Congestive Heart Failure
Congestive heart failure
Congestive heart failure (CHF) is a chronic, progressive condition in which the heart gradually becomes unable to pump enough blood to meet the needs of the body. This can result in failure of other organs and death . CHF is the leading cause of hospitalizations of people over age 65.
The heart is a muscle containing four compartments or chambers that separate oxygen-poor blood from oxygen-rich blood. The atria are the top chambers. They receive blood from the body. The ventricles are the bottom chambers. They pump blood out to the body. Oxygen-poor blood enters the right atrium, then moves through a valve to the right ventricle. It is then pumped out of the right ventricle to the lungs where it picks up oxygen. The oxygen-rich blood returns to the left atrium of the heart, flows through a valve to the left ventricle, and is then pumped out to the body. This sequence occurs with every heartbeat. The timing of the contraction of each chamber of the heart must be tightly coordinated in order for each chamber empty efficiently and completely.
In CHF, the heart fails to pump enough blood to meet the needs of other organs in the body. This failure occurs for one of two reasons. In systolic heart failure (systole is the period when the heart contracts), disease weakens the wall of the ventricles, so that they pump less forcefully. In response, the heart muscle stretches to create larger chambers in the ventricles. This compensates for the heart's reduced pumping ability, but over time, the heart wall thickens, the chambers narrow, and the heart pumps out less and less blood. The volume of blood pumped out of the ventricle is called the ejection fraction (EF). In a healthy heart, the EF is greater than 50%, while in people with CHF, it is less than 50% and can be as low as 30%. Systolic heart failure is the most common kind of CHF.
In diastolic heart failure (diastole is the period when the heart relaxes and re-fills with blood), the heart is not weakened, but it becomes stiff. After each contraction, it does not relax enough to fill completely. The EF is normal (over 50%), but with less blood in the ventricle, the absolute amount of blood pumped is decreased. Diastolic heart failure is most common among people over age 75.
When the left side of the heart begins to fail, fluids collect in the lungs causing lung congestion (pulmonary edema ) and difficulty breathing. When the right side of the heart begins to fail, fluid collects in the feet and legs causing swelling. CHF is often complicated by other health problems such as coronary artery disease, diabetes, high blood pressure , alcoholism, emphysema , chronic obstructive pulmonary disease (COPD), and renal (kidney) disease.
About 5 million Americans have CHF, with about 500,000 new cases diagnosed each year. Most people with CHF are elderly. Only 1% of people under age 50 are diagnosed with CHF, but it is found in about 5% of people over age 75 and 25% of people over age 80. Men ages 40–75 are more likely to have CHF than women, but after age 75, the percentage of men and women with CHF is about equal. African Americans are 1.5 times more likely to die of CHF than white Americans. The number of people with CHF is expected to increase as the American population ages.
Causes and symptoms
The end cause of CHF is failure of the heart to pump enough blood, but many other conditions can contribute to or accelerate this failure. These include heart damage caused by disease and lifestyle. Some common conditions contributing to CHF that make the heart work harder and can increase the risk of CHF include:
- coronary artery disease
- prolonged, uncontrolled high blood pressure (hypertension)
- previous heart attack (myocardial infarction)
- heart valve abnormalities
- prolonged heart arrhythmias
- infection of the heart muscle or surrounding tissue (endocarditis)
- damage to the heart muscle from alcohol, cocaine, or other substance abuse
- congenital (present at birth) heart defects
- diabetes, particularly poorly controlled diabetes
Symptoms of CHF usually begin gradually and initially may go unnoticed. The exception is after a heart attack , when moderate-to-severe symptoms can develop rather rapidly. CHF symptoms are similar to those caused by many diseases, making diagnosis more difficult. Often symptoms are complicated by other diseases in the elderly such as diabetes, emphysema or other lung diseases, and reduced kidney function.
The first symptom usually noticed is shortness of breath when performing normal activities such as walking, cleaning the house, or doing easy yard work, along with general fatigue. Symptoms then progress to include:
- shortness of breath and difficulty breathing even at rest
- fluid retention and swelling of the feet and legs
- weakness and extreme fatigue
- dizziness from not enough oxygen reaching the brain
- fast and/or irregular heartbeat
Diagnosis begins with a complete physical examination and a health, medication, and lifestyle history. The following tests are used to make a diagnosis of CHF:
- chest x ray: non-invasive test shows if fluid is building up in the lungs or if the heart is enlarged.
