Congestive Heart Failure

Heart failure does not mean the heart has stopped working. Rather, it means that the heart’s pumping power is weaker than normal. With heart failure, blood moves through the heart and body at a slower rate, and pressure in the heart increases. As a result, the heart cannot pump enough oxygen and nutrients to meet the body’s needs. The chambers of the heart respond by stretching to hold more blood to pump through the body or by becoming more stiff and thickened. This helps to keep the blood moving for a short while, but in time, the heart muscle walls weaken and are unable to pump as strongly. As a result, the kidneys often respond by causing the body to retain fluid (water) and sodium. If fluid builds up in the arms, legs, ankles, feet, lungs or other organs, the body becomes congested, and congestive heart failure is the term used to describe the condition.

Heart failure is caused by many conditions that damage the heart muscle, including:

• Coronary artery disease. Coronary artery disease (CAD), a disease of the arteries that supply blood and oxygen to the heart, causes decreased blood flow to the heart muscle. If the arteries become blocked or severely narrowed, the heart becomes starved for oxygen and nutrients.
• Heart attack. A heart attack may occur when a coronary artery becomes suddenly blocked, stopping the flow of blood to the heart muscle and damaging it. All or part of the heart muscle becomes cut off from its supply of oxygen. A heart attack can damage the heart muscle, resulting in a scarred area that does not function properly.
• Cardiomyopathy. Damage to the heart muscle. Causes include artery or blood flow problems, infections, and alcohol and drug abuse.
• Conditions that overwork the heart. Conditions including high blood pressure (hypertension), heart valve disease, thyroid disease, kidney disease, diabetes or heart defects present at birth can all cause heart failure. In addition, heart failure can occur when several diseases or conditions are present at once.

Systolic dysfunction (or systolic heart failure) occurs when the heart muscle doesn’t contract with enough force, so there is less oxygen-rich blood that is pumped throughout the body.

Diastolic dysfunction (or diastolic heart failure) occurs when the heart contracts normally, but the ventricle – the main pumping chamber — does not relax properly, reducing the amount of blood that can enter the heart.

A test called the ejection fraction (EF) is used measure how well your heart pumps with each beat to help determine if systolic or diastolic dysfunction is present. The ejection fraction is a measure of the percentage of blood that your heart pumps out with each beat. Your doctor can discuss which condition you have.

In patients with systolic heart failure, the ejection fraction is less than 40%. Imaging studies such as X-ray and an echocardiogram (heart ultrasound) show the heart is enlarged and pumps out less than a normal amount of blood with each beat.

In contrast, patients with diastolic heart failure usually have a normal ejection fraction, normal heart pumping capability, but the imaging studies show that the heart does not fill up with blood properly during the heart relaxation phase that occurs between beats.

In 2001, the American Heart Association (AHA) and American College of Cardiology (ACC) developed the “Stages of Heart Failure.” These stages, which were updated in 2005, will help you understand that heart failure is often a progressive condition and can worsen over time. They will also help you understand why a new medication was added to your treatment plan and may help you understand why lifestyle changes and other treatments are needed.

The stages classified by the AHA and ACC are different than the New York Heart Association (NYHA) clinical classifications of heart failure that rank patients as class I-II-III-IV, according to the degree of symptoms or functional limits. Ask your doctor what stage of heart failure you are in.