1. RET 300
Congenital Heart
Defects

2. The Normal Heart

3. The Fetal Heart

4. Fetal Circulation
Blood travels from the placenta through the umbilical cord via the Umbilical Vein (UV) to the fetus
This blood is effectively the baby’s arterial blood in that it is oxygen- and nutrient-rich and scrubbed of waste metabolites and carbon dioxide
This vessel is used after delivery as a site for venous access and delivery of medications and volume expanders
The UV enters the liver where about ½ of the flow supplies the organ and the other ½ flows through the ductus venosus to the inferior vena cava

5. Fetal Circulation
After entering the inferior vena cava, blood mixes in the right atrium with blood from the superior vena cava (deoxygenated blood)
Most of the blood then flows through the foramen ovale into the left atrium
A small amount (~10-15%) of additional deoxygenated blood from the pulmonary veins enters the left atrium, further decreasing the overall saturation before being pumped out of the left ventricle to provide systemic perfusion

6. Fetal Circulation
The blood that is not involved in this normally occurring shunt enters the right ventricle, where it is pumped into the pulmonary artery. Of this, only about % actually passes through the lung and the rest is shunted through the ductus arteriosis into the aorta

7. Transition from Fetal Circulation
At birth, several changes are required to support extra-uterine life
Fluid-filled lungs are air-aerated by the removal of fetal lung fluid by the pulmonary circulation and lymphatics, and squeezing during delivery
With the aid of surfactant to maintain some FRC, pulmonary gas exchange results in elevated PO2’s (must be at least mmHg). This causes vasodilation of the pulmonary circulation and constriction of the ductus arteriosis
Blood from the right heart now follows the normal adult course through the lungs

8. Transition from Fetal Circulation
The consequent fall in right atrial pressures causes the pressure gradient across the foramen ovale to reverse
Functional closure within hours
~20% of adults have some degree of patent foramen ovale that is generally of no consequence
Removal of blood flow through the ductus venosus as the placenta is removed from the equation results in rapid closure of this vessel
The closure of the ductus venosus and loss of the placenta results in an increase in SVR

9. The Fetal Heart

10. Transition from Fetal Circulation
As the placenta dramatically ceases to function, pH and PO2 fall and PCO2 rises. The exact mechanism is unknown; however, the central and peripheral chemoreceptors acutely increase in sensitivity and a stimulus to take the first breath is triggered
The increase in PO2 causes dilation of the pulmonary vascular bed, resulting in a reduction in PVR
SVR is now greater than PVR and right to left shunting is decreased

11. Fetal Circulation – Shunts
Ductus Venosus
Becomes the Ligamentum Venosum, a fibrous cord in the liver
Foramen Ovale
Becomes a depression in the atrial septum called the Fossa Ovalis
Ductus Arteriosis
Atrophies into the ligamentum arteriosum, a fibrous cord between the PA and aorta
Occurs between 24 hrs - 2 weeks postpartum

12. Postpartum Circulation
Blood flow through the foramen ovale and the ductus arteriosus is dependent on the balance between PVR and SVR
This balance can be greatly affected by the presence of congential heart defects
These CHDs can be classified as either
Cyanotic – Right to left shunting
Acyanotic – Left to right shunting

13. Congenital Heart Defects
Acyanotic – CHDs include
Patent Ductus Arteriosus (PDA)
Atrial Septal Defect (ASD)
Ventricular Septal Defect (VSD)
Atrioventricular Septal Defect (AVSD)
Aortic Stenosis
Coarctation of the Aorta

14. Congenital Heart Defects
Cyanotic – CHDs include
Total Anomalous Pulmonary Venous Return (TAPVR)
Tetralogy of Fallot (TEF)
Truncus Arteriosus
Transposition of the great vessels
Tricuspid Atresia
Hypoplastic Left Heart Syndrome (HLHS)
Pulmonary Stenosis

15. Acyanotic Heart
Defects

16. Patent Ductus Arteriosus
Most common in premies
L-R shunt

17. Patent Ductus Arteriosus

18. Patent Ductus Arteriosus Etiology
Postpartum, the Ductus Arteriosus (DA) closes as a result of hormonal, chemical, and blood gas changes
This shifts the blood flow through the DA from right to left, to left to right (Aorta – Pulmonary artery)
Function of the constrictor response of oxygen to the DA and the dilator effect of prostaglandin are functions of gestational age
More premature, the greater the delay in closure of the DA

