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cardiomyopathy

 
Dictionary: car·di·o·my·op·a·thy   (kär'dē-ō-mī-ŏp'ə-thē) pronunciation
n., pl., -thies.
A disease or disorder of the heart muscle, especially of unknown or obscure cause.


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Oncology Encyclopedia: Cardiomyopathy
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Key Terms: Acute pulmonary edema, Angiotensin converting enzyme inhibitors, Beta-blockers, Congestive heart failure, Diuretics.

Definition

Cardiomyopathy is a type of heart disease in which the heart muscle is abnormally enlarged, thickened and/or stiffened. As a result, the heart muscle's ability to pump blood is usually impaired.

Description

When the heart muscle enlarges and is unable to pump effectively, its function declines. This is called congestive heart failure. Congestive heart failure results in a reduction in oxygen delivery to the tissues and a backup of fluid into those tissues. Fluid in the lungs can cause shortness of breath with exertion and a need to sleep with the head elevated. Fluid buildup in other areas can manifest itself as swelling of the feet and ankles or swelling and pain in the liver. Congestive heart failure once carried a grim prognosis, but new advances in medical treatment have improved that prognosis significantly.

People with cardiomyopathy can develop an abrupt buildup of fluid in the lungs, called acute pulmonary edema. This is a medical emergency. In addition to intra-venous medications that remove fluid, support blood pressure, and strengthen the heart's pumping function, acute pulmonary edema is also treated with oxygen and sometimes the temporary use of a respirator.

Almost anything that can damage the heart muscle fibers can produce cardiomyopathy and congestive heart failure. Long-standing high blood pressure, diabetes, heart attacks, alcohol, drugs, and certain viruses are all causes of cardiomyopathy.

In a person with cancer, cardiomyopathy and its symptoms are generally due to the adverse effects of treatment.

Causes

Among the causes of cardiomyopathy in cancer patients is radiation therapy to the chest, which is often employed for breast cancer, cancer of the esophagus or lymphoma. Children who receive radiation therapy to the spinal column can suffer late effects to their hearts. The radiation can damage the heart muscle, leading to cardiomyopathy and heart failure. It can also damage the coronary arteries, leading to angina or a heart attack.

More commonly, cardiomyopathy in a cancer patient is an adverse effect of chemotherapy. Among the chemo-therapeutic drugs known to be toxic to the heart are:

The drugs most frequently associated with cardiotoxicity are doxorubicin and daunorubicin, which are anthracyclines. The total cumulative dose of anthracyclines a person receives determines the likelihood of developing chronic cardiomyopathy. In a few cases, these agents will cause an acute cardiotoxic effect, with symptoms such as abnormal heart rhythms and electrocardiogram changes.

Patients receiving anthracyclines have nuclear imaging scans of their hearts before starting treatment, during treatment and after treatment, since the adverse effects can be delayed. These studies measure the heart's ejection fraction, which is the percentage of blood volume pumped with each heartbeat. A normal ejection fraction is around 60%. In other words, 60% of the blood that collects in the heart between heartbeats is pumped out with each beat. Anthracyclines can cause a significant reduction in ejection fraction and therefore in heart function.

Often used for colon, breast, and head and neck cancers, 5-fluorouracil can cause cardiotoxicity, mostly in those patients with existing coronary artery disease or those who are also receiving radiation therapy to the chest. Cyclophosphamide, often used in those who have had bone marrow transplants, is another cause of cardiomyopathy. The taxanes, paclitaxel and docetaxel, are newer agents often used for breast and ovarian cancers. Taxanes can cause slowing of the heart rate, but this is not usually serious or prolonged.

Trastuzumab is a monoclonal antibody used in some patients with breast cancer. About 30% of women have overexpression of human epidermal growth factor receptors, called HER-2, on the surface of their cancer cells. Trastuzumab selectively attacks those receptors. Heart muscle also has some HER-2 receptors, which is believed to be the reason that trastuzumab can cause cardiomyopathy. Trastuzumab is often used in conjunction with anthracyclines or taxanes, both of which have effects on the heart, and patients on these drugs must be carefully monitored for signs of heart disease.

The diagnosis of cardiomyopathy is made on the basis of the history and physical examination, along with tests of heart function. Occasionally, biopsies of the heart muscle are performed to confirm the diagnosis.

Other forms of damage to the heart can occur with cancer and its treatments. Some cancers can metastasize to the heart muscle or the valves within the heart. Cancers that spread to the pericardium, the outer lining of the heart, can induce fluid collections called pericardial effusions.

