PAGE 22
the scapulae is very soft or
absent , particularly with the onset of cardiac failure . 25 , 27 The right-to-left shunt at duct level will manifest with a reduction in the oxygen saturation in the foot ( post-ductal , see figure 6 ) compared with the right hand ( preductal . A difference of less than 3 % is accepted as normal ; a difference of more than 3 % warrants further investigation . 5 , 6 Occasionally , unrecognised mild desaturation in both the pre-ductal and post-ductal readings may prompt a search for respiratory and / or other causes .
While false positives are reported as 14 out of 10,000 screenings , it is estimated that five out of six children with critical congenital heart disease may be detected . 6 Screening is especially important as it may prevent newborn infants being readmitted to hospital in a shocked state from a rapid closure of the ductus once they are home — as most infants are discharged within 48-72 hours of deliv-
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Figure 3 . Hypoplastic left heart syndrome . |
Centers for Disease Control and Prevention , National Center on Birth Defects and Developmental Disabilities |
Centers for Disease Control and Prevention , National Center on Birth Defects and Developmental Disabilities |
is unclear to the attending clinician . The murmur may be innocent and the rest of the cardiovascular examination normal . Parents do need to know that their child has a normal heart , so if the GP is unable to provide a clear answer , then a referral is warranted .
There is still debate about whether an echocardiogram is required once the attending cardiologist is confident of the diagnosis . A 2020 study suggested that , if the echocardiogram — a non-invasive and relatively inexpensive investigation — is shown to be normal , this further reassures the parent that the murmur is innocent and their child has a normal heart . 30 Occasionally , the echocardiogram may detect an abnormality not suspected by the clinical examination . 31 Echocardiograms done by standalone services need careful interpretation as an incidental finding of a patent foramen ovale , trivial or mild tricuspid or pulmonary incompetence may be normal findings in an infant or young
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ery . A more gradual duct closure may |
child and not the cause of the inno- |
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lead to the baby becoming unwell , |
cent murmur . |
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feeding poorly , developing tachyp- |
A further confounding factor is |
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noea and being brought in for review . |
that trivial or mild pulmonary or aortic |
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Pulse oximetry screening is a simple |
valve stenosis or a small VSD may not |
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investigation that is already compul- |
be readily detected on an echocardio- |
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sory in many states in the US and is |
gram despite the presence of an ejec- |
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increasingly performed in Australia . 28 |
tion click and / or murmur . Note that a |
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Supraventricular tachycardia in the newborn
SVT diagnosed in utero allows for
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congenital abnormality of the aortic valve even if minor , such as a bicuspid valve without a gradient , may be associated with an aortopathy , resulting |
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treatment to be instituted via medicating the mother . 22 However , SVT presenting in the newborn period or shortly after may be missed . SVT can lead to heart rates of 220-240bpm compared with a sinus tachycardia that may jump to 200bpm or more in a crying baby . If the SVT is self-terminating , the infant may appear |
Madfolk67 / CC BY-SA : bit . ly / 3wQrgdp |
in dilatation of the ascending aorta . 32 These patients require long-term surveillance .
