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Sympodurn on Pediatric Cardiology
How to Distinguish Between Innocent
and Pathologic Murmurs in Childhood
Amnon Rosenthal.
M D .*
I
A systolic murmur i s often heard on routine physical emmination in
the well baby or child. OR^ oh the common problems we encounter when
hearing the murmur i s td decide whether it is bmih or whether it is
associated with structurally or hernodynamically significant underlying cardiac disease. WhiIe the distinction may be readily made in most children,
the ability to clearly define and categorize the i n n w n t murmur by precise
criteria is most helpful in identikng those patients who may have more
subtle or early manifestations of a parhologic condition. The diagnosis of an
innocent murmur is based on specific features of the murmur as well as on
the absence of any other evidence .or a cardiac abnormality. The guilt or
innocence of a murmur is more often than not based 6n other features than
the murmur itself. One must remember that the heart is a pump and not
a music box. Any malfunction of the pump may indeed generate sounds
and noises not otherwise present, but the sounds may be just: one of many
changes that are taking place. One should not rely on the murmur alone
for diagnosis but search for other alterations that may result from pump
mafunction. Valuable information may be obtained, for example, from assessment of the upstroke or volume of the peripheml pulses, thrust of
cardiac impulse at the xyphoid or apiml area, and by the observation of
erythema of the fingertips or toes that may be indicative of mild hypoxernia, A complete and systematic cardiovascular evaluation is esseritial if
one is to distinguish between the pathologic and innocent murmur. In the
foliowing discussion I will point out the features helpful in identifying the
patient with probable or definite heart disease and not dwe1I on those with
obvious severe heart problem, i-e.. cyanosis or congestive heart failure.
*Dirtctor, Pediatric Cardiology. Professor o l Pediatrics nnd Communlcabte Diseases, C.S.
Matt Children$ Hospital. University of Michigan Medid Schml, Ann k h r , M i c h i p
Pediatric Clinic* of Norfh A Amprico-Vol
31. No. 6, December 1984
1229
I
-on
R o s ~ m
DEFINITION AND m S S I F I C A T I O N OF M U R M U R S
The most commonly used classitration in the grading of systolic murmurs i s h a t proposed by S a m k v i n e 7 many years ago. The Grade 1 murmur is a faint murmur that you have to listen to w e h l l y to appreciate. It
is usually heard under optimal conditions such as a quiet room, with a
well-behaved child who has a relatively slow heart rate. Crade 2 is a soft
murmur that is readily audible and Grade 3 a prominent or loud murmur.
Grade 4 murmur, by definition, is one that i s accompanied by a palpable
thrill over the precordium. The ability to discern a Crade 5 or 6 murmur
generally adds vety little to diagnostic usefulness. The two major types of
systolic cardiac murmurs initidly categorized by Leathern5 are the systolic
ejection or flow murmur and the systolic regurgitant murmur. The systolic
ejection murmur i s harsh, diamond-shaped, and starts beyond the first
heart sound. I t usually ends befo;e the second sound. R y contrast, the
systolic regurgitant murmur s
~ witsh the first heart sound (i.e., the first
heart sound is buried in the m'urmur and thus mnnot be readily heard)
and plateaus throtffiout systole. It may end prior to or with the second
heG sound. The Gstolic ejection murmur i s characteristic of the i n n w e n t
svstolic flow mumurs: valvular.or rascuIar obstruction (~ulmonarvvalvar
arterial stenosis, aortic stenosis, coarctation of the =&a). wheieas the
systolic regurgitant murmur is usually encountered with mitral: or tricus~id
segurptation and ventricular septa defect. The r e p rgitan t murmur may
be harsh or blowing, whereas the systolic ejection murmur is rarely blowing. The blowing late systolic murmur is chyacteristic of mitral regurgitation, particularly when associated with mitral valve prolapse.
