How Heart Failure Is Diagnosed

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Symptoms of heart failure (such as shortness of breath and swelling) can mimic those of other health issues. It's important to bring such concerns to your doctor's attention, so they can determine whether heart failure or another condition is the cause. 

A heart failure diagnosis is usually made based on your medical history, a physical examination, and heart function tests, primarily electrocardiogram (EKG) and echocardiogram (echo). Brain natriuretic peptide (BNP) measurement has gained attention because it can be done using a blood test. It can be used with an EKG and an echo to piece together a diagnosis of heart failure.

heart failure diagnosis



Recognizing the signs and symptoms of heart failure can help you get tested and receive the medical attention you need early in the course of the illness before your condition worsens. These can be subtle at first and may progress slowly, so it is easy to ignore them or simply chalk them up to aging.

Knowing this, be sure to bring any of these concerns to your doctor's attention:

  • Shortness of breath: This can occur with mild to moderate exertion, when walking, lying down, bending over, or sleeping. You may repeatedly become short of breath even when you are not exercising.
  • Fatigue: You may become easily tired, even when you haven't done anything that should be exhausting.
  • Edema: You may experience swelling or a puffy appearance of your feet or hands; usually, it's not painful or uncomfortable. If you apply pressure to the area and it becomes indented, remaining so for a few seconds or minutes (called pitting), it may indeed be a result of heart failure, rather than weight gain or unrelated fluid retention.

Also tell your doctor if you experience the following symptoms along with those above:

  • Confusion or memory loss
  • Coughing or wheezing, especially at night
  • Dizziness or fainting
  • Nausea or lack of appetite
  • Racing heartbeat or palpitations
  • Swelling in your abdomen
  • Weight gain or loss

Physical Examination

Your doctor will first assess your symptoms and ask how long you've had them. They'll also ask about your medical history and risk factors, particularly whether you've had any heart conditions, such as high blood pressure (hypertension), heart valve problems, an arrhythmia, or a heart attack.

They'll ask what medications you take and determine if you have any lifestyle factors that can affect your heart, such as smoking, heavy drinking, or a poor diet. Your weight and blood pressure will be checked.

Then, your doctor will listen to your heart and lungs using a stethoscope (this is called auscultation). Normally, you should have a pattern of two heart sounds with every heartbeat. Heart failure often causes a third heart sound. Your lungs may sound congested on your lung examination if you have heart failure.

If you have edema, the doctor may also check for pitting. They may look to see if there is clubbing in your fingers or if your nails are pale.

If you initially saw your primary care doctor, you might get a referral to a cardiologist for further testing.

Labs and Tests

If you have the signs and symptoms of heart failure, and your doctor suspects the condition, they may run some tests to confirm a diagnosis.


The most common test used to assess heart function, an EKG is a non-invasive test that involves placing electrodes on the surface of the chest to measure the electrical activity of the heart. If you have any symptoms of heart disease, your doctor is highly likely to order an EKG for you.

A visual representation (or tracing) of that activity is produced on a piece of paper or on a computer. Abnormal patterns on EKG, including the presence of Q waves, left bundle branch block, ST depression, left ventricular hypertrophy, and arrhythmias, are seen in heart failure.

B-Type Natriuretic Peptide (BNP) Test

This is the most common blood test used for heart failure. BNP, a protein hormone, is released into the blood circulation by heart muscle cells whenever the organ's internal pressure becomes too high. BNP causes the kidneys to excrete salt and water and reduces blood pressure to bring things back to normal.

In healthy people, BNP levels are usually below 125 picograms per milliliter (pg/ml), and levels above 450 pg/ml are associated with heart failure. BNP levels between 100 pg/ml and 400 pg/ml are difficult to interpret, which is why this test is not considered diagnostic of heart failure, just supportive of it. It is a reliable test, but sometimes the interpretation may be in a gray zone.

Other Blood Tests

Some other blood tests can help contribute to the diagnosis and rule out other conditions. Tests that are typically ordered include electrolyte levels, cholesterol, glucose, blood counts, and tests to check thyroid, liver, and kidney function.

Heart Failure Doctor Discussion Guide

Get our printable guide for your next doctor's appointment to help you ask the right questions.