- electrocardiogram (ECG): non-invasive test helps detect abnormalities in heart rhythm and heart health by measuring the electrical activity of the heart
- blood tests: check for anemia (low iron) and chemical (electrolyte) imbalances in the blood.
- kidney function tests: help pinpoint the cause of fluid retention
- B-type natriuetic peptide (BNP) test: measures the hormone BNP, which is produced in greater quantity when the heart begins to fail
- echocardiogram: non-invasive imaging test that produces a picture of the heart in motion as it beats; extremely helpful in showing heart and valve damage.
- multiple-gated acquisition (MUGA) scan: imaging test that uses radioactive dye injected in the veins to produce a picture of blood circulation in the heart
- stress test: an electrocardiogram done while exercising or, for people who cannot exercise, while the heart is stimulated by medication
The degree or stage of CHF can be designated using several different scales. The two most common are the New York Heart Association (NYHA) scale that uses a numbered system (I-IV) that classifies CHF by symptoms and functional limits and the American College of Cardiology (ACC) scale that use a letter system (A-D) to designate risk factors for CHF.
Treatment does not cure CHF, but it can slow its progression, extend life, and to some degree improve symptoms. Treatment of CHF falls into three cate-gories: lifestyle changes, drug therapy, and surgery.
Self-care lifestyle changes that help slow the progression of CHF include:
- reducing sodium (salt) in the diet
- eating a heart-healthy diet high in fresh fruits, fresh vegetables and whole grains and low in fats, especially saturated (animal) fats.
- controlling calorie intake and losing weight if overweight or obese
- quitting smoking l avoiding alcohol
- exercising moderately (e.g., walking) or joining a cardiac rehabilitation program
- treating any other health problems or underlying diseases
- elevating the feet when sitting to discourage fluid accumulation
- taking all medicines as prescribed
- weighing daily to check for sudden spikes in fluid retention
- scheduling regular examinations with a healthcare provider
Many drugs are available to treat CHF. People with CHF often need more than one drug to control or slow symptoms. The development of new drugs to treat CHF is an area of active research because of the aging population of many developed countries.
Some common drugs used to treat CHF include:
- angiotensin converting enzyme (ACE) inhibitors. These drugs block the formation of angiotensin, a hormone that may adversely affect the heart. ACE inhibitors include captopril (Capoten), enalapril (Vasotec), lisinopril (Zestril, Prinvil), benazepril (Lotensin), and ramipril (Altace).
- angiotensin receptor blockers. These drugs also block the formation of angiotensin using a different mechanism than ACE inhibitors. They are generally less effective than ACE inhibitors and are given to people who do not tolerate ACE-inhibiting drugs. Examples include losartan (Cozzar), candesartan (Atacand), telmisartan (Micardis), valsartan (Diovan), and irbesartan (Avapro).
- beta-blockers. These drugs block the effect of stimulant hormones such as epinephrine (adrenalin) and norepinephrine (noradrenaline). Carvedilol (Coreg) is approved by the United Sates Food and Drug Administration (FDA) for this use, although other beta-blockers are sometimes prescribed as off-label use.
- digoxin (Lanoxin). This is one of the oldest treatments for CHF. It is a natural compound found in the plant foxglove Digitalis purpurea.
- diuretics. These drugs help rid the body of excess fluid by increasing urine production. Common diuretics include furosemide (Lasix), bumetanide (Bumex), torsemide (Demadex), metolazone (Zaroxolyn), spironolactone (Aldactone), and hydrochlorothiazide.
- hydralazine (Apresoline). A large study showed that this drug benefited African Americans but conferred no benefit on people of other races. Research is ongoing.
There are also drugs that a CHF patient should avoid because they worsen CHF or interfere with treatment drugs. These include nonsteroidal anti-inflammatory drugs (e.g., Aleve, Motrin), decongestants (e.g., Sudafed), calcium channel blockers , anti-arrhythmia drugs, growth hormones, antacids that contain sodium , and salt substitutes. Patients with CHF should not take any herbal remedy or dietary supplement without first consulting their healthcare provider. In addition, some drugs used to treat underlying diseases may need to be adjusted because they interfere with drug therapy for CHF.
