In addition to a physical exam, your doctor may use blood tests, x-rays, an ECG test, an echocardiogram, or other tests to diagnose heart failure.

How is heart failure diagnosed?

Early diagnosis is critical to early treatment, which can delay the onset of some symptoms. Your doctor may use a number of the methods listed below to determine if you have heart failure. The results from any or all of these tests help doctors determine the severity of heart failure and how best to treat the condition.

These results can also help doctors rank heart failure symptoms according to the New York Heart Association (NYHA) classification system. Class I refers to mild cases with the fewest symptoms. Class IV refers to severe cases with the most symptoms.

Physical Exam

Your doctor will start with a physical exam, asking you about:

  • Your medical history
  • Any symptoms you may have

Your doctor will also check for:

  • Heart enlargement
  • Irregular heart sounds 
  • Abnormal sounds in the lungs
  • Swelling or tenderness of the liver
  • Water retention

To confirm a heart failure diagnosis, your doctor might order some of the tests described below.

Blood Tests

Laboratory blood tests can show how well your kidneys and other organs are functioning

Chest X-Rays

A chest x-ray can show whether you have an enlarged heart or fluid around your lungs.

Electrocardiogram (ECG)

The electrocardiogram (ECG) can show problems in the way your heart is beating. During an ECG, a number of wires (called leads) are attached to various places on your chest, allowing the doctor to see the electrical pattern of your heartbeat.


This test (also called an echo) uses ultrasound to create images of your heart as it is beating. The echo helps your doctor learn about your:

  • Heart valve function
  • Heart wall thickness
  • Blood flow through the heart

The echocardiogram also provides your doctor with another important heart measurement: ejection fraction (also called EF). Ejection fraction helps doctors gauge heart failure severity because it measures the percent of blood pumped out of the ventricles during each beat. A normal ejection fraction is approximately 50%. A person with heart failure often has an ejection fraction less than 40%.1

Exercise Test

A 6-minute walk test or other exercise test shows how quickly you:

  • Develop symptoms
  • Reach your exercise limit


In a heart (or cardiac) catheterization, is when one or more catheters are inserted into a blood vessel in your leg, with X-ray guidance. Catheterization can help determine the:

  • Extent of coronary artery disease
  • Amount of blood flowing through your blood vessels and heart

Electrophysiology (EP) Study

An electrophysiology (EP) study can show if you are at higher risk for sudden death. The test involves checking how electrical impulses travel through the heart muscle.