation, hypertrophy, or restriction.
Types
- Primary/intrinsic cardiomyopathies
- Genetic
- Hypertrophic cardiomyopathyHypertrophic cardiomyopathyHypertrophic cardiomyopathy is a disease of the myocardium in which a portion of the myocardium is hypertrophied without any obvious cause...
(HCM or HOCM) - Arrhythmogenic right ventricular cardiomyopathy (ARVC)
- Isolated ventricular non-compaction
- Mitochondrial myopathyMitochondrial myopathyMitochondrial myopathy is a type of myopathy associated with mitochondrial disease. On biopsy, the muscle tissue of patients with this disease usually demonstrate "ragged red" muscle fibers...
- Hypertrophic cardiomyopathy
- Mixed
- Dilated cardiomyopathyDilated cardiomyopathyDilated cardiomyopathy or DCM is a condition in which the heart becomes weakened and enlarged and cannot pump blood efficiently. The decreased heart function can affect the lungs, liver, and other body systems....
(DCM) - Restrictive cardiomyopathyRestrictive cardiomyopathyRestrictive cardiomyopathy is a form of cardiomyopathy in which the walls are rigid, and the heart is restricted from stretching and filling with blood properly....
(RCM)
- Dilated cardiomyopathy
- Acquired
- Takotsubo cardiomyopathyTakotsubo cardiomyopathyTakotsubo cardiomyopathy, also known as transient apical ballooning syndrome, apical ballooning cardiomyopathy, stress-induced cardiomyopathy, Gebrochenes-Herz-Syndrom, and simply stress cardiomyopathy, is a type of non-ischemic cardiomyopathy in which there is a sudden temporary weakening of the...
- Loeffler endocarditisLoeffler endocarditisLoeffler endocarditis, a form of endocarditis, is a form of hypereosinophilic syndrome.It is a restricive cardiomyopathy characterized eosinophilia and eosinophilic penetration leading to the fibrotic thickening of portions of the heart and commonly has large mural thrombi. Common symptoms include...
- Takotsubo cardiomyopathy
- Genetic
- Secondary/extrinsic cardiomyopathies
- Metabolic/storage
- amyloidosisAmyloidosisIn medicine, amyloidosis refers to a variety of conditions whereby the body produces "bad proteins", denoted as amyloid proteins, which are abnormally deposited in organs and/or tissues and cause harm. A protein is described as being amyloid if, due to an alteration in its secondary structure, it...
- hemochromatosis
- amyloidosis
- Inflammatory
- Chagas diseaseChagas diseaseChagas disease is a tropical parasitic disease caused by the flagellate protozoan Trypanosoma cruzi. T. cruzi is commonly transmitted to humans and other mammals by an insect vector, the blood-sucking insects of the subfamily Triatominae most commonly species belonging to the Triatoma, Rhodnius,...
- Chagas disease
- Endocrine
- diabetic cardiomyopathyDiabetic cardiomyopathyDiabetic cardiomyopathy is a disorder of the heart muscle in people with diabetes. It can lead to inability of the heart to circulate blood through the body effectively, a state known as heart failure, with accumulation of fluid in the lungs or legs...
- hyperthyroidismHyperthyroidismHyperthyroidism is the term for overactive tissue within the thyroid gland causing an overproduction of thyroid hormones . Hyperthyroidism is thus a cause of thyrotoxicosis, the clinical condition of increased thyroid hormones in the blood. Hyperthyroidism and thyrotoxicosis are not synonymous...
- acromegalyAcromegalyAcromegaly is a syndrome that results when the anterior pituitary gland produces excess growth hormone after epiphyseal plate closure at puberty...
- diabetic cardiomyopathy
- Toxicity
- chemotherapyChemotherapyChemotherapy is the treatment of cancer with an antineoplastic drug or with a combination of such drugs into a standardized treatment regimen....
- Alcoholic cardiomyopathyAlcoholic cardiomyopathyAlcoholic cardiomyopathy is a disease in which the chronic long-term abuse of alcohol leads to heart failure. Alcoholic cardiomyopathy is a type of dilated cardiomyopathy. Due to the direct toxic effects of alcohol on heart muscle, the heart is unable to pump blood efficiently, leading to heart...
- chemotherapy
- Neuromuscular
- muscular dystrophyMuscular dystrophyMuscular dystrophy is a group of muscle diseases that weaken the musculoskeletal system and hamper locomotion. Muscular dystrophies are characterized by progressive skeletal muscle weakness, defects in muscle proteins, and the death of muscle cells and tissue.In the 1860s, descriptions of boys who...
- muscular dystrophy
- Nutritional diseases
- Other
- "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. Not supported by current cardiomyopathies classification schemes.
- Metabolic/storage
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.EKG abnormalities are often present, although the changes are frequently nonspecific. A pattern characteristic of left ventricular hypertrophy may be present. Flat or inverted T wave
T wave
In electrocardiography, the T wave represents the repolarization of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the absolute refractory period. The last half of the T wave is referred to as the relative refractory period...
s 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 pacemakersArtificial pacemaker
A pacemaker is a medical device that uses electrical impulses, delivered by electrodes contacting the heart muscles, to regulate the beating of the heart...
, defibrillators
Implantable cardioverter-defibrillator
An implantable cardioverter-defibrillator is a small battery-powered electrical impulse generator which is implanted in patients who are at risk of sudden cardiac death due to ventricular fibrillation and ventricular tachycardia. The device is programmed to detect cardiac arrhythmia and correct it...
, or ventricular assist device
Ventricular assist device
A Ventricular assist device, or VAD, is a mechanical circulatory device that is used to partially or completely replace the function of a failing heart...
s (LVADs), or ablation
Ablation
Ablation is removal of material from the surface of an object by vaporization, chipping, or other erosive processes. This occurs in spaceflight during ascent and atmospheric reentry, glaciology, medicine, and passive fire protection.-Spaceflight:...
. 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. Due to the severity of the disease, treatment requires the use of numerous chemicals and drugs, which have to be taken for the rest of the patient's life.