What Causes Heart Failure?
Heart failure has many causes. Coronary
artery disease is the most common cause
of heart failure among adults in the United
States. In coronary artery disease, narrowed
arteries prevent the heart from getting adequate
blood supply, and this prevents the heart muscle
from squeezing properly.
A previous heart attack, known as a myocardial
infarction, can leave the heart muscle
scarred. Because scar tissue does not function
properly, any scarred area of the heart can
not squeeze normally. This makes the overall
function of the heart less efficient.
Hypertension,
or high blood pressure, is another major cause
of heart failure in the United States. Like any
muscle in the body, the heart gets larger when
it has to work harder. When the heart has to
push against the very stiff blood vessels found
in people with high blood pressure, the heart
muscle gets thicker, making it difficult for
the heart to relax and receive blood. This can
cause symptoms of heart failure. If high blood
pressure is allowed to continue for many years,
the heart muscle eventually weakens and stretches,
leading to heart failure.
Heart valve disease also can cause heart failure.
Heart valves that are leaky (regurgitant) make
it difficult for the heart to pump blood forward
into the body. Heart valves that are sticky (stenotic)
restrict the flow of blood coming into or out
of the heart and can lead to heart failure. If
the valve problem is fixed early, permanent heart
failure can be avoided. If the valve problem
continues for years, the heart muscle may become
damaged, leading to permanent heart failure --
even if the valve is repaired or replaced. Valve
disease can be the result of prior rheumatic
fever, infection of the heart valves or a birth
defect, and it can strike a person at any age.
Cardiomyopathies, or diseases that directly
affect the heart muscle, can leave the heart
weakened and unable to meet the full demands
of the body. Cardiomyopathies can be the result
of viral infections, toxic substances such as
alcohol, or rare genetic diseases. In very rare
cases, a pregnant woman may develop a cardiomyopathy during
or shortly after her pregnancy. In many cases
the cause of a cardiomyopathy can not be determined
and in this case the cardiomyopathy is referred
to as idiopathic.
Congenital heart disease, which refers to defects
in the heart present at birth, also can lead
to heart failure. These defects typically are
abnormal connections between the chambers of
the heart or abnormal heart valves.
Sleep apnea, in which the breathing pattern
during sleep becomes irregular, can lead to the
development of hypertension and significantly
increases the risk of stroke, heart attack an
arrhythmia. Recent research has shown an association
between sleep apnea and heart failure.
Lastly, infections of the heart muscle (myocarditis)
or the heart valves (endocarditis) can lead to
heart failure.
Reviewed by: Lee
R. Goldberg, MD, MPH
Last updated: November 2005
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