Diastolic murmurs, genetally fdl into three mJor categories: those
with onset in early diastole due to semilunar (aortic or pulmonary) valve
regur~tation,mid-diastolic flow rumble (associated with a large intracardiac left-to-right shunt or marked atrioventricular valve regurgitation), and
presystolic murmur (due to mihd stenosis, tricuspid stenosis, or dirninished ventricular compliance). Presence of a diastolic murmur is, w i t h few
exceptions, indicative of a hemodynamidly or stmcr~rally significant
heart disease. The third major type of heart murmur i s a continuous murmur. I t is characterid by a diamond shape that peaks at or slightly bevond the second sound and then decrescendos durinr? diastole. The murmur generally is medium to high pitched (sounds 1ike'a washing machine)
and i s typical of such pathologic canditions as a patent ductus arteriosur,
aortapulrnonary collatetals, or surgially created aortopulmonary shunts.
I
I
II
dr
Il i
L/
HOW TO EVALUATE A MURMUR
Auscultation by dissection is crucial to accurate diagnosis. 1 have been
practicing pediatric cardiolol=y for more than 20 years, and each time I
listen to a patient I say to myself: "First. I must listen to the first heart
sound (its intensity, variabili~y,l d i z a t i o n , etc.) then to the second sound
(is it split? does it vary with respiration? i s P, loud?), then I must listen for
a third heart sound, and so on." After listening for the expected I specifi-
'
How TO DISTINCUISII
INNOCENT
tolic murIIe I murreciate. It
rl, with a
L is a soft
murmur.
I
palpable
i murmur
r types of
re systolic
le systolic
the Erst
trast,
the
. the first
r
ily heard)
le second
in nocent
~ryvalvar
cseas
the
tricuspid
mur may
oly blow-egurgitaes:
those
IT)valve
intracar:ion), and
)r dimin-
with few
cgni6cant
OUS mUF-
ghdy bcThe murmachine)
rteriosus,
;hunts.
lave been
vh time I
Erst heart '
)nd sound
listen for
I specih-
FROM PATHOLOGICMURMURS
caIly listen for any abnormal sounds such as a S4 or click. No matter how
experienced the examiner, a step by step ausculation first for heart sounds,
subsequently for systolic murmurs, and then separately for diastolic mutmurs is essential. W h e n evaluating children with heartpurmurs the ability to clearly characterize the second heart sound is perhaps more crucial
than any other sound. The second sound in chiIdhood i s normally spIit
with inspiration and is single on expiration. A widely split second heart
sound that does not vary with respiration (fixed) is characteristic of an atrial
scptd defect. Absence of the second component (PJ of the second heart
sound on auscultation suggests a single truncal *Valve, severe pulmonary
stenosis, or transposition of the great arteries (P, is not heard in ttansposition because the puImonav asZery is posterior to the aorta and further
away from the chest wall). A loud pulmonary cIosvre should suggest the
possibility of pulmonary artery hypertension. Similarly, the detection of a
constant early systolic ejection click at the apex is practically diagnostic of
the bicuspid aortic valve or a dilated aortic root. An ejection sound present
at the left upper sternal border, louder with expiition or heard only on
expiration, i s characteristic pulmonary valvar sltenosis. When a variable
early dick is 1ocaFized between the left lower sternal border and the apex,
it may be asswiated with an aneurysm of the rnembranaceous septum.
