hypertrophic cardiomyopathy

Hypertrophic Cardiomyopathy 

Definition

Cardiomyopathy is an ongoing disease process that damages the muscle wall of the lower chambers of the heart. Hypertrophic cardiomyopathy is a form of cardiomyopathy in which the walls of the heart's chambers thicken abnormally. Other names for hypertrophic cardiomyopathy are idiopathic hypertrophic subaortic stenosis and asymmetrical septal hypertrophy.

Description

Hypertrophic cardiomyopathy usually appears in young people, often in athletes. For this reason it is sometimes called athletic heart muscle disease. However, people of any age can develop hypertrophic cardiomyopathy. Often there are no symptoms of hypertrophic cardiomyopathy. Sudden death can occur, caused by a heart arrhythmia. The American Heart Association reports that 36% of young athletes who die suddenly have probable or definite hypertrophic cardiomyopathy.

Hypertrophic cardiomyopathy is the result of abnormal growth of the heart muscle cells. The wall between the heart's chambers (the septum) may become so thickened that it blocks the flow of blood through the lower left chamber (left ventricle). The thickened wall may push on the heart valve between the two left heart chambers (mitral valve), making it leaky. The thickened muscle walls also prevent the heart from stretching as much as it should to fill with blood.

Causes and symptoms

The cause of hypertrophic cardiomyopathy is not known. In about one-half of cases, the disease is inherited. An abnormal gene has been identified in these patients. In cases that are not hereditary, a gene that was normal at birth may later become abnormal.

Often people with hypertrophic cardiomyopathy have no symptoms. Unfortunately, the first sign of the condition may be sudden death caused by an abnormal heart rhythm. When symptoms do appear, they include shortness of breath on exertion, dizziness, fainting, fatigue, and chest pain.

Diagnosis

The diagnosis is based on the patient's symptoms (if any), a complete physical examination, and tests that detect abnormalities of the heart chambers. Usually, there is an abnormal heart murmur that worsens with the Valsalva maneuver. The electrocardiogram (ECG), which provides a record of electrical changes in the heart muscle during the heartbeat, also is typically abnormal.

Sometimes, a routine chest x ray may show that the heart is enlarged. Echocardiography, a procedure that produces images of the heart's structure, is

This illustration shows hypertrophic muscle in the heart. The abnormally thick wall of muscle prevents the chambers from stretching to fill up with blood, making the heart less efficient. The extra tissue may also push on the heart valve (center), causing it to leak.

(Illustration by Bryson Biomedical Illustrations, Custom Medical Stock Photo. Reproduced by permission.)

usually done. These images can show if the heart wall is thickened and if there are any abnormalities of the heart valves.

Treatment

Treatment of hypertrophic cardiomyopathy usually consists of taking medicines and restricting strenuous exercise. Drugs called beta blockers and calcium channel blockers are usually prescribed. Beta blockers reduce the force of the heart's contractions. Calcium channel blockers can help improve the flexibility of the heart muscle walls, allowing them to stretch more. Antiarrhythmic drugs may also be given to prevent abnormal heart rhythms.

Patients with hypertrophic cardiomyopathy are also told to avoid strenuous exercise to reduce the risk of passing out or sudden death.

In some cases, if the medications do not help relieve symptoms, surgery may help. In an operation called myotomy-myectomy a piece of the septum is removed to improve blood flow through the heart chamber.

Some patients have pacemakers and/or defibrillators implanted to help control the heart rate and rhythm. Pacemakers and defibrillators provide electrical impulses to the heart, which can return the heart beat to a normal rhythm.

If these treatment methods fail and a patient develops heart failure, a heart transplant may be necessary.

Prognosis

Some people with hypertrophic cardiomyopathy may not have obstructed blood flow and may never experience symptoms. Others may only experience mild symptoms. With treatment, symptoms may improve. In some patients, the disease may progress to heart failure.

Prevention

While hypertrophic cardiomyopathy cannot be prevented, precautionary measures may prevent sudden deaths. Anyone planning to take part in a program of strenuous competitive exercise should have a checkup by a physician first. A physical examination before athletic participation can usually, but not always, detect conditions like hypertrophic cardiomyopathy. Anyone who experiences symptoms of shortness of breath, tiredness, or fainting with exercise should see a physician.

Resources

Organizations

American Heart Association. 7320 Greenville Ave. Dallas, TX 75231. (214) 373-6300. http://www.americanheart.org.

National Heart, Lung and Blood Institute. PO Box 30105, Bethesda, MD 20824-0105. (301) 251-1222. http://www.nhlbi.nih.gov.

Texas Heart Institute. Heart Information Service. PO Box 20345, Houston, TX 77225-0345. http://www.tmc.edu/thi.

Key terms

Arrhythmias — Abnormal heartbeat.

Calcium channel blocker — A drug that relaxes blood vessels and lowers blood pressure.

