‘Enlarged Heart’ explained

Defining Cardiomyopathy

Cardiomyopathy is a heart condition, which quite literally translates to “heart muscle disease” (cardio- heart, -myomuscle, -path disease). Cardiomyopathy refers to the deterioration of the myocardium found in the heart. Cardiomyopathy falls into four general categories, dilated cardiomyopathy (known as DCM), restricted cardiomyopathy (known as RCM), hypertrophic and arrythmogenic right ventricular cardiomyopathy. Viral cardiomyopathy is another form of cardiomyopathy and occurs as a result of a viral infection causing swelling and tenderness in the heart.

Cardiomyopathy has several known causes, though it can also occur spontaneously in an individual. It can be both a primary and secondary condition, and comes in different forms. Alcoholic dilated cardiomyopathy is caused by chronic alcohol abuse. Research suggests that the toxins found in the alcohol can directly cause this form of cardiomyopathy. Another alcohol related form of cardiomyopathy is beer-drinkers cardiomopathy. Dilated cardiomyopathy along with hypertrophy can occur from beer-drinkers cardiomyopathy. In some cases of this form of cardiomyopathy, the actual cause is the addition of beer to the beer manufacturing, rather than the actual beer itself. In alcohol related cardiomyopathy, often if it is detected early and the individual is able to cease the alcohol abuse, it can be reversed. Toxic cardiomyopathy, like alcoholic and beer-drinkers cardiomyopathy results from toxins being present in the body. The damage to the myocardium occurs mostly from toxins such as anti-cancer drugs, along with catecholamines, some metals and snake venom.

Dilated cardiomyopathy (or DCM) is the most common form of cardiomyopathy. In DCM the heart, and in particular the left ventricle, enlarge and the contracting action is diminished. It is defined as “a syndrome of ventricular dilation, systolic contractile dysfunction, and often congestive heart failure; the course is usually progressive with a poor prognosis” (Saunders, 2000, p. 287). The myocardial damage can have a variety of causes including, but not limited to, pregnancy, hypertension, alcohol, and particular infections.

Cardiomyopathy that develops during pregnancy is referred to as peripartum cardiomyopathy, and symptoms will usually cease and heart function will return to normal within six to eight weeks of giving birth. Women who do develop peripartum cardiomyopathy where the heart function does not return to normal are advised to avoid further pregnancies as they can endanger the life of both the mother and foetus. Peripartum cardiomyopathy occurs in around 1 in every 10,000 pregnancies and the onset is usually due to the extra pressure placed on the heart during pregnancy. Cardiomyopathy can also present as postpartum, meaning the condition still arises as a result of pregnancy, but the symptoms appear after birth, rather than during the period of pregnancy.

Hypertrophic cardiomyopathy (known as HCM) also affects the left ventricle and causes ventricular hypertrophy. Research suggests that it is possibly an autosomal dominant inheritance which causes this particular kind of cardiomyopathy. A variation of this form of cardiomyopathy is hypertropic obstructive cardiomyopathy (known as HOCM). An obstruction is the cause of limited or interfered ventricular outflow in this form of cardiomyopathy.

Restrictive cardiomyopathy (known as RCM) is an uncommon form of cardiomyopathy. The walls of the ventricles, instead of being weak and floppy as is the case in dilated cardiomyopathy, stiffen and restrict heart function.

Other forms of cardiomyopathy include idiopathic cardiomyopathy, where no known cause is able to be identified. Infiltrative cardiomyopathy is another type of cardiomyopathy which is a falls under the general category of restrictive cardiomyopathy and is characterised by substances being deposited in the heart. Right ventricular cardiomyopathy occurs on the right side of the heart, as suggested by the name, is mostly found in young males and causes a major dilation of the right ventricle. Noncompaction cardiomyopathy occurs when the left ventricle wall fails to grow properly at birth.

Ischemic cardiomyopathy is a secondary cardiomyopathy and occurs from ischemic heart disease, a disease which causes heart failure and refers to myocardial ischemia and infraction. Ischemic cardiomyopathy is a weakness in the myocardium or other cardiac muscle which occurs due to a lack of oxygen delivery to the muscle. Coronary disease is the most common cause of this form of cardiomyopathy, and contributing conditions include sleep apnea, anemia and hyperthyroidism.

Cardiomyopathy is diagnosed via a cardiologist and there are a variety of tests used as diagnostic tools. Echocardiograms are used as a primary diagnostic tool. They are essentially an ultrasound of the heart and can be used to not only view the heart, but to view the function of the heart. An electrocardiogram (known as an ECG) can also be used for diagnosis. An ECG makes a record of the electrical signals throughout the heart. Other tools used for diagnosis include chest x-rays which can show the enlargement of the heart or fluid in the lungs, holter monitors, stress tests (exercise tests designed to place the heart under physical stress), and blood tests.

If a diagnosis is still unable to be obtained from the above mentioned tests, or if a clearer picture is needed of how much damage has been done to the myocardium, or how poorly the heart is functioning there are other tests available. Cardiac catheterisation involves inserting a small tube through a major artery (usually the femoral artery) and into the heart, where a dye is injected and able to be viewed via an x-ray or ultrasound. The purpose of this is to indicate any blockages present in the individual, and to establish other factors, such as damage to the heart. Endomyocardial biopsies involve a very small amount of heart tissue being removed (usually via a vein in the neck) and being examined for abnormalities.


