Pediatric Cardiology 101

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. No shunts No pressure gradients Normal AV valves Normal semilunar valves If this patient was desaturated what would you think?

9. If you have a hole in the heart what affects shunt flow? Pressure – easy enough to understand 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 VSD PDA ASD 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 Presents in infancy w/ heart failure, murmur, and poor growth Left heart enlargement (LHE) Transmits flow and pressure ASD Presents in childhood w/ murmur or exercise intolerance (AVSD or 1o ASD presents earlier) Right heart enlargement (RHE) Transmits flow only

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) ? PBF Truncus arteriosus Total anomalous pulm. venous return (TAPVR) Transposition of the great arteries (TGA) ? PBF Tetralogy of Fallot Tricuspid atresia Ebstein’s anomaly

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 high PBF

19. R?L Shunts ? PBF Presents more often with cyanosis See oligemic lung fields Closure of PDA may worsen cyanosis

21. Different amounts of PBF(Truncus vs ToF)

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

23. Ductal-DependentLesion

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 Respiratory rate and work of breathing Oxygen saturations Abdominal exam Liver size Extremities Perfusion Edema Clubbing

26. Physical Exam Pulses (very important) Differential pulses (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 Heart muscle & valves – myocarditis & endocarditis (pericarditis rare w/o the others) Joints – polyarthritis Brain – Sydenham’s Chorea (“milkmaid’s grip” or better yet, “motor impersistance”) Skin – erythema marginatum (serpiginous border) due to vasculitis 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?