This document provides an overview of pediatric cardiology for medical students. It discusses the fetal, transitional, and postnatal circulations and how congenital heart defects disrupt normal circulation. It describes left-to-right shunts like VSDs and PDA that cause left heart enlargement and right-to-left shunts like Tetralogy of Fallot that cause cyanosis. Obstructive lesions like critical aortic stenosis that require ductal flow are discussed. The physical exam findings for different defects are outlined along with innocent murmurs and hereditary cardiac conditions.

1. Pediatric
Cardiology 101
Misty Carlson, M.D.

2. DISCLAIMER:
 This lecture is based on generalizations.
 In reality, a congenital heart defect (CHD)
can act completely different from one
patient to the next (eg- classic ToF vs
“pink” ToF).
 There are many more CHDs than what
I’ve listed and I hope you can use these
principles to help you out with those.

3. Fetal Circulation
 For the fetus the placenta is the oxygenator
so the lungs do little work
 RV & LV contribute equally to the systemic
circulation and pump against similar
resistance
 Shunts are necessary for survival
 ductus venosus (bypasses liver)
 foramen ovale (R→L atrial level shunt)
 ductus arteriosus (R→L arterial level shunt)

5. Transitional Circulation
 With first few breaths lungs expand and
serve as the oxygenator (and the placenta
is removed from the circuit)
 Foramen ovale functionally closes
 Ductus arteriosus usually closes within
first 1-2 days

6. Neonatal Circulation
 RV pumps to pulmonary circulation and
LV pumps to systemic circulation
 Pulmonary resistance (PVR) is high; so
initially RV pressure ~ LV pressure
 By 6 weeks pulmonary resistance drops
and LV becomes dominant

7. Normal Pediatric Circulation
 LV pressure is 4-5 x RV pressure (this is
feasible since RV pumps against lower
resistance than LV)
 RV is more compliant chamber than LV

8. 100%
90/  No shunts
60 20/8
 No pressure gradients
75% 75% 100%  Normal AV valves
 Normal semilunar
valves
20/ 90/  If this patient was
desaturated what
would you think?

9. If you have a hole in the heart what
affects shunt flow?
1. Pressure – easy enough to understand
2. Resistance – impedance to blood flow
Remember, the LV has higher pressure and
a higher resistive circuit relative to the RV.
Now onto the nitty-gritty …

10. Congenital Heart Disease (CHD)
 Occurs in 0.5-1% of all live births
 Simple way to classify is:
 L→R shunts
 Cyanotic CHD (R→L shunts)
 Obstructive lesions

11. L→R Shunts (“Acyanotic” CHD)
 Defects
1. VSD
2. PDA
3. ASD
4. AVSD (or complete atrioventricular canal)
 May not be apparent in neonate due to
high PVR (ie- bidirectional shunt)

12. L→R Shunts – General Points
PDA & VSD ASD
 Presents in childhood w/
 Presents in infancy w/
murmur or exercise
heart failure, murmur,
intolerance (AVSD or 1o ASD
and poor growth
presents earlier)
 Left heart enlargement  Right heart enlargement
(LHE)
(RHE)
 Transmits flow and  Transmits flow only
pressure
AVSD can present as either depending on size of ASD & VSD component

14. Increased PBF
Left Heart Right Heart
Overload Overload

15. Pulm vasc
markings
equal in
upper and
lower zones
Cardiomegaly

16. Eisenmenger’s Syndrome
 A long standing L→R shunt will eventually
cause irreversible pulmonary vascular
disease
 This occurs sooner in unrepaired VSDs
and PDAs (vs an ASD) because of the
high pressure
 Once the PVR gets very high the shunt
reverses (ie- now R→L) and the patient
becomes cyanotic

