C harles M ady, R icardo N acruth
N a tu r a l h is to r y o f c h r o n ic
C h a g a s ' h e a r t d is e a s e : p r o g n o s is f a c to r s
Heart Institute, Hospital das Clinicas da Faculdade
de Medicina
da Universidade de Siio Paulo - Siio Paulo, Brazil
C h ro n ic C h a g a s ' d is e a s e s h o w s s e v e ra l p ro g re s s io n m o d e s . U s u a lly , th e d iffe re n t c lin ic a l s y n d ro m e s m a n ife s t th e m s e lv e s to g e th e r, h o w e v e r, is o la te d fo rm s c a n o c c u r. C a rd ia c a rrh y th m ia s , w h ic h a re v e ry fre q u e n t, a re p re s e n t in a b o u t 5 0 % o f p a tie n ts . T h e c a rd ia c d a m a g e m a n ife s ts its e lf la te r, w ith th e e m e rg e n c e o f h e a rt fa ilu re . T h ro m b o e m b o lis m c a n o c c u r in b o th p u lm o n a ry a n d
s y s te m ic c irc u la tio n . P u lm o n a ry e m b o lis m is th e m o s t fre q u e n t, a p p e a rin g in m o re a d v a n c e d p h a s e s o f h e a rt d is e a s e . S u d d e n d e a th is th e fa ta l o u tc o m e o f th e s e p a tie n ts . It p re d o m in a te s in m a le s a n d it g e n e ra lly o c c u rs in a d is e a s e s ta g e w h e n p a tie n ts h a v e th e ir h ig h e s t p ro d u c tiv ity . T h e p re s e n c e o f s e rio u s v e n tric u la r a rrh y th m ia s , c o n d u c tio n d is tu rb a n c e s in th e e le tro c a rd io g ra m ,
a n d h e a rt fa ilu re , p ro v id e a n u n fa v o ra b le p ro g n o s is .
U N IT E R M S : C h ro n ic C h a g a s ' d is e a s e . N a tu ra l h is to ry . P ro g n o s tic .
T
h ef i r s tc h r o n i cs t u d i e d C h a g a s 'i n 1 9 2 2 d i s e a s eb y C h a g a sc a r d i o m y o p a t h ya n d V i l l e l a ( 5 ) .w a sT h e c h r o n i c c a r d i o m y o p a t h y c o m p r i s e s t h e m o s t
i m p o r t a n t c l i n i c a l f o r m o f t h e d i s e a s e . T h o s e a u t h o r s h a v e
b e e n a b l e t o e s t a b l i s h c o n c l u s i o n s v e r y c l e a r a b o u t i t s
c l i n i c a l p i c t u r e , p r o g r e s s i o n a n d d i s e a s e p r o g n o s i s s i n c e
t h a t t i m e .
A f t e r t h e a c u t e p h a s e , w h i c h l a s t s a b o u t t w o m o n t h s ,
t h e p a t i e n t c a n r e m a i n i n d e f i n i t e l y i n t h e i n d e t e r m i n a t e
f o r m ( 1 1 ) , o r t h e c h r o n i c C h a g a s ' d i s e a s e c a n m a n i f e s t s
A ddress for correspondence: C harles M ady
Instituto do C orar;ao - H ospital das C lfnicas da FM U SP Av. D r. Eneas de C arvalho Aguiar, 44
Sao Paulo - Sao Paulo - Brasil - C EP 05403-000
i t s e l f a f t e r s o m e d e c a d e s o f p r o g r e s s i o n . T h e c h r o n i c
C h a g a s ' d i s e a s e d i s p l a y s d i f f e r e n t c a r d i a c m a n i f e s t a t i o n s
w i t h t h e p r e s e n c e o f a r r h y t h m i a s a n d / o r c o n d u c t i o n
d i s t u r b a n c e s , h e a r t f a i l u r e , t h r o m b o e m b o l i s m a n d s u d d e n
d e a t h a r e t h e m o s t c o m m o n ( t a b l e 1 ) . T h e s e c l i n i c a l
s y n d r o m e s c a n b e m a n i f e s t e d s e p a r a t e l y , b u t t h e y u s u a l l y
s u r f a c e t o g e t h e r .
