What is dilated cardiomyopathy? — Dilated cardiomyopathy is a condition in which the heart muscle weakens and one or more of the spaces inside the heart (called “chambers”) gets bigger (figure 1). When this happens, the heart sometimes becomes unable to pump blood as well as it should. This can lead to a problem called “heart failure.”

The term “heart failure” is misleading. If your doctor tells you that you have heart failure, it does not mean your heart has stopped working. It just means that your heart has trouble keeping up with your body’s demand for blood and oxygen (which is carried in the blood). But it is still working.

What are the symptoms of dilated cardiomyopathy? — At first, dilated cardiomyopathy often does not cause symptoms. But as the condition gets worse, it can cause:

  • Trouble breathing, especially during exercise
  • Trouble breathing when lying down or asleep
  • Trouble doing physical activity or exercise
  • Swelling in the feet, ankles, or legs

Is there a test for dilated cardiomyopathy? — Yes. If your doctor or nurse suspects you have cardiomyopathy, he or she might order one or more of these tests:

  • A chest X-ray – An X-ray can show if your heart is enlarged.
  • An electrocardiogram (ECG or EKG) — This test measures the electrical activity in your heart. It can show if your heart beats in a normal rhythm and if you have had a heart attack in the past. Some people wear a device all day that takes an ECG reading (figure 2).
  • An echocardiogram (or “echo” for short) — An echo uses sound waves to create an image of the heart. This test allows doctors to measure the walls and chambers of the heart, see how the heart is pumping, and see how the heart valves are working. (Heart valves are flaps of tissue that open and close like swinging doors. They help keep blood flowing in one direction.)
  • A stress test — During a stress test, you might be asked to run or walk on a treadmill while you also have an ECG. Physical activity increases the heart’s need for blood. This test helps doctors see if the heart is getting enough blood. If you cannot walk or run, your doctor might do this test by giving you a medicine to make your blood vessels widen or make your heart pump faster.
  • Cardiac catheterization — Cardiac (heart) catheterization is also known as cardiac “cath.” During this test, the doctor inserts a thin tube (called a catheter) into a large artery in your leg and threads it up to your heart. The doctor uses this tube to measure the pressure inside your arteries and heart. The doctor might also inject a dye into your arteries that shows up on an X-ray. This part of the test is called “coronary angiography.” Coronary angiography can show whether any of the arteries in your heart are clogged. In some cases, the doctor will also take a tiny piece of heart muscle (a “biopsy”). This can help the doctor find the cause of your cardiomyopathy.

How is dilated cardiomyopathy treated? — Treatment for dilated cardiomyopathy depends on what is causing it and how severe it is. For example, in people who have cardiomyopathy caused by alcohol use, an important part of treatment is avoiding alcohol. If dilated cardiomyopathy is causing heart failure, the treatment is generally similar to that for other causes of heart failure.