Doctor Discussion Guide Old Man


Imaging tests can be helpful in visualizing anatomical and functional changes in the heart, as well as some changes in the lungs, which can differentiate heart failure from other cardiac and pulmonary problems. Several options may be considered.


A chest X-ray is a relatively quick imaging test that is often very helpful in diagnosing heart disease. Your chest X-ray may show that your heart appears enlarged or may show signs of congestion in your lungs if you have heart failure. If your doctor is concerned about lung or heart problems, it is likely that you will have a chest X-ray.


An echocardiogram, often referred to as an echo, is a non-invasive ultrasound test that visualizes the heart while it is in action. A small probe is placed on your chest, which a technician will move to capture the action of your heart valves and chambers as your heart naturally cycles. Your echo can provide a great deal of information about your heart function.

In the setting of heart failure specifically, the thickness of your heart muscle, the filling and emptying of each chamber, and the heart rhythm are expected to be abnormal. Your doctor may order an echocardiogram for you if you have a heart rhythm abnormality or a possible heart muscle abnormality. 

Nuclear Imaging

These imaging tests, including positron emission test (PET) and single photon emission computerized tomography (SPECT), involve the injection of radioactive dyes. The heart will either take up or not take up these radioactive particles depending on how the heart muscle is functioning.

These color changes can help your doctor detect if certain muscles of your heart are not able to pump as they normally would. PET and SPECT are both used to assist in the diagnosis of heart conditions, including CAD and heart failure.

Stress Test

A stress test uses controlled exercise to uncover cardiac problems that may be brought out by exertion. It is particularly useful in evaluating angina (chest pain) caused by coronary artery disease.

Your doctor may consider a stress test if you have symptoms that are worse with exertion. Often, people with advanced heart failure cannot tolerate a stress test, but it may also identify early heart failure.

Differential Diagnosis

If you have symptoms of heart failure, your medical team may consider other conditions that also cause shortness of breath or swelling of the extremities. Most of the time, there are diagnostic tests that can differentiate between these conditions and heart failure. However, the diagnosis can become more complicated if you have heart failure as well as another medical condition.

Chronic obstructive pulmonary disease (COPD): This condition causes shortness of breath, which is worse with exertion. COPD also causes wheezing and a cough that usually is associated with mucus. While some of the symptoms are similar to those of heart failure, COPD can be distinguished from heart failure by characteristic abnormalities on pulmonary function tests. COPD generally is caused by smoking and requires treatment with oxygen in late stages.

Pulmonary embolus (PE): A PE, a blood clot in one of the blood vessels of the lungs, causes breathing difficulties and chest pain. The characteristics of these symptoms often differ between a PE and heart failure and can provide clues as to their cause. However, diagnostic testing is usually required to make the correct diagnosis.

Kidney failure: Kidney failure, like heart failure, can take time to develop, causing progressively worsening symptoms. When kidneys do not function as they should, fatigue and edema of the legs and arms can develop, similar to heart failure. In general, kidney failure causes a change in electrolyte levels in the blood, which is not seen in heart failure.

Deep vein thrombosis (DVT): A DVT is a blood clot that often causes edema and may eventually cause a PE. A big difference between the edema of DVT and that of heart failure is that in DVT, the edema usually involves only one leg and it is not typically pitting. A DVT may cause a weak pulse in the affected limb and can be diagnosed with an ultrasound of the leg.

Frequently Asked Questions

  • What does heart failure feel like?

    In the beginning you may not feel any different, but as the condition progresses you'll begin to feel unusually tired and be short of breath (known as dyspnea) even after normal activity. You may also feel pain in your chest and experience heart palpitations (fluttering, throbbing, or other odd sensations). These symptoms will become more pronounced over time, so that eventually you'll notice them even when you're resting.

  • What is the prognosis after being diagnosed with heart failure?

    Typically not very good if there's not an underlying cause that can be treated. The five-year survival rate for people hospitalized for heart failure is around 35%.

  • Is heart failure the same as a heart attack?

    No. Heart failure is a chronic condition in which the heart loses the ability to pump blood properly. A heart attack, also known as myocardial infarction, is a singular event caused by a blockage in an artery that supplies blood to the heart. Having a heart attack can lead to heart failure.

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Article Sources
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