Heart Failure

  • Basics

    Congestive heart failure is a condition in which the heart does not pump blood properly. Congestive heart failure occurs when the heart, due to a defect, injury, or disease, is not able to pump enough blood to meet the body's needs. When this happens, body tissues, which depend on the oxygen and nutrients in blood circulated from the heart, no longer receive enough nourishment. As a result, patients experience shortness of breath when climbing stairs and walking quickly, and tire easily. Because the heart's ability to pump blood is reduced, fluid other than blood builds up in the tissues that were being nourished by a constant flow of blood — this causes the tissues to retain fluid and to swell. Also, because the heart is weakened, it cannot prevent excess fluid from backing up in the lungs, which is why patients have difficulty breathing. The “congestive” in congestive heart failure refers to the buildup of fluid in tissues and the lungs.

    Heart failure can occur on the left or right side of the heart, and usually affects either the left or right ventricle Figure 01. Left ventricle failure is more common. When this happens, fluid backs up into the lungs, and, because the pumping action of the heart slows down, fluid builds up throughout the body. In right ventricle failure, blood backs up in the veins, which often leads to swelling in the ankles and legs. Because the functions of the different parts of the heart are interrelated, failure on the left side often results in failure on the right.

    Click to enlarge: The flow of blood through a healthy heart (animation and audio)

    Figure 01. The flow of blood through a healthy heart (animation and audio)

    Heart failure is a chronic disease that develops slowly. Noticeable symptoms may not appear for years, but as the heart gradually loses pumping capacity, it tries to adjust by enlarging, thickening, and beating more often. Blood vessels also begin to narrow, diverting blood away from less important tissues to the major organs of the body. These strategies on the part of the heart hide the problem, and patients may not be aware that they have congestive heart failure until the serious symptoms of chronic fatigue and shortness of breath appear.

    Nearly five million Americans live with congestive heart failure. Congestive heart failure is a growing health problem, and is the most common diagnosis for hospitalized patients aged 65 years and older. Each year 400,000 people learn they have the condition. While most common among older adults, people of any age, including children, can suffer from congestive heart failure. The disease affects men and women in equal numbers. However, prevalence is 25% higher in the African American population than among whites.

    A combination of medications and self-care techniques helps patients live longer and more comfortably.

    Treatment may include surgery to restore blood supply to the heart, or to replace damaged valves. Transplant surgery is considered only as a last resort.

  • Causes

    Damage to the heart muscle from a heart attack or infection prevents the heart from pumping blood efficiently Figure 02. If the heart muscle is damaged by heart diseases such as heart attack (myocardial infarction) or coronary artery disease, the risk of a person developing congestive heart failure increases. Heart damage can also be caused by infections, which can injure either the heart muscle or the valves that connect the chambers within the heart. Chronic alcohol and drug abuse also can damage the heart. Once the heart is injured, congestive heart failure often follows.

    Click to enlarge: What happens during a heart attack

    Figure 02. What happens during a heart attack

    Diseases that make the heart work harder, such as chronically high blood pressure and lung disease, may weaken the heart and lead to congestive heart failure Figure 03. High blood pressure (hypertension) forces the heart to pump harder, eventually causing the chambers of the heart to become larger and weaker. Serious lung disease, such as asthma or emphysema, reduces the amount of oxygen available to the heart, causing the heart to work harder to supply oxygen throughout the body. Diabetes also places an increased strain on the heart, which can lead to congestive heart failure.

    Click to enlarge: Blood pressure chart

    Figure 03. Blood pressure chart

    Heart damage present at birth can cause congestive heart failure. Some people are born with abnormalities in the structure of the heart muscle or valves. Because other parts of the heart compensate for the weakness, the heart overall is damaged, making it more likely that the person will develop congestive heart failure.

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