High-output cardiac failure is an unusual form of heart failure that results when the body senses a lowered total blood volume. This can occur with anemia, a side effect of many treatments, or with large tumors that have large numbers of blood vessels, drawing blood away from the general circulation.

Amyloidosis is a condition in which abnormal proteins are deposited in tissues throughout the body, including the heart. Amyloidosis is seen with multiple myeloma.

Abnormal heart rhythms can occur due to toxic effects of chemotherapeutic drugs and perhaps radiation treatments on the electrical conducting system of the heart.

Treatments

The treatment of cardiomyopathy in cancer patients consists of removing the cause when possible and using cardiac medications to reduce symptoms.

Since the most common cause of cardiomyopathy in cancer patients is due to the use of anthracyclines, oncologists keep a careful record of the total dose administered to patients over the course of their treatment, and stop the drug before the known toxic dose has been reached.

Newer forms of anthracyclines have been formulated which are called liposome encapsulates. These have been shown to be less toxic to the heart and still effective against cancer. Administering anthracyclines weekly, rather than every three to four weeks, and giving the dose more slowly both seem to reduce the cardiac toxicity. The simultaneous administration of drugs that might protect the heart is under study, but their use is not yet recommended routinely.

The treatment of an established cardiomyopathy and heart failure due to cancer treatment is a combination of medications that are used for heart failure of any origin. One of these is digoxin, which improves the heart's pumping function in addition to other beneficial effects. Diuretics, often called water pills, flush water and salt from the body and are used to reduce swelling. Angiotensin-converting enzymes or ACE inhibitors comprise the third group of drugs useful for heart failure. These relax the arteries, which reduces the work that the heart must do to effectively pump blood. The fourth group of medications includes beta-blockers, which slow the heart rate and reduce its workload. This combination of medications has significantly improved the prognosis for people with heart failure.

Lifestyle changes can reduce symptoms of heart failure. Reducing salt and fluid intake and avoiding alcohol are beneficial. A judicious exercise plan can increase stamina without overtaxing a failing heart. Many people who have undergone cancer treatment also have coronary artery disease, which can aggravate the symptoms of heart failure caused by chemotherapy toxicity. Patients whose cancer prognosis is good can sometimes benefit from treatment of their coronary artery disease.

Some patients whose cancer is cured but whose cardiomyopathy progresses despite medication are candidates for heart transplant.

Alternative and Complementary Therapies

Naturopaths might prescribe hawthorn for symptoms of congestive heart failure. No studies have demonstrated either benefit or harm from this preparation.

Acupuncture and acupressure are sometimes beneficial in reducing symptoms of shortness of breath and may offer some relief to those with heart failure due to cardiomyopathy. The pressure point for the heart is said to be on the palm of the hand, over the bones between the fourth and fifth fingers.

Resources

Books

Moore, Katen, and Libby Schmais. Living Well with Cancer: A Nurse Tells You Everything You Need to Know About Managing the Side Effects of Your Treatment. New York: Putnam Publishing Group, 2001.

Periodicals

Ginsburg, A.D. "Doxorubicin-induced Cardiomyopathy." New England Journal of Medicine 340, no. 8 (February, 1999): 654.

Other

Heart Center Online Home Page. [cited June 6, 2001]. . This website serves cardiologists and their patients and has sections on pericardiocentesis, pericarditis and tamponade.

—Marianne Vahey, M.D.

Food and Nutrition: cardiomyopathy
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Any chronic disorder affecting the muscle of the heart. May be associated with alcoholism and vitamin B1 deficiency.

Veterinary Dictionary: cardiomyopathy
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A general diagnostic term designating primary myocardial disease of unknown cause.

