I
HEART FAILURE
TYPES OF CONGENITAL HEART DISEASE
The major malformations are atrial
and ventricular
s e p t a l d e f e c t s ;
c o a r c t a t i o n o f t h e a o r t a ; t r a n s p o s i t i o n
o f t h e g r e a t v e s s e l s ; p a t e n t d u c t u s
a r t e r i o s u s ; t e t r a l o g y o f F a l l o t ;
h y p o p l a s t i c l e f t h e a r t s y n d r o m
e ;
p u l m o n a r y s t e n o s i s ;
and
a o r t i c
s t e n o s i s
(not shown). Affected areas
are shown in darkblue.
5
%
Pulmonary stenosis
This is a narrowing ofthe
pulmonaryvalve, or (rarely)
ofthe upper right ventricle,
and reduces the blood flow
to the lungs.
How blood circulates
Deoxygenated blood (grey) is pumped from the
right ventricle through the pulmonary arteries
into the lungs, where it exchanges carbon dioxide
for oxygen. Oxygenated blood (blue) enters the
left side ofthe heart; it is pumped from the left
ventricle through the aorta to the body tissues.
Ventricular septal defect
This is a hole in the wall
(septum) between the
ventricles, causing blood to
flow from the left ventricle to
the right and into the lungs.
Coarctation of the aorta
In this disorder, localized
narrowing of the aorta
reduces the supply of
blood to the lower part
of the body.
|
| 8%
Patent ductus arteriosus
The ductus arteriosus fails to
close after birth and blood
from the aorta continues to
flow through it into the
pulmonary artery.
[
14%
Tetralogy of Fallot
This defect includes a hole
in the ventricular septum,
pulmonary stenosis, a
displaced aorta, and a
thickened right ventricle.
Transposition of the
great vessels
Oxygenated blood passes
backto the lungs, instead
ofthrough the aorta to the
bodytissues.
H
n a r y a r t e r i e s , u s u a l l y d u e t o
a t h e r o s c l e r -
o s i s
,
t h a t
r e s u l t s
i n
a
r e d u c e d
b l o o d
s u p p l y ( s e e
c o r o n a r y a r t e r y d i s e a s e
).
heart failure
I n a b i l i t y
o f t h e
h e a r t
t o
c o p e w i t h i t s
w o r k l o a d
o f
p u m p i n g
b l o o d
t o
t h e
l u n g s a n d t o t h e r e s t o f t h e b o d y . H e a r t
f a i l u r e
c a n
p r i m a r i l y
a f f e c t
e i t h e r
t h e
r i g h t o r t h e l e f t s i d e o f t h e h e a r t ; h o w -
e v e r ,
i t
m
o s t
c o m
m o n l y
a f f e c t s
b o t h
s i d e s .
H e a r t
f a i l u r e
c a n
b e
a c u t e
o r
c h r o n i c ( c o n g e s t i v e ) .
TYPES AND CAUSES
Left-sided heart failure
L e f t - s i d e d f a i l u r e
m a y b e d u e t o
h y p e r t e n s i o n
( h i g h b l o o d
p r e s s u r e ) ,
a n a e m i a
,
h y p e r t h y r o i d i s m
( o v e r -
a c t i v i t y
o f t h e t h y r o i d g l a n d ) ,
a
h e a r t
v a l v e
d e f e c t ( s u c h a s
a o r t i c s t e n o s i s , a o r t i c
i n c o m p e t e n c e
,
o r
m i t r a l i n c o m p e t e n c e
),
o r a
c o n g e n i t a l h e a r t d e f e c t ( s e e
h e a r t d i s e a -
s e , c o n g e n i t a l
).
I n a l l o f t h e s e c o n d i t i o n s ,
t h e
l e f t
s i d e
o f t h e
h e a r t
m u s t
w o r k
h a r d e r t h a n n o r m a l t o p u m p t h e s a m e
a m o u n t o f b l o o d . S o m e t i m e s , t h e h e a r t
c a n c o m p e n s a t e f o r t h e e x t r a w o r k l o a d
b y a n i n c r e a s e i n t h e s i z e o f t h e l e f t s i d e
a n d i n t h e t h i c k n e s s o f i t s m u s c u l a r w a l l s ,
o r b y a n i n c r e a s e i n t h e
h e a r t r a t e
.
