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What Is Heart Failure?

Heart failure (HF) is a complex syndrome with physiological signs and symptoms that develop when the heart is not functioning properly. A heart failure diagnosis, according to established guidelines, is based on several criteria including the presence of symptoms and evidence of cardiac dysfunction on diagnostic tests, and/or a favorable response to treatment.1

The term heart failure doesn’t mean your heart has stopped beating. It is a condition in which the heart is unable to pump enough blood through the body. HF generally describes people with established chronic heart failure which develops slowly. It can be caused by coronary artery disease, heart attack, or high blood pressure. Congestive heart failure can affect people of all ages, from infants to children, and adults. It is most common in people over age 65.2-4

Congestive heart failure

Congestive heart failure (CHF) is another name for chronic heart failure. CHF is a condition that exists when the heart cannot fill properly or pump blood forward, causing fluid to build up in the tissues of the body, resulting in congestion or swelling. The predominant symptom of heart failure is congestion.3,4

When the heart muscle is weak or has a defect, blood cannot circulate normally. As circulation slows, the blood making the return trip to the heart can back up or pool. Congestion then develops in the tissues of the body. Other typical symptoms are shortness of breath and fatigue. Not everyone with HF will have congestion, some people only experience fatigue and decreased physical activity tolerance. People who develop congestion may have swelling in the ankles and legs, abdomen, or lungs.

Shortness of breath and pulmonary edema, swelling in the lungs, can cause breathing difficulties, leading to respiratory distress if not treated. Heart failure can also affect the kidneys’ ability to process and eliminate sodium and water, resulting in additional fluid retention and subsequent swelling.3

Heart attack or cardiac arrest?

A heart attack is different from cardiac arrest. A heart attack is a problem with the plumbing and cardiac arrest is an electrical problem.5

Heart attack

A heart attack happens when the flow of blood through the arteries that brings oxygen to the heart muscle is severely restricted or completely blocked. If the blood supply gets cut off it can damage the tissues of the heart, causing some of it to die and weaken its ability to effectively pump blood.6

A heart attack is also known as a myocardial infarction or type 1 heart attack. This means there is an interruption of blood supply to a part of the heart muscle, causing damage or death to the affected heart tissue. It is caused by a blockage or clot which obstructs the artery.5 The blockage is typically made up of fatty deposits, cholesterol, and other substances which together form plaque. When the plaque breaks off it can form a clot, blocking the blood flow through the arteries and resulting in a heart attack.5,7

Most people are conscious when they have a heart attack able to call for emergency help and to describe their symptoms.8

Cardiac arrest

Cardiac arrest happens when the heart’s electrical system malfunctions.5 It can be caused by heart failure, a clot in the lungs, a severe imbalance of minerals in the blood, a drug overdose, or a severe blow to the chest.5 During cardiac arrest, the heart stops pumping blood through the body and there is an immediate loss of heart function, breathing, and consciousness.5,9

Cardiac arrest can lead to death. CPR, cardiopulmonary resuscitation, using a defibrillator or chest compressions, can improve a person’s chances of survival until emergency services arrive. CPR is only performed on someone in cardiac arrest.9 A heart attack can cause a disruption to the heart’s rhythm, creating an electrical disturbance, which can result in a cardiac arrest; but this is not common.9

Whether you or someone you are with is having a heart attack or are in cardiac arrest, always call 911 and seek emergency care.

Written by: Linda Minton | Last reviewed: November 2019
  1. Mosterd A, Hoes AW. Clinical epidemiology of heart failure. Heart. 2007;93:1137-1146.
  2. NCI Dictionary of Cancer Terms. National Cancer Institute Available at : https://www.cancer.gov/publications/dictionaries/cancer-terms/def/chronic-heart-failure. 8.24.19
  3. What is Heart Failure. American Heart Association. Available at: https://www.heart.org/en/health-topics/heart-failure/what-is-heart-failure. Accessed 10/19/19.
  4. Congestive Heart Failure and Congenital Defects. American Heart Association. Available at: https://www.heart.org/en/health-topics/congenital-heart-defects/the-impact-of-congenital-heart-defects/congestive-heart-failure-and-congenital-defects. Accessed 10/19/19.
  5. Heart attack versus cardiac arrest. Harvard Health. Available at: https://www.health.harvard.edu/blog/the-difference-between-a-heart-attack-and-cardiac-arrest-2018042613711. Accessed 10/20/19.
  6. Atherosclerosis. American Heart Association. Available at: https://www.heart.org/en/health-topics/cholesterol/about-cholesterol/atherosclerosis, Accessed 10/19/19.
  7. Heart Attack. Mayo Clinic. Available at: https://www.mayoclinic.org/diseases-conditions/heart-attack/symptoms-causes/syc-20373106. Accessed 10/21/19.
  8. Heart Attack (Myocardial Infarction) Cleveland Clinic. Available at: https://my.clevelandclinic.org/health/diseases/16818-heart-attack-myocardial-infarction. Accessed 10/21/19.
  9. Sudden Cardiac Arrest. Mayo Clinic. Available at: https://www.mayoclinic.org/diseases-conditions/sudden-cardiac-arrest/symptoms-causes/syc-20350634. Accessed 10/21/19.