Congestive Heart Failure

  • Diagnosis

    Doctors can often make a preliminary diagnosis of heart failure by medical history and careful physical examination.

    A thorough medical history may identify risks for heart failure that include:

    • High blood pressure
    • Diabetes
    • Abnormal cholesterol levels
    • Heart disease or history of heart attack
    • Thyroid problems
    • Obesity
    • Lifestyle factors (such as smoking, alcohol use, and drug use)

    The following physical signs, along with medical history, strongly suggest heart failure:

    • Enlarged heart
    • Abnormal heart sounds
    • Abnormal sounds in the lungs
    • Swelling or tenderness of the liver
    • Fluid retention in legs and abdomen
    • Elevation of pressure in the veins of the neck

    Laboratory Tests

    Both blood and urine tests are used to check for problems with the liver and kidneys and to detect signs of diabetes. Lab tests can measure:

    • Complete blood counts to check for anemia
    • Kidney function blood and urine tests
    • Sodium, potassium, and other electrolytes
    • Cholesterol and lipid levels
    • Blood sugar (glucose)
    • Thyroid function
    • Brain natriuretic peptide (BNP), a hormone that increases during heart failure. BNP testing can be very helpful in correctly diagnosing heart failure in patients who come to the emergency room complaining of shortness of breath (dyspnea).


    An electrocardiogram (ECG) is a test that measures and records the electrical activity of the heart. It is also called an EKG. An electrocardiogram cannot diagnose heart failure, but it may indicate underlying heart problems. The test is simple and painless to perform. It may be used to diagnose:

    • Previous heart attack
    • Abnormal cardiac rhythms
    • Enlargement of the heart muscle, which may help to determine long-term outlook
    • A finding called a prolonged QT interval may indicate people with heart failure who are at risk for severe complications and therefore need more aggressive therapies.

    A completely normal ECG means that heart failure is unlikely.

    The electrocardiogram (ECG, EKG) is used extensively to diagnose heart disease, from congenital heart disease in infants to myocardial infarction and myocarditis in adults. There are several different types of electrocardiograms.


    The best diagnostic test for heart failure is echocardiography. Echocardiography is a noninvasive test that uses ultrasound to image the heart as it is beating. Cardiac ultrasounds provide the following information:

    • Evaluations of valve function
    • Information about how well the heart is pumping, especially a measurement called left ventricle ejection fraction (LVEF)
    • Type of heart failure
    • Changes in the structure of the heart that may be a result of heart failure

    Doctors use information from the echocardiogram for calculating the ejection fraction (how much blood is pumped out during each heartbeat), which is important for determining the severity of heart failure. Stress echocardiography may be needed if coronary artery disease is suspected.


    Doctors may recommend angiography if they suspect that blockage of the coronary arteries is contributing to heart failure. This procedure is invasive.

    • A thin tube called a catheter is inserted into one of the large arteries in the arm or leg.
    • It is gently guided through the artery until it reaches the heart.
    • The catheter measures internal blood pressure at various locations, giving the doctor a comprehensive picture of the extent and nature of the heart failure.
    • Dye is then injected through the tube into the heart.
    • X-rays called angiograms are taken as the dye moves through the heart and arteries.
    • These images help locate problems in the heart's pumping action or blockage in the arteries.
    Click the icon to see an image of cardiac catheterization.

    Radionuclide Ventriculography. Radionuclide ventriculography is an imaging technique that uses a tiny amount of radioactive material (called a trace element). It is very sensitive in revealing heart enlargement or evidence of fluid accumulation around the heart and lungs. It may be done at the same time as coronary artery angiography. It can help diagnose or exclude the presence of coronary artery disease and helps demonstrate how the heart works during exercise.

    Other Imaging Tests

    Chest x-rays can show whether the heart is enlarged. Computed tomography (CT) and magnetic resonance imaging (MRI) may also be used to evaluate the heart valves and arteries.

    Exercise Stress Test

    The exercise stress test measures heart rate, blood pressure, electrocardiographic changes, and oxygen consumption while a patient is performing physically, usually walking on a treadmill. It can help determine heart failure symptoms. Doctors also use exercise tests to evaluate long-term outlook and the effects of particular treatments. A stress test may be done using echocardiography or may be done as a nuclear stress test (myocardial perfusion imaging).