HEART SOUNDS
H
1 0 0 b e a t s p e r m i n u t e i s t e r m e d a
t a c h y -
c a r d i a
,
a n d a r a t e b e l o w
6 0
b e a t s p e r
m i n u t e i s k n o w n a s a
b r a d y c a r d i a
.
( S e e
a l s o
a r r h y t h m i a , c a r d i a c
.)
heart sounds
T h e s o u n d s m a d e
b y t h e
h e a r t
d u r i n g
e a c h
h e a r t b e a t
.
I n e a c h h e a r t c y c l e , t h e r e
a r e t w o m a i n h e a r t s o u n d s t h a t c a n c l e a r -
l y b e h e a r d t h r o u g h a
s t e t h o s c o p e
.
T h e
f i r s t i s l i k e a “ l u b b ” . I t r e s u l t s f r o m c l o -
s u r e o f t h e
t r i c u s p i d
a n d
m i t r a l v a l v e s
a t t h e
e x i t s o f t h e a t r i a ( u p p e r h e a r t c h a m b e r s ) ,
w h i c h o c c u r s w h e n t h e v e n t r i c l e s ( l o w e r
h e a r t
c h a m b e r s )
b e g i n
c o n t r a c t i n g
t o
p u m p b l o o d o u t o f t h e h e a r t . T h e s e c o n d
s o u n d i s a h i g h e r - p i t c h e d “ d u p p ” c a u s e d
b y c l o s u r e o f t h e p u l m o n a r y a n d a o r t i c
v a l v e s a t t h e e x i t s o f t h e v e n t r i c l e s w h e n
t h e v e n t r i c l e s f i n i s h c o n t r a c t i n g .
A b n o r m a l h e a r t s o u n d s m a y b e a s i g n
o f v a r i o u s d i s o r d e r s . F o r e x a m p l e , h i g h -
p i t c h e d s o u n d s o r “ c l i c k s ” a r e d u e t o t h e
a b r u p t h a l t i n g o f v a l v e o p e n i n g , w h i c h
c a n o c c u r i n p e o p l e w i t h c e r t a i n
h e a r t
v a l v e
d e f e c t s . H e a r t
m u r m u r s
a r e a b n o r -
m a l s o u n d s c a u s e d b y t u r b u l e n t b l o o d
f l o w . M u r m u r s m a y b e d u e t o h e a r t v a l v e
d e f e c t s o r t o c o n g e n i t a l h e a r t d i s e a s e .
heart surgery
A n y o p e r a t i o n t h a t i s p e r f o r m e d o n t h e
h e a r t
.
O p e n h e a r t s u r g e r y
a l l o w s t h e t r e a t -
m e n t o f m o s t t y p e s o f h e a r t d e f e c t t h a t
a r e p r e s e n t a t b i r t h
( 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
)
a s w e l l a s v a r i o u s d i s o r d e r s
o f t h e
h e a r t v a l v e s
.
C o r o n a r y a r t e r y b y p a s s
i s
p e r f o r m e d
t o
r e d i r e c t
b l o o d
a w a y
f r o m a b l o c k e d c o r o n a r y a r t e r y . A n g i o -
p l a s t y b a l l o o n s ( s e e
a n g i o p l a s t y , b a l l o o n
)
c a n b e u s e d t o o p e n u p n a r r o w e d h e a r t
v a l v e s
i n
c a s e s
w h e r e
t h e
p a t i e n t
i s
u n s u i t a b l e f o r o p e n h e a r t s u r g e r y
( s e e
v a l v u l o p l a s t y
).
H e a r t
t r a n s p l a n t
s u r g e r y
c a n o f f e r h o p e t o p e o p l e w i t h p r o g r e s -
s i v e , i n c u r a b l e h e a r t d i s e a s e .
heart transplant
R e p l a c e m e n t o f a p a t i e n t ’s d a m a g e d o r
d i s e a s e d
h e a r t
w i t h
a
h e a l t h y
h e a r t
t a k e n f r o m a d o n o r w h o h a s j u s t d i e d .
T y p i c a l l y ,
a
t r a n s p l a n t
p a t i e n t
h a s
a d -
v a n c e d
c o r o n a r y a r t e r y d i s e a s e
o r
c a r -
d i o m y o p a t h y
( d i s e a s e o f h e a r t m u s c l e ) .
D u r i n g t h e
o p e r a t i o n ,
t h e f u n c t i o n o f
t h e h e a r t i s t a k e n o v e r b y a
h e a r t - l u n g
m a c h i n e
.
M o s t o f t h e d i s e a s e d h e a r t i s
r e m o v e d , b u t t h e b a c k w a l l s o f t h e a t r i a
( u p p e r c h a m b e r s ) a r e l e f t i n p l a c e . T h e
v e n t r i c l e s
( l o w e r
c h a m b e r s )
a r e
t h e n
a t t a c h e d t o t h e r e m a i n i n g a r e a s o f t h e
r e c i p i e n t ’s h e a r t . B e c a u s e t h e t r a n s p l a n t -
HEART-VALVE REPLACEMENT
Any one of the four heart valves (aortic, pulmonary, mitral, or tricuspid) may be
replaced by a natural or an artificial valve. The procedure shown in the steps below
is for replacement of the aortic heart valve.
1
In nearly all heart-valve surgery, an incision
is made through the breastbone (sternum)
into the chest cavity. The patient is put on a
h e a r t - l u n g m a c h i n e ,
the beating ofthe heart
is stopped, and the heart is opened.
3
The replacement valve is sutured into
position and the aorta is closed. The
patient is disconnected from the heart-lung
machine and the chest wall is sewn up. The
operation takes between two and four hours.
2
The valve is first examined to determine
whether it can be repaired or whether it
must be replaced. If the latter is necessary (as
here), the valve is excised. (The dotted line in
this picture shows where the incision is made.)
Artificial heart valve in place
This chest X-ray shows the metal components
of an artificial heart valve. A ball-and-cage
valve has been used to replace the patient’s
diseased valve.
e d h e a r t h a s n o n e r v e s u p p l y , p a t i e n t s
t e n d t o h a v e a h i g h r e s t i n g h e a r t r a t e
a n d n o v a r i a t i o n i n b l o o d p r e s s u r e f r o m
d a y t o n i g h t .
A f t e r
t h e
i m m e d i a t e
p o s t - o p e r a t i v e
p e r i o d , t h e o u t l o o k i s g o o d . P a t i e n t s d o ,
h o w e v e r , f a c e t h e l o n g - t e r m
p r o b l e m s
a s s o c i a t e d w i t h o t h e r f o r m s o f
t r a n s p l a n t
s u r g e r y
,
i n c l u d i n g
r e j e c t i o n
a n d
i n f e c -
t i o n . ( S e e
h e a r t - l u n g t r a n s p l a n t
).
heart valve
A s t r u c t u r e a t t h e e x i t o f a
h e a r t
c h a m -
b e r ,
c o n s i s t i n g
o f t w o
o r
t h r e e
c u p -
s h a p e d f l a p s , t h a t a l l o w s b l o o d t o f l o w
o u t
o f
t h e
c h a m b e r
b u t
p r e v e n t s
i t
f r o m w a s h i n g b a c k . T h e r e a r e f o u r h e a r t
v a l v e s :
a o r t i c ,
p u l m o n a r y ,
m i t r a l ,
a n d
t r i c u s p i d . T h e
o p e n i n g a n d c l o s i n g
o f
t h e h e a r t v a l v e s d u r i n g e a c h h e a r t c y c l e
p r o d u c e s
h e a r t s o u n d s .
372
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