When evaluating children with a heart murmur. I listen to the heart
both in the supine and the sitting position, during expiration and inspiration, and in addition frequently detersnine the changes induced by exercise
or the Valsalva maneuver. In the supine position cardiac end-diastolic volume is larger, and therefore stroke volume greater than in the sitting or
standing position. Outflow mumurs that are dependent on the amount of
flow will therefore tend to be louder in the supine
An exception
m u r s in children with idiopathic hypertrophic subaartic stenosis. The
small intracardiac volume i n the erect or sitting position will increase left
ventricular outflow obstruction and thus the intensity of the murmur. Adequate appreciation of variation and splitting of the second beart sound,
systolic ejection clicks of semilunar stenosis, as well as the midsystolic
clicks of m i d valve proplapse are often best detected in the sitting position. Murmurs originating From the right heart are likely to increase in
intensity with inspiration (for example tricupsid regurgitation and pdmonary stenasis), whereas left-sided events tend to be Iouder during expiration (for example, murmur of ventricular septal defect, mitral regurgitation. or valvar aortic stenosis). During inspiration there is an increase in
venous return to the right herut and on expiration an increase in flow from
the lungs to the left heart, I find the ValsaIva maneuver most useful in
children I suspect may have hypertrophic subaortic stenosis or rnitral valve
prolapse. Valsalva is performed in children most easdy by asking them to
place their thumb in their mouth and then blow hard on it. In h e child
with hypertrophic subaortic stenosis the increase in intratheracic pressure
and decreased venous return results in a decrease in intracardiac volume,
mare severe abstmction to the left ventricular evtRow tract, and an increase in the intensity of the systoIic murmur. In the child with mitral
valve prolapse. the decrease in the left ventricular volume may result in
the detection or increased intensity of rnitrall regurgitation murmur and
'
AMNOW ROSE^
IIow TO Dry
the early appearance of the systolic click. The intensity of innwent systolic
outflow murmurs decreases during the Valsalva maneuver. Release of the
Valsdva maneuver will m i o n d 1 y be helpful inhhying to determine
whether the murmur io due to a right or left heart event. With initial
release of Valsalva, b l d first returns to the right heart and thus tends to
accentuate murmurs that originate in the right heart, On the second or
third heart beat, murmurs originating in thc left side (i.e., ventricular septal defect. aortic stenosis) will became louder. Using exercise in the offiee
is particularly useful when attempting to assess the magnitude of a left-toright shunt or severity of valvular (mftral or tricuspid) incompetence. In
The mi:
lows: they o
intensity (nc
crescendo-dt
dium, and, I
diovascular I
from the left
in Table 1. !
charaeterizer
the schrwl-age child, exercise in the office is readily performed by asking
the child to do U) situps. With the child starting in h e prone position
on the examining table, the examiner stands on the child's right side and
gently pulls the child's right hand while lifting or nudging his right shoulder. With a bit of coaching and guidance I have rarely encountered a child
who is not able to do 20 situpsj Immediately after exercise I listen to the
patient in the supine position to determine if a middiastolic flow murmur
i s present. Exercise increases pulmonary bEmd Bow and thus increases the
flow across the respective atrioventricular valve, resulting in the generation o l a rnid-diastolic flow rumble. I n patients with a ventricular septa1
defect or atrial septa1 defect the appearance of a flow rumble suggests that
the pulmonary b l d flow i s approximately ~ c oremore the magnitude
of systemic blood flow and that the defect may require surgical closure.
Similarly, in the patient with mitrd regurgitation the appearance of a diastolic flow murmur suggests that the regurgitation is modeiare in degree.
rather distin
border and i
of flow in th
infancy and
so-called ph
harsh, b
.
fore likely tl
ill, the incre
in the appe:
nized or a n
of its eflect
the intensity
The sul
CWSSXFICATION AND FEATURES OF INNOCENT MURMURS
Innocent murmurs by definition are murmurs that arc not assosiated
with any anatomic or physiologic abnormality. These murmurs have in the
past also been referred to as functional, inorganic, normal, innocuous. dynamic, or benign, k prefer the term innocent murmur. which was pmbahly
fint used by William Evans in 1943.' Normd murmur is also acceptable.
Both terms underscore the absence d underlying heart disease. Functional
is a vague and meaningless term to parents. It is important to emphasize
that innocent murmurs are heard in more than 50 p e r mnt of normal children from infancy through adolescene and that they are physiologjc in
nature. These murmurs result fmm turbulence at the origin of the great
arteries." 11- The great arteries arise from the ventricles at a slight angle
and are relatively narrower than the respective ventricle from which they
arise. The murmur is more readily heard in children than adults because
of their somewhat thinner chest and proxjmity of the heart to the anterior
chest wall. An analogy that most parents clearly understand i s the noise or
turbulence that could be heard when one tistens to water as it comes out
from the spigot into a hose. Increasing the flow of water or gently bending
the hose results in a louder noise or murmur. A similar s i t ~ ~ a t j om
n u r s in
the cardiovascular system.
d
supine posit
ventricular c
m u r m ~ r sart
volume and
above
and
n
right than th
at the site ol
tolic ejccEor
systole. It is
Table 1.
