MYOCARDIAL ISCHAEMIA
M
FEATURES OF MYOCARDIAL INFARCTION
Myocardial infarction (heart attack), in which an area of heart muscle is
deprived of blood and suffers tissue death as a result, causes severe pain and
can be fatal. Most cases result from atherosclerosis of the coronary arteries, a
condition in which plaques (patches of fatty deposits) collect inside the arteries.
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L e f t p u l m o n a r y a r t e r y
R i g h t c o r o n a r y a r t e r y
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• A raised blood cholesterol level (for which
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there may be a genetic tendency) increases
the risk. A high-fat diet is also a factor.
L e ft v e n t r i c le
• Physical inactivity is also a major riskfactor.
RISKFACTORS
Uncontrollable factors include family history of
heart disease, increasing age, and being male.
Cigarette smokers have a substantially
increased riskofdying of myocardial infarction.
High blood pressure is a major riskfactor, and
the risk increases the higher the pressure.
The riskofatherosclerosis and coronary artery
disease increases dramatically in those who
are more than 30 per cent overweight.
O u t e r l a y e r
B l o o d c l o t
F a t t y d e p o s i t
( a t h e r o m a )
H e a r t m u s c l e
I n n e r
lin in g
Atherosclerosis
Plaques of atheroma develop on the inner lining
ofthe arteries, restricting the blood flow. The
plaques develop a fibrous covering, which may
rupture or become roughened. Platelets (tiny
blood cells)maythen stickto the plaque and
trigger the formation of a blood clot. The clot may
completely blockthe artery, causing a sudden
stoppage ofblood flow to the heart.
PAIN
Some people who suffer myocardial infarction have a history ofangina pectoris,
in which blood flow through the coronary arteries is impaired but the resulting
chest pain is relieved by rest. The pain ofinfarction usually comes on suddenly,
and ranges from a tight ache to intense, crushing agony. It lasts for longer than
10 minutes, and is not relieved by rest.
Central chest
A feeling of
pressure in the
central chest,
ranging from mild
to severe, occurs
in almost every
myocardial
infarction that is
due to coronary
obstruction.
Chest to arm
In manycases,
pain radiates from
the chest down
the left arm; it may
cause a feeling of
weakness in the
arm muscles.
Jaw to back
In some cases,
pain radiates
up into the
jaw and through
to the back.
Sometimes, it
occurs only in
these places.
Upper abdomen
More rarely, pain
may be felt in the
upper abdomen.
If it occurs only
here, it maybe
mistaken for
another disorder.
A o r t a
u n d e r g o a
r e h a b i l i t a t i o n
p r o g r a m m e t o
h e l p t h e m r e t u r n t o f u l l a c t i v i t y a n d t o
i n c r e a s e a w a r e n e s s o f r i s k f a c t o r s .
m y o c a rd ia l is c h a e m ia
A n i n s u f f i c i e n t b l o o d s u p p l y t o t h e
h e a r t
m u s c l e . I t i s u s u a l l y c a u s e d b y n a r r o w i n g
o r b l o c k a g e o f t h e c o r o n a r y b l o o d v e s s e l s
( w h i c h s u p p l y t h e h e a r t m u s c l e ) , d u e t o
a t h e r o s c l e r o s i s
( a n
a c c u m u l a t i o n
o f f a t t y
d e p o s i t s o n t h e w a l l s o f a r t e r i e s ) . M y o c a r -
d i a l i s c h a e m i a c a u s e s t h e h e a r t m u s c l e t o
b e d e p r i v e d o f o x y g e n , a n d m a y g i v e r i s e
t o p r o b l e m s s u c h a s
a n g i n a p e c t o r i s
a n d
m y o c a r d i a l i n f a r c t i o n
( h e a r t a t t a c k ) .
m y o c a rd itis
I n f l a m m a t i o n
o f
h e a r t
m u s c l e ,
u s u a l l y
d u e t o c o x s a c k i e v i r u s i n f e c t i o n . I t i s a l s o
a c h a r a c t e r i s t i c f e a t u r e o f
r h e u m a t i c f e v e r .
SYMPTOMS
T h e r e a r e
o f t e n n o
s y m p t o m s .
R a r e l y ,
t h e r e m a y b e a s e r i o u s d i s t u r b a n c e
o f
t h e h e a r t b e a t , b r e a t h l e s s n e s s , c h e s t p a i n ,
a n d
h e a r t f a i l u r e
.
I n
s e v e r e
c a s e s
o f
m y o c a r d i t i s ,
d e a t h
m a y
r e s u l t
f r o m
c a r d i a c a r r e s t
.
DIAGNOSIS AND TREATMENT
M y o c a r d i t i s m a y b e s u s p e c t e d f r o m t h e
p a t i e n t ’s
h i s t o r y
a n d
f r o m
a
p h y s i c a l
528
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