T a b le 1
C a r d ia c m a n ife s ta tio n s o f c h r o n ic C h a g a s ' d is e a s e
• A rrh y th m ia s a n d /o r c o n d u c tio n d is tu rb a n c e • H e a rt fa ilu re
• T h ro m b o e m b o lis m • S u d d e n d e a th
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O n e o f t h e c h r o n i c C h a g a s ' d i s e a s e a t t r i b u t e s i s t h e
g r e a t v a r i e t y o f c a r d i a c r h y t h m d i s t u r b a n c e s p r e s e n t i n
a b o u t 5 0 % o f t h e p a t i e n t s . C a r d i a c r h y t h m c h a n g e s a r e
t h e m o s t f r e q u e n t c l i n i c a l f o r m o f t h e d i s e a s e .
T h e c h r o n i c C h a g a s ' c a r d i o m y o p a t h y , w i t h i t s
d i f f u s e , p r o g r e s s i v e a n d f i b r o t i c c h a r a c t e r i s t i c s , i s a n
e x c e l l e n t a n a t o m i c a n d p a t h o l o g i c a l b a c k g r o u n d f o r t h e r e - e n t r y 's p h e n o m e n o n w i t h t h e c o n s e q u e n t t h e o c c u r r e n c e
o f a r r h y t h m i a s .
A n d r a d e ( 1 ) , s t u d i e d t h e m o r p h o l o g i c a l b a s i s o f t h e
c a r d i a c a r r h y t h m i a s i n c h r o n i c C h a g a s ' d i s e a s e . H e
d i s c u s s e s t h a t a l l t h e h e a r t c o n d u c t i o n s y s t e m c a n b e
a s s a i l e d , i n c l u d i n g t h e s i n u s - a t r i a l n o d e , a t r i o v e n t r i c u l a r
n o d a l , H i s ' b u n d l e , H i s ' b u n d l e b r a n c h e s a n d P u r k i n j e 's
f i b e r s .
O n e c a n s p l i t t h e a r r h y t h m i a s i n t h r e e g r o u p s :
e x t r a s y s t o l e s , b r a d y a r r h y t h m i a s a n d t a c h y a r r h y t h m i a s .
T h e m o s t f r e q u e n t e l e c t r o c a r d i o g r a p h i c c h a n g e s a r e
v e n t r i c u l a r e x t r a s y s t o l e s , c o m p l e t e r i g h t b u n d l e b r a n c h
b l o c k , a n t e r o - s e p t a l d i v i s i o n a l b l o c k o f l e f t b r a n c h , s e v e r a l
g r a d e s o f a t r i o v e n t r i c u l a r b l o c k s a n d c h a n g e s i n t h e
v e n t r i c u l a r r e p o l a r i z a t i o n ( 3 ) . T h e v e n t r i c u l a r e x t r a s y s t o l e s
a r e a c o m m o n f i n d i n g , m a i n l y t h e p o l y m o r p h i c g r o u p o f
e x t r a s s y s t o l e s .
F r e q u e n t l y , o n e o b s e r v e s v e n t r i c u l a r e x t r a s y s t o l e s
a s s o c i a t e d w i t h d i v i s i o n s a n d b r a n c h e s b l o c k s . T h e
p r e s e n c e o f t h e c o m p l e t e r i g h t b r a n c h b l o c k i s u s u a l l y
a s s o c i a t e d t o a n t e r o s e p t a l d i v i s i o n a l b l o c k o f l e f t b r a n c h .
