Congestive Heart Failure
What is it?
Congestive heart failure (CHF) is a serious condition marked by the inability of the heart to pump enough blood to meet the body's oxygen demands. Heart failure can result from either a reduced ability of the heart muscle to contract or from a mechanical problem that limits the ability of the heart's chambers to fill with blood. When weakened, the heart is unable to keep up with the demands placed upon it; blood returns to the heart faster than it can be pumped out so that it gets backed up or congested—hence the name of the disorder.
The heart attempts to compensate in a number of ways. It beats faster and expands somewhat more than usual as it fills with blood, so that when it contracts, more blood is forced out to the body. In addition, the decreased volume of blood reaching the kidneys causes them to stimulate a hormonal cascade (renin-angiotensin system), which results in the retention of sodium and water. These efforts help meet the body's demands in the short term, but they ultimately have deleterious long-term effects. Faster beating allows less time for the heart to refill after contraction, so that less blood ends up being circulated. Also, the extra effort increases the heart muscle's demand for oxygen.
Failure of the left side of the heart (left-sided failure) is more common. It leads to increased pressure in the pulmonary veins in the lungs, which forces fluid into the surrounding microscopic air sacs, or alveoli, that transfer oxygen to the bloodstream. As the alveoli fill with fluid, they no longer function properly, which limits the amount of oxygen available to the body (see Pulmonary Edema for more information) and produces the most characteristic symptoms of congestive heart failure: fatigue and shortness of breath. In right-sided f ailure, the increased pressure in the veins returning blood from the rest of the body combined with the compensatory retention of sodium and water leads to fluid accumulation and swelling in the abdomen, liver, and legs. Often, both left- and right-sided heart failure occur together.
Congestive heart failure should not be confused with a heart attack, which involves sudden tissue death of the heart muscle. Although heart failure may occur suddenly in some cases, gradual loss of function is more common. Fatigue, shortness of breath on exertion, and increased frequency of night-time urination develop and worsen over time. Shortness of breath is often worse when lying down—a condition known as orthopnea—as fluid from the legs pools in the lungs. Elevating the head with pillows eases chest congestion, but in advanced stages the patient may be unable to recline at all without severe breathlessness, and may need to sleep upright in a chair.
CHF occurs most frequently in those over age 60 and is the leading cause of hospitalization and death in that age group. In over 50 percent of cases, sudden death occurs due to a cardiac arrhythmia, or irregular heartbeat. Unfortunately, antiarrhythmic medications may not be effective in controlling arrhythmias caused by CHF.
There is no cure for heart failure, although measures are taken to treat the underlying cause, if possible. Restricted salt intake, and medication are used to ease the strain on the heart and to relieve symptoms. CHF is a serious health risk; for many patients the outlook is uncertain and depends on the extent of the disease and the patient's response to therapy. However, with proper treatment it is possible for many patients to live with CHF and to manage many symptoms effectively. It is important that patients adhere to prescribed treatment regimens; noncompliance with a doctor's recommendations regarding diet or medication increase the risk that the disease will worsen.
What Causes It?
- Coronary artery disease (obstruction of the coronary arteries by atherosclerotic plaque so that heart tissue is starved of oxygen) often leads to a heart attack, which damages the heart muscle and causes CHF (see Coronary Artery Disease and Heart Attack for more information).
- Heart muscle injury due to viral infections (see Myocarditis) or long-term drug or alcohol use(see Cardiomyopathy) may result in CHF.
- Conditions that overwork the heart may lead to CHF. Such conditions include: heart valve defects, high blood pressure, increased levels of thyroid hormones (thyrotoxicosis), and anemia.
- Infiltration of the heart muscle by other tissue, as occurs with amyloidosis (accumulation of a waxy substance), may cause CHF.
- Triggers for CHF to develop in a weakened heart include bacterial or viral infections, pregnancy or childbirth, and physical overexertion.
- Right-sided heart failure most commonly results from left-sided heart failure.
- CHF may result from restricted entry of blood into the heart due to thickening of the tissue surrounding the heart (pericardium), or to accumulation of excessive fibrous tissue in the heart muscle.
Prevention
- Don't smoke.
- Consume no more than two alcoholic beverages a day.
- Eat a healthy, balanced diet low in salt and fat, exercise regularly, and lose weight if you are overweight.
- Adhere to a prescribed treatment program for other forms of heart disease.
Diagnosis
- Patient history and physical examination.
- Chest x-rays.
- Blood and urine tests.
- An electrocardiogram (ECG) may be performed to measure the electrical activity of the heart. ECG abnormalities can indicate rhythm disturbances, heart muscle damage, inadequate blood flow to segments of the heart, and enlargement of the heart muscle. You may be given a portable ECG device, known as a Holter monitor, to measure the heart's electrical activity over a 24-hour period.
- Exercise stress testing, in which blood pressure, heart rate, ECG, and oxygen consumption rates are measured while you walk on a treadmill.
- An echocardiogram, which uses sound waves to produce images of the heart, may be performed.
- A coronary angiography may be performed to evaluate narrowings of the coronary arteries. In this procedure a tiny catheter is inserted into an artery in a leg or arm and threaded up to the coronary arteries. A contrast material is then injected, which provides a clear image of the blood vessels on x-ray.
How to Treat It
- Your doctor will advise you to reduce your salt intake (salt contributes to fluid retention andswelling) and to eat smaller, more frequent meals (less effort is required to digest smaller portions).
- Caffeine, which may exacerbate heartbeat irregularities, should be avoided.
- Vasodilators, such as hydralazine or ACE inhibitors (for example, captopril and enalapril), may be prescribed to dilate blood vessels, thus reducing blood pressure and easing blood flow.
- Spironolactone, a potassium-sparing diuretic, may be prescribed; in studies, it has been shown to substantially reduce symptoms of CHF, as well as hospitalizations for CHF and overall mortality in patients with severe CHF.
- Various other types of diuretics, such as hydrochlorothiazide, metolazone, furosemide, orbumetanide, may be prescribed to help eliminate excess fluid from body tissues.
- Digoxin may be prescribed to strengthen contractions of the heart muscle (in the United States digoxin is the most commonly prescribed type of digitalis).
- The addition of a beta-blocker, such as carvedilol, to standard drug treatment for CHF has been shown to reduce both overall mortality and hospitalizations in CHF patients.
- Special elastic support stockings that reduce swelling in the legs may be prescribed.
- In severe cases it may be necessary to administer oxygen through a nasal tube. Mechanical devices for administration of oxygen are available for home use after the condition has stabilized in the hospital.
- Surgery may be required to repair or replace heart valves or bypass blocked coronary arteries.
- Percutaneous transluminal angioplasty (insertion and then inflation of a small balloon in an obstructed coronary artery via a catheter) may be performed to widen the artery and improve blood flow.
- A heart transplant may be advised if the heart muscle has been badly damaged. The survival rate for this surgery is 80 percent after one year and over 60 percent after four years.
When to Call a Doctor
- Make an appointment with a doctor if you regularly experience fatigue and shortness of breath after mild physical activity.
- Call a doctor if you experience any of the following during treatment for congestive heart failure: fever, rapid or irregular heartbeat, wheezing, severe shortness of breath, or any worsening of the other symptoms of congestive heart failure.
- EMERGENCY Call an ambulance immediately if you experience severe breathlessness.
- EMERGENCY Call an ambulance if you experience crushing chest pain, with or without nausea, vomiting, profuse sweating, breathlessness, weakness, or intense feelings of dread. Such symptoms may indicate a heart attack.