Pediatric Cardiology 101

7/31/2019 Pediatric Cardiology 101

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Pediatric

Cardiology 101

Misty Carlson, M.D.


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DISCLAIMER:

This lecture is based on generalizations.

In reality, a congenital heart defect (CHD)

can act completely different from onepatient to the next (eg- classic ToF vspink ToF).

There are many more CHDs than whatIve listed and I hope you can use these

principles to help you out with those.


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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 similarresistance

Shunts are necessary for survival

ductus venosus (bypasses liver) foramen ovale (RL atrial level shunt)

ductus arteriosus (RL arterial level shunt)


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Transitional Circulation

With first few breaths lungs expand andserve as the oxygenator (and the placenta

is removed from the circuit) Foramen ovale functionally closes

Ductus arteriosus usually closes within

first 1-2 days


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Neonatal Circulation

RV pumps to pulmonary circulation and LVpumps to systemic circulation

Pulmonary resistance (PVR) is high; soinitially RV pressure ~ LV pressure

By 6 weeks pulmonary resistance drops

and LV becomes dominant


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Normal Pediatric Circulation

LV pressure is 4-5 x RV pressure (this isfeasible since RV pumps against lower

resistance than LV) RV is more compliant chamber than LV


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No shunts

No pressure gradients

Normal AV valves Normal semilunar

valves

If this patient wasdesaturated whatwould you think?

75% 100%

20/ 90/

20/890/

60

100%

75%


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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


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Congenital Heart Disease (CHD)

Occurs in 0.5-1% of all live births

Simple way to classify is:

LR shunts

Cyanotic CHD (RL shunts)

Obstructive lesions


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LR Shunts (Acyanotic CHD)

Defects

1. VSD

2. PDA

3. ASD

4. AVSD (or complete atrioventricular canal)

May not be apparent in neonate due tohigh PVR (ie- bidirectional shunt)


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LR Shunts General Points

PDA & VSD

Presents in infancy w/heart failure, murmur,and poor growth

Left heart enlargement(LHE)

Transmits flow andpressure

ASD Presents in childhood w/

murmur or exerciseintolerance (AVSD or 1oASD presents earlier)

Right heart enlargement

(RHE) Transmits flow only

AVSD can present as either depending on size of ASD & VSD component


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Increased PBF

Left Heart

Overload

Right Heart

Overload


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Pulm vasc

markings

equal in

upper and

lower zones

Cardiomegaly


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Eisenmengers Syndrome

A long standing LR shunt will eventuallycause 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 RL) and the patient

becomes cyanotic


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RL Shunts (CCHD)

PBF

Truncus arteriosus

Total anomalous pulm.

venous return (TAPVR) Transposition of the great

arteries (TGA)

PBF

Tetralogy of Fallot

Tricuspid atresia

Ebsteins anomaly

Blue blood bypasses the lungs Degree of cyanosis varies Classify based on pulmonary blood flow (PBF)

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)


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RL Shunts

PBF

Presents more often

with heart failure(except TGA)

Pulmonary congestionworsens as neonatal

PVR lowers Sats can be 93-94% if

there is high PBFEqual

pressures

here too

There is unimpeded

PBF; thus, extreme

pulmonary

overcirculation.


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RL Shunts

PBF

Presents more often

with cyanosis See oligemic lung

fields

Closure of PDA mayworsen cyanosis

Dynamic subvalvular

obstruction here

causes Tet spells

Why are

pressures

equal?


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70%

70%

99%

99%

90%

60%

60%

99%

99%

70%

Pulmonary

overcirculation Too little

PBF


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Different amounts of PBF

(Truncus vs ToF)


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Obstructive Lesions

Ductal Dependent

1. Critical PS/AS

2. Critical CoA/IAA3. HLHS

Presents in CV shock at2-3 days of age when

PDA closes +/- cyanosis

Needs PGE1

Non-Ductal Dependent

1. Mild-moderate AS

2. Mild-moderate CoA3. Mild-moderate PS

Presents in olderchild w/ murmur,

exercise intolerance,or HTN (in CoA)

Not cyanotic


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Without a PDA there is no

blood flow to the abdomen

and lower extremities.