N a c r u t h a n d c o l . ( 1 3 ) , i n a r e t r o s p e c t i v e s t u d y o f 1 4 3
p a t i e n t s , f o u n d t h e p r e d o m i n a n c e o f c o m p l e t e r i g h t b r a n c h
b l o c k a s s o c i a t e d t o a n t e r o s e p t a l d i v i s i o n a l b l o c k o f l e f t
b r a n c h ( B R D e B D A S ) ( 2 4 ,4 7 % ) f o l l o w e d b y a n i s o l a t e d
B C R D ( 1 3 ,2 8 % ) a n d B D A S ( 9 ,7 % ) .
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1. A 20 year-old m ale patient w ith C hagas' disease com plained of palpitations during physical efforts. H e alsoreported tw o syncope attacks during practicing sports. H e had an unrem arkable chest X -ray. H is conventional E K G presented an A Q R S axis deviation to the right and a B C R D . The H olter m onitoring show ed both sustained and non-sustained ventricular tachycardia. The patient died suddenly death during physical effort about one m onth after the identification of the ventricular tachyarrhythm ia. H e w as taking am iodarone.
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2 . A 3 6 ye a r-o ld m a le p a tie n t w ith C h a g a s' d ise a se w ith a b a sa l lin e E K G (A ) sh o w in g a n in co m p le te a n dco m p le te rig h t b u n d le b ra n ch b lo ck a n d ve n tricu la r e xtra systo le s su g g e stin g in a ctive a re a s;
(8 ) S u sta in e d ve n tricu la r ta ch yca rd ia . E ch o ca rd io g ra m sh o w e d se g m e n ta l d isju n ctio n a n d lo w e r m id d le -b a sa l a kin e sis.
T h e a r r h y t h m i a s u s u a l l y p r o v o k e p a l p i t a t i o n s a n d
v e r t i g o a n d d e p e n d i n g o n t h e s e v e r i t y , t h e a r r h y t h m i a s c a n
c a u s e f a i n t i n g , s y n c o p e a n d s e i z u r e s d u e t o l o w c a r d i a c
a n d c e r e b r a l b l o o d f l o w .
I n t h i s c o n t e x t , t h e v e n t r i c u l a r t a c h y a r r h y t h m i a s
h a v e a v i t a l i m p o r t a n c e i n t h e o c c u r r e n c e o f s u d d e n d e a t h
( f i g u r e 1 ) .
I n g e n e r a l , v e n t r i c u l a r t a c h y a r r h y t h m i a s c o m e a l o n g
w i t h c a r d i o m e g a l y a n d b r a n c h a n d / o r d i v i s i o n a l b l o c k s .
H o w e v e r , v e n t r i c u l a r a r r h y t h m i a s i s h a r d l y o b s e r v e d i n
s u b j e c t s w i t h a n o r m a l c a r d i a c a r e a a n d / o r a p r e v i o u s
e l e c t r o c a r d i o g r a m w i t h o u t a c o n d u c t i o n d i s t u r b a n c e
( F i g u r e 2 ) .
S o m e n o n i n v a s i v e c a r d i a c t e s t s , s u c h a s H o l t e r
m o n i t o r i n g , e r g o m e t r i c t e s t a n d e c h o c a r d i o g r a m , h e l p o n
e v a l u a t i o n t h e a r r h y t h m i a s . T h e H o l t e r t e s t i s t h e m o s t
s e n s i t i v e t o d e t e c t a r r h y t h m i a s . E r g o m e t r i c t e s t i s l e s s
s e n s i t i v e t h a n t h e H o l t e r t e s t . T h e e r g o m e t r i c t e s t c a n
s o m e t i m e s d e t e c t t a c h y a r r h y t h m i a s , b e i n g v e r y u s e f u l i n
t h o s e p a t i e n t s w i t h p h y s i c a l e f f o r t - r e l a t e d s y m p t o m s . T h e
e f f o r t t e s t , i n s o m e o c c a s i o n s , i d e n t i f i e s p a t i e n t s w i t h
C h a g a s ' d i s e a s e p r e d i s p o s e d t o s u d d e n d e a t h .
