HEART DISEASE, ISCHAEMIC
H
D e v e l o p m e n t a l e r r o r s l e a d i n g t o d e f e c t s
a r i s e
e a r l y
i n
t h e
l i f e
o f t h e
e m b r y o .
R u b e l l a
( G e r m a n m e a s l e s ) i n t h e m o t h e r
i s t h e m o s t c o m
m
o n k n o w n c a u s e , b u t
i n m o s t c a s e s t h e r e a s o n s f o r t h e d e f e c t s
a r e n o t k n o w n .
H e r e d i t a r y f a c t o r s d o n o t s e e m t o b e
s i g n i f i c a n t . I f a c o u p l e h a v e a n a f f e c t e d
c h i l d , t h e r e i s l i t t l e i n c r e a s e d r i s k o f a
s e c o n d c h i l d b e i n g a f f e c t e d . P e o p l e b o r n
w i t h h e a r t d e f e c t s h a v e l i t t l e i n c r e a s e d
r i s k o f h a v i n g a n a f f e c t e d c h i l d .
SYMPTOMS AND COMPLICATIONS
S y m p t o m s
o f c o n g e n i t a l h e a r t
d i s e a s e
a r i s e f r o m e i t h e r i n s u f f i c i e n t o r e x c e s -
s i v e c i r c u l a t i o n o f b l o o d t o t h e l u n g s o r
t h e b o d y . D e f e c t s i n h e a r t a n a t o m y c a n
a l s o c a u s e s o m e d e o x y g e n a t e d b l o o d t o
b e p u m p e d t o t h e b o d y i n s t e a d o f t h e
l u n g s
o r
s o m e
o x y g e n a t e d
b l o o d
t o
t h e
l u n g s
i n s t e a d
o f t h e
b o d y .
S o m e
h e a r t
a n o m a l i e s
c a u s e
c y a n o s i s
( b l u e -
n e s s o f t h e s k i n ) a n d b r e a t h l e s s n e s s , b u t
o t h e r s m a y g o u n d e t e c t e d .
P o s s i b l e
c o m p l i c a t i o n s
r e s u l t i n g
f r o m
a n u n t r e a t e d h e a r t d e f e c t i n c l u d e u n d e r -
d e v e l o p m e n t o f t h e l i m b s a n d m u s c l e s ,
a n d
p n e u m o n i a
a f t e r e v e n m i l d r e s p i r a -
t o r y i n f e c t i o n s . W
i t h p r o l o n g e d c y a n o s i s ,
c l u b b i n g
( t h i c k e n i n g
a n d
b r o a d e n i n g )
o f t h e e n d s o f f i n g e r s a n d t o e s m a y d e v e -
l o p . I f t h e r e i s i n s u f f i c i e n t c a p a c i t y i n t h e
h e a r t t o i n c r e a s e b l o o d f l o w o n e f f o r t ,
t h e c h i l d m a y r a p i d l y t i r e d u r i n g p h y s i -
c a l e x e r c i s e . I n s o m e u n t r e a t e d c a s e s , a
s e r i o u s c o m p l i c a t i o n c a l l e d
E i s e n m e n g e r
c o m p l e x
( i n c r e a s e d r e s i s t a n c e o f t h e l u n g s
t o b l o o d f l o w ) d e v e l o p s .
DIAGNOSIS AND TREATMENT
A n t e n a t a l
d i a g n o s i s ,
u s i n g
s p e c i a l i z e d
u l t r a s o u n d s c a n n i n g
,
i s p o s s i b l e f o r m o s t
d e f e c t s . A f t e r b i r t h , a n y s u s p e c t e d d e f e c t
i s i n v e s t i g a t e d u s i n g
c h e s t X - r a y s
,
E C G
,
o r
e c h o c a r d i o g r a p h y
.
O x y g e n
a n d v a r i o u s
d r u g t r e a t m e n t s
m a y i m p r o v e t h e s y m p t o m s . S o m e c o n -
d i t i o n s , s u c h a s s m a l l s e p t a l d e f e c t s o r
p a t e n t
d u c t u s
a r t e r i o s u s ,
m a y
b e c o m e
s m a l l e r o r m a y d i s a p p e a r o f t h e i r o w n
a c c o r d . O t h e r d e f e c t s w i l l r e q u i r e s u r -
g i c a l c o r r e c t i o n . N a r r o w e d h e a r t v a l v e s
c a n o f t e n b e t r e a t e d b y b a l l o o n
v a l v u l o -
p l a s t y
.
I n o t h e r c a s e s ,
o p e n h e a r t s u r g e r y
o r a
h e a r t t r a n s p l a n t
m a y b e r e q u i r e d .