(Blue blood is better than no blood.)

Ductal-Dependent

Lesion


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Physical Exam

Inspection and palpationCardiac cyanosis must be central

Differential cyanosis = RL PDA shuntDifferential edema/congestion implies

obstruction of SVC or IVC

Increased precordial activity

Displaced PMI

RV heave = RV hypertension


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Physical exam

Lungs Respiratory rate and work of breathing

Oxygen saturations

Abdominal exam Liver size

Extremities

Perfusion Edema

Clubbing


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Physical Exam

Pulses (very important)Differential pulses (weak LE) = CoA

Bounding pulse = run-off lesions (LR PDAshunt, AI, BT shunt)

Weak pulse = cardiogenic shock or CoA

Pulsus paradoxus is an exaggerated SBP

drop with inspiration tamponade or badasthma

Pulsus alternansaltering pulse strength LV mechanical dysfunction


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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 cardiacdysfunction/ volume overload

Muffled heart sounds and/or a rub = pericardialeffusion tamponade


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Physical Exam

Types of Murmurs

Systolic Ejection Murmur (SEM) =

turbulence across a semilunar valveHolosystolic murmur = turbulence begins

with systole (VSD, MR)

Continuous murmur = pressure difference

in systole and diastole (PDA, BT shunt)


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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 witha valvular click and heard best overprecordium


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Innocent murmurs

Stills 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


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Innocent murmurs

Pulmonary flow murmur

Often heard in older children and adolscents

Soft SEM at ULSB, little radiation; normal secondheart sound

Not positional

Need to differentiate b/w mild PS and especially an

ASD Hint: ASD would have a fixed split second heart sound


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Innocent murmurs

Venous hum

Often heard in toddlers, young children

Low pitched continuous murmur often heard best ininfraclavicular area, normal heart sounds

Positional diminishes or goes completely awaywhen pt in supine position or with compression of

jugular vein

Need to differentiate between a PDA


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Syndrome Associations

DownAV canal and VSD

TurnerCoA, AS

Trisomies 13 and 18 VSD, PDA

Fetal alcoholLR shunts, ToF

CHARGE conotruncal (ToF, truncus)


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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


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Kawasaki Disease (KD)

Now the #1 cause of acquired heartdisease

A systemic vasculitis (etiology-unknown) Tests CBC, CMP, CRP, ESR, EKG,

ECHO

Rx IVIG at 2g/kg and high-dose ASA PrognosisCoronary artery dilatation in

15-25% w/o IVIG and 4% w/ IVIG (if givenwithin 10 days of fever onset). Risk of

coronary thrombosis.


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Kawasaki Clinical criteria

Fever for at least 5 days AND 4 of thefollowing 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


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Rheumatic Fever

A post-infectious connective tissue disease

Follows GAS pharyngitis by 3 weeks (vs. nephritogenicstrains 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


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Rheumatic Fever organs

affected1. Heart muscle & valves myocarditis &

endocarditis (pericarditis rare w/o the others)

2. Joints polyarthritis3. BrainSydenhams Chorea (milkmaids grip or

better yet, motor impersistance)

4. Skin erythema marginatum (serpiginous border)

due to vasculitis5. Subcutaneous nodules non-tender, mobile and on

extensor surfaces


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In case you havent had enough.


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A ductal-dependentlesion

One ventricle pumpsboth PBF & SBF

Difficult to balancePBF & SBF


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Norwood Procedure

What is the purposeof the BT shunt?

Is there a murmur? What is your guess

for the arterialsaturation?


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Bidirectional Glenn

What is the purposeof the Glenn?




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Fontan circuit

What is the path ofblood?



Pediatric Cardiology 101

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