E l e c t r o p h y s i o l o g i c a l s t u d i e s p r o v i d e i m p o r t a n t i n f o r m a t i o n
f o r t h e e v a l u a t i o n o f t h e d e v e l o p m e n t a n d c o n d u c t i o n
d i s t u r b a n c e o f t h e s t i m u l u s . T h e s e s t u d i e s a r e a b l e t o
i n d u c e v e n t r i c u l a r t a c h y c a r d i a i n s o m e p a t i e n t s . A c c o r d i n g
t o D e P a o l a ( 6 ) , i t i s p o s s i b l e t o i n d u c e t h e s a m e a r r h y t h m i a
i n 8 1% o f t h e p a t i e n t s w i t h c h r o n i c C h a g a s ' d i s e a s e a n d
r e c u r r e n t v e n t r i c u l a r t a c h y c a r d i a . B e s i d e s t h e c l i n i c a l
a r r h y t h m i a i n d u c t i o n , t h e e l e c t r 9 p h i s i o l o g i c a l s t u d y
l o c a l i z e s t h e a r r h y t h m o g e n i c f o c u s o f t h e v e n t r i c u l a r
t a c h y c a r d i a t h r o u g h t h e e n d o c a r d i c m a p p i n g . T h e
e n d o c a r d i c m a p p i n g o f t h e a r r h y t h m o g e n i c f o c u s d u r i n g
t h e e l e c t r o p h i s i o l o g i c a l s t u d y h a s b e e n a c c o m p l i s h e d
n o w a d a y s w i t h p r o m i s i n g r e s u l t s ( 7 ) .
HEART FAILURE
T h e h is to p a th o lo g ic a l fin d in g s in c a rd ia c c h ro n ic
C h a g a s ' d is e a s e a re d iffe re n t fro m th e th o s e fo u n d in th e
a c u te p h a s e a n d in th e m y o c a rd itis o f o th e r e tio lo g ie s . T h e
a n a to m ic b a c k g ro u n d o f c h ro n ic C h a g a s ' d is e a s e is a
p ro g re s s iv e , fib ro tic a n d d iffu s e c h ro n ic m y o c a rd itis , th a t
s lo w ly d e s tro y s th e m y o c a rd ia l fib e rs le a d in g to h e a rt
fa ilu re .
In g e n e ra l, th e h e a rt fa ilu re m a n ife s ts its e lf b e tw e e n
th irty a n d fo rty y e a rs o f a g e . H o w e v e r, it c a n m a n ife s t
its e lf in a n y p ro g re s s iv e p e rio d . T h e h e a rt fa ilu re u s u a lly
a p p e a rs la te r w h e n c o m p a re d to th e a rrh y th m ia s . It
d e v e lo p s s lo w ly a n d it ra re ly d e v e lo p s in a q u ic k w a y w ith
h a e m o d y n a m ic d e te rio ra tio n in a s h o rt p e " rio d o f tim e .
T h e h e a rt fa ilu re is g lo b a l, b u t m a n ife s ta tio n s o f rig h t
h e a rt fa ilu re c a n b e p re d o m in a n t, a n d th e y a re o n e
p e c u lia rity o f h e a rt fa ilu re fro m C h a g a s ' e tio lo g y . It is
in te re s tin g to o b s e rv e th e c o n tra s t b e tw e e n th e d e g re e o f
s y s te m ic p a s s iv e c o n g e s tio n , a n d th e fe w c lin ic a l
m a n ife s ta tio n s o f th e le ft v e n tric u la r fa ilu re . W e fre q u e n tly
o b s e rv e p a tie n ts w ith m a rk e d ju g u la r tu rg e s c e n c e , p a in fu l
h e p a to m e g a lia a n d lo w e r lim b e d e m a , b e a rin g q u ite w e ll
th e d o rs a l d e c u b itu s .
N o c tu rn a l p a ro x y s m a l o rth o p n e a a s w e ll d y s p n e a a re
n o t o b s e rv e d w ith th e s a m e fre q u e n c y a s th e y a re fo u n d in
h e a rt fa ilu re o f o th e r e tio lo g ie s . T h e h e p a to m e g a lia is
m a n ife s te d e a rly a n d th e p a tie n t's m a in c o m p la in t is u s u a lly
p a in in th e rig h t h y p o c h o n d riu m (1 9 ).