19. Patent Ductus Arteriosus Pathophysiology
Failure of the constrictor responses results in an increase in pulmonary blood flow through the PDA
Presence of PDA results in pulmonary overflow, resulting in pulmonary congestion
Pulmonary hypertension and congestive heart failure may follow
Impairs lung function and compliance
If untreated, it leads to reversal of the shunt back to right to left from an increase in PVR

20. Patent Ductus Arteriosus Clinical Manifestations
Preductal and postductal assessment of oxygenation either invasively or non-invasively
Should result in a difference of greater than 15 mmHg or % in saturation
CXR may result in increased vascular markings if congestive heart failure develops
Definitive diagnosis is done by echocardiology determining the presence of the PDA
Normal ABGs and pulse oximetry can be expected post-repair

21. Patent Ductus Arteriosus Management/Treatment
Infants are kept euvolemic with high end of normal hemoglobin levels
Treatment includes a trial of indomethacin given in the first 24 hrs postpartum – reduces the risk of a PDA developing
Use of PEEP may assist in reducing the shunt
Surgical repair of the PDA will reduce the duration of ventilatory support
PDA ligation

22. Atrial Septal Defect
Communication between the right atrium and left atrium through a defect of the upper or lower septal wall

23. Atrial Septal Defect

24. Atrial Septal Defect (ASD) Etiology
The communication develops from
Incompetent foramen ovale
Developmental defect in the septum
Failure to develop the endocardial cushion
Three types of ASD may present
Primum (lower)
Secundum (Central)
Sinus Venosus (Upper)

25. Atrial Septal Defect Pathophysiology
Left to right shunting of blood occurs
Rarely produces pulmonary congestion
May produce right ventricular hypertrophy from pulmonary overflow

26. Atrial Septal Defect – Clinical Manifestations
CXR are usually normal unless there is pulmonary congestion – An increase in vascular markings
Most children with an ASD will not become symptomatic until school age
This may manifest as
SOB on exertion
Chest palpitations
Frequent pulmonary infections
Dyspnea
Normal ABGs and pulse oximetry can be expected post-repair

27. Atrial Septal Defect Management/Treatment
Diagnosis is usually made by
Echocardiogram
Cardiac catheterization
Repair is dependent on the condition of the child and the degree of pulmonary involvement and cardiomegaly
Open chest surgical repair will require cardiopulmonary bypass
ASD repair by cardiac catheterization

28. Ventricular Septal Defect
Most common cardiac defect

29. Ventricular Septal Defect

30. Ventricular Septal Defect (VSD) Etiology
A communication between the right and left ventricles
Size may range from a pinhole to absence of the septal wall
The majority of small VSDs close without intervention between the ages of 1 and 2

31. Ventricular Septal Defect Pathophysiology
VSD results in left to right shunting across the opening following the pressure gradient
Recalling that PVR is less than SVR
Shunting of blood primarily occurs during the systolic period
Increased pulmonary blood flow may lead to thickening and fibrosis of the pulmonary arterioles (Permanent damage)
Leads to pulmonary hypertension and congestive heart failure

32. Ventricular Septal Defect Clinical Manifestations
CXR
Small VSD may not show anything on CXR
Larger VSD may have increased cardiac shadow
Increased pulmonary vascular markings if congestive heart failure develops
PaO2 and saturation will be on the low end of normal
Children may have poor growth development
Pulmonary hypertension

33. Ventricular Septal Defect Management/Treatment
Medical management may include digoxin and furosemide
Dacron banding of the pulmonary artery root to allow child to grow for permanent repair
Surgical repair depends on the degree of the VSD
Suturing closed for small VSD
Patch sewn into place for the larger VSD
Surgical Repair of ASD and VSD
Normal ABGs and pulse oximetry can be expected post-repair

34. Atrioventricular Septal Defect

35. Atrioventricular Septal Defect

36. Atrioventricular Septal Defect Pathophysiology
Incomplete development of both the atrial septal walls and ventricular septal walls
No tricuspid or mitral valves formed
Single large valve forms across the defect
L-R shunt via ASD and VSD
Most common in Down’s Syndrome
If severe, seen at wks
Mixing of atrial and ventricular blood

37. Atrioventricular Septal Defect Clinical Manifestations
CXR
Cardiomegaly and increased pulmonary vascular markings
Congestive heart failure
Oxygenation
Saturations usually run between %

38. Atrioventricular Septal Defect Management/Treatment
Oxygenation
Supplemental oxygen should be used cautiously to prevent pulmonary vasodilation
Pulmonary artery banding to increase PVR – Temporary fix until infant has increased in size for surgical correction
Surgical correction of ASD and VSD with formation of tricuspid and mitral valves
Normal ABG values can be expected if complete surgical repair is done

