What Are the Stages of Heart Failure?

The term “heart failure” is a bit misleading, and it can be scary to hear. Heart failure (HF for short) means that your heart is not pumping blood through your body as well as it should. It does not mean that your heart has completely failed or stopped working altogether. With HF, you may experience symptoms such as fatigue, shortness of breath, or rapid heartbeat.¹

HF can result from several different heart conditions. Depending on its cause, HF will likely progress over time. After diagnosing you with HF, your doctor may assign the disease a stage and/or class. Both stage and class indicate how well your heart is still working. Stage and class are similar, but they assess heart function in slightly different ways.²

HF stages

The American Heart Association and the American College of Cardiology identify 4 stages of HF. The stages begin before HF has been detected.^3,4

Stage A – At risk for HF

People in stage A do not yet have heart failure, but they are at risk of developing it. They likely have 1 or more of the known risk factors for HF. These risk factors include:^3,4

• High blood pressure (hypertension)
• Vascular disease (disease of the blood vessels)
• Diabetes
• Obesity
• History of alcohol use disorder
• Previous drug treatment that could affect the heart

Stage B – Pre-HF

People in stage B do not feel symptoms of HF. But their doctor has found 1 of the following:^3,4

• Changes or irregularities in the structure of their heart
• Increased pressure inside the heart as it fills
• Increases in certain proteins in the blood that can indicate damage or irregular function of the heart
• Other irregularities in the way their heart works

Stage C – Symptomatic HF

People in stage C of HF meet the criteria for stage B and have begun to experience symptoms. At this stage, symptoms are typically manageable through treatment according to current HF guidelines. Symptoms might come and go depending on the level of activity. Possible symptoms include:^1,3,4

• Fatigue
• Shortness of breath
• Swelling in the legs or feet
• Fast or irregular heartbeat
• Limited ability to exercise
• Chest pain
• Swollen or bloated belly

Stage D – Advanced HF

Stage D is the most severe stage of HF. In this stage, people have symptoms that interfere with their daily lives and may experience these symptoms even at rest. These symptoms do not improve with treatment. People in this stage may require repeated hospitalization despite treatment.^3-5

HF classes

Another way your doctor might note the progression of your HF is by assigning it a class. Doctors often begin assigning people a class once their HF has reached stage C.³

The most commonly used classification system for HF was created by the New York Heart Association. It lists 4 classes based on how severe symptoms are during physical activity:^2,3,6

• Class 1 – People with class 1 HF have a diagnosis of heart disease but no limitations on physical activity. Ordinary activity does not cause typical HF symptoms.
• Class 2 – People with class 2 HF have a diagnosis of heart disease and slight limitations on physical activity. Symptoms of HF occur with ordinary activity but not when the person is at rest.
• Class 3 – People with class 3 HF have significant limitations on physical activity. They still may have no symptoms at rest, but symptoms develop with only mild physical activity. It may be hard to complete regular daily tasks.
• Class 4 – People with class 4 HF cannot engage in any physical activity without having symptoms. They also experience symptoms when they are at rest.

Measuring heart function with LVEF

Along with assigning your HF a stage or class, your doctor may measure how well your heart is pumping blood with a test of your left ventricular ejection fraction (LVEF). The left ventricle is the chamber of the heart that pumps oxygen-rich blood from the heart into the rest of the body. LVEF is a measurement of the amount of blood that leaves your heart with every beat.⁷

Your doctor can measure your LVEF with a variety of tests, including an echocardiogram, MRI scan, or computed tomography scan (CT scan). LVEF measurements are reported in percentages:⁷

• About 50 to 70 percent is considered a normal LVEF. People with HF but normal LVEF are considered to have HF with preserved ejection fraction (HFpEF)
• About 41 to 49 percent is considered mildly reduced LVEF, known as HF with mildly reduced ejection fraction (HFmrEF)
• Less than 40 percent is considered reduced LVEF, known as HF with reduced ejection fraction (HFrEF)

If your LVEF is under 50 percent, your heart may not be functioning as well as it should. Even if your LVEF is above 50, your heart may not be completely healthy. It is important to differentiate between different levels of heart function, as your treatment options may differ depending on whether you have HFpEF, HFmrEF, or HFrEf. Your doctor will use the information they have gathered, including health history, stage, class, and LVEF, to determine the best treatment plan for you.^4-7

The goal of treatment is to slow your progression through the stages or classes of HF and to reduce the impact of HF symptoms on your day-to-day activities. You may even be able to reverse your HF by successfully treating its underlying cause.^2,4