A t th is s ta g e , it is p o s s ib le to o b s e rv e la rg e
c a rd io m e g a lie s a n d e le c tro c a rd io g ra p h ic c h a n g e s in n e a rly
a ll p a tie n ts . T h e e c h o c a rd io g ra m s h o w s h y p o k in e tic a re a s ,
d y s k in e tic , v o rte x le s io n , in tra c a v ita ry th ro m b u s a n d /o r
d ia s to lic d y s fu n c tio n o f le ft v e n tric le .
In th e fo llo w -u p o f a p a tie n t w ith c h ro n ic C h a g a s
(5 ) d is e a s e , it is o b s e rv e d th a t, w h e n th e h e a rt fa ilu re s ta rts
to m a n ife s t, th e p ro g n o s is g ro w s w o rs e w ith a n e v id e n t
in c re a s e in th e m o rb id ity a n d m o rta lity .
It is re la tiv e ly fre q u e n t th e p re s e n c e o f v e n tric u la r
a rrh y th m ia s in p a tie n ts w ith h e a rt fa ilu re , p a rtic u la rly th e
v e n tric u la r e x tra s y s to le s a n d s u s ta in e d a n d n o t-s u s ta in e d
v e n tric u la r ta c h y c a rd ia .
THROMBOEMBOLISM
T h e o c c u rre n c e o f th ro m b o e m b o lis m in c h ro n ic
C h a g a s ' d is e a s e is fre q u e n t in s y s te m ic a n d p u lm o n a ry
794
c irc u la tio n s , h o w e v e r it is m o re fre q u e n t in th e p u lm o n a ry
o n e . It u s u a lly o c c u rs in a d v a n c e d p h a s e s o f h e a rt fa ilu re ,
b u t is a ls o o b s e rv e d in th e in itia l p h a s e s o f h e a rt d is e a s e .
T h e g re a t im p o rta n c e o f v o rte x le s io n in
th ro m b o e m b o lic p h e n o m e n o n o c c u rre n c e is p o in te d o u t.
T h e v o rte x le s io n o r a p e x le s io n , w h ic h is c h a ra c te ris tic
o f c h ro n ic C h a g a s ' d is e a s e , c o n s is ts o f d e p o p u la tio n a n d
a tro p h y o f th e m y o c a rd iu m o f th e v o rte x re g io n ,
p re d is p o s in g to th e th ro m b u s fo rm a tio n . T h e p re v a le n c e
o f a p ic a l le s io n in c h ro n ic C h a g a s ' d is e a s e is v a ria b le a n d
it c a n o s c illa te a ro u n d 5 0 % to 8 0 % o f p a tie n ts , b e in g m o re
fre q u e n t in p a tie n ts w ith h e a rt fa ilu re .
O th e r fa c to rs , s u c h a s c irc u la to ry s ta s is th a t is p re s e n t
in h e a rt fa ilu re a n d a tria l fib rilla tio n , it a ls o p re d is p o s e s
to th ro m b o e m b o lis m .
A n d ra d e a n d A n d ra d e (2 ) s tu d ie d 2 0 8 p a tie n ts a n d
fo u n d th ro m b o s is in th e fo llo w in g p la c e s : rig h t a triu m
(5 6 ,2 % ), a p e x o f th e le ft v e n tric le (4 7 ,1 % ), le ft a triu m
a n d a p e x o f th e rig h t v e n tric le (1 2 ,9 % ), m u ra l
e n d o c a rd iu m o f th e le ft v e n tric le (1 0 ,6 % ) a n d o f th e rig h t
v e n tric le (1 ,4 % ). It w a s n o t o b s e rv e d in tra c a v ita ry th ro m b i
in 5 0 p a tie n ts (2 4 % ). It d ra w s o n e 's a tte n tio n th e h ig h
in c id e n c e o f th is p h e n o m e n o n in th e s e p a tie n ts .
