By Ashley Braun, MPH, RD 

 Medically reviewed by Richard N. Fogoros, MD

Congestive heart failure (CHF), also simply called heart failure, is a chronic condition in which the heart progressively becomes weaker and less efficient at pumping blood around the body. Heart failure impacts about 6.5 million people in the United States, and it's one of the most common reasons older adults get admitted to the hospital.1

This article will explore the causes of CHF, how it develops, and possible complications.

KatarzynaBialasiewicz / Getty Images

What Is Pathophysiology?

Pathophysiology is the study of functional changes that happen with a particular disease or condition. This includes the causes of a disease, the consequences of changes that happen due to the disease, and how it affects other diseases the person has at the same time (concomitant, or associated, conditions).

What Is the Pathophysiology of Heart Failure?

Heart failure develops when there are changes to the structure of the heart muscle and it can't pump blood as efficiently as it should. When this happens blood can back up and fluid may build up in the lungs or arms and legs, indicating congestive heart failure.

What Is Ejection Fraction?

The ejection fraction (EF) is a measurement your doctor will use to determine the type of heart failure and to assess the stage of heart disease.

The ejection fraction represents the percentage of blood pumped out of the left ventricle when the heart contracts. When blood leaves the left ventricle, it moves into the aorta to deliver blood loaded with oxygen to the rest of the body.

In a healthy heart, the ejection fraction ranges from around 52%–74%. When the ejection fraction drops below 52%, it’s considered low.2 Your healthcare professional may use your ejection fraction to determine the severity of heart failure.

What Causes Congestive Heart Failure?

CHF usually develops after infections or other conditions weaken the heart muscles. Examples of conditions and risk factors for developing heart failure include:3

• High blood pressure is a condition in which the force of blood against the walls of blood vessels is too high. This condition can lead to other complications like heart disease, stroke, and kidney disease.

• Older adults are more likely to develop heart failure.

• Heart valve problems lead to issues with how blood flows, either limiting the amount that can move forward or allowing blood to flow in the wrong direction. 

• Coronary artery disease is the buildup of plaques in the arteries that cause narrowed blood vessels and problems with blood flow.

• Heart attack, also called myocardial infarction, occurs when part of the heart muscle isn’t getting enough blood. 

• Congenital heart defects are conditions affecting the heart structure and function that are present before a baby is born.

• Arrhythmia, also called an irregular heartbeat, is a problem with how fast or slow your heart is beating. It can also be a problem with an irregular rhythm of beating.

• Uncontrolled diabetes with consistently high blood sugar levels can cause damage to tissues throughout the body, including the heart muscle.

• Thyroid disease, either too much or too little thyroid hormone, can lead to problems with heart function.

• Human immunodeficiency virus (HIV) attacks the immune system and is associated with an increased risk of developing heart failure.

• Infection can damage the heart, especially a few rare types like viral cardiomyopathy.

• Substance use, like heavy alcohol consumption, cigarette smoking, and cocaine use, increase heart failure risk.

Types of Heart Failure

The two types of heart failure include:

• Heart failure with reduced ejection fraction (HFrEF), previously known as systolic heart failure, develops when the ejection fraction is 40% or less.4 A 2020 research review stated about 50% of heart failure cases have a reduced ejection fraction.5 Additional risk factors for HFrEF include male sex, age, cardiomyopathy, and other heart diseases.1

• Heart failure with preserved ejection fraction (HFpEF), previously known as diastolic heart failure, is heart failure in people who don't have a significant change in ejection fraction. Additional risk factors for HFpEF include atrial fibrillation, pulmonary hypertension, high body mass index (BMI), and smoking.1

Another type of heart failure called right-sided heart failure can develop. However, it's a more uncommon condition with different causes and symptoms.

Stages of Heart Failure

CHF is usually an irreversible condition that gets worse over time. The stages of heart failure describe the severity of the conditions. Here are the four stages of heart failure according to the American College of Cardiology:4

• Stage A: People have a high risk for developing heart failure, but there are no symptoms or changes in heart function. People in this category often have one or more conditions that may lead to heart failure.

• Stage B: People with stage B heart failure have changes to the heart function but haven’t experienced symptoms of heart failure. The ejection fraction may be below normal range.

• Stage C: During this stage, people will experience decreased heart function and currently or previously experienced symptoms of heart failure.

• Stage D: In stage D, people experience constant symptoms of heart failure. If they have heart failure with reduced ejection fraction. the ejection fraction will be significantly lower.

Symptoms and Consequences of Heart Failure

Signs and symptoms of heart failure may include:6

• Shortness of breath when lying flat or while moving

• Fatigue

• Weakness

• Irregular heartbeat

• Nausea and vomiting

• Problems focusing

• Cough or wheezing

• Swelling in the abdomen, feet, ankle, or legs (edema)

As heart failure progresses, you may notice it becoming more and more challenging to exercise and complete your normal daily tasks. Even walking across your home may become difficult because of problems moving oxygen through the body.

Concomitant Conditions

Other conditions that often develop alongside heart failure include:

• Kidney disease: Progressive condition in which the kidneys become less effective at filtering out waste products

• Diabetes: A condition causing high blood sugar

• Chronic obstructive pulmonary disease (COPD): A condition that causes problems moving air in the lungs and exchanging oxygen and carbon dioxide

• Obstructive sleep apnea (OSA): Conditions in which air becomes blocked while sleeping, causing short pauses in breath

Summary

Heart failure develops when there is injury to the heart muscle, and it can’t contract effectively to move blood around the body. The damage to the heart may be due to coronary artery disease, high blood pressure, smoking, alcohol, diabetes, infection, or other conditions.

As the heart becomes progressively weaker, a variety of symptoms are seen, including shortness of breath, weakness, fatigue, and edema. Other conditions that commonly occur along with heart failure include diabetes, COPD, sleep apnea, and kidney disease.

Sources

Lee MP, Glynn RJ, Schneeweiss S, et al. Risk factors for heart failure with preserved or reduced ejection fraction among medicare beneficiaries: application of competing risks analysis and gradient boosted model. Clin Epidemiol. 2020;12:607-616. doi:10.2147/CLEP.S253612

Kosaraju A, Goyal A, Grigorova Y, Makaryus AN. Left ventricular ejection fraction. In: StatPearls. StatPearls Publishing; 2021.

Malik A, Brito D, Chhabra L. Congestive heart failure. In: StatPearls. StatPearls Publishing; 2021.

Heidenreich P, Bozkurt B, Aguilar D, et al. 2022 AHA/ACC/HFSA guideline for the management of heart failure. J Am Coll Cardiol. 2022;79(17):e263–e421. doi:10.1016/j.jacc.2021.12.012

Murphy SP, Ibrahim NE, Januzzi JL. Heart failure with reduced ejection fraction: a review. JAMA. 2020;324(5):488-504. doi:10.1001/jama.2020.10262

American Heart Association. Warning signs of heart failure.

By Ashley Braun, MPH, RD
Ashley Braun, MPH, RD, is a registered dietitian and public health professional with over 5 years of experience educating people on health-related topics using evidence-based information. Her experience includes educating on a wide range of conditions, including diabetes, heart disease, HIV, neurological conditions, and more.