Cardiomyopathy is a disease of the heat muscle and has many different types.
Dilated, Hypertrophic, and Restrictive are the three main types of cardiomyopathy. Each of these types have different causes, signs and symptoms, and treatments. In cardiomyopathy, the heart muscle can become enlarge, thick, or rigid, and in some rare incidents the muscle tissue can become replaced with scar tissue. As the condition worsens, the heart becomes weaker and less able to pump blood throughout the body. The heart will also become unable to maintain a normal electrical rhythm. Results from cardiomyopathy can lead to heart failure or irregular heartbeats called arrthymias (American Heart Association, 2016).
Dilated cardiomyopathy is the most common type of cardiomyopathy, occurring in adults between the ages of 20-60. It affects more of the male population then the female population. Dilated cardiomyopathy affects the heart’s lower (ventricles) and upper (atria) chambers of the heart. The disease starts in the left ventricle (heart’s main pumping chamber).
As the chamber dilates, the heart muscle doesn’t contract normally and can’t pump blood very well. The inside of the chamber enlarges and the problem often spreads to the right ventricle and then to the atria (Elliot. 2000). Signs and symptoms of dilated cardiomyopathy• Systemic embolism ( blood clot in arterial circulation)• Pulmonary congestion (excess fluid in the lungs)• Low cardiac output• Fatigue for many months or years• Intercurrent illness• Development of arrhythmias• Genetics• Sudden death (Elliot, 2000)Myocarditis an inflammation of the heart muscle is known to be a cause of dilated cardiomyopathy. A carnitine and calcium deficiency can also lead to dilated cardiomyopathy. Excessive alcohol and drug use such as Anthracyclines have been linked to the cause of dilated cardiomyopathy.
Anomalous coronary arteries, a malformation of coronary vessels and arteriovenous malformations, a congenial disorder of blood vessels in the brain are some other known causes. X linked diseases such as Becker’s and Duchene’s muscular dystrophies are linked to dilated cardiomyopathy as well as mitochondrial mutations. Becker’s muscular dystrophy is an x linked recessive inherited disorder in which the leg and pelvis muscle slowly weakens. Duchene’s muscular dystrophy is a severe form that is caused by an x linked genetic defect that prevents the production of dystrophin, a normal protein found in muscles. Most cases of dilated cardiomyopathy are idiopathic (Elliot, 2000).
Diagnosis for dilated cardiomyopathy starts with an assessment of the patient’s family history, specially paying attention to a history of muscular dystrophy, mitochondrial diseases (epilepsy), and signs/symptoms of other inherited diseases. A complete drug history is also essential, both in the administration of drugs that are toxic to the heart and the use of illegal drugs such as cocaine. An ECG in patients with dilated cardiomyopathy could be remarkably normal, but abnormalities in an isolated T wave to septal changes to Q wave can show up with patients who have extensive left ventricular fibrosis, prolonged AV conductions, and bundle branch block may be seen. 20%-30% of patients have non-sustained ventricular tachycardia and a small percent present with sustained ventricular tachycardia.
Metabolic exercise testing may be able to provide diagnostic information in patients with ventricular impairment by detecting a severe state of low blood pH (Elliot, 2000). There is no specific treatment for dilated cardiomyopathy. The primary aim of treatment is to control the symptoms, prevent disease progression, and prevent complications of progressive heart failure, sudden death, and obstruction of blood vessels by a blood clot. Warfin is used to treat patients with moderate ventricular dilation.
Partial left ventriculectomy is performed to reduce the left ventricular size by removing a portion of its circumference to reduce stress on the wall and to improve ventricular blood flow (Elliot, 2000). Hypertrophic cardiomyopathy (HCM) is a primary disease of the muscle of the heart in which a portion of the heart muscle is thickened without any obvious cause. The thickening of the heart muscle creates functional impairment and can make it harder for the heart to pump blood. This type of cardiomyopathy is the leading cause of sudden death in young athletes. HCM can often go undiagnosed because most people have few, if any symptoms and can lead normal lives with no significant problems. However, a small number of people with a thickened heat muscle may experience shortness of breath, chest discomfort, fainting, dizziness, palpitations, and extreme fatigue.
