Congestive Heart Failure
Congestive heart failure (CHF) is a condition in which the heart is unable to pump an adequate amount of blood to the lungs and the rest of the body. CHF is often the result of failure to treat previously existing heart problems. It can be related to a variety of diseases and conditions, such as a heart attack, coronary artery disease, high blood pressure, heart valve defects, congenital (present from birth) heart disease, anemia, cardiomyopathy (degenerative disease of the heart muscle), or arrhythmia. All of these problems can cause the heart to pump inefﬁciently. When the heart cannot do its job, the body becomes overloaded with water and sodium, causing ﬂuid backup and swelling in the lungs, liver, and legs and, eventually, fatigue, dizziness, and low blood pressure. If not treated, CHF can be fatal.
About 5 million Americans have congestive heart failure. Each year there are an estimated 400,000 new cases. Incidence of this chronic condition is reaching epidemic proportions in the United States. CHF is the most common health problem in hospital patients over age 65. Congestive heart failure affects equal numbers of men and women, and about a fourth of the 5 million people who have this condition are under age 60. CHF occurs in about 2 percent of Ameri- cans ages 40 to 59; in about 5 percent of Americans ages 60 to 69; and in about 10 percent of Americans age 70 or older. African Americans have a 25 percent greater chance than whites of developing CHF.
Symptoms of congestive heart failure include:
• shortness of breath, especially on exertion or while lying down
• swelling in the ankles and lower legs
• sudden large weight gain (20 pounds or more) due to ﬂuid retention
• frequent urination at night
Heart failure affects either the left ventricle (called left-sided failure) or the right ventricle (called right-sided failure). In left-sided failure, the left ventricle must work harder to pump the same amount of blood throughout the body. This increased workload may cause the left ventricle to enlarge, the ventricle walls to thicken, and the heart rate to increase. These changes temporarily allow the heart to pump more blood, but gradually they lead to heart failure.
As the left side of the heart fails, the left ventricle does not completely empty of blood with each contraction. The retained blood creates back pressure on the lungs, causing them to become congested with blood. This in turn causes pul- monary edema (excess ﬂuid in the lungs), which leads to breathing difﬁculties.
In right-sided heart failure, there is back pressure in the circulation from the heart into the veins. This is often caused by pulmonary hypertension (raised pressure and resistance to blood ﬂow through the lungs), which leads to dis- tended (enlarged) neck veins, enlarged liver, and edema (ﬂuid retention and swelling) in the tissues.
Your doctor may perform echocardiography (an ultrasound examination of the heart) to determine the overall condition of your heart. You also may undergo an exercise stress test (see page 212) to evaluate how well your heart functions. Other diagnostic tests also may be performed to evaluate blood ﬂow through the heart and to eliminate chronic lung disease as a possible cause of your symptoms.
Treatment for congestive heart failure includes dietary restrictions. Your doc- tor probably will recommend that you avoid caffeine, consume less sodium (salt), and eat smaller, more frequent meals. He or she also will advise you to decrease your level of physical activity to reduce the demands on your heart. Your doctor probably will prescribe a combination of three types of medications to strengthen the heartbeat and reduce the size of the heart (digitalis drugs), improve blood ﬂow (vasodilators such as ACE inhibitors), and eliminate excess ﬂuids and sodium from the body (diuretics). For people who have heart failure, beta-blockers are used to improve their symptoms and to prolong their life.
Once the heart failure has stabilized, attention is shifted to treating the under- lying cause or causes of this condition. High blood pressure (see page 217) and arrhythmias (see page 230) usually are treated with medication. Heart valve defects, congenital heart defects, and coronary obstructions are corrected with surgery. When the cause of CHF is a long-term disease, such as emphysema (see page 247), the outlook is generally not as good. In severe cases of congestive heart failure, a heart transplant may be performed.
Studies are ongoing to better understand how the heart contracts normally and what goes wrong in CHF, to ﬁnd new drug therapies and other innovative treat- ments, and to ﬁnd better ways to detect the condition. Another approach is to develop devices to help a damaged heart function better. For example, a small mechanical pump called a left ventricular assist device (LVAD) can temporarily help the heart pump blood in people with severe CHF who are awaiting a heart transplant. After months of use, an LVAD often improves heart function in these people—so much so that a transplant is no longer needed. Efforts are under way to identify patients who may beneﬁt from using a longer-term LVAD.