An Overview of the Heart Failure Classification Systems

After being diagnosed with heart failure, healthcare professionals must classify the person's degree of heart failure. Classifying a person's heart failure can be difficult because the condition affects each person differently due to risk factors and underlying issues that can complicate heart failure.

Determining the category of heart failure using the heart failure classification system allows healthcare professionals to develop individualized treatment plans.

doctor listening to a patient's heart

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What Is Heart Failure?

The heart's pumping ability is measured by the ejection fraction. Using percentages, the ejection fraction is a measure of the amount of blood pumped out of the heart with each heartbeat. A normal ejection fraction is 55% to 70%.

Heart failure occurs when the heart cannot pump enough blood to meet the body's needs. Essentially, the demands of the body exceed the heart's pumping ability. The heart then attempts to meet the body's needs by developing several compensatory mechanisms:

  • Stretching or enlarging: Stretching allows the heart to fill with more blood, which it can then pump to meet the body's demands. Eventually, the heart struggles to maintain the larger size, and its ability to pump blood declines.
  • Developing more muscle mass: Initially, this allows the heart to pump more blood. But, over time, the heart cannot sustain the increase in muscle mass, and its ability to pump blood lessens.
  • Pumping faster: Increasing your heart rate lets the heart pump more blood, at least initially. Over time, the heart cannot keep up with the higher pace and eventually pumps more slowly.

As the heart's compensatory mechanisms begin to fail, the ejection fraction drops. Lower percentages indicate heart failure, and the lower the percentage, the worse the condition. Depending on the heart failure classification system used, ejection fraction can be a major determining factor in classifying a person's stage of heart failure.

Heart Failure Classification Systems

The most commonly used heart failure classification systems are the New York Heart Association Functional Classification and the American College of Cardiology/American Heart Association Classification.

New York Heart Association Functional Classification

The New York Heart Association Functional Classification system focuses on categorizing people with heart failure based on their doctor's objective assessment of the impact the condition has on their day-to-day activities:

  • Class I: There is no objective evidence of cardiovascular disease, and there are no symptoms or limitations with ordinary physical activity.
  • Class II: There is slight objective evidence of cardiovascular disease, you are comfortable at rest, and light physical activity induces mild symptoms of heart failure.
  • Class III: There is objective evidence of moderately severe cardiovascular disease, and you are only comfortable at rest. Even less than normal physical activity results in limitations due to heart failure symptoms.
  • Class IV: There is objective evidence of severe cardiovascular disease, and you have symptoms of heart failure even at rest. There are severe limitations with physical activity due to the severity of your heart failure symptoms.

American College of Cardiology/American Heart Association Classification

The American College of Cardiology/American Heart Association classification of heart failure stages focus more on the condition's structural impact on the heart, such as the measurement of ejection fraction:

  • Stage A: You do not have any structural disorder of the heart, but are at high risk for developing congestive heart failure due to a family history of heart failure or a personal history of hypertension, diabetes, coronary artery disease, alcohol abuse, viral infections, or use of drugs that are toxic to the heart.
  • Stage B: You have a structural disorder of the heart and an ejection fraction of 40% or less, but no symptoms of heart failure.
  • Stage C: You have a structural disorder of the heart and you have currently or previously displayed symptoms of heart failure.
  • Stage D: People in this final stage of heart failure do not get better with treatment.

Treatments for Every Heart Failure Stage

Heart failure cannot be reversed. Treatment aims at keeping people with heart failure at their current stage or slowing disease progression:

  • Stage A: Primary treatment is focused on preventing heart failure. Eating a healthy diet and participating in regular exercise can keep the heart healthy. If you have been diagnosed with medical conditions that can lead to heart failure, such as high blood pressure, diabetes, or high cholesterol, following the treatment plan developed by your doctor and scheduling routine visits can also prevent heart failure.
  • Stage B: Stage A practices are still important in Stage B. Additionally, a healthcare professional may prescribe medications to prevent the heart from developing compensatory mechanisms that ultimately cause more problems. Your treatment plan may also involve cardiac surgery to remove blockages or correct structural abnormalities.
  • Stage C: This stage incorporates all of the Stage A and Stage B treatments. Additional therapies in Stage C include medications to target specific symptoms of heart failure, diet restrictions, and possible heart surgery to help the heart pump more effectively.
  • Stage D: In this stage, people with heart failure require specialized treatments, such as continuous infusions of medication through IV to optimize the heart's pumping ability, or heart surgery to implant a device to take over the mechanical pumping of the heart. People at this stage may be considered for a heart transplant or possible hospice and palliative care.

Managing Heart Failure

A diagnosis of heart failure does not mean a person has to stop their daily activities. While some activities may need to be avoided if heart failure symptoms worsen, it is possible to prevent or slow down the progression of heart failure.

It is possible to continue to enjoy life by following these basic lifestyle and treatment options:

  • Eat a healthy, balance diet
  • Stay active
  • Manage other conditions that can worsen heart failure over time, like high blood pressure or diabetes
  • Call your doctor if your heart failure symptoms worsen or new symptoms appear

A Word From Verywell

Whether you are at risk for developing heart failure or have been diagnosed with heart failure, it is important that you establish regular care with a healthcare professional. There are several organizations like the American Heart Association, that provide support, education, and resources to help you learn more about your condition, and know what type of questions to ask your doctor.

Frequently Asked Questions

  • Are there different heart failure classification systems used in the U.S.?

    Yes. The New York Heart Association Functional Classification system is based on both patient symptoms with physical activity and a healthcare professional's objective assessment. Another one is the American College of Cardiology/American Heart Association Classification, which focuses on heart failure's impact to the structure of the heart.

  • How is mild heart failure categorized?

    The New York Heart Association Functional Classification and American College of Cardiology/American Heart Association Classification systems do not specify "mild" as a category. In the New York Heart Association Functional Classification system, Class I and II could be considered mild heart failure since there are no apparent symptoms in either of these classes. In the American College of Cardiology/American Heart Association Classification, Stages A and B could be considered mild heart failure.

  • Is there a universal heart failure classification system?

    The American College of Cardiology is attempting to address the lack of a universal heart failure classification system. In 2021, the American College of Cardiology's Universal Definition and Classification of Heart Failure consensus included members from the Heart Failure Society of America, the Heart Failure Association of the European Society of Cardiology, and the Japanese Heart Failure Society.


    Individuals from 14 countries across continents worked to create this new universal consensus definition, which will allow healthcare professionals to better collaborate with people with heart failure on treatment plans. The 2021 Universal Definition and Classification of Heart Failure also changes the focus from heart failure to heart function, which can profoundly impact how people with heart failure can optimize personal heart health and minimize heart failure's impact on daily living.

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5 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. American Heart Association.  What is heart failure? Updated May 31, 2017.

  3. Bozkurt B, Hershberger RE, Butler J, et al. 2021 ACC/AHA key data elements and definitions for heart failure: a report of the american college of cardiology/american heart association task force on clinical data standards. Circ Cardiovasc Qual Outcomes. 2021;14(4):e000102. doi:10.1161/HCQ.0000000000000102

  4. American Heart Association. Classes of heart failure. Updated May 31, 2017.

  5. American College of Cardiology. Universal definition and classification of heart failure: a step in the right direction from failure to function. Updated July 13, 2021.