Chapter 30Chapter 30Congenital Heart DefectsCongenital Heart Defects

•http://www.youtube.com/watch?v=KRy8gfmGSxg

Cardiac Defects• Patent Ductus Arteriosus• Atrial Septal Defect• Ventricular Septal Defect• Tetralogy of Fallot• Transposition of the Great Arteries• Coarctation of the Aorta• Anomalous Venous Return• Truncus Arteriosus• Hypoplastic Left-Heart Syndrome

Heart• Congenital heart disease (CHD) occurs in 1/125

live births.• Neonates may present with a variety of non-

specific findings, including: - tachypnea - cyanosis - pallor - lethargy - FTT - sweating with feeds

• More specific findings include: - pathological murmurs - hypertension - abnormal pulses - syncope

Neonatal cardiac physiology

• The transformation from fetal to neonatal circulation involves two major changes:

1. A marked increase in systemic resistance.• caused by loss of the low-resistance placenta.

2. A marked decrease in pulmonary resistance.• caused by pulmonary artery dilation with the neonate’s first

breaths.

•Fetal Circulation

•No circulation to lungs

•Foramen ovale

•Ductus arteriosum

•Circulation must go to placenta

•Umbilical aa., vv.

Fetal cardiac physiologyFetal circulation:• Blood flows from the placenta

IVC RA through the PFO LA LV

• ascending aorta

• brain• returns via

the SVC

Fetal cardiac physiologyFetal circulation:• From the SVC

RA RV

• pulm aa

• through the PDA• descending

aorta

• lower

extremities and

placenta

Fetal cardiac physiologyFetal circulation: • Only a very small amount of

blood is directed through the right and left pulmonary aa’s to the lungs.

Neonatal cardiac physiologyNeonate circulation:• The transformation to neonatal

circulation occurs with the first few breaths.

• The two remaining remnants of the fetal circulation are a patent foramen ovale...

• and ductus arteriosus.

Congenital Heart Disease• Neonates with CHD often rely on a patent ductus

arteriosus and/or foramen ovale to sustain life.• Unfortunately for these neonates, both of these

passages begins to close following birth.– The ductus normally closes by 72hrs.– The foramen ovale normally closes by 3 months.– http://www.youtube.com/watch?v=FG-CNV501bc

CHD

• That being said, in the presence of hypoxia or acidosis (generally present in ductus-dependent lesions), the ductus may remain open for a longer period of time.

• As a result, these patients often present to the ED during the first 1-3 weeks of life.

– i.e. as the ductus begins to close.

Classifying CHD

• There are many different classification systems for CHD.

– None are particularly good.

• I will be discussing the Pink/Blue/Grey-Baby system:

1. Pink Baby – Left to right shunt2. Blue Baby – Right to left shunt3. Grey Baby – LV outflow tract

obstruction

Pink Baby (L R shunt)

• L R shunts cause CHF and pulmonary hypertension.

• This leads to RV enlargement, RV failure, and cor pulmonale.

• These babies present with CHF and respiratory distress.

– They are not typically cyanotic.– http://www.youtube.com/watch?

v=46tmI2_RVuE&list=PLA81DD78BDE77FBFC

Pink Baby (L R shunt)

•ASD

•VSD

• These lesions include (among others) ASD’s, VSD’s, and persistently patent ductus arteriosus.

Pink Baby (L R shunt)

•Persistently patent ductus

arteriosus

Pink Baby (L R shunt)• Diagnosing L R shunts depends on:

1. Examination findings:• Non-cyanotic infant in resp distress.• Crackles, widely-fixed second heart sound, elevated JVP, cor

pulmonale.2. CXR:

• Increased pulmonary vasculature (suggestive of CHF).• RA and/or RV enlargement.

Pink Baby (L R shunt)• Initial management should be directed at

reducing the pulm edema.– Adminster Lasix 1mg/kg IV.

• Peds Cardiology/ PICU should be consulted urgently regarding use of:

– Morphine– Nitrates– Digoxin– Inotropes

Ductus Arteriosus• Fetal Circulation Component

– Connects Pulmonary Artery to Aorta– Shunts blood away from lungs– Maintained patent by presence of prostaglandins

• Closure secondary to:– Increase in PaO2_

– Decrease in level of prostaglandins

Patent Ductus Arteriosus

• 5-10% of all births (1 of 2000 live births)– 80% of premature babies

• 2-3 times more common in females than males.• 5th or 6th most common congenital cardiac defect.

– Often associated with other defects.– May be desirable with some defects.

• Morbidity/Mortality related to degree of blood flow through PDA.

