Cardiomyopathy | |
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Opened left ventricle showing thickening, dilatation, and subendocardial fibrosis noticeable as increased whiteness of the inside of the heart. | |
Specialty | Cardiology |
Symptoms | |
Complications | |
Types | |
Causes |
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Treatment | Depends on type and symptoms [5] |
Frequency | 2.5 million with myocarditis (2015) [6] |
Deaths | 354,000 with myocarditis (2015) [7] |
Cardiomyopathy is a group of primary diseases of the heart muscle. [1] Early on there may be few or no symptoms. [1] As the disease worsens, shortness of breath, feeling tired, and swelling of the legs may occur, due to the onset of heart failure. [1] An irregular heart beat and fainting may occur. [1] Those affected are at an increased risk of sudden cardiac death. [2]
As of 2013, cardiomyopathies are defined as "disorders characterized by morphologically and functionally abnormal myocardium in the absence of any other disease that is sufficient, by itself, to cause the observed phenotype." [8] [9] Types of cardiomyopathy include hypertrophic cardiomyopathy, dilated cardiomyopathy, restrictive cardiomyopathy, arrhythmogenic right ventricular dysplasia, and Takotsubo cardiomyopathy (broken heart syndrome). [3] In hypertrophic cardiomyopathy the heart muscle enlarges and thickens. [3] In dilated cardiomyopathy the ventricles enlarge and weaken. [3] In restrictive cardiomyopathy the ventricle stiffens. [3]
In many cases, the cause cannot be determined. [4] Hypertrophic cardiomyopathy is usually inherited, whereas dilated cardiomyopathy is inherited in about one third of cases. [4] Dilated cardiomyopathy may also result from alcohol, heavy metals, coronary artery disease, cocaine use, and viral infections. [4] Restrictive cardiomyopathy may be caused by amyloidosis, hemochromatosis, and some cancer treatments. [4] Broken heart syndrome is caused by extreme emotional or physical stress. [3]
Treatment depends on the type of cardiomyopathy and the severity of symptoms. [5] Treatments may include lifestyle changes, medications, or surgery. [5] Surgery may include a ventricular assist device or heart transplant. [5] In 2015 cardiomyopathy and myocarditis affected 2.5 million people. [6] Hypertrophic cardiomyopathy affects about 1 in 500 people while dilated cardiomyopathy affects 1 in 2,500. [3] [10] They resulted in 354,000 deaths up from 294,000 in 1990. [7] [11] Arrhythmogenic right ventricular dysplasia is more common in young people. [2]
The presentation of cardiomyopathy is:[ citation needed ]
Cardiomyopathies can be of genetic (familial) or non-genetic (acquired) origin. [12] Genetic cardiomyopathies usually are caused by sarcomere or cytoskeletal diseases, neuromuscular disorders, inborn errors of metabolism, malformation syndromes and sometimes are unidentified. [13] [14] Non-genetic cardiomyopathies can have definitive causes such as viral infections, myocarditis and others. [15] [16]
Cardiomyopathies are either confined to the heart or are part of a generalized systemic disorder, both often leading to cardiovascular death or progressive heart failure-related disability. Other diseases that cause heart muscle dysfunction are excluded, such as coronary artery disease, hypertension, or abnormalities of the heart valves. [17] Often, the underlying cause remains unknown, but in many cases the cause may be identifiable. [18] Alcoholism, for example, has been identified as a cause of dilated cardiomyopathy, as has drug toxicity, and certain infections (including Hepatitis C). [19] [20] [21] Untreated celiac disease can cause cardiomyopathies, which can completely reverse with a timely diagnosis. [22] In addition to acquired causes, molecular biology and genetics have given rise to the recognition of various genetic causes. [20] [23]
A more clinical categorization of cardiomyopathy as 'hypertrophied', 'dilated', or 'restrictive', [24] has become difficult to maintain because some of the conditions could fulfill more than one of those three categories at any particular stage of their development. [25]
The current American Heart Association (AHA) definition divides cardiomyopathies into primary, which affect the heart alone, and secondary, which are the result of illness affecting other parts of the body. These categories are further broken down into subgroups which incorporate new genetic and molecular biology knowledge. [26]
The pathophysiology of cardiomyopathies is better understood at the cellular level with advances in molecular techniques. Mutant proteins can disturb cardiac function in the contractile apparatus (or mechanosensitive complexes). Cardiomyocyte alterations and their persistent responses at the cellular level cause changes that are correlated with sudden cardiac death and other cardiac problems. [27]
