Getting to the Heart of the Matter: Congestive Heart Failure
Feb 2010
In a normal, healthy heart, blood vessels called veins deliver impure (oxygen-deficient) blood to the right upper and lower chambers of the heart. This blood is then pumped into the lungs by the right lower chamber of the heart. Once in the lungs, the blood is enriched with oxygen and then poured into the heart’s left upper and lower chambers. From there it is pumped by the strong muscle of the left lower chamber to the rest of the body to keep it well nourished and energized. Valves guard each of the exit points of the heart’s chambers to prevent the blood from flowing backwards.
What is Congestive Heart Failure?
Congestive heart failure, simply put, is an inability of the heart to pump enough blood. This, in most cases, is a result of malfunction in the heart’s mechanics. If the heart cannot pump adequate amounts of blood, the blood backs up from the left side of the heart into the lungs and then through the right side of the heart, leaking into the lungs, the gastrointestinal tract (gut) and the legs.
The most common symptom of congestive heart failure is shortness of breath initially noted with low levels of exertion. Symptoms then progress to shortness of breath at rest and then result in an inability to lie down or even sleep. Sometimes the breathing difficulty may come on so suddenly and severely that an individual finds himself or herself gasping for air. Other symptoms may include cough (typically worsening at night or with exercise), chest discomfort, fatigue or lethargy, loss of appetite, leg swelling and a bloating sensation in the abdomen.
Why Does the Heart Fail?
While congestive heart failure is nearly always caused by mechanical failings of the heart, there are several reasons why the heart might fail:
1. Rhythm disturbances of the heart. If the heart rate is too fast, irregular or too slow, the heart pumps less efficiently.
2. Weakness in the heart muscle. Heart muscle weakness can be caused by a heart attack, multiple blockages in the blood vessels of the heart, certain viral infections, diabetes and/or uncontrolled high blood pressure, excessive alcohol use or illicit drug use.
3. Heart valve abnormalities. Leakage of heart valves, especially in the left side of the heart, results in a back flow of blood. The heart must then pump harder to maintain adequate forward blood flow. This ultimately enlarges and weakens the heart muscle, leading to progressive congestive heart failure. If the leakage occurs suddenly, the heart has no time to compensate, and the individual immediately enters a state of congestive heart failure and may begin gasping for air.
Sometimes age or conditions such as high blood pressure, high cholesterol or structural abnormalities may cause the heart muscle to thicken or become too rigid. As a result, the valves do not open freely. As the valve openings narrow, the heart must work harder to push the blood through them. This process can also ultimately cause congestive heart failure.
4. Abnormal relaxation of the heart muscle. When the heart muscle is unable to relax adequately, blood does not flow freely into the heart’s left lower chamber. This can result in congestive heart failure. The two most common causes of abnormal relaxation are uncontrolled high blood pressure and advanced age.
Much less frequently, congestive heart failure can occur in a normal, otherwise healthy heart—when the body develops an abnormally high demand for blood. This can be due to:
• Severe anemia (low red blood cell count)
• Severe and abnormally high activity of the thyroid gland, causing a very high metabolism
• Extremely strenuous exercise to unaccus- tomed levels
• Very high fever and/or severe infections
Any of the above causes of congestive heart failure can coexist. For instance, a valve leakage and a rhythm abnormality can develop in an already weak heart and result in congestive heart failure. Also, if a heart is weak but still functioning adequately, even a modest degree of increase in the demands of the body can cause congestive heart failure.
How is CHF Treated?
The goal of treatment is to improve quality and quantity of life for patients. Several medications are available which can prevent deterioration or even improve the heart’s ability to pump blood. Under appropriate circumstances, surgery can be recommended to improve blood flow to the heart and also to correct valve abnormalities. In some patients, certain types of pacemakers and implantable cardiac defibrillators* (ICDs) can also be useful.
Lifestyle modification is an integral part of treating congestive heart failure. Here are some take-away tips to live by if you are showing early signs of this disease or may be at risk:
• Limit salt intake to less than two grams (2,000 mg) a day.
• Start a regular exercise program under the guidance of a physician.
• Avoid strenuous exercise that your body is not accustomed to. (In other words, don’t be a weekend warrior!)
• Eat sensible, moderately portioned meals.
• Strive to achieve your ideal body weight— this reduces the demands on the heart. (Visit www.cdc.gov/healthyweight/index.html to calculate your current body mass index versus where you need to be.)
• Quit smoking.