39. Atrioventricular Septal Defect Management/Treatment
Care is taken to not disrupt the AV conduction system, but pacing wires are usually in place for the postoperative period to prevent arrhythmias
Pulmonary HTN may develop postoperatively, leading to an increased risk in mortality
If PA banding is performed, there is increased risk for mixing of deoxygenated and oxygenated blood
PaO2 = mmHg and SaO2 = %

40. Aortic Stenosis
Stenosis above (supravalvular), at or below (subaortic) the aortic valve
Stenosis is often associated with
Coarctation of aorta
Hypoplastic aortic arch
Interrupted aortic arch
Clinical manifestations are dependent on severity of stenosis

41. Aortic Stenosis

42. Aortic Stenosis Pathophysiology
Myocardial hypertrophy and ventricular overdistention related to restriction in flow
Increased pressure in LV
Decreased CO
LHF backup of pressure can cause RHF
Systemic blood flow – Ductal-dependent

43. Aortic Stenosis Clinical Manifestations
CXR
Congestive heart failure with enlarged cardiac silhouette
Increased pulmonary markings – pulmonary venous congestion
Infants often are acidotic and hypoxic
Decreased cardiac output
Decreased systemic BP
Chest pain – Tachycardia
Syncope

44. Aortic Stenois Management/Treatment
Prostaglandin E1
Supplement oxygen to support oxygenation
Cardiac catheterization – Valvotomy
Surgical intervention
Aortic valvoplasty
Replacement with artificial valve
Pulmonary valve autograph (Ross Procedure)
Widening of atenotic area
Ventilation to support WOB and acidosis

45. Aortic Stenosis Management/Treatment
Normal ABGs and pulse oximetry post-correction
Limiting systemic BP postoperatively
Ross Procedure – Aortic valve replacement

46. Coarctation of Aorta
Coarctation – A stricture or narrowing, especially of a canal or vessel
Constriction of aorta severely restricting bld flow
Occurs anywhere along aorta
Pre-ductal – R-L shunt
Post-ductal – L-R shunt
Usually near entry of ductus

47. Coarctation of Aorta

48. Coarctation of Aorta Pathophysiology
Severe narrowing of the aorta – Decreased blood flow distal to the stricture
Increased LV work and filling pressures
Increased LV outflow resistance
LV hypertrophy may occur if DA closes before the coarctation is identified
RV hypertrophy in infancy

49. Coarctation of Aorta Pathophysiology
Preductal narrowing
Associated with VSD and aortic stenosis
Descending aorta perfused by RV via ductus arteriosis (right to left shunt)
Closure of DA results in decrease in systemic perfusion (Shock – like presentation) and renal shutdown
Postductal narrowing
May develop collateral circulation

50. Coarctation of Aorta Clinical Manifestations
CXR
Enlarged heart shadow
Pulmonary vascular congestion
Dyspnea
Tachycardia
Hypertension – Upper extremities
Poor BP in lower extremities

51. Coarctation of Aorta Management/Treatment
Inotropic support for decreased BP and cardiac output
Ventilatory support for the patient presenting with shock
Prostaglandin E1
Diuretic therapy – Congestive heart failure

52. Coarctation of Aorta Management/Treatment
Surgical correction once patient is able to tolerate
Excision of the coarctated segment aorta
Tubular graft bypass of the coarctated
Patch aortoplasty from the subclavian artery
Normal ABGs and oximetry can be expected
May develop postoperative rebound hypertension
Coarctation of aorta repair

53. Cyanotic Heart Defects

54. Total Anomalous Pulmonary Venous Return
Pulmonary veins no connection with LA; they drain through multiple alternate routes
Supracardiac
Cardiac
Infracardiac
Mixed
Requires PFO, ASD, or VSD for survival

55. Total Anomalous Pulmonary Venous Return

56. Total Anomalous Pulmonary Venous Return

57. Total Anomalous Pulmonary Venous Return Pathophysiology
Mixing of pulmonary and systemic blood – Venous admixture
Increased blood volume and pressures in the RA
Pulmonary overflow and increased right to left shunt from PDA
Systemic oxygenation is dependent on right to left shunt through ASD or PFO
Infracardiac defect may result in pulmonary vein obstruction