Occasionally , murmurs that sound innocent may arise from an underlying cardiac abnormality . For example , the innocent vibratory or musical murmur of childhood may arise from trivial / mild subaortic stenosis or a soft
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well . If the episode is prolonged , |
ejection systolic murmur in the pul- |
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that is lasting more than 12-24 hours , |
monary area commonly designated as |
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signs of congestive cardiac failure |
an innocent physiological pulmonary |
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may develop . These include tachyp- |
flow murmur may be due to increased |
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noea , the development of a large |
flow across the pulmonary valve aris- |
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liver , slight pitting oedema over the |
ing from a large ASD or unobstructed |
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dorsum of the foot or anterior to the |
total anomalous pulmonary veins . 2 |
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tibia , poor feeding and irritability . 29 |
The same may apply to a venous |
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If an ECG is done during an epi- |
hum , where a continuous murmur is |
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sode , a regular narrow complex |
heard at the upper-right sternal edge . |
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tachycardia is noted , typical of the |
If heard elsewhere , consider the pos- |
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common re-entry SVT . However , if |
sibility of a coronary artery fistula . |
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the arrhythmia reverts spontane- |
Note that the presence of a scar may |
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ously , the diagnosis may not be con- |
be related to the surgical insertion of |
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sidered . An interval ECG that shows |
a modified aortopulmonary shunt as |
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pre-excitation suggests the possi- |
required in an infant with pulmonary |
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bility of SVT . Most infants with SVT |
atresia or a severe tetralogy of Fallot . |
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seemingly outgrow the problem , with only a third re-presenting in later childhood / adulthood . |
Figure 4 . Twin-to-twin transfusion . |
Any murmur presenting with additional cardiovascular signs ( see box 2 ) warrants referral . |
DIAGNOSIS OF HEART DISEASE IN INFANCY AND CHILDHOOD
ROUTINE examination of an infant
at one month of age may detect murmurs related to communications between the systemic and pulmonary
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Table 1 . Changes in pO2 in respiratory and cardiac conditions
Condition Room air 100 % oxygen
Respiratory cause
Transposition of the great vessels 28-30mmHg 30-32mmHg
Substantial rise of the pO2 to 150mmHg or more , reaching levels of 250mmHg
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systolic murmur may be heard in the pulmonary area from increased flow across the pulmonary valve . 7 Suspect this diagnosis if there is wide splitting of the second heart sounds . A soft diastolic murmur from increased flow across the tricuspid valve might be difficult to hear . |
Confounding features
PULMONARY HYPERTENSION A serious cardiac abnormality may occasionally be present with little or no murmur . This is especially so if the pulmonary vascular resistance fails to drop following the birth of the infant . As an example , some infants with Tri-
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circulations , such as a VSD , PDA or an atrioventricular septal defect ( AVSD ).
It takes about a month for the PVR to fall to about half of the suprasystemic level before delivery and about six months to fall to less than a third of systemic vascular resistance . 3
The fall in pulmonary resistance allows for an increasing left-to-right
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Right-to-left shunts arising , for example , from a severe tetralogy of Fallot
Obligatory mixing as occurs with an unobstructed total anomalous pulmonary venous drainage or a truncus arteriosus
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35-40mmHg
75-80mmHg
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45-50mmHg
120-130mmHg
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As a general rule , stenotic lesions ( even if trivial or mild ) usually result in a murmur — for example , mild aortic or pulmonary stenosis . A murmur arising from incompetence of the mitral , tricuspid , aortic and , occasionally , pulmonary valve only becomes audible if there is at least mild , but probably moderate , regurgitation . 27 |
somy 21 remain relatively well with minimal tachypnoea and no murmurs but signs suggestive of pulmonary hypertension , which may be difficult to recognise in infants and young children . The infant ’ s heart rate is fast , with the second heart sounds summated into a single sound . Here , a louder summated second heart |
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shunt , depending on the size of the |
Murmurs are also detected in |
sound in the pulmonary area com- |
communication . |
the newborn . A murmur from an ASD |
decreased compliance of the hypertro- |
older infants and children when they |
pared with the aortic area suggests |
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Turbulence related to the shunt |
will take longer to manifest as the |
phied RV in the newborn , which takes |
present with an intercurrent illness , |
pulmonary hypertension . Occasion- |
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results in a murmur , although occa- |
left-to-right shunt is at atrial level and |
many months to atrophy following a |
usually an URTI . The presence of a |
ally , the summated second heart |
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sionally turbulence from a small mus- |
occurs mainly during diastole . This |
drop in the pulmonary arterial pres- |
murmur that persists after the child is |
sound or the second component of |
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cular VSD may result in a murmur in |
shunt is limited to some extent by the |
sures . Even then , only a soft ejection |
well warrants referral if the diagnosis |
the second heart sounds may be so |