|
|
Heart failure is a condition in which the heart can’t pump enough blood
throughout the body. Heart failure does not mean that your heart has stopped
or is about to stop working. It means that your heart is not able to pump
blood the way that it should. The heart can’t fill with enough blood or pump
with enough force, or both.
Heart failure develops over time as the pumping action of the heart grows
weaker. It can affect the left side, the right side, or both sides of the
heart. Most cases involve the left side where the heart can’t pump enough
oxygen-rich blood to the rest of the body. With right-sided failure, the heart
can’t effectively pump blood to the lungs where the blood picks up oxygen.
The weakening of the heart’s pumping ability causes:
- Blood and fluid to "back up" into the lungs
- The buildup of fluid in the feet, ankles, and legs
- Tiredness and shortness of breath
Heart failure is a serious condition. About 5 million people in the United
States have heart failure, and the number is growing. Each year, another
550,000 people are diagnosed for the first time. It contributes to or causes
about 300,000 deaths each year.
Symptoms
The most common signs and symptoms are:
- Shortness of breath or difficulty breathing
- Feeling tired
- Swelling in the ankles, feet, legs, and sometimes the abdomen
Shortness of breath and feeling tired are caused by the buildup of fluid in
the lungs and around the lungs. When symptoms start, you may feel tired and
short of breath after routine physical exertion. Climbing two flights of
stairs makes you feel winded. As heart failure progresses, the symptoms get
worse. You may begin to feel tired and short of breath after simple
activities, like getting dressed or walking across the room. Some people have
shortness of breath when lying flat.
Fluid buildup in the lungs can also cause a cough. The cough is worse at
night and when you are lying down. Excessive fluid in the lungs can cause a
life-threatening condition called acute pulmonary edema. This condition
requires emergency treatment.
The swelling is from the buildup of fluid in your body (edema). Other signs
of fluid buildup are:
- Weight gain
- Frequent urination
Limitation on Physical Activity
Doctors also classify your symptoms based on how much they limit your daily
activity. By class of symptom, your doctor means:
- Class 1: No limits—ordinary physical activity does not cause undue
tiredness or shortness of breath.
- Class 2: Slight or mild limits—comfortable at rest, but ordinary
physical activity results in tiredness or shortness of breath.
- Class 3: Marked or noticeable limits—comfortable at rest, but less
than ordinary physical activity causes tiredness or shortness of breath.
- Class 4: Severe limits—unable to carry on any physical activity
without discomfort. Symptoms are also present at rest. If any physical
activity is undertaken, discomfort increases.
Diagnosis
There is not a specific test to determine if you have heart failure. A
clinical diagnosis of heart failure is usually made when symptoms appear. The
symptoms—shortness of breath, tiredness, and fluid buildup—are common in
other conditions.
Your doctor will determine if you have heart failure by performing a
detailed medical history, a physical exam, and several tests. The purpose of
these is to:
- Identify the presence of diseases and conditions that can cause heart
failure
- Rule out other causes of your symptoms
- Determine the amount of damage to and the pumping capability of your
heart
Medical and Family History
Your doctor will ask if you or others in your family have or have had any
of the diseases and conditions that can cause heart failure. Your doctor will
also ask about your symptoms. This includes the types of symptoms, when they
occur, how long you have had them, and their severity. The answers will help
your doctor determine the limits on your ability to perform daily activities.
Physical Examination
Your doctor will:
- Listen to your heart for abnormal sounds
- Listen to your lungs for the buildup of fluid
- Look for swelling in your ankles, feet, legs, and abdomen
- Look for swelling in the veins in the neck
Tests
If you have signs and symptoms of heart failure, your doctor may order the
following tests:
- EKG (electrocardiogram). This test is used to measure the rate and
regularity of your heartbeat. It may show if you have had a heart attack
or if there is thickening of the walls in your heart’s pumping chambers
(ventricles).
- Chest x ray. A chest x ray takes a picture of your heart and lungs. It
can show if your heart is enlarged, if you have fluid in your lungs, or if
you have lung disease.
- BNP blood test. This new test checks the level of a hormone called BNP
(B-type natriuretic peptide) that rises in heart failure.
If your doctor suspects heart failure after asking about your medical and
family history and performing a physical exam and initial tests (such as tests
of kidney function), he or she may refer you to a cardiologist. A cardiologist
is a doctor who specializes in the diagnosis and treatment of heart disease.
The cardiologist will perform a physical exam and order additional tests.
An echocardiogram is the most useful test for diagnosing heart failure.
This test uses sound waves to create a moving picture of your heart.
Echocardiogram provides information about the size and shape of your heart and
how well your heart chambers and valves are functioning. The test also can
identify areas of poor blood flow to the heart, areas of heart muscle that are
not contracting normally, and previous injury to the heart muscle caused by
poor blood flow.
