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Heart Failure
Risk Factors
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| There are a number of diseases,
medical conditions and other factors that put people at
higher-than-average risk for heart failure. Not everyone
with these risk factors develops heart failure, but they
put extra stress on the heart that may lead to the condition.
The odds of developing heart failure are especially high
in people who have more than one of these risk factors.
Coronary Artery Disease (CAD)
Like all the organs and tissues of the body, the heart
needs oxygen and other nutrients carried by the blood
to remain healthy. When the blood vessels become narrow
or clogged so that not enough blood reaches the heart,
damage is done to the heart muscle which, in turn, may
affect its ability to pump blood efficiently. The most
common cause of CAD is arteriosclerosis (sometimes called
"hardening of the arteries"), a condition in which cholesterol
and fatty deposits called "plaque" build up in the arteries.
CAD also may be caused by blood clots that lodge in the
arteries and interfere with the normal flow of blood.
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A substance called arteriosclerotic plaque clogs
the blood vessel.
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Past heart attack (myocardial infarction)
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| A heart attack occurs when an artery that supplies blood to
the heart is blocked so that no oxygen reaches the heart muscle.
When this happens, part of the heart "dies" (the area of dead
muscle is called an "infarct"). The remaining, healthy tissue
must take over the job of pumping blood, an extra burden that
may weaken the heart's pumping ability.
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Heart Rhythm Disorders (arrhythmias)
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| When the heartbeat is too fast, too slow or irregular (out
of rhythm), it may not be able to pump enough blood to meet
the needs of the body. In these cases, once the underlying problem
is identified and treated, the symptoms of heart failure may
go away before significant damage is done to the heart muscle.
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A normal heart rhythm (left).
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The abnormal rhythm (right) is a potential cause
of cardiac arrest. |
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Alcohol and Drug Abuse
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| Excessive use of alcohol, or abuse of drugs such as cocaine
and amphetamines place added stress on the heart that can lead
to heart failure or other heart diseases. These substances also
can damage the cells of the heart. Some environmental toxins
and prescription drugs also can contribute to the problem.
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Abnormal heart valves
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The valves that open and close to allow blood to pass between
the chambers of the heart may be damaged by disease or infection
(endocarditis). Sometimes, heart valve defects are present at
birth. Whatever the cause, if the valves don't open or close
completely with each heartbeat, the heart muscle has to pump
harder to keep the blood moving. If the workload becomes too
great, heart failure can develop.
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Heart muscle disease (cardiomyopathy) or inflammation (myocarditis)
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Any damage to the heart muscle itself increases the risk of
heart failure. Heart muscle disease or infection may be caused
by a number of factors, including congenital problems (defects
present at birth), drug or alcohol abuse, bacterial or viral
infections or other, unknown reasons.
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Heart defects present at birth (congenital heart disease)
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If the heart and its chambers don't form correctly in the developing
fetus, the normal parts of the heart must make up for defects
by working harder. Over time, the added stress may cause healthy
structures to "fail" and lead to HF.
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Diabetes
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Diabetes tends to increase the levels of cholesterol and triglycerides
-- unhealthy fats that contribute to coronary artery disease.
People with diabetes also are more likely to be overweight and
have high blood pressure. These factors must be carefully monitored
and controlled because they put extra strain on the heart and
can lead to heart failure, as well as to other cardiovascular
diseases, such as heart attack and stroke.
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High blood pressure (hypertension)
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Uncontrolled high blood pressure doubles a person's risk of
developing heart failure. If the pressure created by blood flow
through the vessels of the circulatory system is too high, the
heart has to pump harder to keep the blood circulating. Over
time, the extra burden can thicken the heart muscle and eventually
weaken the heart.
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Sometimes, an otherwise healthy heart may temporarily have
trouble keeping up with the body's need for oxygen and other
nutrients carried by the blood because of problems unrelated
to the cardiovascular system. These problems are less common
than other causes for heart failure, but it is important to
monitor heart function in people who have:
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An abnormally low number of red blood cells (severe anemia)
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| It is the job of the red cells to carry the oxygen needed
to maintain life in all the cells of the body. If there are
not enough of these cells, the heart pumps at a faster rate
to circulate the smaller number of red cells quickly enough
to supply the oxygen the body needs. Over time, the extra burden
may lead to heart muscle damage.
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An overactive thyroid gland (hyperthyroidism)
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The thyroid gland affects the rate at which the body metabolizes
food and other substances. If the thyroid is overactive, the
body works at a faster pace, and the heart may be overworked
as it adjusts to keep up with the body's increased demand for
oxygen and other nutrients. Waste products also build up more
quickly in the cells, and must be picked up by the circulating
blood and carried to the kidneys, liver and elsewhere to be
processed and excreted.
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Lifestyle Factors that Increase the
Risk of HF
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