OUTLOOK
F o l l o w i n g s u c c e s s f u l s u r g e r y , t h e c h i l d ’s
h e a l t h o f t e n i m p r o v e s d r a m a t i c a l l y , w i t h
r e s u m e d g r o w t h , i n c r e a s e d a c t i v i t y , a n d
a n e a r - n o r m a l l i f e e x p e c t a n c y .
C h i l d r e n w i t h h e a r t d e f e c t s ( c o r r e c t -
e d o r u n c o r r e c t e d )
a r e a t a n i n c r e a s e d
r i s k o f b a c t e r i a l
e n d o c a r d i t i s
,
a p o t e n t i a l -
l y
d a n g e r o u s
i n f e c t i o n
o f
t h e
h e a r t
l i n i n g a n d h e a r t v a l v e s . T o p r e v e n t t h i s ,
s u c h c h i l d r e n a r e g i v e n
a n t i b i o t i c d r u g s
b e f o r e a l l s u r g i c a l p r o c e d u r e s , i n c l u d i n g
d e n t a l t r e a t m e n t s .
heart disease, ischaemic
T h e m o s t c o m
m o n f o r m o f h e a r t d i s -
e a s e . I n i s c h a e m i c h e a r t d i s e a s e , t h e r e i s
n a r r o w i n g o r o b s t r u c t i o n o f t h e c o r o -
DISORDERSOFTHE HEART
Heart disorders are by far the most
common cause of death in developed
countries.They also affect the quality of
life of millions of people.A wide range
of conditions can affect the heart’s
structure and/or disrupt its action.
Congenital defects
Structural abnormalities in the heart are
among the most common birth defects.
They result from errors of development
in the fetus and include
s e p t a l d e f e c t s
(“holes in the heart”) and some types
of
h e a r t v a l v e
abnormalities (see
h e a r t
d i s e a s e , c o n g e n i t a l ) .
Genetic disorders
Genetic factors do not usually play a
large part in causing heart disorders.
They do, however, contribute to
h y p e r -
l i p i d a e m i a s ,
which predispose affected
people to
a t h e r o s c l e r o s i s
and
c o r o n a r y
a r t e r y d i s e a s e
.
Infection
Infection of the lining of the heart and
of the heart valves (see
e n d o c a r d i t i s
)
can result in malfunction of the heart
valves.Viral infections can lead to
some types of
c a r d i o m y o p a t h y
(malfunctioning of the heart muscle)
or
m y o c a r d i t i s
(inflammation of the
heart muscle).
Tumours
Tumours arising in the heart tissues are
rare. The main types are noncancerous
m y x o m a s ,
which develop inside the heart
chambers, and cancerous
s a r c o m a s
.
Secondary tumours, spreading from
elsewhere in the body, are more common
than primary tumours.
Arterial disorders
The coronary arteries (supplying blood to
the heart) may become narrowed due to
atherosclerosis. Areas of heart muscle may
be starved of oxygen, and
a n g i n a p e c t o r i s
or,
eventually,
m y o c a r d i a l i n f a r c t i o n
may result.
Nutritional disorders
O b e s i t y
is an important factor in heart
disease, probably through its effect on
other risk factors, such as
h y p e r t e n s i o n ,
d i a b e t e s m e l l i t u s ,
and
c h o l e s t e r o l .
Malnutrition may cause the heart muscle
to become thin and flabby from lack of
protein and calories.
T h i a m i n e
(vitamin Bj)
deficiency, common in alcoholics, causes
b e r i b e r i
with congestive
h e a r t f a i l u r e .
Poisoning
The most common toxin affecting the
heart is alcohol. Excessive drinking
over many years may cause a type of
cardiomyopathy. Another common source
of toxins is smoking; nicotine and carbon
monoxide in tobacco smoke are
thought to encourage the development
of atherosclerosis, which can lead to
coronary artery disease.
Drugs
Certain medications, such as the
anticancer drug
d o x o r u b i c i n , t r i c y c l i c
a n t i d e p r e s s a n t s ,
and even drugs used to
treat heart disease, may disturb the
heartbeat or damage the heart muscle.
Other heart disorders
Many disorders may be complications
of an underlying condition, such as
cardiomyopathy or a congenital defect.
They include cardiac
a r r h y t h m i a ;
some
cases of
h e a r t b l o c k ;
heart failure; and
c o r
p u l m o n a l e ,
which is a failure of the right
side of the heart due to lung disease.
INVESTIGATION
Techniques used for investigating heart
disorders include auscultation (listening
to the heart);
ECG
(electrocardiography);
imaging techniques
such as chest X-ray,
echocardiography
,
coronary
angiography,
CT scanning,
and
MRI
;
cardiac
catheterization (see
catheterization,
cardiac); blood tests
;
and, rarely, by a
biopsy
of the heart muscle.
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