Symptoms and Diagnosis of Cardiomyopathy

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It’s important to identify people who may be at high risk for cardiomyopathy. Some people with cardiomyopathy never have signs or symptoms. Others don’t have signs or symptoms in the early stages of the disease.

If people without symptoms recognize their heightened risk for cardiomyopathy, there’s a better chance of diagnosing it early, when treatment may be most effective.

Signs and symptoms of cardiomyopathy include:

  • Shortness of breath or trouble breathing, especially with physical exertion
  • Fatigue or tiredness even after resting
  • Swelling in the ankles, feet, legs, abdomen and veins in the neck
  • Dizziness
  • Fainting
  • Arrhythmias (abnormal heartbeats)
  • Chest pain, especially after physical exertion or heavy meals
  • Heart murmurs (extra or unusual sounds heard with heartbeats)

How is cardiomyopathy diagnosed?

Your health care professional will diagnose cardiomyopathy based on your medical history, family history, a physical exam and diagnostic test results.

A cardiologist or pediatric cardiologist usually diagnoses and treats cardiomyopathy. These doctors specialize in heart diseases.

Medical and family histories

Your health care professional will want to learn about your medical history as well as any signs and symptoms you may have. Your health care professional will also want to know whether anyone in your family has been diagnosed with cardiomyopathy, heart failure or cardiac arrest.

Physical exam

Using a stethoscope, your health care professional will listen to your heart and lungs for sounds that may suggest cardiomyopathy. Particular sounds may even suggest a certain type of the disease.

Certain physical signs also help your doctor diagnose cardiomyopathy. Swelling of the ankles, feet, legs, abdomen or veins in your neck suggests fluid buildup, a sign of heart failure.

Diagnostic tests

One or more of the following tests may be recommended to diagnose cardiomyopathy:

  • Blood tests: A small amount of blood is usually drawn from a vein in your arm using a needle.
  • Chest X-ray: A chest X-ray takes pictures of the organs and structures inside your chest. It can show whether your heart is enlarged or if fluid is building up in your lungs. 
  • Electrocardiogram (EKG or ECG): An EKG records the heart’s electrical activity, showing how fast the heart is beating and whether its rhythm is steady or irregular. An EKG may reveal changes from cardiomyopathy as well as other problems, including heart attacks, arrhythmias (abnormal heartbeats) and heart failure.     
  • Holter and event monitors: Both are portable devices that record your heart’s electrical activity during your normal daily activities. A Holter monitor records the heart’s electrical activity for a 24- or 48-hour period. An event monitor records your heart’s electrical activity only at certain times. You may have to wear this portable monitor to diagnose heart problems that come and go.
  • Echocardiogram (Echo): An echocardiogram is a test that uses sound waves to create a moving picture of your heart. It shows how well your heart is working as well as its size and shape. The types of echocardiography include “stress echo,” which is administered as part of a stress test. Another type, transesophageal echo (or TEE), provides a view of the back of the heart.
  • Stress test: The aim of a stress test is to make your heart work hard (and beat fast) while tests are performed. These tests may include nuclear heart scanning, echo, and positron emission tomography (PET) scanning. You’ll be asked to walk in place on an inclined treadmill. If you're unable to exercise, you may be given medicine to simulate the effects of exertion.

Diagnostic procedures

Confirming a diagnosis may involve one or more medical procedures. If surgery is planned, a diagnostic procedure may be performed in preparation for surgery. Such diagnostic procedures may include:

  • Cardiac catheterization: Cardiac catheterization checks the pressure and blood flow in your heart’s chambers. A long, thin, flexible tube called a catheter is inserted through a blood vessel and threaded to the heart. This allows your health care professional to collect blood samples and check your heart’s arteries for blockages using X-ray imaging.
  • Coronary angiography (PDF): This procedure often is done during cardiac catheterization. Dye that can be seen on an X-ray is injected into your coronary arteries. The dye allows your health care professional to study blood flow or detect blockages within your heart and blood vessels.
  • Myocardial biopsy: In this procedure, which can be done during cardiac catheterization, a small piece of your heart muscle is removed. The muscle is studied under a microscope to see whether cell changes have occurred, which may suggest cardiomyopathy.
  • Genetic testing: Your health care professional may suggest genetic testing to look for signs of cardiomyopathy in your parents, brothers and sisters or other family members. Genetic testing can show how the disease runs in families and can reveal the chances of parents passing the genes for the disease on to their children. Genetic testing may also be useful if it is suspected that you may have cardiomyopathy, but you don’t yet exhibit signs or symptoms.