58. Total Anomalous Pulmonary Venous Return Clinical Manifestations
CXR
Relatively normal heart shadow
May have increased pulmonary vascular markings with severe obstruction
ABGs
PaO2 = 40 mmHg
PaCO2 = 40 mmHg
SpO2 = 75%
Cyanosis – Degree is dependent on severity of obstruction
Poor exertional tolerance – Dyspnea and tachypnea

59. Total Anomalous Pulmonary Venous Return Management/Treatment
All TAPVR must be surgically repaired soon after diagnosis (May include neonatal period)
Balloon atrial septoplasty – Enlarge ASD
Oxygen therapy – May have refractory hypoxia
Postoperative ventilation – Normal blood gases
Pulmonary edema may prolong ventilation
Postoperative pulmonary hypertension
Total anomalous pulmonary venous return

60. Tetralogy of Fallot Consists of four conditions Overriding aorta
Pulmonary stenosis
VSD
RV hypertrophy

61. Tetralogy of Fallot

62. Tetralogy of Fallot Pathophysiology
Large VSD – Increased RV pressure
RV pressure = LV pressure
Pulmonary stenosis – RV hypertrophy
Dextroposition of aorta (Off to side)
Pulmonary blood flow (Qp) depends on
Severity of ventricular outflow obstruction
Systemic Vascular Resistance (SVR)
Presence of PDA
Mild stenosis – Left to right (Acyanotic)
Severe stenosis – Right to left (Cyanotic)

63. Tetralogy of Fallot Clinical Manifestations
CXR – “Boot-shaped” from narrow mediastinum and RV hypertrophy

64. Tetralogy of Fallot Clinical Manifestations
“TET” spells (2 - 4 months of age)
Hyperpnea or exaggerated breathing
Irritability and prolonged crying
Increasing cyanosis – Increased PVR – Increases R to L shunting = increased hypoxia
Decreased intensity of the heart murmur
Fainting
Treatment of “TET” spells
Hold in knee-to-chest position
Morphine sulphate – Decrease respiratory drive
Administer oxygen
Sodium Bicarbonate – Acidosis
Vasoconstrictors – Increase SVR
Minimize interventions that precipitate “TET” spell

65. Tetrology of Fallot Management/Treatment
Prostaglandin E1 – Maintain PDA
Oxygen therapy
Surgical correction done under cardiopulmonary bypass
Widening of RV outflow tract
Reconstruction of stenotic pulmonary artery
Closure of VSD
Blalock-Taussig shunt to improve systemic to pulmonary circulation (Severe stenosis)
Tetralogy of fallot repair

66. Tetralogy of Fallot Blalock-Taussig Shunt

67. Tetralogy of Fallot Management/Treatment
Ventilatory support – Postoperative period
Normal ABGs can be expected – Complete repair
Atrial and ventricular pacing wires – Atrial junctional tachycardia

68. Truncus Arteriosus
Failure of embryonic trunk of the heart to divide into pulm art. and aorta
VSD always present
Systemic and pulm. circulation pass through the trunk

69. Truncus Arteriosus

70. Truncus Arteriosus Pathophysiology
Single large artery (truncal vessel) comes from single large ventricle
Large VSD (RV and LV act as one common ventricle)
Truncal valve similar to aortic valve
Systemic circulation and oxygenation is dependent on balance between PVR and SVR
If PVR decreases = increase in Qp and Qs decreases
If SVR decreases = increase in Qs and Qp decreases

71. Truncus Arteriosus Clinical Manifestations
CXR
Enlarged heart shadow – Dilation of LA and LV
Congestive heart failure
ABGs
Rule of 40’s applies
Acidosis
Hypoxemia – Dependent on balance between SVR and PVR
Tachypnea
Poor feeding and lethargy

72. Truncus Arteriosus Management/Treatment
Oxygen therapy – Careful administration to prevent imbalances in PVR
Inotropic support – Systemic circulation
Diuretics – Maintain an euvolemic state
Pulmonary artery banding – Palliative procedure to allow infant to stabilize
Surgical correction under cardiopulmonary bypass using a Rastelli procedure
Normal ABGs can be expected post-correction
Truncus arteriosus repair

73. Truncus Arteriosus Management/Treatment
Rastelli procedure
Right and left pulmonary arteries separated from main truncus
Conduit from RV to pulmonary arteries is developed
Truncus is then patched – It then acts as the aorta
VSD is repaired

74. Transposition of the Great Vessels
Two parallel circulations
Aorta rises from RV
Pulmonary artery rises from LV

75. Transposition of the Great Vessels

76. Transposition of the Great Vessels Pathophysiology
Right circulation – Deoxygenated blood circulates through RA, RV, aorta, systemic circulation, and back to RA
Left circulation – Oxygenated blood from pulmonary veins has continuous circuit through LA,LV pulmonary circulation, and back to LA
Must have connection between R+L heart
ASD
PFO
PDA
Will result in death if not corrected