Mitral valve — The heart valve that controls blood flow between the heart's left upper chamber (atrium) and left lower chamber (ventricle).

Septum — The muscular wall dividing the left and right heart chambers.

Ventricles — The two lower chambers of the heart.

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cardiomyopathy /car·dio·my·op·a·thy/ (-mi-op´ah-the)

1. a general diagnostic term designating primary noninflammatory disease of the heart.

2. more restrictively, only those disorders in which the myocardium alone is involved and in which the cause is unknown and not part of a disease affecting other organs.cardiomyopath´ic

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alcoholic cardiomyopathy  dilated cardiomyopathy in patients chronically abusing alcohol.

beer-drinkers' cardiomyopathy  cardiac dilatation and hypertrophy due to excessive beer consumption; in at least some cases it has been due to the addition of cobalt to the beer during the manufacturing process.

congestive cardiomyopathy , dilated cardiomyopathy a progressive syndrome of ventricular dilatation, systolic contractile dysfunction, and, often, congestive heart failure, believed due to myocardial damage by factors such as alcohol or infection.

hypertrophic cardiomyopathy  (HCM) a form marked by ventricular hypertrophy, particularly of the left ventricle, with impaired ventricular filling due to diastolic dysfunction.

hypertrophic obstructive cardiomyopathy  (HOCM) a form of hypertrophic cardiomyopathy in which the location of the septal hypertrophy causes obstructive interference to left ventricular outflow.

infiltrative cardiomyopathy  restrictive cardiomyopathy characterized by deposition in the heart tissue of abnormal substances, as may occur in amyloidosis, hemochromatosis, etc.

ischemic cardiomyopathy  heart failure with left ventricular dilatation resulting from ischemic heart disease.

restrictive cardiomyopathy  a form in which the ventricular walls are excessively rigid, impeding ventricular filling.

right ventricular cardiomyopathy  a right-sided cardiomyopathy occurring particularly in young males, with dilatation of the right ventricle with partial to total replacement of its muscle by fibrous or adipose tissue, palpitations, syncope, and sometimes sudden death.

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hypertrophic cardiomyopathy,

an abnormal condition characterized by gross hypertrophy of the interventricular septum and left ventricular free wall of the heart. Ventricular hypertrophy results in impaired diastolic filling and reduced cardiac output. Signs and symptoms, such as fatigue and syncope, are often associated with exercise when the demand for increased cardiac output cannot be met. This is commonly a genetic disease, with numerous genes implicated. Also called hypertrophic obstructive cardiomyopathy.

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cardiomyopathy

a general diagnostic term designating primary myocardial disease of unknown cause.

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Boxer cardiomyopathy

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 cardiomyopathy

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 cardiomyopathy

a distinctive cardiomyopathy is seen in Doberman pinscher dogs, often presenting as an acute pulmonary edema, cardiogenic shock and sometimes sudden death.

hypertrophic cardiomyopathy

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 cardiomyopathy

myocardial disease secondary to deposition in the heart tissue of abnormal substances such as amyloid or neoplastic infiltration.

inherited cardiomyopathy

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 cardiomyopathy

in the subclinical stage, but detectable with echocardiography and ambulatory electrocardiographic recording methods.

restrictive cardiomyopathy

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.

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hypertrophic cardiomyopathy

Idiopathic hypertrophic subaortic stenosis Cardiology A condition affecting 1:500 persons, causing an array of clinical and pathologic changes, either symmetric–concentric or asymmetric–eccentric hypertrophy, with disproportionate thickening beneath the mitral valve, seen without other cardiac disease;¹⁄₂ are congenital, with an AD pattern; in general in HC, ↑ obstruction is associated with ↓ venous return Clinical Younger Pts, ranging from asymptomatic to diastolic dysfunction, dyspnea, fatigue, chest pain and syncope, an ↑ incidence of severe obstruction, CHF, sudden death, simulating acute MI Clinical–older Pts SOB, angina, syncope EKG ↑ QRS complexes, T-wave inversion, Q waves in inferior and left precordial leads Management Symptomatic–ie, relief of dyspnea or chest pain Drugs β-adrenergics are effective short-term; CCBs–which ↑ diastolic ventricular filling may be effective long-term Surgery Recalcitrant HC may require a transaortic ventricular septal myotomy-myectomy. See Cardiac myosin-binding protein C. Cf Dilated cardiomyopathy.

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Patient discussion about hypertrophic cardiomyopathy.

Q. I have hypertrophic cardiomyopathy and an ICD. Is it possible to get breast implants with an ICD? I have no further symptoms: I workout and run 6 days a week, in good shape and only 27 years old.

A. Some medical equipment can damage your ICD If you are visiting your doctor , tell him or her that you have an ICD BEFORE they do any testing or treatment.i'm pretty sure they'll find a creative way to do the implant.any way- before doing any procedure- ask the cardiologist that handles you about it.