There are several different types of echocardiograms, including a stress
echocardiogram. During this test, an echocardiogram is done both before and
after your heart is stressed either by having you exercise or by injecting a
medicine into your bloodstream that makes your heart beat faster and work
harder. A stress echocardiogram is usually done to find out if you have
decreased blood flow to your heart (coronary artery
disease).
The cardiologist may order any of the following tests. These tests can help
identify the cause of your heart failure:
- Holter monitor (ambulatory electrocardiography, EKG). For this test, a
small box called a Holter monitor is attached to patches (electrodes) that
are placed on your chest. The box may be carried in a pouch around your
neck or attached to your belt. The Holter monitor is usually worn for 24
hours and provides a continuous recording of heart rhythm during normal
activity.
- Nuclear heart scan. This test provides your doctor with moving pictures
of the blood passing through your heart's chambers and arteries and shows
the level of blood flood to the heart muscle. A small amount of a
radioactive tracer is injected into your bloodstream through a vein,
usually in your arm. A special camera is placed in front of your chest to
show where the tracer lights up in healthy heart muscle and where it
doesn't light up (in heart muscle that has been damaged or has a blocked
artery).
- There are different types of nuclear heart scans. Most
scans have two phases—taking pictures of the heart at rest and while it
is beating faster (called a stress test), although sometimes only a rest
scan is done. Many heart problems show up more clearly when your heart is
stressed than when it is at rest. By comparing the nuclear heart scan of
your heart at rest to your heart at "stress," your doctor can
determine if your heart is functioning normally or not.
- Cardiac catheterization. A thin, flexible tube is passed through an
artery at the top of the leg (groin) or in the arm to reach the coronary
arteries. This allows your doctor to study the inside of your arteries to
see if there is any blockage. Your doctor can check the pressure and blood
flow in the heart's chambers, collect blood samples from the heart, and
examine the arteries of the heart by x ray.
- Coronary angiography. This test is usually performed along with cardiac
catheterization. A dye that can be seen by x ray is injected into the
coronary arteries. Your doctor can see the flow of blood to the heart
muscle. Dye can also be injected into the chambers of the heart to
evaluate the pumping function of your heart.
- Stress Test. Some heart problems are easier to diagnose when your heart
is working harder and beating faster than when it's at rest. During stress
testing, you exercise (or are given medicine if you are unable to
exercise) to make your heart work harder and beat faster while heart tests
are performed.
- During exercise stress testing, your blood pressure and
EKG readings are monitored while you walk or run on a treadmill or pedal a
bicycle. Other heart tests, such as nuclear heart scanning or
echocardiography, also can be done at the same time. These would be
ordered if your doctor needs more information than the exercise stress
test can provide about how well your heart is working.
- If you are unable to exercise, a medicine can be
injected through an intravenous line (IV) into your bloodstream to make
your heart work harder and beat faster, as if you are exercising on a
treadmill or bicycle. Nuclear heart scanning or echocardiography is then
usually done.
- During nuclear heart scanning, radioactive tracer is
injected into your bloodstream, and a special camera shows the flow of
blood through your heart and arteries. Echocardiography uses sound waves
to show blood flow through the chambers and valves of your heart and to
show the strength of your heart muscle.
- Your doctor also may order two newer tests along with
stress testing if more information is needed about how well your heart
works. These new tests are magnetic resonance imaging (MRI) and positron
emission tomography (PET) scanning of the heart. MRI shows detailed images
of the structures and beating of your heart, which may help your doctor
better assess if parts of your heart are weak or damaged. PET scanning
shows the level of chemical activity in different areas of your heart.
This can help your doctor determine if enough blood is flowing to the
areas of your heart. A PET scan can show decreased blood flow caused by
disease or damaged muscles that may not be detected by other scanning
methods.
- Thyroid functions tests. These are common procedures done to find out
how well the thyroid is functioning. They include blood tests, various
imaging procedures, and stimulating thyroid function. These tests are very
important because both an overactive and an underactive thyroid can be the
main or a contributing cause of heart failure.
Heart failure is caused by other diseases or conditions that damage or
overwork the heart muscle. Over time, the heart muscle weakens and is not able
to pump blood as well as it should.
The leading causes of heart failure are:
CAD, including angina and heart
attack is the most common underlying cause of heart failure. People who
have a heart attack are at high risk of developing heart failure.
Most people with heart failure also have high blood pressure, and about one
in three has diabetes.
Other Causes of Heart Failure
Other heart diseases and conditions that can lead to heart failure are:
Other conditions that may injure the heart muscle and lead to heart failure
include:
- Treatments for cancer, such as radiation and certain chemotherapy drugs
- Thyroid disorders (having either too much or too little thyroid hormone
in the body)
- Alcohol abuse
- HIV/AIDS
- Cocaine and other illegal drug use
Reference:
National Heart, Lung, and Blood Institute, USA.
|