Heart failure occurs when the heart muscle fails to pump as much blood as the body needs. The faulty pumping means the body doesn't get the oxygen it needs, blood backs up in the veins and lungs and other changes occur that make the heart even weaker.
Heart failure is usually caused by a problem with the lower left chamber of the heart. Normally, it pumps out more than 50% of the blood that fills it during each heartbeat. In most heart failure patients, it pumps out less than 40% of the blood that fills it during each heartbeat. As a result, a large portion of blood remains in the chamber, and there is less room for blood coming from the lungs during the next heartbeat. Blood may back up inside the heart and lungs. The heart's lower right chamber may also not be working well, causing blood to back up in the body.
When the heart does not pump normally, the patient's hormone and nervous systems try to step in. To make up for not getting enough blood, the body may raise the blood pressure, hold on to salt and water and make the heart beat faster. The muscular walls of the heart may get bigger and thicker. At first, all these reactions may help. In time, however, the heart is no longer able to keep up. The symptoms then get worse.
Many people with severe heart disease in time develop heart failure. When and how it develops depends on the type of underlying heart disease.
Today heart disease is identified earlier and treated more effectively. This extends the lives of millions of individuals. Although patients with heart disease are living longer, they now have a greater chance of developing heart failure.
Heart failure can affect persons of any age, even young children, especially if they are born with a heart defect. It most often affects older persons who may already have hearts weakened by age-related conditions or disease.
In the early stages of congestive heart failure, a person may have no symptoms. When symptoms do develop, they may include:
- A dry, hacking cough, especially when lying down
- Confusion, sleepiness and disorientation may occur in older people
- Dizziness, fainting, fatigue or weakness
- Fluid buildup, especially in the legs, ankles and feet
- Increased urination at night
- Nausea, abdominal swelling, tenderness or pain (may result from the buildup of fluid in the body and the backup of blood in the liver)
- Weight gain (due to fluid buildup)
- Weight loss as nausea causes a loss of appetite and as the body fails to absorb food well
- Rapid breathing, bluish skin and feelings of restlessness, anxiety and suffocation
- Shortness of breath and lung congestion as the blood backs up in the lungs
- Tiring easily
- Wheezing and spasms of the airways similar to asthma
Causes of Heart Failure and Risk Factors
Heart failure is generally the result of another disease, such as:
- A blood clot in an artery of the lungs
- An over- or underactive thyroid gland, which can speed up or slow down the pumping of the heart, causing it not to completely fill or empty as it should
- Certain lung disorders
- Certain parasites that get into the heart muscle in tropical countries
- Constrictive pericarditis
- Coronary artery disease
- Disorders of the heart's electrical conduction system
- Heart valve disorders
- Kidney failure, which causes fluid to build up in the blood stream, making it harder for the heart to work
- Untreated or inadequately treated high blood pressure
A doctor will diagnose heart failure using:
- An electrocardiogram and chest X-ray
- An echocardiogram, which is the best way to diagnose heart failure
- Cardiac blood pool scans are often used when echocardiography results are less likely to be accurate due to a person's weight, breast size or the presence of severe lung disease
- Thallium scans use a radioactive tracer to show the blood flow through the coronary artery
- Cardiac catheterization with angiography. A special substance is injected into the blood vessel that reveals the inside of the artery.
Treating conditions, such as high blood pressure, thyroid disorders and coronary artery disease, as early as possible can help prevent heart failure. Treatment depends on the cause of the heart failure, how severe the symptoms are and how well the body is able to make up for the heart's not being able to pump enough blood. While heart failure cannot be cured or made to go away, it is possible to make physical activity more comfortable, improve the quality of the life and prolong life.
Heart failure treatments focus on:
- Treating the underlying disorder that may be causing heart failure
- Controlling the elements that can make heart failure worse
- Treating the heart failure itself
- Drugs. In most cases, patients with heart failure have the disease for the rest of their lives and require specific drugs. A combination of drugs may be used, including ACE inhibitors,diuretics,beta-blockers and digoxin. These do not cure heart failure. They can relieve symptoms, improve heart function, slow the progress of the disease and reduce the risk of complications, hospitalization and premature death.
- Biventricular pacing, which is a promising new procedure to improve the output of blood from the heart. This is a type of pacemaker that coordinates the pumping of the lower left and right chambers. Less blood leaks through the mitral valve, and the muscles of the left lower chamber can pump better.
- Surgery to open blocked blood vessels in the heart can restore normal blood flow. Surgery to correct certain types of heart valve disease may also improve symptoms of heart failure.
- Ventricular assist devices (VAD) are machines that help a failing heart pump blood through the body. VADs have been used in patients as young as seven years old and as old as 70.
- The Cardiac Mechanical Assist Device Program at Cedars-Sinai Heart Center provides complete state-of-the-art mechanical support for patients with end-stage heart failure
- Heart transplant
- In most heart failure patients, treatment is also needed to correct or control related health problems (such as high blood pressure or coronary artery disease) and any other heart failure triggers (such as fever, anemia or infection)
- Lifestyle changes, such as losing weight, starting an exercise program approved by your doctor or in a reducing the amount of salt and fat in the diet, quitting smoking and avoiding alcohol
Heart failure that develops or gets worse quickly needs to be treated on an emergency basis in a hospital. If there is severe swelling in the lungs, oxygen will be given through a face mask. Diuretics can be injected, and drugs (such as nitroglycerin) can be given to improve comfort. In some cases it may be necessary to use a mechanical ventilator to assist in breathing. Certain hormones similar to adrenaline can be given on a short-term basis to help the heart muscle work more effectively.