T h i s
c o m p e n s a t i o n i s o n l y t e m p o r a r y , h o w -
e v e r , a n d h e a r t f a i l u r e e v e n t u a l l y f o l l o w s .
O t h e r c a u s e s o f l e f t - s i d e d h e a r t f a i l u r e
i n c l u d e
c o r o n a r y a r t e r y d i s e a s e
,
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 ) ,
c a r d i a c a r r h y t h -
m i a s
( i r r e g u l a r i t i e s
o f
h e a r t
r h y t h m ) ,
a n d
c a r d i o m y o p a t h y
( d i s e a s e o f t h e h e a r t
m u s c l e ) . I n c a r d i o m y o p a t h y , t h e p u m p -
i n g p o w e r o f t h e h e a r t i s r e d u c e d t o a
p o i n t w h e r e i t c a n n o l o n g e r d e a l w i t h
i t s n o r m a l w o r k l o a d .
W
h a t e v e r
t h e
u n d e r l y i n g
c a u s e ,
i n
l e f t - s i d e d h e a r t f a i l u r e t h e l e f t s i d e
o f
t h e h e a r t f a i l s t o e m p t y c o m p l e t e l y w i t h
e a c h
c o n t r a c t i o n ,
o r
h a s
d i f f i c u l t y
i n
a c c e p t i n g b l o o d t h a t h a s b e e n r e t u r n e d
f r o m t h e l u n g s . T h e r e t a i n e d b l o o d c r e -
a t e s a “ b a c k p r e s s u r e ”
t h a t
c a u s e s t h e
l u n g s t o b e c o m
e c o n g e s t e d w i t h b l o o d .
T h i s c o n d i t i o n l e a d s t o
p u l m o n a r y o e d e m a
( e x c e s s f l u i d i n t h e l u n g s ) , o f w h i c h t h e
m a i n s y m p t o m i s s h o r t n e s s
o f b r e a t h ,
e v e n t u a l l y e v e n w h e n a t r e s t . T h e p a t i e n t
m a y
a w a k e n
a t
n i g h t
w i t h
a t t a c k s
o f
b r e a t h l e s s n e s s , w h e e z i n g , a n d s w e a t i n g .
Right-sided heart failure
R i g h t - s i d e d f a i l -
u r e i s m o s t o f t e n c a u s e d b y
p u l m o n a r y
h y p e r t e n s i o n
( r a i s e d
b l o o d
p r e s s u r e
i n
t h e a r t e r i e s s u p p l y i n g t h e l u n g s ) . T h i s i s
i t s e l f c a u s e d b y l e f t - s i d e d h e a r t f a i l u r e ,
o r
a
l u n g
d i s e a s e
s u c h
a s
c h r o n i c
o b s t r u c t i v e p u l m o n a r y d i s e a s e ( s e e
p u l -
m o n a r y d i s e a s e
,
c h r o n i c o b s t r u c t i v e
).
R i g h t -
s i d e d f a i l u r e c a n a l s o b e d u e t o a h e a r t
v a l v e
d e f e c t ,
s u c h
a s
t r i c u s p i d i n c o m p -
e t e n c e
,
o r t o a c o n g e n i t a l h e a r t d e f e c t .
I n a l l t y p e s o f r i g h t - s i d e d h e a r t f a i l u r e ,
t h e r e i s b a c k p r e s s u r e i n t h e c i r c u l a t i o n
f r o m t h e h e a r t i n t o t h e v e n o u s s y s t e m ,
c a u s i n g
s w o l l e n
n e c k
v e i n s ,
e n l a r g e -
m
e n t o f t h e l i v e r , a n d
o e d e m a
( e x c e s s
f l u i d i n b o d y t i s s u e s ) ,
e s p e c i a l l y s w e l -
l i n g o f t h e l e g s a n d a n k l e s . I n a d d i t i o n ,
t h e i n t e s t i n e s m a y
b e c o m e
c o n g e s t e d ,
c a u s i n g d i s c o m f o r t a n d i n d i g e s t i o n .
INVESTIGATION AND TREATMENT
I n v e s t i g a t i o n o f s u s p e c t e d h e a r t f a i l u r e
m a y
i n v o l v e
a
p h y s i c a l
e x a m i n a t i o n ,
X - r a y
,
E C G
,
a n d
e c h o c a r d i o g r a p h y
.
369
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