Pathophysiology - PDA

• With a drop in pulmonary arterial pressure (reduction in hypoxic pulmonary vascular constriction), blood will flow through PDA.– LEFT TO RIGHT SHUNT

• Increased pulmonary blood flow may lead to pulmonary edema.– Reduced blood flow to all postductal organs

• NEC

• If pulmonary artery pressure rises above Aortic pressure, blood will move in the other direction.– RIGHT TO LEFT SHUNT

Diagnosis - PDA

• Loud grade I to grade III systolic murmur at left sternal border.– Washing machine

• Echocardiography

Treatment - PDA

• Restrict fluids.• Diuretics• Prostaglandin Inhibitors - Indomethacin• Surgical closure (ligation).

Atrial Septal Defect

• 6-10% of all births (1 of 1500 live births)• 2 times more common in females than males.• Types:

– Ostium Secundum (at or about the Foramen Ovale)– Sinus Venous

– In 1950 most children with ASD did not reach the first grade. Today, first year surgery facilitates normal growth and development.

ASD: Pathophysiology and Diagnosis

• Pathophysiology– Left to Right Shunt

• Inefficient recirculation of good blood through pulmonary arteries.

– May not manifest symptoms and may be found later in life.

– If defect is significant, may cause problems later in life due to inefficiencies.

• Diagnosis– Murmur– Echocardiography

Treatment - ASD• Surgical closure.• Non-Surgical closure via cardiac catheterization.

Ventricular Septal Defect

• 1% of all births (2 to 4 of 1000 live births)– Vast majority the hole is small.

• In 1950, fatal. Today almost all VSD can be closed successfully, even in small babies. Lillehei was the first person in history to correct both ASD and VSD on 8/31/54.

VSD: Pathophysiology & Diagnosis

• Pathophysiology– May be isolated or associated with other

congenital cardiac defects.– With normal PVR:

• LEFT TO RIGHT SHUNT

– With elevated PVR (RDS):• RIGHT TO LEFT SHUNT

• Diagnosis– Echocardiography

Treatment - VSD

• Nothing if VSD is small.• With CHF or Failure to Thrive: Surgical closure.

Blue Baby (R L shunt)• R L shunts cause hypoxia and central cyanosis.• Neither hypoxia or cyanosis tend to improve with

100% oxygen.• R L lesions include (among others):

– Tetralogy of Fallot (TOF)– Transposition of the Great Arteries (TGA)

Blue Baby (R L shunt)

• Hypoxia and cyanosis (unresponsive to oxygen) in the neonatal period suggests a ductus-dependent lesion.

• Treatment is a prostaglandin-E1 (PGE1) infusion.– Dosing discussed momentarily

• This should obviously be accompanied by urgent Peds Cardiology and PICU consultation.

Tetralogy of Fallot• Characterized by:

1. Pulmonary aa OTO2. RV hypertrophy3. VSD4. Over-riding aorta

• With severe pulmonary OTO...

•*•*

•*

•*• bloodflow to the

lungs may be highly ductus-dependent.

Tetralogy of Fallot• The classic CXR finding in TOF is

the boot-shaped heart.

• Pulmonary vasculature is typically decreased.

Tetralogy of Fallot• 1% of neonates.• Most common of the cyanoticcyanotic cardiac diseases.• Mortality increases with age (1 year-old has a 25%

mortality, 40 year-old has 95%).• In 1950, fatal. Today, less than 5% mortality with

children operated on in infancy, leading normal lives.Four Defects– Pulmonary Artery Stenosis (determinant factor related to

severity)– VSD (usually large)– Overriding Aorta– RV hypertrophy

Tetralogy of Fallot: Diagnosis and Treatment• Tet Spells (Blue spells)

• CXR: Boot-shaped Heart• Diagnosed with echocardiography.• Surgical correction.

– Reparative or Palliative (Blalock-Taussig)

Blalock-Taussig• Something the

Lord Made.– Vivien

Thomas

Tetralogy of Fallot

Transposition of the Great Arteries

• TGA is one of the most common cyanotic lesion presenting in the first week of life.

• Anatomically:– RV aorta– LV pulmonary aa

• To be compatible with life, mixing of the two circulations must occur via an ASD, VSD, or PDA.

• http://www.youtube.com/watch?v=O83cYwKOKtI&list=PLA81DD78BDE77FBFC

Transposition of the Great Arteries

• The CXR findings in TGA are typically less dramatic than in TOF.

• Pulmonary vasculature is typically increased.

• http://www.youtube.com/watch?v=b-TkE_wygT4&list=PLA81DD78BDE77FBFC&index=1

Complete Transposition of the Great Arteries

• Second most common form (5-7%) of congenital cardiac anomalies.

• Aorta arises from RV and Pulmonary Arteries from LV.

• Without an abnormality, life would not be possible.– ASD– VSD (30-40%)– PDA

Transposition – Diagnosis and Treatment• Diagnosis

– Chest X-Ray: “Egg on a String”– Echocardiography– Cardiac Catheterization (?)

