ANXIOLYTICS
AORTIC STENOSIS
such as the fear of open spaces or spi-
ders, that lead to avoidance of certain
situations or objects.
CounseUing, psychotherapy,
and group
or individual cognitive-behaviour ther-
apy are used to treat anxiety disorders.
Antianxiety drugs
(especially
benzodi-
azepine drugs)
may be used for short-
term treatment but are addictive,
anxiolytics See
antianxiety drugs.
aorta The body's main
artery,
which
supplies oxygenated blood to all other
parts. The aorta arises from the left ven-
tricle (the main pumping chamber of
the
heart
) and arches up over the heart
AORTA
before descending, behind it, through
the chest cavity. It terminates in the
abdomen by dividing into the 2 com-
mon iliac arteries of the legs.
The aorta is thick-walled and has a
large diameter in order to cope with the
high pressure and large volume of blood
passing through it. (See also
arteries,
disorders of; circulatory system.)
aortic incompetence Leakage of blood
through the aortic valve (one of the
heart valves),
resulting in a backflow of
blood from the aorta into the left ventri-
cle (the heart's main pumping chamber).
Failure of the aortic valve to close
properly may be due to a
congenital
abnormality in which the valve has 2
flaps rather than 3. The valve leaflets
can be destroyed by infective
endocardi-
tis.
Aortic incompetence is associated
with
ankylosing spondylitis,
and
Marfan's
s}mdrome. Atherosclerosis
may damage
the valve, causing a combination of
aor-
tic stenosis
and incompetence. Aortic
incompetence is also found in untreat-
ed
syphilis,
which is now rare.
Aortic incompetence may not cause
symptoms and is sometimes found dur-
ing a routine medical examination. The
heart compensates for the backflow of
blood into the left ventricle by working
harder, which may eventually lead to
heart failure-,
this causes breathing diffi-
culty and
oedem a
(fluid accumulation).
Chest X-ray, ECG,
and
echocardiogra-
phy
may be carried out to diagnose
aortic incompetence. A cardiac catheter
is sometimes used to demonstrate the
degree of incompetence (see
catheter-
ization, cardiac).
Heart failure resulting
from aortic incompetence can be treated
with
diuretic drugs. Heart-valve surgery
to replace the damaged valve may
eventually be necessary,
aortic stenosis Narrowing of the open-
ing of the aortic valve (one of the heart
valves), causing obstruction of blood flow
into the circulation. This makes the heart
work harder and causes the muscle in
the wall of the left ventricle (the main
pumping chamber) to thicken. Narrowing
of the valve also reduces the amount of
blood flowing into the coronary arteries.
The most common cause of aortic
stenosis is deposition of calcium on the
aortic valve, usually associated with
atherosclerosis.
Aortic stenosis may also
be caused by a
congenital
abnormality.
Aortic stenosis may not cause symp-
toms. When symptoms do occur, they
AORTIC STENOSIS
NORMAL AORTA
STENOSED AORTA
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