Damaged heart muscle, leading to enlargement of the heart
- More common over the age of 45
- More common in males
- Alcohol abuse increases the risk
- Genetics is not a significant factor
Healthy heart muscle is vital for the heart to pump blood effectively. In dilated cardiomyopathy, the muscular walls of the heart become damaged. The weakened muscle then stretches, making the heart larger. This weakening and the enlargement of the heart muscle reduce the heart’s pumping action, leading to chronic heart failure. In some cases, dilated cardiomyopathy is caused by alcohol abuse. It may also be due to an autoimmune disorder, in which the body attacks its own tissues, or it may occur after a viral illness or after treatment with some anticancer drugs. Often, the underlying cause is not found.
The symptoms of dilated cardiomyopathy are similar to those of chronic heart failure. Therefore, before making a diagnosis of dilated cardiomyopathy, your doctor may wish to carry out tests that exclude other disorders that cause heart failure, such as coronary artery disease and heart valve disorders. Dilated cardiomyopathy is more common over the age of 45 and in men.
What are the symptoms?
In many mild cases, there are no symptoms. If symptoms do occur, they usually develop gradually over a number of years and may include:
Shortness of breath during exertion.
Palpitations (awareness of an irregular or abnormally rapid heartbeat).
Swelling of the ankles.
As the disorder progresses the heart’s pumping efficiency decreases and symptoms, such as shortness of breath, worsen. The heart enlargement may stretch the valves, causing them to become leaky, and may eventually lead to the development of chronic heart failure or an abnormal heart rhythm (see Arrhythmias). If the chambers in the heart cannot empty fully because they are too large, a blood clot can form, which may break off and block a vessel elsewhere in the body.
How is it diagnosed?
Diagnosis involves a number of tests, many of which are used to exclude other possible causes of your symptoms, such as coronary artery disease. You may have an ECG to monitor the heart’s electrical activity and echocardiography to image the interior of the heart. You may also have a chest X-ray to detect enlargement of the heart. Coronary angiography is used to exclude coronary artery disease. To evaluate valve function, a cardiac catheter may be passed from an artery into the heart to measure blood pressure inside it. If you have palpitations, an ECG may be carried out over a 24-hour period to monitor your heartbeat while you carry out your normal daily activities (see Ambulatory ECG).
What is the treatment?
If the cause of dilated cardiomyopathy is unknown, no specific treatment can be given. If alcohol abuse is the cause, you must stop drinking. Symptoms of heart failure may be relieved by drugs such as digoxin (see Digitalis drugs) to improve the function of the heart, diuretic drugs to remove excess fluid, and beta-blockers and ACE inhibitors, which may help to prevent deterioration. You may also have drugs that prevent blood clotting. However, if heart failure worsens in spite of drug treatment, a heart transplant may be considered. Without a transplant, only about 3 in 10 people with dilated cardiomyopathy survive for more than 5 years.
From the 2010 revision of the Complete Home Medical Guide © Dorling Kindersley Limited.
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