What is a Heart Failure?
A diagnosis of heart failure sounds scary, as if your heart could stop at any moment. But the underlying heart conditions that commonly cause heart failure, such as coronary artery disease or high blood pressure, typically develop slowly over many years. The development of heart failure usually means that your heart's ability to pump blood has weakened, so it can't circulate enough blood to meet your body's needs. Shortness of breath, fatigue and leg swelling may result. When fluid builds up, heart failure is called congestive. Sometimes the heart becomes too stiff to fill properly, and that also can lead to heart failure.
About five million Americans are living with heart failure, and between 400,000 and 700,000 new cases are diagnosed every year. Heart failure is serious and can be life-threatening. About 250,000 people die annually of heart failure.
Although sometimes there's no way to reverse damage to your heart, treatments can significantly improve signs and symptoms. You can also make lifestyle changes, such as exercising, reducing salt intake, and losing weight, to help your weakened heart work as efficiently as possible.
Your best defense against heart failure is to prevent or control risk factors that lead to coronary artery disease, such as high blood pressure, high cholesterol levels, diabetes, smoking, alcohol abuse, inactivity and obesity.
Signs and symptoms of Heart Failure
Heart failure typically doesn't occur suddenly. It develops slowly, over time. It's usually a chronic, long-term condition. The first and often only symptom may be shortness of breath. Signs and symptoms of heart failure can include:
- Fatigue and weakness
- Shortness of breath (dyspnea) when you exert yourself or when you lie down
- Persistent wheezing or cough with white or pink blood-tinged phlegm
- Pronounced neck veins
- Swelling (edema) in your legs, ankles and feet
- Swelling of your abdomen (ascites)
- Rapid weight gain from fluid retention
- Lack of appetite and nausea
- Difficulty concentrating or decreased alertness
- Irregular or rapid heartbeat
Causes of Heart Failure
Your circulatory system includes arteries and veins. Arteries deliver oxygen-rich blood to the organs and tissues of your body. Veins bring oxygen-poor blood back to your heart to be cycled through your heart and lungs and back out to the rest of your body, via your arteries.
Your heart, the center of your circulatory system, consists of four chambers. Throughout your life, your heart beats approximately once a second. In a single day, your heart beats about 100,000 times. Your heart's two upper chambers, the atria, receive blood. The two lower chambers, the ventricles, pump blood.
Blood returning to your heart enters the right upper chamber (right atrium) of your heart. From there, blood empties into the right ventricle underneath. The right ventricle pumps blood into your lungs, where blood is oxygenated. Oxygenated blood from your lungs then returns to your heart, but this time to the left side â€” to the left upper chamber (left atrium). Blood then flows into the left ventricle underneath â€” your heart's main pumping chamber. With each heartbeat, your left ventricle pumps blood into your body's largest artery (aorta) and onward to the rest of your body.
Heart failure can involve the left side, right side or both sides of your heart. Typically, heart failure begins with the left side â€” specifically the left ventricle, your heart's main pumping chamber. Your doctor may refer to your condition as left-sided or left ventricular heart failure. He or she may define it further as systolic heart failure (when the left ventricle loses its ability to contract vigorously) or diastolic heart failure (when the left ventricle loses its ability to relax or fill fully) or a combination of both. The distinction is important because the drug treatments for each type may be different. Right-sided heart failure can occur independently or be a consequence of left ventricular heart failure.
Heart failure often occurs because other cardiac conditions have damaged or weakened your heart, forcing it to work harder. A weakened heart can't pump blood efficiently throughout your body. This causes blood to pool in your legs, feet and ankles, your kidneys to retain excess water and sodium, and fluid to back up into your lungs, leading to shortness of breath. This buildup of fluid is called congestive heart failure.
Heart failure often results from the stress of a heart attack, high blood pressure, or other forms of heart disease such as valve disorders. In fact, all of the behaviors that you probably associate with heart attack or heart disease â€” such as smoking, being overweight, eating foods high in cholesterol and fat, and not exercising â€” also cause or contribute to heart failure. Sometimes, your heart becomes weakened without explanation, a condition known as idiopathic dilated cardiomyopathy.
If you have heart failure, chances are you've had one or more of the following conditions, which can damage or weaken your heart. Some of these can be present without you even knowing it:
- Coronary artery disease. Coronary artery disease is the most common form of heart disease. Over time, arteries that supply blood to your heart muscle can become narrowed from a buildup of fatty deposits (atherosclerosis). Blood moves more slowly through narrowed arteries. As a result, some areas of your heart muscle may be chronically deprived of oxygen-rich blood. These areas may become weak from the lack of oxygen and pump less vigorously. Sometimes this results in a heart attack with death of heart muscle, but in many cases the blood flow to the muscle is just enough to keep the muscle alive but not functioning well.