HCM is caused by a gene mutation and appears in 50% of people of any generation. The mutated gene influences certain proteins that are part of the heart muscle (Maron, 2002). Hypertrophic cardiomyopathy is usually identified by an echocardiogram that produces ultrasound images of the thickened wall of the heart muscle. HCM is most prominent in the wall separating the left and right ventricle (ventricular septum).
Echocardiograms may also show partial obstruction of blood flow from the left ventricle into the aorta, caused by forward motion of the mitral valve and whether there is abnormal leakage through the mitral valve. Atrial fibrillation occurs frequently in HCM and accounts for the high numbers of unexpected hospitalizations. A-fib in older patients can cause heart failure and stroke, so anticoagulants may be recommended (Maron, 2002). Implantable cardioverter-defibrillator (ICD) is the most reliable and effective treatment for hypertrophic cardiomyopathy patients at high-risk. ICD has the potential to alter the course of the disease by automatically sensing and terminating lethal disturbances of heart rhythm, often in young people with little to no symptoms. If blood flow obstruction is detected, then a septal myectomy operation is recommended.
A surgeon removes a small amount of muscle from the upper part of the septum. Treatment options are more limited to patients who have severe symptoms and these patients may become candidates for a heart transplant. Sudden death occurs in young patients who are athletes due to vigorous exertion (Maron, 2002). Restrictive cardiomyopathy (RCM) is a rare form of heart muscle disease that is characterized by restrictive filling of the hearts ventricles.
The squeezing (contractile) function of the heart and wall thickness are usually normal, but the relaxation or filling phase of the heart is very abnormal. The lower walls of the heart become abnormally rigid and lack the flexibility to expand and to fill with blood. RCM is found mostly in children ages 5-6 years old and mostly in girls. There is no known cause (Goldstein, 2014).
Signs and Symptoms of RCM• Repeated lung infections• Appearance of an enlarged heart• Fluid in abdomen• Enlarged liver• Edema• Abnormal heart sound• Signs of heart failure• Fainting• Sudden death (Goldstein, 2014). Diagnosis for restrictive cardiomyopathy is very difficult to establish and is only made after certain symptoms become present such as decreased exercise tolerance, a gallop heart sound, syncope (fainting), or chest pain during exercise. Once suspected, certain test are performed to help confirm a diagnosis. An ECG can be most helpful by showing abnormalities of the atria.
Cardiac catheterization is used to confirm a diagnosis of RCM, a catheter is slowly advanced through an artery or vein into the heart, while the doctor is watching it on a TV monitor, so the pressure in the hearts chambers can be measured. These measurements show significant elevated pressure during the relaxation period of the heart. In rare cases a cardiac biopsy may be performed to look for potential causes of RCM (Goldstein, 2014). Currently there is no “cure” for restrictive cardiomyopathy. Treatment is used to improve the symptoms of RCM.
Diuretics, sometimes called water pills, can be taken to reduce excess fluid in the lungs and other organs by increasing urine production. Beta-blockers can be also given to slow the heartbeat and increase relaxation time of the heart. This can allow the heart to fill better with blood before each heart beat and decrease some of the symptoms created by stiff pumping chambers. Heart transplantation is the only effective surgery offered for patients with RCM, particularly those who already have symptoms at the time of diagnosis or have reactive pulmonary hypertension (Goldstein, 2014).
Prognosis for cardiomyopathy is based on the different types. For dilated cardiomyopathy the prognosis is poor. 50% of patients die within 2 years of diagnosis and 25% survive longer than five years with treatment. The common cause of death for dilated cardiomyopathy is progressive heart failure and arrthymia. The overall annual mortality rate for hypertrophic cardiomyopathy is 3-5% in adult and at least 6% in children.
Severity of disease and prognosis varies according to the genetic features associated with HCM. Restrictive cardiomyopathy has a very poor prognosis with patients dying within a year of the diagnosis even with treatment (Oakley, 1997).
