ARSENIC
ARTERITIS
A
can cause fainting,
dizziness,
chest
pain, and breathlessness, which may be
the 1st symptoms.
Arrhythmias are diagnosed by an
ECG
.
If they are intermittent, a continuous
recording may need to be made using
an
ambulatory ECG.
Treatments for arrhythmias include
anti-
arrhythmic drugs,
which prevent or slow
tachycardias. With an arrhythmia that
has developed suddenly, it may be pos-
sible to restore normal heart rhythm by
using electric shock to the heart (see
defibrillation).
Abnormal conduction path-
ways in the heart can be treated using
radio frequency ablation during cardiac
catheterization (see
catheterization
,
car-
diac).
In some cases, a pacemaker can
be fitted to restore normal heartbeat by
overriding the heart's abnormal rhythm.
arsenic
A poisonous metallic element
that occurs naturally in its pure form
and in various compounds. Arsenic poi-
soning, which is now rare, used to occur
as a result of continuous exposure to
industrial pesticides.
arterial reconstructive surgery
An
operation to repair
arteries
that are nar-
rowed, blocked, or weakened. Arterial
reconstructive surgery is most often
performed to repair arteries that have
been narrowed by
atherosclerosis
. It is
also used to repair
aneurysms
and
arteries damaged as a result of injury.
(See also
angioplasty
,
balloon
;
coronary
artery bypass; endarterectomy.)
arteries, disorders of
Disorders of
the arteries may take the form of abnor-
mal narrowing (which reduces blood
flow and may cause tissue damage),
complete obstruction (which may cause
tissue death), or abnormal widening
and thinning of an artery wall (which
may cause rupture of the blood vessel).
Atherosclerosis
, in which fat deposits
build up on artery walls, is the most
common arterial disease. It can involve
arteries throughout the body, including
the brain (see
cerebrovascular disease
),
heart (see
coronary artery disease
), and
legs (see
peripheral vascular disease
).
Atherosclerosis is the main type of
art-
eriosclerosis
, a group of disorders that
cause thickening and loss of elasticity
of artery walls.
Hypertension
is another
common cause of thickening and nar-
rowing of arteries, and it increases the
risk of a
stroke
or
kidney failure. Arteritis
is inflammation of artery walls that
causes narrowing and sometimes block-
age.
Aneurysm
is ballooning of an
artery wall caused by the pressure of
blood flowing through a weakened area.
Thrombosis
occurs when a blood clot
forms in a blood vessel, causing obs-
truction of the blood flow. Blockage of
an artery by a fragment of blood clot or
other material travelling in the circula-
tion is called an
embolism. Raynaud's
disease
is a disorder involving intermit-
tent spasm of small arteries in the
hands and feet, usually due to cold.
arteriography
An alternative name for
angiography
, an X-ray technique for
imaging arteries.
arteriole
A blood vessel that branches
off an
artery
. Arterioles branch to form
capillaries
. They have muscular walls,
and their nerve supply enables them to
be narrowed or widened to meet the
blood-flow needs of tissues they supply.
arteriopathy
Any disorder of an artery
(see
arteries
,
disorders of
).
arterioplasty
Surgical repair of an art-
ery (see
arterial reconstructive surgery
).
arteriosclerosis
A group of disorders
that cause thickening and loss of elas-
ticity of artery walls.
Atherosclerosis
is
the most common type , and the 2 terms
are often used synonymously. Other
types are medial arteriosclerosis (in
which muscle and elastic fibres in larger
arteries are replaced by fibrous tissue)
and Monckeberg's arteriosclerosis (in
which there are calcium deposits in the
arterial lining).
arteriovenous
fistula
An abnormal
communication directly between an art-
ery and a vein. An arteriovenous fistula
may be present at birth or result from
injury. A fistula can also be created
surgically for easy access to the blood-
stream in
dialysis
.
arteritis
Inflammation of an artery wall,
causing narrowing or complete block-
age of the affected artery,
reduced
blood flow, and, in some cases,
throm-
bosis
and tissue damage. There are
several types, including
Buerger's dis-
ease
, an arteritis that affects the limbs,
50
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