~t
R
1
st
C
N
I
How TO D ~ N C W I S
I NHN O C E FROM
~
PATHOLOCIC
MURMURS
)SEVI-LU
t systolic
;e of the
*tenmine
h initial
tends to
:mnd or
~ l a sepr
he office
1 left-to-
znce. In
n to the
murmur
ases the
.
!
generatr septa1
3sts that
I
1
The common clinical features of innocent outflow murmur are as folIows: they m u r in early systole, are generally of short duration and low
intensity (nearly always Grade 1 or Grade 2, -ionally
Grade 3) are
crescendo-decrescendo, are p r l y tmnsrnitted elsewhere to the precordium, and, perhaps most important, are not associated with any other cardiovasculat abnormalities. Innocent murmurs have been shown by intracardiac phonocardiographic recordings to originate from the right heart
and more recently by echocardiographic and Doppler studies to originate
from the IeR heart. The clinical classification of innocent murmurs is shown
in Table 1. Sfill's mumurkZ i s the most common innocent murmur and is
characterized by groaning, vibratory, or musical harmonic qualities. It is
rather distinctive and heard best between the apex and left lower sternal
&order and in the supine position. The murmur orip-iates from turbulance
of flow in the left ventricular outflow tract. It is commonly heard beyond
infancy and into adolescence. The second common outflow murmur is the
s o d l e d /physiologic pulmonary systolic ejection murmur. I t is slightly
harsh, heard best at the second to third left intemstal space, and in the
supine position. The m m u ( is due to tlirbulence of flow in the right
ventricular ouidow tract. 11 is common in children and adolescents. Both
murmurs are louder in the supine position because of the increased stroke
volume and ejection velocity astociated with the supine position. Still's
murmur is of low frequency and is beard best with the bell of the stethoscope. Physiologic pulmonary ejection murmur is heard best with the diaphragm because of the somewhat higher frequencies of the murmur. An
altered physiologic state that i s associated 4 t h an increased m d i a c output
would be expected to increase the intensity of either murmur. It is therefore likely that if the child is examined while anxious. febrile, or acutely
ill, the increased mrdiac output assmiated with these conditions may result
in the appearance of an outflow murmur that was not previously recognized or a murmur that may be louder than expected. Exercise, by virtue
of i t s efFect on increasing heart rate and cardiac output, will also increase
Table I.
anterior
noise or
Clinical Classification of Murmurs in Children with No Sign$cant
Heart Disease
SYSKItIC
i
mes out
still-$murmur
Pulmonary systolic ejection murmur
~upracIavicuIatarterial bmit
6rdiorespimtai-y (!ate systolic)
Neonatal peripheral pulmonary stcnosis
bending
I C - ~ U ~in
S
1233
CQNnHUOUS
C~M*C
venous
~
hum
Mammary soume
Cephalic bruit
A
-
I
I
I
i
~ N O ROSENTH~~
N
tion, and with the use of a bell. Occasionally it may be assmiated with a
faint thrill over the carotid. One a n make the murmur disappear by asking
the patient t o bend his arms at the ellmws and hyperextend the arms backwards. Another rare innocent murmur, occrsiondly encountered in older
children, is the ~ardiores~iratory
murmur. It is a very superficial murmur
heard only during inspiration and consists of a wishing sound in systole.
It i s best appreciated a t the apex and must not be confused with a late
systolic murmur of rnitral prolapse. There are a few other innocent murmurs that are head under special circumstances. The murmur of neonatal
physiologic peripheml ptrlmonosy stenosb is a low-intensity systoTic ejection murmur heard best at the base of the heart, axillae, and back bilater" ally. Et is present in the neonatal period'and often persists until: 3 to 6
months of age. 7 l e murmur is due to the relative hypoplasia of the branch
pulmonary arteries at birth (associated with low pulmonary blood flow in
I the fetus) and the relatively acute angle at the bifurcation of the right and
left pulmonary arteries in tly neonate. The associated turbulence of flow
a t the bhrcation of the pulmonary arteries gives risc to the murmur which
tends to disappear with advancing age as the pulmonary blood flow gradualy increases and the p u l m o n w arteries enlarge. The murmur i s clearly
remgnized by its distribution and radiation to the base and back bilaterally. The mamrrmry soufie, a continuous murmur, is restricted rc lactating
women. It may be heard in the adolescent who is breast-feeding her infant.