- High blood pressure (hypertension). Blood pressure is the force of blood pumped by your heart through your blood vessels. If your blood pressure is high, your heart has to work harder than it should to circulate blood throughout your body. Over time, the heart muscle may enlarge and become thicker to compensate for the extra work it must perform. Eventually your heart muscle may either become too stiff or too weak to effectively pump blood forward.
- Heart attack. Heart failure can be a complication of a heart attack. A heart attack occurs when a blood clot forms in a narrowed coronary artery, blocking blood flow to a portion of your heart muscle and damaging it. The damaged portion of your heart can no longer pump as well as it should. The rest of your heart tries to make up for the loss, but may be unable to or may become weakened by the extra workload.
- Faulty heart valves. The four valves of your heart keep blood flowing in the proper direction through the heart. A damaged valve forces your heart to work harder to keep blood flowing as it should. Over time this extra work can weaken your heart.
- Cardiomyopathy. This is damage to the heart muscle. Some of the many causes of cardiomyopathy include infections, alcohol abuse, and the toxic effect of drugs such as cocaine and some drugs used for chemotherapy. In addition, systemic diseases such as lupus that may affect the body as a whole also can damage heart muscle. In many cases a specific cause can't be determined. This is referred to as idiopathic dilated cardiomyopathy. In some cases cardiomyopathy may be inherited.
- Heart defects present at birth (congenital heart defects). If your heart and its chambers don't form correctly, the healthy parts of your heart have to work harder to compensate. Genetic defects contribute to the risk of certain types of heart disease, which in turn may lead to heart failure.
- Abnormal heart rhythms (heart arrhythmias). Abnormal heart rhythms may cause your heart to beat too fast. This creates extra work for your heart. Over time, this extra work can weaken your heart muscle, producing heart failure. A heartbeat that's too slow also may prevent your heart from adequately circulating blood and lead to heart failure.
Other diseases â€” such as diabetes, severe anemia, hyperthyroidism, kidney or liver failure, and emphysema â€” also may precipitate heart failure.
Screening and diagnosing Heart Failure
In many cases, doctors diagnose heart failure by taking a careful medical history and performing a physical examination. Your doctor will also check for the presence of risk factors such as high blood pressure. Using a stethoscope, your doctor can listen to you breathe and identify the sounds of lung congestion. The stethoscope also picks up the abnormal heart sounds that may indicate heart failure.
In addition to a physical exam, your doctor may recommend any of a variety of tests to diagnose heart failure. Your doctor may refer you to a cardiologist â€” a doctor who specializes in the study of the heart and its function â€” for tests such as:
- Chest X-ray. X-ray images help your doctor see the condition of your lungs and heart. In heart failure, your heart may appear enlarged and fluid accumulation may be visible in your lungs. Your doctor can also use an X-ray to diagnose conditions other than heart failure that may explain your signs and symptoms.
- Electrocardiogram (ECG). This test records the electrical activity of your heart through electrodes attached to your skin. Impulses are recorded as waves displayed on a monitor or printed on paper. This test helps your doctor diagnose heart rhythm problems and damage to your heart from a heart attack that may be underlying heart failure.
- Echocardiogram. An echocardiogram uses sound waves to produce a video image of your heart. This image can help doctors determine the capacity at which your heart is pumping. The percentage of blood pumped out of your heart's main pumping chamber (the left ventricle) with each heartbeat is referred to as the ejection fraction. This percentage can be measured by an echocardiogram or other imaging techniques. In a healthy heart, the ejection fraction is about 60 percent. In someone with systolic heart failure, it's usually 40 percent or less. An echocardiogram also helps distinguish systolic heart failure from diastolic heart failure, in which the pumping function is normal but the heart is stiff.
- Coronary catheterization (angiogram). In this test a thin, flexible tube (catheter) is inserted into a blood vessel at your groin or arm and guided through your main artery, the aorta, into your coronary arteries. A dye injected through the catheter makes the arteries supplying your heart visible on an X-ray. This test helps doctors identify narrowed arteries to your heart (coronary artery disease) that can be a cause of heart failure. The test also helps doctors determine the strength of the left ventricle â€” the heart's main pumping chamber â€” and the health of the heart valves.
- Nuclear scan. Tests such as radionuclide ventriculography (RNV) or multiple gated acquisition (MUGA) scanning allow your doctor to see how much blood your heart pumps with each beat. The tests are done using a small amount of dye injected into your veins. A special camera can detect the radioactive material as it flows through your heart.