77. Transposition of the Great Vessels Clinical Manifestations
CXR
Usually normal, may be able to see malposition of the great vessels
Malposition is described as “Egg-shaped” in appearance

78. Transposition of the Great Vessels Clinical Manifestations
ABGs
Shunting from aorta to PA, and LA to RA provides adequate mixing of blood
Closure of ductus arteriosus results in severe cyanosis and hypoxemia
Infant will develop severe acidosis and hypercapnia
Infant will present with
Tachypnea
Retractions, grunting, nasal flaring, etc.

79. Transposition of the Great Vessels Management/Treatment
Prostaglandin E1 – Maintain PDA upon recognition of abnormality
Intubation and ventilation to manage blood gas abnormalities
Oxygen therapy – Balance between PVR and SVR
Atrial septoplasty of ASD – Increase shunt from RA to LA
PA banding to increase LV conditioning to support systemic circulation post-surgical correction

80. Arterial Switch (Jatene Operation)
Most commonly performed surgical correction – Dependent on the level of involvement of the defect
Requires good LV function
Trunks of PA and aorta transected at take-off from heart
Aorta attached to LV
PA attached to RV
Coronary arteries excised from aorta root and attached to PA on LV

81. Rastelli Procedure Selected if there is a VSD present as well
Redirection of blood flow is at the ventricular level
Conduit is attached from RV to PA
VSD is repaired, allowing blood to flow only to the aorta

82. Transposition of the Great Vessels Management/Treatment
Post-surgical correction; normal blood gases can be expected
Infants will require inotropic support to balance circulations pre- and post-correction
Postoperative ventilation can be expected
Arterial switch – Philadelphia Children’s Hospital
Arterial switch – Miami Children’s Hospital

83. Hypoplastic Left Heart Syndrome (HLHS)
Combination of poorly formed structures on LH – hypoplastic LV, coarctation of aorta, aortic + mitral valve stenosis, or atresia

84. Hypoplastic Left Heart Syndrome

85. Hypoplastic Left Heart Syndrome Pathophysiology
Shunting occurs at two sites
PFO or ASD – L-R shunt through ASD
PDA – R-L shunt through PDA = Systemic blood flow (Systemic blood flow provided by RV)
Blood flow through LH obstructed = decreased CO
Postnatal closure of DA results in decreased CO
Infant will present with circulatory shock
Metabolic acidosis
Death usually occurs in the first month if not surgically corrected

86. Hypoplastic Left Heart Syndrome Clinical Manifestations
CXR
Will show increased pulmonary vascular markings
Globular shape
ABGs
Hypoxemia
Metabolic acidosis
Patients may present with cyanosis, tachypnea, grunting, retractions

87. Hypoplastic Left Heart Syndrome Management/Treatment
Preoperative treatment
Prostaglandin E1 – Maintain PDA
Maintain high PVR relative to SVR – Hypercarbia and acidosis (Permissive hypercapnia and pH ~ 7.20)
Maintain SpO2 ~ %
Mechanical ventilation to manage PVR
Addition of mechanical deadspace to ventilator circuit
Reduction in minute ventilation
Adding CO2 to the patient circuit

88. Repair of Hypoplastic Left Heart Syndrome

89. Stage 1 Repair – Norwood Procedure
Reconstruction of the aorta
Blalok-Taussig shunt or RV-PA conduit
PA banding
Atrial septoplasty
PDA ligation

90. Stage 1 Repair – Sano Shunt (RV-PA Conduit)

91. Postoperative Management of Stage 1 Repair
PA banding – Reduction in pulmonary blood flow
BT shunt – Connects left or right subclavian to the pulmonary artery
RV-PA conduit – Replaces normal connection between the two structures
RV is connected to the neo-aorta
Requires cardiopulmonary bypass surgery
Postoperative management
Control PVR and optimize systemic perfusion
Rule of “40’s”
Avoid hyperventilation – Decrease in PVR

92. Stage 2 Repair – Bidirectional Glenn Shunt 4 - 6 Months

93. Stage 3 Repair – Fontan Procedure > 2 Years of Age

94. Postoperative Mangement of Stage 2 and 3 Repairs
Low rate and high tidal volume ventilation
Increase Te = decreased MAP
Early Extubation – Negative intrathoracic pressures
HLHS – Stage 1 repair