Cardiomyopathies are generally varied individually. Different factors can cause Cardiomyopathies in adults as well as children. To exemplify, Dilated Cardiomyopathy in adults is associated with Ischemic Cardiomyopathy, Hypertension, Valvular diseases, and Genetics. While in Children, Neuromuscular diseases such as Becker muscular dystrophy, including X-linked genetic disorder, are directly linked with their Cardiomyopathies. [28]
Among the diagnostic procedures done to determine a cardiomyopathy are: [29]
Cardiomyopathies can be classified using different criteria: [30]
Treatment may include suggestion of lifestyle changes to better manage the condition. Treatment depends on the type of cardiomyopathy and condition of disease, but may include medication (conservative treatment) or iatrogenic/implanted pacemakers for slow heart rates, defibrillators for those prone to fatal heart rhythms, ventricular assist devices (VADs) for severe heart failure, or catheter ablation for recurring dysrhythmias that cannot be eliminated by medication or mechanical cardioversion. The goal of treatment is often symptom relief, and some patients may eventually require a heart transplant. [29]
Acoramidis (Attruby) was approved for medical use in the United States in November 2024, to treat adults with cardiomyopathy of wild-type or variant (hereditary) transthyretin-mediated amyloidosis (ATTR-CM) to reduce death and hospitalization related to heart problems. [35]
Cardiology is the study of the heart. Cardiology is a branch of medicine that deals with disorders of the heart and the cardiovascular system. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease, and electrophysiology. Physicians who specialize in this field of medicine are called cardiologists, a sub-specialty of internal medicine. Pediatric cardiologists are pediatricians who specialize in cardiology. Physicians who specialize in cardiac surgery are called cardiothoracic surgeons or cardiac surgeons, a specialty of general surgery.
Cardiac muscle is one of three types of vertebrate muscle tissues, the others being skeletal muscle and smooth muscle. It is an involuntary, striated muscle that constitutes the main tissue of the wall of the heart. The cardiac muscle (myocardium) forms a thick middle layer between the outer layer of the heart wall and the inner layer, with blood supplied via the coronary circulation. It is composed of individual cardiac muscle cells joined by intercalated discs, and encased by collagen fibers and other substances that form the extracellular matrix.
Myocarditis is inflammation of the cardiac muscle. Myocarditis can progress to inflammatory cardiomyopathy when there is associated ventricular remodeling and cardiac dysfunction due to chronic inflammation. Symptoms can include shortness of breath, chest pain, decreased ability to exercise, and an irregular heartbeat. The duration of problems can vary from hours to months. Complications may include heart failure due to dilated cardiomyopathy or cardiac arrest.
Arrhythmogenic cardiomyopathy (ACM) is an inherited heart disease.
Hypertrophic cardiomyopathy is a condition in which muscle tissues of the heart become thickened without an obvious cause. The parts of the heart most commonly affected are the interventricular septum and the ventricles. This results in the heart being less able to pump blood effectively and also may cause electrical conduction problems. Specifically, within the bundle branches that conduct impulses through the interventricular septum and into the Purkinje fibers, as these are responsible for the depolarization of contractile cells of both ventricles.
Dilated cardiomyopathy (DCM) is a condition in which the heart becomes enlarged and cannot pump blood effectively. Symptoms vary from none to feeling tired, leg swelling, and shortness of breath. It may also result in chest pain or fainting. Complications can include heart failure, heart valve disease, or an irregular heartbeat.
Desmin is a protein that in humans is encoded by the DES gene. Desmin is a muscle-specific, type III intermediate filament that integrates the sarcolemma, Z disk, and nuclear membrane in sarcomeres and regulates sarcomere architecture.
Malouf syndrome is a congenital disorder that causes one or more of the following symptoms: intellectual disability, ovarian dysgenesis, congestive cardiomyopathy, broad nasal base, blepharoptosis, and bone abnormalities, and occasionally marfanoid habitus.
Cardiomegaly is a medical condition in which the heart becomes enlarged. It is more commonly referred to simply as "having an enlarged heart". It is usually the result of underlying conditions that make the heart work harder, such as obesity, heart valve disease, high blood pressure (hypertension), and coronary artery disease. Cardiomyopathy is also associated with cardiomegaly.