It i s usually audible just above the breasts. T h e murmur can be eliminated
by pressing with the fingers on the enlarged arterial blood vessels supplying mammary tissue. The appearance oh the murmur during lactation and
its subsequent disappearance i s characteristic. Benign cephalic bruits are
common in the first decade of life, They are of low intensity, continuous
or less often systolic, may be present anywhere over the head and are
usually bilateral. The systolic bruit should be considered of no significance
unless armrnpanied by other clinical evidence.
The cervical venous hum is a continuous murmur that spans both systole and diastole and indeed sounds like a hum. It i s characteristicdly
heard at the right base in the sitting position 'but ctan often also be heard
well along the third lefi intercostal space. The murmur is most prevalent
in children between the ages of 3 and 8 years. It presumably results from'
turbulence of venous flow at the sharp angle made beween the right sub
cEavian vein or innominate vein and the superior vena cava. The intensity
of the murmur is greater in the erect or sitt~ngposition, during inspiration,
or when turning the head to the contralateral side. The most uselul
method to determine that the murmur i s indeed a venous hum i s to listen
over the right upper sternal border in both the supine and sitting position,
The murmur will markedly diminish in intensity or disappear in the supine
position, IC i t remains audible, gentle pressure over the supracIavicular
area in the supine positiop wilt result in 'its disappearance.
How TO I
diovascul
exclude t
systemic
high card
venous Em
ii
I
may then
ence of a
ple, the p
anemia ar
card ia, h!
systolic b'
bility of :
diagnostic
periphera
over h e
thology. I
that the s
sult in a 1
A loud S3
ally an S4
mitral v a ~
history, a
the athlei
underlyin
n ~ c e n c ea
of the idic
are the a
upstroke,
the Valsal
and if any
ventricula
but usual1
the m u m
rysm of tl
-
I
Still's mum
Pulrnonvy
DIFFERENTIAL DMCXQSfS OF THE INNOCENT MURMUR
Vrnoui hur
-
Res~mia
How -ro DISTIN~WISH
INNOCENT
ated with a
diowrmlar abnormalities might b e present?". My initial approach is to
exclude the possibility that the heart murmur may be due to n o n d i a c
systemic physiologic alterations. Any pathologic situation associated with
high d i a c output, such ns anemia. thyrotoxicosis, or peripheral arteriovenous fistula, can cause a systolic a t f l o w murmur. T h e audible murmur
may thererore not be so innocent. Its guilt may be established by the presence of a systemic illness, despite a structurally normal heart. Eat example, the presence of pallor and tachymrdia should lead to the suspicion of
anemia and determination of a hemoglobin concentration.If there i s bchycardia, hyperactive premrdium, mildly bounding pulses, mildly elevated
systolic blood pressure, and pulse pressure, one should consider the possibility at hyperthyroidism. The presence of an enlarged thyroid may be
diagnostic. Similar catdiovascularfindings may m u r in the presence of a
peripheral arterjwenous fistuaI (head, liver, neck) and direct auscultation
over the area may id en^ q c o n t i n t ~ o ubmit
~
and localize the site of pathology. One must be aware /when examining the very athletic adolescent
that the slower heart rate and associated increased stroke volume may result in a prominent left ventricular impulse and a systolic outflow murmur.
k loud S3 may also be present due to increased tilling ~ h a s e ,and m i o n ally an 54 may be audible as well. Becalrsc OFthe increased Row across the
m i d v$lve, some athletes have a middiastolic murmur at the apex. The
history, athletic habitus, and bradycardia are the characteristic features of
the athletic adolescent. O n e it has been ascertained thar there are no
underlying physiologic explanations for the murmur nor; systemic illness,
one must exdude the possiblc presence ofstructural or hemodynamidly
significant mrdiac abnormality.