- Blood tests. Your doctor may take a sample of your blood to check for indicators of other diseases that affect the heart. In addition, your doctor may order a blood test that specifically checks for heart failure. The test checks for levels of a hormone called brain natriuretic peptide (BNP). Your heart secretes BNP in high levels when it's overworked. A large amount of BNP in your blood may indicate heart failure.
Results of these tests help doctors determine the cause of your signs and symptoms and develop a program to treat your heart. To determine the best course of treatment, doctors classify heart failure using a scale of one to four. Class I heart failure is the mildest. You can perform everyday activities and not feel winded or fatigued. Class IV is the most severe, in which you're short of breath even at rest.
Treating Heart Failure
Doctors sometimes can correct heart failure by treating the underlying cause. For example, controlling a fast heart rhythm may reverse heart failure. But in most cases, once you have heart failure, it's there to stay. However, with treatment, a failing heart can become stronger and signs and symptoms of heart failure can improve.
Doctors usually treat heart failure with medications. Several types of drugs have proved useful in the treatment of heart failure. They include:
- Angiotensin-converting enzyme (ACE) inhibitors. These drugs â€” the mainstay treatment for congestive heart failure â€” help people with congestive heart failure live longer and feel better. Examples include enalapril (Vasotec), lisinopril (Prinivil, Zestril) and captopril (Capoten). ACE inhibitors lower blood pressure and decrease your heart's workload. They also blunt some of the effects of hormones that promote salt and water retention. Because ACE inhibitors lower blood pressure, you could feel weak or dizzy shortly after taking them. Your doctor may recommend that you take them just before bedtime so that you'll be lying down soon after taking the drug. ACE inhibitors also cause an irritating cough in some people. Sometimes it may be best to put up with the cough, if you can, to gain the medication's benefits. But be sure to discuss this with your doctor. Switching to another ACE inhibitor may relieve the problem.
- Angiotensin II (A-II) receptor blockers. These drugs, which include losartan (Cozaar) and valsartan (Diovan), have many of the beneficial effects of ACE inhibitors, but they don't cause a persistent cough. They may be an alternative for people who can't tolerate ACE inhibitors.
- Diuretics. Often called water pills, diuretics make you urinate more frequently and keep fluid from collecting in your body. Commonly prescribed diuretics for congestive heart failure include bumetanide (Bumex) and furosemide (Lasix, Fumide). The drugs also decrease fluid in your lungs, so you can breathe more easily. Because diuretics make your body lose potassium and magnesium, your doctor may prescribe supplements of these minerals. If you're taking a diuretic, your doctor will likely monitor levels of potassium and magnesium in your blood through regular blood tests.
- Spironolactone (Aldactone). This potassium-sparing diuretic may improve survival for people with severe congestive heart failure. Unlike some other diuretics, spironolactone can raise potassium levels in your blood. Therefore, if you're taking this drug, your doctor will want to check the potassium level in your blood periodically. Occasionally, spironolactone can also cause breast swelling and tenderness.
- Digoxin (Lanoxin). This drug, also referred to as digitalis, increases the strength of your heart muscle contractions. It also tends to slow the heartbeat. Digoxin reduces heart failure symptoms and improves your ability to live with the condition.
- Beta blockers. This class of drug slows your heart rate and reduces blood pressure. These medicines also reduce the risk of some abnormal heart rhythms. Beta blockers may reduce signs and symptoms of congestive heart failure and improve heart function.
You'll probably need two or more medications to treat heart failure. Your doctor may prescribe other heart medications â€” such as nitrates for chest pain, calcium channel blockers to lower blood pressure and improve circulation or blood-thinning medications to help prevent blood clots â€” along with heart failure medications.
For people with severe congestive heart failure, there's an intravenous drug called nesiritide (Natrecor). Nesiritide is a synthetic version of a naturally occurring hormone in the body called brain natriuretic peptide. BNP is secreted in high levels by the heart when it's overloaded with pressure and its volume is expanded. BNP causes the body to excrete excess fluid, helping to combat the effects of congestive heart failure.
Sometimes symptoms of heart failure become severe enough for you to be hospitalized and monitored for a few days. While in the hospital, you may receive medications that work quickly to help your heart pump better and relieve your symptoms. You may also receive supplemental oxygen through a mask or small tubes placed in your nose. If you have severe heart failure, you may need to use supplemental oxygen long term.
A study published in November 2004 in The New England Journal of Medicine showed that adding a combination of hydralazine and isosorbide dinitrate (BiDil) to the standard therapy for African Americans with advanced heart failure increased overall survival rates.
How to prevent Heart Failure
The best defense against heart failure is the prevention of heart disease. You can control or eliminate many of the risk factors for heart disease â€” high blood pressure and coronary artery disease, for example â€” by making lifestyle changes along with the help of any needed medications.