Restrictive cardiomyopathy (RCM) is a form of cardiomyopathy in which the walls of the heart are rigid. Thus the heart is restricted from stretching and filling with blood properly. It is the least common of the three original subtypes of cardiomyopathy: hypertrophic, dilated, and restrictive.
Loeffler endocarditis is a form of heart disease characterized by a stiffened, poorly-functioning heart caused by infiltration of the heart by white blood cells known as eosinophils. Restrictive cardiomyopathy is a disease of the heart muscle which results in impaired diastolic filling of the heart ventricles, i.e. the large heart chambers which pump blood into the pulmonary or systemic circulation. Diastole is the part of the cardiac contraction-relaxation cycle in which the heart fills with venous blood after the emptying done during its previous systole.
Desmoplakin is a protein in humans that is encoded by the DSP gene. Desmoplakin is a critical component of desmosome structures in cardiac muscle and epidermal cells, which function to maintain the structural integrity at adjacent cell contacts. In cardiac muscle, desmoplakin is localized to intercalated discs which mechanically couple cardiac cells to function in a coordinated syncytial structure. Mutations in desmoplakin have been shown to play a role in dilated cardiomyopathy and arrhythmogenic right ventricular cardiomyopathy, where it may present with acute myocardial injury; striate palmoplantar keratoderma, Carvajal syndrome and paraneoplastic pemphigus.
Athletic heart syndrome (AHS) is a non-pathological condition commonly seen in sports medicine in which the human heart is enlarged, and the resting heart rate is lower than normal.
Noncompaction cardiomyopathy (NCC) is a rare congenital disease of heart muscle that affects both children and adults. It results from abnormal prenatal development of heart muscle.
Cardiac muscle troponin T (cTnT) is a protein that in humans is encoded by the TNNT2 gene. Cardiac TnT is the tropomyosin-binding subunit of the troponin complex, which is located on the thin filament of striated muscles and regulates muscle contraction in response to alterations in intracellular calcium ion concentration.
The following outline is provided as an overview of and topical guide to cardiology, the branch of medicine dealing with disorders of the human heart. The field includes medical diagnosis and treatment of congenital heart defects, coronary artery disease, heart failure, valvular heart disease and electrophysiology. Physicians who specialize in cardiology are called cardiologists.
Desmocollin-2 is a protein that in humans is encoded by the DSC2 gene. Desmocollin-2 is a cadherin-type protein that functions to link adjacent cells together in specialized regions known as desmosomes. Desmocollin-2 is widely expressed, and is the only desmocollin isoform expressed in cardiac muscle, where it localizes to intercalated discs. Mutations in DSC2 have been causally linked to arrhythmogenic right ventricular cardiomyopathy.
The Association for Inherited Cardiac Conditions is the UK national professional body for experts in genetics and cardiology dealing with inherited diseases of the heart. These include heart muscle diseases such as hypertrophic cardiomyopathy, dilated cardiomyopathy, noncompaction cardiomyopathy, and arrhythmogenic cardiomyopathy, as well as inherited arrhythmia disorders such as long QT syndrome, Brugada syndrome, and catecholaminergic polymorphic ventricular tachycardia (CPVT). The AICC also represents experts in aortic disease such as Marfan syndrome and other systemic diseases which affect the heart or circulation.
Sports cardiology is an emerging subspecialty field of Cardiology. It may also be considered a subspecialty field of Sports medicine, or alternatively a hybrid subspecialty that spans cardiology and sports medicine. Emergency medicine is another medical specialty that has some overlap with Sports Cardiology. Sports cardiology is now considered to be a distinct subspecialty in Europe and the USA, with a core curriculum developed in both regions. In Europe it has traditionally been grouped under Preventive Cardiology, but the subspecialty of Sports Cardiology is now considered a distinct field. In the USA, it has developed from being a special interest area to a distinct subspecialty as well.
Ali J. (AJ) Marian is an American physician-scientist in the fields of cardiovascular medicine and genetics. He is a professor of molecular medicine (Genetics), professor of medicine (Cardiology), and director of the Center for Cardiovascular Genetic Research at the Brown Foundation Institute of Molecular Medicine at the University of Texas Health Science Center, Houston, Texas. He also holds the James T. Willerson Distinguished Chair in Cardiovascular Research and is most known for his works on the molecular genetics, genomics, and biology of cardiomyopathies.