The diAerenliaI diagnosis OF h e innocent murmur is dutlined in able
2. The mast important single differentiat diagnosis in establishing the innocence of Still's or vibratory murmur fs the exclusion of subaortic stenosis
of the idiopathic hypertrophic type. The useful: distinguishing features here
are the a b s c n ~of a positive family history, absence o l a rapid m t i d
upstroke, and disappearanceor decrease in intensity of the murmur during
the Ynlsalva maneuver. A normal e1ectrbcardiograrn is also v e v reassuring
and d any doubt remains an a e h d f o g r a m should be performed. A m a l l
ventricular septat defect may omasionally be confused with Still's murmur
but usually can be distinguished from i t by the more regurgitant nature of
t h c munnur, presence of a variable click (when associated with an anenrysm of the mernbranaceous septum), history ol a louder murmur that has
asking
arms backtd in older
~rby
ial murmur
in systole.
with a late
xent murof neonatal
ntil 3 to 6
the bmch
locE flow
in
!
1
ck bilatcr-
-
her infant.
eliminated
bmtts are
mntinuous
d and are
ignifimce
: position.
he suuine
~clavlcular
I
1
1
1
1
?
I
murmur
: and car-
i
PAMOLOC~CMUMVRS
Table 2. Difierentld Diagnod of Cummon lnnocent Murmurs
Stlll'c murmur
Sub aortic stenosis
Small ventrhlar sep!al defmt
Pulmonary rystolic ejection murmur
Atrial septa] defcct
Tsiv<d ~efniluoustenosis
Supcrlavimlar artcrid hruit
1hfUR
FROM
Bicuspid aortic J a v e
coarctation o r the aorta
Arteriovenous 6,stula
- -.
&NOH
,
I
ROSE-
mduaily decreased in intensity. and sometimes evidence for leA ventricular volume overload on the ECC,
Perhaps the most Frequently missed underlying heart disease when a
pulmonary systolic ejection murmur is heard is an atrial septal defect.
While a small ventricular septal defect, subaortic stenosis, or trivial semilunar stenosis may also be missed, the potential therapeutic implications
are greatest when an aMd septal defect is not identified. The diagnosis of
an atrial septal, defect can be made in the presence of a hyperdynamic
cardiac impulse at the xyphoid or parasternal area. loud S1. widely split
d fixed second heart sound, and h e often present early diastolic flow
rumble along the left sternal: border at rest or immediately after exercise.
The electrr>cardiogmrn usrtaIty discIoses right ventricular conduction delay
with or without right axis deviation and mild right ventricular hypertraphy. Mild cardiornegaly, a prominent main pulmonary artery segment. and
increased pulmonary vascularity b e present on chest x-ray.
The supraclavicular arterial bruit must be distinguished from bicuspid aortic valve, semilunar stenosis,,and coarctation of t)lc aorta. The clinid diagnosis of the bicuspid aortic valve in a child is made in the presence
of a constant early systolic ejection click at the apex, which is usually heard
best in the sitting position. There i s often an associated low intensity systolic ejection murmur at the third IeR intercostal space or Fight upper sternal border and occasionally a low intensity, short, early diastolic decrescendo murmur of trivial aortic incompetence. If the m u h u r i s heard at
the tight upper sternal border or third left intercostal space. this i s not a
benign supmdavicular ~ e r i a lbruit. One must suspect bicuspid aortic
valve with or without aortic stenosis. Although the lesion may not b e herndynamidly s i p i ficant, bicuspid aortic valve dws require antimicrobial
prophylaxis for the prevention of infective endomrditis, whereas pmphylaxis is not required in the presence of a benign supraclavicular arterial
bruit. f i e diagnosis of marctation of the aorta muse be excluded by palpation of the femoral pulses, which in coarctation are diminished and delayed in comparison with the radial pulses. The hallmark of coarctation of
the aorta is the presence ofa systolic pressure gradient between the upper
and lower extremities. Normally the systolic b l d pressure in the lower
extremities is equal to or higher than that of the upper extremities. In
coarctation, pressure in the legs is lower than in the arms. The murmur in
children with coarctation is generally loudest at the left interscapular area
of the back. A final word of caution a b u t a thrill palpable in the suprasternal notch: If a thriII is present in the suprasternal notch, one of four
cardiovascular anomalies are usually present: aottic stenosis, pulmonary
stenosis, coarctation of the aorta, or patent ductus arteriosus.