Surgery does not cure CHF although it can prolong life and improve the quality of life. Surgery can be done to remedy a defect or condition that is contributing to CHF. Examples are heart valve repair and coronary artery surgery to improve blood flow in the heart. Complete heart transplant surgery to treat CHF is severely limited by the number of donor hearts available. It is normally done only on younger patients such as those with congenital heart defects.
Sodium (Na) found in salt promotes water retention in the body. People with CHF need to severely restrict their intake of salt. Salt is found in many processed foods, so that even a “no salt added” diet provides between 4,000–6,000 mg of salt daily. People with CHF need to limit their salt intake to no more than 2,000 mg of salt per day. This requires careful reading of food labels (sodium content is listed in the nutrition panel) and for many, a major change in the foods they eat. Fluid intake is also a concern for people with CHF and is often limited to no more than 8 cups (2 L) of fluids daily from all sources combined.
Studies have found that limited, supervised exercise can benefit people with CHF. An individualized cardiac rehabilitation program can provide an appropriate type and level of exercise.
CHF is a progressive condition; it can be slowed but not cured. Between 30% and 40% of people with CHF are hospitalized every year, and it is a leading cause of death among the elderly. About half the deaths among people with CHF are from progressive heart failure, and the other half are sudden deaths, most often due to severe heart arrhythmias . The average survival time from diagnosis is 3.2 years in men and 5.4 years in women. Nevertheless, survival times vary widely depending on the individual's general health, the treatment they receive, and how well they maintain their lifestyle and drug regimens.
QUESTIONS TO ASK YOUR DOCTOR
- What stage is my CHF?
- Do you recommend that I exercise or join a cardiac rehabilitation program?
- Can you give me information or salt-restricted diets or refer me to a dietitian?
- What kind of changes can I expect to see with the medications you have prescribed for me?
- What changes in symptoms are important enough that I should call you for an immediate appointment?
Prevention activities are the same as the lifestyle changes used to slow the progression of CHF, namely eating a heart-healthy diet, exercising regularly, maintaining a healthy weight, avoiding tobacco products, and limiting alcohol consumption. Treating or controlling any underlying diseases such as diabetes and high blood pressure also are important preventative steps.
Staying on the prescribed drug regimen and making positive lifestyle changes is important in slowing the progression of CHF and improving patient symptoms. People with CHF often take multiple drugs several times a day. Care givers can help their charges achieve maximum benefits from their medications by familiarizing themselves with the required drug regimen and organizing a system that makes it easy for them and their charges to remember to take these medications. A medicine box with separate compartments for several times of day and all the days of the week is helpful. Another part of caring for a person with CHF is organizing a daily weighing in order to determine if fluid retention has suddenly increased. Finally, the care giver must understand and conform to the dietary needs of their charge, with special care paid to the amount of salt in the diet.
Arrhythmia —An abnormal heart rhythm.
Atrium (plural Atria) —The right or left upper chamber of the heart.
Cardiac rehabilitation —A structured program of education and activity offered by hospitals and other organizations.
Coronary artery disease —Also called atherosclerosis, it is a build-up of fatty matter and debris in the coronary artery wall that causes narrowing of the artery.
Echocardiogram —A non-invasive imaging procedure used to create a picture of the heart's movement, valves, and chambers.
Electrocardiogram (ECG) —A noninvasive test records the electrical activity of the heart and is useful is assessing general heart health.
Off-label use —Drugs in the United States are approved by the Food and Drug Administration (FDA) for specific uses based on the results of clinical trials. However, it is legal for physicians to administer these drugs for other “off-label” uses. It is not legal for pharmaceutical companies to advertise drugs for off-label uses.
Stress test —A test that involves an electrocardiogram during rest and exercise to determine how the heart responds to stress.
Ventricle —A lower pumping chambers of the heart. There are two ventricles, right and left. The right ventricle pumps oxygen-poor blood to the lungs to be re-oxygenated. The left ventricle pumps oxygen-rich blood to the body.
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American Heart Association, 7272 Greenville Avenue, Dallas, TX, 75231, (800) 242–8721, http://www.americanheart.org.
National Heart Lung and Blood Institute Health Information Center, P.O. Box 30105, Bethesda, MD, 20824-0105, (301) 592–8573; TTY: (240) 629–3255, (240) 629–3246, [email protected], http://www.nhlbi.nih.gov.
Tish Davidson A. M.