O liv e ira (1 4 ) u p o n a n a ly s in g 5 1 5 p a tie n ts w ith
c a rd ia c th ro m b o s is , o b s e rv e d th a t th e le ft c a rd ia c c h a m b e rs
w e re a ffe c te d m o re fre q u e n tly , b e in g th e v e n tric u la r c a v ity
th e m o s t a ffe c te d . R ig h t c h a m b e r th ro m b o s is w a s le s s
fre q u e n t, w ith p re d o m in a n c e o f a tria l th ro m b o s is .
T h e p re s e n c e o f th ro m b o s is is o b s e rv e d th ro u g h th e
e c h o c a rd io g ra m o r th ro u g h v e n tric u lo g ra p h ic s tu d ie s a n d
it s h o u ld b e s u g g e s te d b y th e p re s e n c e o f h y p o k in e tic o r
a k in e tic a re a s .
SUDDEN
DEATH
T h e h ig h p re v a le n c e o f s u d d e n d e a th in c h ro n ic
C h a g a s ' d is e a s e is k n o w n s in c e a lo n g tim e a g o in e n d e m ic
re g io n s a n d it w a s re m a rk e d b y C a rlo s C h a g a s (4 ) in 1 9 1 2 .
T h e p re v a le n c e o f s u d d e n d e a th in m e d ic a l lite ra tu re
is v a ria b le . P o rto (1 7 ) d e te c te d s u d d e n d e a th in 3 7 ,5 % o f
h is p a tie n ts . K o b e rle (8 ) o b s e rv e d th a t 3 0 % o f h is p a tie n ts
w ith C h a g a s ' d is e a s e w h o w e re s u b m itte d to a n a u to p s y ,
d ie d fro m s u d d e n d e a th . L o p e s a n d c o l (1 0 ) n o tic e d th a t
1 2 ,6 % o f h is p a tie n ts w ith C h a g a s ' w h o w e re s u b m itte d
to a n a u to p s y , d ie d fro m s u d d e n d e a th .
S u d d e n d e a th c a n b e e ith e r u n e x p e c te d o r n o t. T h e
u n e x p e c te d s u d d e n d e a th o c c u rs in th o s e p a tie n ts w h o a re
w e ll, a s y m p to m a tic , a n d it is n o t v e ry fre q u e n t. T h e
e x p e c te d s u d d e n d e a th o c c u r s in p a tie n ts in w h o s e p r e v io u s
s y m p to m s c o u ld b e o b s e r v e d , a n d , in m o s t o f th e tim e ,
w ith a d v a n c e d h e a r t d is e a s e . I t p r e d o m in a n tly a s s a ils m e n ,
a n d o c c u r s , m o r e f r e q u e n tly , b e tw e e n th e th ir d a n d f if th d e c a d e s o f lif e .
T h e s y m p to m s o f p a tie n ts w h o d ie d s u d d e n ly a r e th e
c o n s e q u e n c e s o f th e p r e s e n c e o f v e n tr ic u la r a r r h y th m ia s ,
m a n if e s tin g th e m s e lv e s b y p a lp ita tio n s , v e r tig o , lip o th y m ia a n d S to k e s - A d a m s . S u s ta in e d v e n tr ic u la r ta c h y c a r d ia is
th e m o s t c o m m o n a r r h y th m ia , p r o g r e s s in g to v e n tr ic u la r f ib r illa tio n .
G e n e r a lly , s u d d e n d e a th o c c u r s d u r in g p h y s ic a l
a c tiv ity . T h e r e a r e f a m ily h is to r ie s o f s u d d e n d e a th in m o r e th a n 8 0 % o f th e p a tie n ts ( 1 8 ) .