  • Boxer c. — a dilated cardiomyopathy, believed to be inherited, is seen in adult Boxers that show syncope, episodic weakness, arrhythmias, and left or biventricular heart failure.
  • congestive c. — a syndrome characterized by cardiac enlargement, especially of the left ventricle, poor myocardial contractility, and congestive heart failure. Occurs most commonly in young to middle-aged dogs of the large and giant breeds with rapidly developing signs of biventricular failure, atrial fibrillation and occasionally systolic murmurs. Cats usually show acute signs of cardiac failure with pleural effusion but not ascites, and sometimes thromboembolism. Called also dilated cardiomyopathy.
  • Doberman c. — a distinctive cardiomyopathy is seen in Doberman pinscher dogs, often presenting as an acute pulmonary edema, cardiogenic shock and sometimes sudden death.
  • hypertrophic c. — occurs most commonly in cats, sometimes secondary to hyperthyroidism, occasionally in dogs and rarely in cattle in association with generalized glycogenosis. There is myocardial hypertrophy, primarily in the left ventricle and ventricular septum, resulting in increased resistance to filling and sometimes an outflow obstruction. In cats there is often an associated aortic thromboembolism.
  • infiltrative c. — myocardial disease secondary to deposition in the heart tissue of abnormal substances such as amyloid or neoplastic infiltration.
  • inherited c. — occurs in calves and probably in the other species. In calves it causes death due to acute heart failure up to the age of 3 months. Recorded in polled Hereford and Japanese black cattle. There may be a brief period of dyspnea and blood-stained frothy nasal discharge before death. Myocardial degeneration is obvious at necropsy.
  • occult c. — in the subclinical stage, but detectable with echocardiography and ambulatory electrocardiographic recording methods.
  • restrictive c. — impaired left ventricular compliance reduces ventricular filling. Uncommon in animals but seen most often in cats, caused by endomyocardial fibrosis or abnormal left ventricular moderator bands. Called also obliterative cardiomyopathy.
Wikipedia: Cardiomyopathy
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Cardiomyopathy
Classification and external resources

Opened left ventricle of heart shows a thickened, dilated left ventricle with subendocardial fibrosis manifested as increased whiteness of endocardium. Autopsy.
ICD-10 I42.0
ICD-9 425.4
DiseasesDB 2137
MedlinePlus 001105
MeSH D009202

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.[1]

Cardiomyopathies can be categorized as extrinsic or intrinsic.[2]

Contents

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:[2]

Ischemic cardiomyopathy

Commonly used term "ischemic cardiomyopathy," referring to myocardial ischemia and infarction, is not supported by current cardiomyopathies classification schemes[3][4].

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 myocardial scarring (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.

refer to "takotsubo 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 things). The term intrinsic cardiomyopathy does not describe the specific etiology of weakened heart muscle. The intrinsic cardiomyopathies consist of a variety 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,[2][5] 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.

Signs and symptoms

Cardiomyopathy is usually found incidentally—"case finding"—by healthcare professionals during a routine checkup. The only test for hypertension is a blood pressure measurement. Hypertension in isolation usually produces no symptoms although some people report headaches, fatigue, wanting to sleep more than usual, dizziness, blurred vision, facial flushing or tinnitus.[citation needed]

Malignant Cardiomyopathy (or accelerated Cardiomyopathy) is distinct as a late phase in the condition, and may present with headaches, blurred vision and end-organ damage.

Cardiomyopathy is often confused with mental tension, stress and anxiety. While chronic anxiety and/or irritability is associated with poor outcomes in people with hypertension, it alone does not cause it. Accelerated hypertension is associated with somnolence, confusion, visual disturbances, and nausea and vomiting (hypertensive encephalopathy).

Treatment

Treatment depends on the type of cardiomyopathy, but may include medication, implanted pacemakers, defibrillators, or ventricular assist devices (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.

Famous cases

In 1966, the addition of cobalt compounds to stabilize beer foam in Canada led to cardiomyopathy, which came to be known as beer drinker's cardiomyopathy.[6]

Dave Williams of Drowning Pool died of cardiomyopathy in 2002.

Dr. Robert Atkins, inventor of "The Atkins Diet" suffered from cardiomyopathy in the years before his death from a fall.

Alexei Cherepanov, 19 year old professional ice hockey player, died of cardiomyopathy during an ice hockey game in 2008.

Andy Hallett, a 33 year old actor from the television series Angel, died of congestive heart failure in 2009, brought on by a cardiomyopathy from a tooth infection five years earlier.

Michael James Hegstrand aka Road Warrior Hawk an American professional wrestler.

Slash, guitarist for Guns N Roses, survived cardiomyopathy .

Reggie Lewis, captain and all-star of the Boston Celtics, died from hypertrophic cardiomyopathy at age 27.

Marc-Vivien Foe, Cameroonian international & West Ham United professional football (soccer) player, collapsed and died of hypertrophic obstructive cardiomyopathy (HOCM) aged 28 during a FIFA Confederations Cup Match on 26 June 2003.

Cuttino Mobley, a retired NBA player who last played for the LA Clippers, was forced to retire after being diagnosed with hypertrophic cardiomyopathy in late 2008.

Hank Gathers, a college basketball star recruit who played for Loyola Marymount University, collapsed during a free throw attempt against UCSB and later again against the University of Portland. The second time he never got up and was pronounced dead on arrival.

Nick Carter of the Backstreet Boys was diagnosed with cardiomyopathy after suffering chest pains.

Katie Gallagher, who placed second on the TV reality show Survivor: Palau, was diagnosed with viral cardiomyopathy several years later.

