How Is Heart Failure Diagnosed?

There is not a specific test to determine if you have heart failure. A clinical diagnosis of heart failure is usually made when symptoms appear. The symptoms—shortness of breath, tiredness, and fluid buildup—are common in other conditions.

Your doctor will determine if you have heart failure by performing a detailed medical history, a physical exam, and several tests. The purpose of these is to:

• Identify the presence of diseases and conditions that can cause heart failure
• Rule out other causes of your symptoms
• Determine the amount of damage to and the pumping capability of your heart

Medical and Family History

Your doctor will ask if you or others in your family have or have had any of the diseases and conditions that can cause heart failure. Your doctor will also ask about your symptoms. This includes the types of symptoms, when they occur, how long you have had them, and their severity. The answers will help your doctor determine the limits on your ability to perform daily activities.

Physical Examination

Your doctor will:

• Listen to your heart for abnormal sounds
• Listen to your lungs for the buildup of fluid
• Look for swelling in your ankles, feet, legs, and abdomen
• Look for swelling in the veins in the neck

Tests

If you have signs and symptoms of heart failure, your doctor may order the following tests:

• EKG (electrocardiogram). This test is used to measure the rate and regularity of your heartbeat. It may show if you have had a heart attack or if there is thickening of the walls in your heart’s pumping chambers (ventricles).
• Chest x ray. A chest x ray takes a picture of your heart and lungs. It can show if your heart is enlarged, if you have fluid in your lungs, or if you have lung disease.
• BNP blood test. This new test checks the level of a hormone called BNP (B-type natriuretic peptide) that rises in heart failure.

If your doctor suspects heart failure after asking about your medical and family history and performing a physical exam and initial tests (such as tests of kidney function), he or she may refer you to a cardiologist. A cardiologist is a doctor who specializes in the diagnosis and treatment of heart disease. The cardiologist will perform a physical exam and order additional tests.

An echocardiogram is the most useful test for diagnosing heart failure. This test uses sound waves to create a moving picture of your heart. Echocardiogram provides information about the size and shape of your heart and how well your heart chambers and valves are functioning. The test also can identify areas of poor blood flow to the heart, areas of heart muscle that are not contracting normally, and previous injury to the heart muscle caused by poor blood flow.

There are several different types of echocardiograms, including a stress echocardiogram. During this test, an echocardiogram is done both before and after your heart is stressed either by having you exercise or by injecting a medicine into your bloodstream that makes your heart beat faster and work harder. A stress echocardiogram is usually done to find out if you have decreased blood flow to your heart (coronary artery disease).

The cardiologist may order any of the following tests. These tests can help identify the cause of your heart failure:

• Holter monitor (ambulatory electrocardiography, EKG). For this test, a small box called a Holter monitor is attached to patches (electrodes) that are placed on your chest. The box may be carried in a pouch around your neck or attached to your belt. The Holter monitor is usually worn for 24 hours and provides a continuous recording of heart rhythm during normal activity.
• Nuclear heart scan. This test provides your doctor with moving pictures of the blood passing through your heart's chambers and arteries and shows the level of blood flood to the heart muscle. A small amount of a radioactive tracer is injected into your bloodstream through a vein, usually in your arm. A special camera is placed in front of your chest to show where the tracer lights up in healthy heart muscle and where it doesn't light up (in heart muscle that has been damaged or has a blocked artery).
• There are different types of nuclear heart scans. Most scans have two phases—taking pictures of the heart at rest and while it is beating faster (called a stress test), although sometimes only a rest scan is done. Many heart problems show up more clearly when your heart is stressed than when it is at rest. By comparing the nuclear heart scan of your heart at rest to your heart at "stress," your doctor can determine if your heart is functioning normally or not.
• Cardiac catheterization (KATH-e-ter-i-ZA-shun). A thin, flexible tube is passed through an artery at the top of the leg (groin) or in the arm to reach the coronary arteries. This allows your doctor to study the inside of your arteries to see if there is any blockage. Your doctor can check the pressure and blood flow in the heart's chambers, collect blood samples from the heart, and examine the arteries of the heart by x ray.
• Coronary angiography. This test is usually performed along with cardiac catheterization. A dye that can be seen by x ray is injected into the coronary arteries. Your doctor can see the flow of blood to the heart muscle. Dye can also be injected into the chambers of the heart to evaluate the pumping function of your heart.
• Stress Test. Some heart problems are easier to diagnose when your heart is working harder and beating faster than when it's at rest. During stress testing, you exercise (or are given medicine if you are unable to exercise) to make your heart work harder and beat faster while heart tests are performed.
• During exercise stress testing, your blood pressure and EKG readings are monitored while you walk or run on a treadmill or pedal a bicycle. Other heart tests, such as nuclear heart scanning or echocardiography, also can be done at the same time. These would be ordered if your doctor needs more information than the exercise stress test can provide about how well your heart is working.
• If you are unable to exercise, a medicine can be injected through an intravenous line (IV) into your bloodstream to make your heart work harder and beat faster, as if you are exercising on a treadmill or bicycle. Nuclear heart scanning or echocardiography is then usually done.
• During nuclear heart scanning, radioactive tracer is injected into your bloodstream, and a special camera shows the flow of blood through your heart and arteries. Echocardiography uses sound waves to show blood flow through the chambers and valves of your heart and to show the strength of your heart muscle.
• Your doctor also may order two newer tests along with stress testing if more information is needed about how well your heart works. These new tests are magnetic resonance imaging (MRI) and positron emission tomography (PET) scanning of the heart. MRI shows detailed images of the structures and beating of your heart, which may help your doctor better assess if parts of your heart are weak or damaged. PET scanning shows the level of chemical activity in different areas of your heart. This can help your doctor determine if enough blood is flowing to the areas of your heart. A PET scan can show decreased blood flow caused by disease or damaged muscles that may not be detected by other scanning methods.
• Thyroid functions tests. These are common procedures done to find out how well the thyroid is functioning. They include blood tests, various imaging procedures, and stimulating thyroid function. These tests are very important because both an overactive and an underactive thyroid can be the main or a contributing cause of heart failure.