17. R→L Shunts (CCHD)
• “Blue blood bypasses the lungs”
• Degree of cyanosis varies
• Classify based on pulmonary blood flow (PBF)
↑ PBF ↓ PBF
 Truncus arteriosus  Tetralogy of Fallot
 Total anomalous pulm.  Tricuspid atresia
venous return (TAPVR)  Ebstein’s anomaly
 Transposition of the great
arteries (TGA)
Please note: This is a generalization. In reality most of these defects can present with
low or high PBF (eg- ToF with little PS acts more like a VSD with high PBF)

18. R→L Shunts
↑ PBF
 Presents more often
with heart failure
(except TGA)
 Pulmonary congestion
worsens as neonatal
PVR lowers
 Sats can be 93-94% if
There is unimpeded Equal
there is high PBF
PBF; thus, extreme pressures
pulmonary here too
overcirculation.

19. R→L Shunts
↓ PBF
 Presents more often
with cyanosis
 See oligemic lung
fields
 Closure of PDA may
worsen cyanosis
Dynamic subvalvular
Why are
obstruction here
causes “Tet spells”
pressures
equal?

20. Pulmonary
90% overcirculation Too little
70% PBF
70% 99% 60% 99%
99%
99%
70% 60%

21. Different amounts of PBF
(Truncus vs ToF)

22. Obstructive Lesions
Ductal Dependent Non-Ductal Dependent
1. Critical PS/AS 1. Mild-moderate AS
2. Critical CoA/IAA 2. Mild-moderate CoA
3. HLHS 3. Mild-moderate PS
 Presents in CV shock at  Presents in older
2-3 days of age when child w/ murmur,
PDA closes
exercise intolerance,
 +/- cyanosis or HTN (in CoA)
 Needs PGE1  Not cyanotic

23. Ductal-Dependent
Lesion
Without a PDA there is no
blood flow to the abdomen
and lower extremities.
(Blue blood is better than no blood.)

24. Physical Exam
 Inspection and palpation
 Cardiac cyanosis must be central
 Differential cyanosis = R→L PDA shunt
 Differential edema/congestion implies
obstruction of SVC or IVC
 Increased precordial activity
 Displaced PMI
 RV heave = RV hypertension

25. Physical exam
 Lungs
 Respiratoryrate and work of breathing
 Oxygen saturations
 Abdominal exam
 Liver size
 Extremities
 Perfusion
 Edema
 Clubbing

26. Physical Exam
 Pulses (very important)
 Differentialpulses (weak LE) = CoA
 Bounding pulse = run-off lesions (L→R PDA
shunt, AI, BT shunt)
 Weak pulse = cardiogenic shock or CoA
 Pulsus paradoxus is an exaggerated SBP
drop with inspiration → tamponade or bad
asthma
 Pulsus alternans – altering pulse strength →
LV mechanical dysfunction

27. Physical Exam
 Heart sounds
 Ejection click = AS or PS
 Mid-systolic click = MVP
 Loud S2 = Pulmonary HTN
 Single S2 = one semilunar valve (truncus),
anterior aorta (TGA), pulmonary HTN
 Fixed, split S2 = ASD, PS
 Gallop (S3) – may be due to cardiac
dysfunction/ volume overload
 Muffled heart sounds and/or a rub = pericardial
effusion ± tamponade

28. Physical Exam
 Types of Murmurs
 Systolic Ejection Murmur (SEM) =
turbulence across a semilunar valve
 Holosystolic murmur = turbulence begins
with systole (VSD, MR)
 Continuous murmur = pressure difference
in systole and diastole (PDA, BT shunt)

29. Innocent murmurs
 Peripheral pulmonic stenosis (PPS)
 Heard in newborns – disappears by one year
of age (often earlier)
 Soft SEM at ULSB w/ radiation to axilla and
back (often heard best in axilla/back)
 Need to differentiate b/w PPS and actual
pulmonic stenosis. PS often associated with
a valvular click and heard best over
precordium