Genetic causes of cardiomyopathy[7]
Phenotype Inheritance pattern Chromosomal locus Gene Protein Skeletal myopathy
Dilated cardiomyopathy X-linked Xp21 dystrophin Dystrophin Duchenne / Becker muscular dystrophy
X-linked Xq28 G4.5 Tafazzin Barth syndrome
Autosomal dominant 15q14 actin Actin Nemaline myopathy
2q35 desmin Desmin Desmin myopathy
5q33 δ-sarcoglycan δ-sarcoglycan Limb girdle muscular dystrophy 2F
1q32 Troponin T Troponin T
14q11 β-myosin heavy chain β-myosin heavy chain
15q2 α-tropomyosin α-tropomyosin Nemaline myopathy
Midna Mitochondrial respiratory chain Mitochondrial respiratory chain Mitochondrial myopathy
Dilated cardiomyopathy with conduction disease Autosomal dominant 1q21 lamin A/C Lamin A/C Emery-Dreifuss muscular dystrophy
Hypertrophic cardiomyopathy Autosomal dominant 14q11 β-myosin heavy chain β-myosin heavy chain
14q11 β-myosin heavy chain β-myosin heavey chain
1q32 Troponin T Troponin T
12q23 Troponin T Troponin T
15q2 α-tropomyosin α-tropomyosin Nemaline myopathy
11q11 myosin-binding protein C myosin-binding protein C
3p21 myosin essential light chain myosin essential light chain
3p21 myosin regulatory light chain myosin regulatory light chain
2p31 titin Titin
Hypertrophic cardiomyopathy with Wolf-Parkinson-White syndrome 7q3 AMPK AMPK
MIDINA Mitochondrial respiratory chain Mitochondrial respiratory chain Mitochondrial myopathy
Left ventricular noncompaction X-linked Xq28 G4.5 Tafazzin Barth syndrome
Autosomal dominant 18q12 α-dystrobrevin α-Dystrobrevin Muscular dystrophy

References

  1. ^ Kasper, Denis L. et al. (2005). Harrison's Principles of Internal Medicine, 16th edn. McGraw-Hill. ISBN 0-07-139140-1. 
  2. ^ a b c 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)
  3. ^ Elliott, P.; Andersson, B.; Arbustini, E.; Bilinska, Z.; Cecchi, F.; Charron, P.; Dubourg, O.; Kuhl, U. et al. (2007). "Classification of the cardiomyopathies: a position statement from the european society of cardiology working group on myocardial and pericardial diseases". European Heart Journal 29: 270. doi:10.1093/eurheartj/ehm342.  edit
  4. ^ Maron, B. J.; Towbin, J. A.; Thiene, G.; Antzelevitch, C.; Corrado, D.; Arnett, D.; Moss, A. J.; Seidman, C. E. et al. (2006). "Contemporary Definitions and Classification of the Cardiomyopathies: an American Heart Association Scientific Statement from the Council on Clinical Cardiology, Heart Failure and Transplantation Committee; Quality of Care and Outcomes Research and Functional Genomics and Translational Biology Interdisciplinary Working Groups; and Council on Epidemiology and Prevention". Circulation 113: 1807. doi:10.1161/CIRCULATIONAHA.106.174287.  edit
  5. ^ Cardiomyopathy Association. "About cardiomyopathy". http://www.cardiomyopathy.org/html/about_cardio.htm. Retrieved 2006-09-28. 
  6. ^ Donald G. Barceloux; Donald Barceloux (1999). "Cobalt". Clinical Toxicology 37 (2): 201–216. doi:10.1081/CLT-100102420. 
  7. ^ Towbin, JA; Bowles NE (January 2002). "The failing heart". Nature 415 (6868): 227–233. PMID 11805847. 

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Dictionary. The American Heritage® Dictionary of the English Language, Fourth Edition Copyright © 2007, 2000 by Houghton Mifflin Company. Updated in 2009. Published by Houghton Mifflin Company. All rights reserved.  Read more
Oncology Encyclopedia. Gale Encyclopedia of Cancer. Copyright © 2006 by The Gale Group, Inc. All rights reserved.  Read more
Food and Nutrition. A Dictionary of Food and Nutrition. Copyright © 1995, 2003, 2005 by A. E. Bender and D. A. Bender. All rights reserved.  Read more
Veterinary Dictionary. Saunders Comprehensive Veterinary Dictionary 3rd Edition. Copyright © 2007 by D.C. Blood, V.P. Studdert and C.C. Gay, Elsevier. All rights reserved.  Read more
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