Clinical Presentation

Symptoms of cardiomyopathy vary depending on both the classification of the illness as well as the severity of the illness in the individual. Common symptoms include headaches, blurred vision, shortness of breath (particularly upon exertion), ankle swelling, chest pain, a general feeling of lack of energy and fatigue, and muscle fatigue which occurs when the cardiac output is low and the body cannot get enough blood which leads to muscles being unable to contract normally. These symptoms can often be mistaken in the individual as anxiety, stress and mental tension.

Hypertension (commonly called high blood pressure), is one of the main symptoms of cardiomyopathy. Hypertension in the case of cardiomyopathy, is referred to medically as “secondary hypertension”, meaning that is it secondary to another condition. Noticeable symptoms of hypertension usually occur after organ damage has already happened as a result of the condition. This usually occurs more frequently in individuals who have reached blood pressures of over 180/120 mmHg. The symptoms of hypertension include headaches, which are a warning sign that early arterial damage has occurred in the brain and retina. Other symptoms include breathlessness, which is the main symptom of early heart failure, and nosebleeds and other subconjunctival haemorrhage.

Heart failure is a common symptom of cardiomyopathy. Atrial fibrillation (known as AF) is also another common symptom. The rhythms of the heart are irregular and can be rapid, which in turn causes palpitations, fatigue and shortness of breath. AF can also increase the risk of clots forming, and a common treatment for this particular symptom is the medication Warafin, which is an anticoagulant used to thin the blood. Blood clots can be incredibly dangerous if developed, they can lead to stroke and other damage.

Any symptom that leads to irregular heart rhythms can cause dizziness, palpitations, shortness of breath and occasionally fainting. The irregular heart rhythms include; ventricular ectopics, which are the addition of the occasional single heart beat and generally they do not cause any problems. Ventricular tachycardia on the other hand may require the implantation of an ICD to regulate the heart beat, as the heart beats rapidly and can cause complications. Ventricular fibrillation (known as VF) is rare, but can cause serious complications and even death if left untreated as it is affects the electrical activity of the heart.

Chest infections are a common illness associated with cardiomyopathy. Because of diminished heart function fluid builds up in the tissues, and in particular the lungs which can lead to infection. Circulation is often bad in individuals with cardiomyopathy, and can result in the sensation of tingling in the extremities (hands and fingers, feet and toes). Problems with circulation can also lead to difficulty healing if an injury is obtained.

Another common symptom of cardiomyopathy is a blue tinge to the skin, which results from a lack of oxygen due to diminished heart function. This is usually found in the extremities, but in more severe cases can be found all over the body. Prominent veins in the neck and chest are another visual symptom of cardiomyopathy.

Cardiomyopathy currently has no cure, and for most cardiomyopathies there is no prevention.


Treatment Options

Cardiomyopathy related hypertension is treated with one or more classes of drugs which fall into nine groups. Group 1 consists of diuretics, Group 2 consists of beta blockers, Group 3 of Angiotensin converting-enzyme (ACE) inhibitors, Group 4 of Angiotensin receptor blockers, Group 5 of Vasodilators, Group 6 of Calcium-channel blockers, and Group 7 of drugs acting mainly on the brainstem. Groups 8 and 9 are considered a last resort and cover Adrenegic neurone blockers (Group 8), and Ganglion blockers (Group 9).

The drugs used to treat hypertension are used as either a primary or secondary treatment for cardiomyopathy, depending on the severity of the condition exhibited in the individual. Other medications used to treat cardiomyopathy include digoxin, anticoagulants, antiarrythmics, and surgery.

Vasodilators enlarge (or dilate) the blood vessels, which in turn makes it easier for the heart to pump blood throughout the body. The most common side effects of vasodilators include low blood pressure, fluid retention, weakness, dizziness, and fainting; which usually occurs as a symptom of low blood pressure.

ACE inhibitors work by inhibiting the production of the enzyme which causes blood vessels to narrow. Medications which fall into this category used to treat cardiomyopathy include the following; Benazepril, Captopril, Enalapril, Fosinopril, Lisinopril, Perindopril, Quinapril, Ramipril and Trandolapril.

Warfarin is commonly used as part of the treatment for cardiomyopathy. It is an anticoagulant (blood thinner), and can assist in the prevention of arterial and venous thrombosis, embolisation in thromboemoblic disorders, recurrence of heart attack, and stroke in patients with atrial fibrillation. It also can treat acute coronary syndrome and helps to prevent blood clots after mitral valve replacement.

Digoxin is an antiarrythmic and cardiotonic glycoside medication. This means that it assists in regulating the heart beat and acts as a heart stimulant. It is the main drug of choice in congestive heart failure and blood levels must be checked often in order to monitor the dosage.

Common surgeries used to correct or assist the cardiovascular system when cardiomyopathy is presented in a patient include the implantation of a pacemaker, ICD (Implantable cardioverter defibrillator) and a VADs (Ventricular assist devices). Other surgical options include mitral valve repair or replacement, and in severe cases, heart transplantation.

A cardiac pacemaker is a device which influences the rate of the heart beats by delivering electrical impulses to regulate the rhythms of the heart . Pacemakers fall into different categories, such as the antiachycardia pacemaker which controls tachycardia (rapid heartbeat), the atrial asynchronous pacemaker which is used to stimulate the atrium at a specific rate, and many others.

Author: Rebecca Millar

Rebecca is a freelance PR and Communications Specialist, Author, Science Writer, and Star Trek fan with a fondness for caffeine and all things geek. When she's not getting her comms specialist on, she's usually introverting Trekkie style, studying her Masters in Astronomy, or at her local fire brigade where she volunteers as a firefighter.

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