Pediatric-Cardiology-101.ppt

Pediatric
Cardiology 101
Misty Carlson, M.D.

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.

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)

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

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

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

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?

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 …

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

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)

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

Increased PBF

Left Heart Right Heart
Overload Overload

Pulm vasc
markings
equal in
upper and
lower zones

Cardiomegaly

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

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)

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.

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?

Pulmonary
90% overcirculation Too little
70% PBF

70% 99% 60% 99%

99%

99%
70% 60%

Different amounts of PBF
(Truncus vs ToF)

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

Ductal-Dependent
Lesion
Without a PDA there is no
blood flow to the abdomen
and lower extremities.

(Blue blood is better than no blood.)

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

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

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

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

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)

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

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

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

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

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)

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

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.

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

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

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

In case you haven’t had enough….

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

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

Bidirectional Glenn

 What is the purpose
of the Glenn?
for the arterial
saturation?

Fontan circuit
 What is the path of
blood?
for the arterial
saturation?

Pediatric-Cardiology-101.ppt

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