• Treatment– Balloon septostomy during

cardiac cath.• Rashkind’s Procedure• Reestablish Foramen Ovale

– Prostaglandin E1 to keep PDA open.

– Surgical Correction• Jantene Operation

Grey Baby (LVOTO)

• Left-ventricular outflow tract obstructions (LVOTO’s) lead to cyanosis, acidosis, and shock early in the neonatal period.

• Complete obstruction is universally fatal unless shunting occurs through an ASD, VSD, or PDA.

• Examples of these lesions include:– Severe coarctation of the aorta– Hypoplastic left heart syndrome (HLHS)

• X

Grey Baby (LVOTO)

• Treatment:– Any neonate presenting with shock unresponsive to

fluids +/- pressors has a LVOTO until proven otherwise.

– As with the Blue babies, appropriate management is an urgent PGE1 infusion and emergent consultation.

Coarctation of the Aorta

• 7% of congenital cardiac defects.• Constriction of the aorta.

– Results in severely reduced blood flow.• Increased work on the heart leading to CHF

and cardiovascular collapse.• Location of narrowing determines the clinical

signs.• Usually associated with PDA, VSD and a

defective aortic valve.

•http://www.youtube.com/watch?v=SiNJfvK_qeI

Location of Coarctation

• Pre-Ductal– Less common but more serious– Associated with VSD, PDA, Transposition

• Post-Ductal– More common– Often associated with collateral circulation beyond

coarctation, which minimizes effect.– Diagnosed by a difference in blood pressure between

lower extremities and upper ones.• Pressure in upper extremities > lower

Coarctation – Diagnosis and Treatment

• Diagnosis– Chest X-Ray – Echocardiography– Cardiac catheterization

• Treatment– Support with inotropic agents (Dopamine).– Prostaglandins to maintain PDA.– Surgical repair– http://www.youtube.com/watch?v=AGohu9fqKHg&list=PLF81322B9674D16CF

Anomalous Venous Return

• Return of pulmonary venous blood to the right atrium instead of the left.– ASD is present to sustain life.– Can also be partial.

• Cyanosis usually present.• Diagnosed with echocardiography.• Surgical correction with reimplantation of

pulmonary veins.

Truncus Arteriosus• Defect in which one large vessel arises from right and

left heart over a large VSD.• Cyanosis is often present.• CHF common.• Diagnosed with echocardiography and cardiac

catheterization.• Surgery:

– Separate pulmonary arteries from truncus.– Closure of VSD– Create valved connection between RV and Pulmonary

Artery– http://www.youtube.com/watch?v=HXlWeSGIR7A

Repair of Truncus

Arteriosus

Hypoplastic Left-Heart Syndrome• Several anomalies:

– Coarctation of the aorta– Hypoplastic left ventricle– Aortic and mitral valve stenosis or atresia.

• Cyanotic defect.• Right heart pumps blood to body through PDA.• Closure of PDA results in hypotension, shock, and

death.– Maintain hypoxemia with normalized CO2 levels.

• “40-40 Club”

http://www.youtube.com/watch?v=DcbiHP6zvus

•

                                                                                     

1 Patent foramen ovale

2 Coarctation of the aorta

3 Patent ductus arteriosus

4 Narrowed aorta5 Hypoplastic left

ventricle6 Aortic atresia

Surgical Treatment of Hypoplastic Left Heart Syndrome

• Three separate surgeries.– Norwood procedure

• First few days after birth.– Glenn Shunt (Cavo

Pulmonary Connection)• 3-9 months of age

– Fontan Procedure • 2 years of age

– Less wait because of damage from pulmonary hypertension.

Stage I - Norwood Procedure

Stage II - Glenn Shunt

Stage III – Fontan Procedure

Prostaglandin-E1

• PGE1 promotes ductus arteriosus patency.

• Use an IV infusion at 0.05-0.1 ug/kg/min.• A response should be seen within 15 min.

– If ineffective, try doubling the dose.– If effective, try halving the dose.

• The lowest possible dose should be used– as adverse-effects of PGE1 can include:

- fever- flushing- diarrhea- periodic apnea (be ready to intubate)

Remnants of Fetal Circulation

• Ligamentum teres = Round ligament– Remnant of the umbilical vein– Anterior abdominal wall

• Ligamentum venosum– Remnant of ductus venosum– On liver’s inferior surface

• Medial Umbilical Ligaments– Remnant of umbilical arteries– Anterior abdominal wall below navel– Also gives branch to urinary bladder

Clinical Monitoring

• Blood pressure• Oxygen saturation• End tidal carbon dioxide

Respiratory Care of Patients with Cardiac Anomalies

• Vascular resistance• Ventilator management• Inhaled nitric oxide• Subambient oxygen• Hypercarbia