The benign venous hum must be differentiated from a patent ductus
arteriosus. T h e most useful points to remember in distinguishing these are
that the venous hum is heard best along the right base, is loud in the
sitting position. diminishes markedly in h e supine position, and can be
completely eliminated by pressure over the supracIavicular area and jugular venous pulse. Dy contrast, in a child with a patent ductus arteriosus,
the mumur will be best heard at the Ieft base (hecause most individuals
have a left aorttc arch and left patent ductus arteriosus), the intensity of
-
How ro Drs'
the nunhur
annot be c
neck. 0 t h
Heretofc
mur should t
theless, somt
pathoIogic GI
astolic m u m
stolic rumble
adolescent w
shaped diastc
been descrjbr
murs are abr
very rare c a ~
a piecordial t
murmur i s s t
continuous m
hum and
and
ma
childhm
rndities are p
much more c
1. AII
e. dl
3. pnr
rL
HOW to D I ~ ~ N C UINNOCENT
ISH
FROM PATHOLOGIC
MURMURS
r-
the murmur does not vary significantly with position, and the murmur
cannot b obliterated by pressure over the supraclavicular area or the
neck. Other findings that may be present when a patent ductus arterjosus
i s hernodynamically significant are bounding peripheral pulses, elevated
systolic pressure for age, and a wide pulse pressure (genedly greater t&
50 mrnHg), hyperdynam ic left ventricular impulse. and mu!tiple clicks interspersed in the murmur (often referred to as t h e sound of "shaking
dice"'). An electrocardiogram may show left ventricuIar hypertrophy and
left atrid hypertrophy and chest x-ray left ventricular enlargement and
pulmonary plethora. One should maintain a high index of suspicion for
possible patent ductus arteriosus in any child Born prematurely or when
there is a family history of patent ductus arterjosus.
a
I-
IS
of
ic
lit
,w
e,
9
0-
la
h
FEATURES OF PATHOLOGIC MURMURS
I
IS-
nce
rd
4-
:rCS-
at
la\-
leof
res
vex
In
in
rea
~raJUT
aV
US
are
the
Heretofore 1 have emphasized that the innocence or guilt ol thc musmur should be established by findin+ other than the murmur itselE. Nonetheless, some generalizations can be made regarding criteria that identi&
pathologic cardiac rnurmurs.These criteria are outlined in Table 3. All diastolic murmurs should be considered-abnormal: Omasionally a rniddiastolic rumble can be heard in a child with severe anemia or in the athletic
adolescent with a very slow heart rate. A low intensity, early, diamond
shaped diastolic murmur arising wishin the left ventricuPar cavity has also
been described in a few normal children.6 All pansystolic regurgitant murmurs arc abnormal as are late systolic murmurs, except perhaps for the
very rare rardiorespiratory murmur. A very loud murmur ass'bciated with
a precordial thrill is pathologic. By and large, a Grade 3 6 or louder systoIic
murmur is strongly suggestive of the presence of pathology. A-precordial
continuous murmur should also & considered abnormal, once the venous
hum and m a m m q souffle have been excluded. The identification of any
. 'associated cardiac abnormalities on inspection, palpation. or auscuf fatiun
wiIl usually establish with certainty the pathaIogic nature of the monnur,
its etiology, and need for further diagnostic studies and therapy. I n infancy
and childhood an index of suspicion that mngenital heart disease may be
present should be heightened when one or more of the following abnarrnalities are present: (1) History ofprematurity. Patent ductus arteriosus is
much more common in preterm infants. (2) Small for gestational age. A
significant percentage of babies with congenital heart disease are small for
gestational age. The incidence is particuFarly high for ventricular septal
defect, patent ductus arteriosus, atrial septd defect. and tetralogy of Fallot. (33 The presence of an identifiable syndrome with or without an assoTable 3. Criteda That ~dentify Pathologic Cardiac Murmurs
be
1. All diastolic murmurs
XI1 pansystolic murmurs
3. h t e systolic rnkrrmurs
2.