T h e r e a r e s o m e p r e d is p o s in g f a c to r s to s u d d e n d e a th : c h r o n ic m y o c a r d itis , f ib r o s is , c o n d u c tio n s y s te m c h a n g e ,
a p ic a l le s io n ( a r r h y th m o g e n ic s o u r c e ) , s e x a n d a g e . I n f a c t,
s e v e r a l c lin ic a l s y n d r o m e s o f c h r o n ic C h a g a s ' d is e a s e p r e d is p o s e to s u d d e n d e a th ..
PROGNOSTIC
FACTORS
T h e c h r o n ic C h a g a s ' d is e a s e s h o w s a s lo w a n d u n r e le n tin g p r o g r e s s io n . I t d e v e lo p s f a s t s o m e tim e s ,
c a u s in g im p o r ta n t c lin ic a l m a n if e s ta tio n s in y o u n g p e o p le .
T h e e a r lie r th e c lin ic a l b e c o m e s m a n if e s te d , th e w o r s e th e p r o g n o s is w ill b e .
S o m e f a c to r s in f lu e n c e th e p r o g n o s is o f c h r o n ic f o r m
o f C h a g a s ' d is e a s e in a n e g a tiv e w a y : h e a r t f a ilu r e ,
a r r h y th m ia s s u c h a s v e n tr ic u la r e x tr a s y s to le s , p o ly m o r p h ic
o r c lu s te r f ib r illa tio n , a tr ia l f lu tte r , v e n tr ic u la r ta c h y c a r d ia ,
to ta l a tr io v e n tr ic u la r b lo c k a n d in a c tiv e a r e a s ( 1 9 ) .
T h e p r e s e n c e o f f a ilu r e a n d /o r s u s ta in e d v e n tr ic u la r
ta c h y c a r d ia is c o n s id e r e d th e w o r s t p r o g n o s tic f a c to r .
T h e e le c tr o c a r d io g r a m s h o w s a r e a l p r o g n o s tic v a lu e
in th e c h r o n ic C h a g a s ' d is e a s e . A n o r m a l
e le c tr o c a r d io g r a m in d ic a te s a g o o d p r o g n o s is . T h e
p r e s e n c e o f c o m p le te r ig h t b r a n c h b lo c k d o e s n o t in d ic a te
a b a d p r o g n o s is , h o w e v e r th e s itu a tio n g r o w s w o r s e w h e n
th e b lo c k is a s s o c ia te d to a x is d e v ia tio n to th e le f t. T h e
c o m p le te le f t b r a n c h b lo c k , w h ic h o c c u r s le s s f r e q u e n tly ,
in d ic a te s a b a d p r o g n o s is ( 1 7 ) . S im ila r r e s u lts w e r e
o b s e r v e d b y N a c r u th a n d c o ls . ( 1 3 ) .
G e n d e r in f lu e n c e s th e d is e a s e 's n a tu r a l h is to r y .
G e n e r a lly , th e c a r d ia c d a m a g e is g r e a te r in m e n , a n d th a t
c a n e x p la in th e w o r s t p r o g r e s s io n in th is s e x ( 1 5 ) .
T h e o th e r f a c to r is a g e . I t h a s g r e a t im p o r ta n c e ,
b e c a u s e th e m a jo r ity o f th e p a tie n ts w h o d ie , a r e in th e
h ig h e s t p r o d u c tiv e p h a s e o f th e ir liv e s . L a r a n ja a n d c o l.
( 9 ) , a n a ly z e d 2 0 0 p a tie n ts w h o d ie d a n d o b s e r v e d th a t 5 5 %
o f th e m w e r e b e tw e e n 2 1 a n d 4 0 y e a r s o f a g e .
W e ju d g e th a t th e s u ita b le k n o w le d g e o f th o s e
p r o g n o s tic f a c to r s h e lp s u s in te n s e ly , b o th in s o c ia l a n d
p r o f e s s io n a l w o r d s o f a d v ic e a n d in th e th e r a p e u tic o r ie n ta tio n o f th e p a tie n ts .
Sao Paulo Medical Journal/RPM 113(2) Mar/Apr 1995
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