The Medical Definition of Congestive Heart Failure

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Congestive heart failure (CHF) is a progressively worsening condition in which the heart becomes weak and congested. Other heart conditions, such as coronary artery disease, untreated high blood pressure, or a history of heart attack, contribute to the development of CHF.

It typically affects people who are over age 65. When you have CHF—the heart continues to work, but it is unable to pump blood sufficiently to meet the demands of the body.

Symptoms of Congestive Heart Failure

Theresa Chiechi / Verywell

What Is Congestive Heart Failure?

CHF usually develops over a long period of time. The course and symptoms of heart failure depend on which regions of the heart are affected. 

CHF can lead to severe complications, and the condition requires ongoing medical treatment.

Types of CHF include:

CHF can also be caused by heart failure with preserved ejection fraction. Heart failure on one side of the heart predisposes to heart failure on the other side, so it is common to have both types.

Classes of Congestive Heart Failure

There are several ways that CHF has been classified. healthcare providers usually identify each stage of heart failure according to the severity of symptoms. 

The New York Heart Association (NYHA) Functional Classification defines class I through IV based on limitations in physical functioning.

The categories are outlined below.

Classes of Heart Failure
Class I No limitation of physical activity. Ordinary physical activity does not cause undue fatigue, palpitation, dyspnea (shortness of breath).
Class II Slight limitation of physical activity. Comfortable at rest. Ordinary physical activity results in fatigue, palpitation, dyspnea (shortness of breath).
Class III Marked limitation of physical activity. Comfortable at rest. Less than ordinary activity causes fatigue, palpitation, or dyspnea.
Class IV Unable to carry on any physical activity without discomfort. Symptoms of heart failure at rest. If any physical activity is undertaken, discomfort increases.

Heart failure generally worsens, and it is not possible to reverse it or go to a less advanced stage. Treatment can help prevent progression.

Symptoms of Congestive Heart Failure

The severity and duration of heart failure symptoms depend on several factors, including the type and class of heart failure.

Some of the most common symptoms include:

  • Shortness of breath: This may be more prominent with exertion or when lying down. Shortness of breath with exertion occurs due to insufficient blood supply to the body's cells and tissues with left heart failure. Shortness of breath when lying down can develop when fluid congestion backs up in the lungs due to right heart failure. 
  • Dizziness, confusion, trouble concentrating, and/or fainting: This can occur with even a mild deficiency of oxygen-rich blood flow to the brain.
  • Fatigue: Inadequate supply of oxygen-rich blood to the body's organs and muscles leads to fatigue.
  • Diminished ability to exercise: Due to fatigue and shortness of breath.
  • Nocturia (waking up during the night to urinate): This is caused by an excess of blood flowing through the kidneys when lying down at night. When the kidneys make more urine, it causes an increase in urination.
  • Edema (swelling): Typically affecting the ankles, feet, lower legs, and abdomen, due to backup of blood to the right side of the heart with right-sided heart failure.
  • Rapid or irregular heartbeats (also called palpitations): With inefficient heart-pumping action, the heart may intermittently speed up. 
  • A dry, hacking cough: This is caused by pulmonary edema (fluid in the lungs).

It is important to note that symptoms of CHF may wax and wane. If your symptoms improve, you should continue to follow your CHF treatment plan.

Diagnosis of Congestive Heart Failure

If you have symptoms of CHF, your healthcare provider will consider your diagnosis based on a review of your symptoms, a physical examination, blood tests, imaging tests, and other diagnostics designed to measure heart function.

If you have CHF, it will be classified to direct the appropriate course of treatment.

A Word From Verywell

Receiving a CHF diagnosis can be overwhelming. Remember, you can live well with CHF for many years. Find support from family and friends. The more they understand your condition, the better they can help you achieve your therapy goals. Try asking your healthcare provider for a referral to a support group in your area or connect with others online through the American Heart Association Support Network.

4 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.
  1. National Cancer Institute. CHF.

  2. American Heart Association. Classes of heart failure.

  3. Cleveland Clinic. Understanding heart failure.

  4. Cleveland Clinic. Understanding heart failure.

By Sherry Christiansen
Sherry Christiansen is a medical writer with a healthcare background. She has worked in the hospital setting and collaborated on Alzheimer's research.