30. Innocent murmurs
 Still’s murmur
 Classic innocent murmur
 Heard most commonly in young children (3-5 yrs of
age) but can be heard in all ages
 “Vibratory” low-frequency murmur often heard along
LSB and apex
 Positional – increases in intensity when pt is in supine
position
 Also louder in high output states (i.e. dehydration,
fever)
 Need to differentate from VSD

31. Innocent murmurs
 Pulmonary flow murmur
 Often heard in older children and adolscents
 Soft SEM at ULSB, little radiation; normal second
heart sound
 Not positional
 Need to differentiate b/w mild PS and especially an
ASD
 Hint: ASD would have a fixed split second heart sound

32. Innocent murmurs
 Venous hum
 Often heard in toddlers, young children
 Low pitched continuous murmur often heard best in
infraclavicular area, normal heart sounds
 Positional – diminishes or goes completely away
when pt in supine position or with compression of
jugular vein
 Need to differentiate between a PDA

33. Syndrome Associations
 Down – AV canal and VSD
 Turner – CoA, AS
 Trisomies 13 and 18 – VSD, PDA
 Fetal alcohol – L→R shunts, ToF
 CHARGE – conotruncal (ToF, truncus)

34. Hereditary Diseases
 Marfan (AD)– aortic root aneurysm ± dissection, MVP,
MR, AI
 HCM (AD) – outflow tract obstruction, arrhythmias
 Noonan (AD) – HCM, PS
 DMD/BMD (X-link) – DCM (>12 y.o.)
 Williams (AD) – supravalvar AS
 Tuberous sclerosis – rhabdomyoma
 Romano-Ward – AD LQTS
 Jervell & Lange-Nielsen – AR LQTS & deafness

35. Kawasaki Disease (KD)
 Now the #1 cause of acquired heart
disease
 A systemic vasculitis (etiology-unknown)
 Tests – CBC, CMP, CRP, ESR, EKG,
ECHO
 Rx – IVIG at 2g/kg and high-dose ASA
 Prognosis – Coronary artery dilatation
in 15-25% w/o IVIG and 4% w/ IVIG (if
given within 10 days of fever onset). Risk
of coronary thrombosis.

36. Kawasaki – Clinical criteria
 Fever for at least 5 days AND 4 of the
following 5 criteria:
 Eyes - conjunctival injection (ie- no exudate)
 Lips & mouth - erythema, cracked lips, strawberry
tongue
 Hands & feet - edema and/or erythema
 Skin - polymorphous exanthem (ie- any rash)
 Unilateral, cervical lymphadenopathy

37. Rheumatic Fever
 A post-infectious connective tissue disease
 Follows GAS pharyngitis by 3 weeks (vs. nephritogenic
strains of GAS)
 Injury by GAS antibodies cross-reacting with tissue
 Dx – JONES criteria (major and minor)
 Tests – Throat Cx, ASO titer, CRP, ESR, EKG, +/-
ECHO
 Rx – PCN x10 days and high-dose ASA or steroids
 2o Prophylaxis – daily po PCN or monthly IM PCN

38. Rheumatic Fever – organs
affected
1. Heart muscle & valves – myocarditis &
endocarditis (pericarditis rare w/o the others)
2. Joints – polyarthritis
3. Brain – Sydenham’s Chorea (“milkmaid’s grip” or
better yet, “motor impersistance”)
4. Skin – erythema marginatum (serpiginous border)
due to vasculitis
5. Subcutaneous nodules – non-tender, mobile and on
extensor surfaces

39. In case you haven’t had enough….

40.  A ductal-dependent
lesion
 One ventricle pumps
both PBF & SBF
 Difficult to balance
PBF & SBF

41. Norwood Procedure
 What is the purpose
of the BT shunt?
 Is there a murmur?
 What is your guess
for the arterial
saturation?

42. Bidirectional Glenn
 What is the purpose
of the Glenn?
 Is there a murmur?
 What is your guess
for the arterial
saturation?

43. Fontan circuit
 What is the path of
blood?
 Is there a murmur?
 What is your guess
for the arterial
saturation?