4. Very loud murmurs
5. Continuous murmurs
6. Associated cardiac
abnormnlities
How m Dtmucurs~cI N N O C E ~FROM PA'IHOLOGIC
M WILWURS
t
hrldren with
P S very m m phenorype),
pulmonary
congenital
ur. Nearly a
racardiac anarticularly in
strointestind
genital heart
*r respiratory
dying large
r
IC
Y
i
ray. or echo-
/I
the vast
I
t h e basis OF
~yrnpternatic
s distinguish
systemic or
iancy in mrtio on,
pasen-
.!a1 follow-up
e necessary.
: { u i r d heart
useful these
these
noninvasive
scrirninating
ted
280 chil-
tfter obtainprized each
e , and dcfiay,
y
and M-
reviewed.
dart disease.
disease the
noses, howence of any
detected by
~y identified
se, the test
1
had heart
disease on foISow-up (rnitrd valve prolapse), It is therefore possible, given
sufficient experience, to differentiate between children with and without
underlying cardiac disease. Results of noninvasive laboratory tests are with
rare exception unlikely to change the diagnosis of no heart disease made
by a qualified pediatric cardiologist. The use of noninvasive studies, particularly the echocardiogram, in determining the innocence or guilt o f a murmur is usually unwarranted. Furthermore, appropriate performance and
interpretation of the echocardiogram in childhood requires expertise usually limited to the pediatric cardiologist or available only in centers in
which a large number of infants and children with mn~enitdheart disease
are evaluated. The phonocardiogsam and vectorcardioiram have h e n entirely replaced by the echocardiogram and Doppler examination when further evaluation of a child with a murmur is desired.
MANAGEMENT
-
If on initial evaluation in the officethe index of suspicion For cardiac
abnormality is low, it i s preferable to reevaluate the child over s e v e d
years rathcr than obtain the entire array of noninvasive studics.8.g Should
there bc persistent parcntal or physician conceni that heart disease may
be present, referral to a mrdiologist i s appropriate. As a general rule thc
younger the child the more important is an earlier diagnosis and referral.
A newborn should be referred within hours, neonate within days. alder
infant within a few weeks, and the asymptomatic child within months.
It should be emphasized that the child with an innwent murmur has,
by definition, no hernodynamic or structural crardiac abnormalities. He or
she is normal. The parents should be so infomed and clearly reassured.
Failure to do so may lead to anxiety, cardiac phobias, and either adverse
physiologic or physical handicaps.
psimary physician who does not
inform the parents that an innocent murmur i s present is often confronted
by greater parental anxiety after an emergency room physician or his partner has heard the murmur. The pamphlet on innwent mumuss, available
&om the American Heart Association in both English and Spanish. i s often
helphl to parents. In children with an innwent murmur antimicrobial prophylaxis i s not required for dental or other surgical procedures and long
term follow-up by a cardiologist is unnecessary.
fn summary, innocent murmurs are common in childhood and generally originate from the left or right ventricular outflow tract. The innocence
of the murmur is established by the absence of any evidence for other
r~rdiovascularabnormalities. Awareness of the children at high risk for
congenital or acquired heart disease, specific features of murmurs, and associated cardiovascular abnomaIi ties on physial examination will incriminnte the murmur and identtfy the patient with heart disease. In the great
majority of children a g o d history and physical examination combined
with simple physiologic maneuvers will sufljce to distinguish the children
with innocent murmurs. In a minority an electrocardiogram and chest Kray will be required. and in a very few an additional cchocarrliogram or
Doppler study.
me
nal, then an
1 with
.
I
I
THE
In
i
I
1239