FETAL HEART DEFECTS, CLASSIFICATION, & TYPES
*Fetal ductus arteriosus: artery that connects to aorta + pulmonary artery
*Heart Shunt: abnormal pattern of blood flow through heart
*Left-to-Right Shunt: abnormal pattern of blood flow through heart ; allows the oxygenated (saturated) pulmonary venous blood to
return directly to the lungs rather than being pumped to the body; some can go away on its own without treatment
*Right-to-Left Shunt: abnormal pattern of blood flow through heart; some blood does NOT get oxygenated; allows the
deoxygenated, systemic venous return to bypass the lungs and return to the body without becoming oxygenated; usually require
surgery to correct.
LEGEND: ASD= Atrial septal defect; CHD= congenital heart disease; HLHS = hypoplastic left heart syndrome; PDA = patent ductus arteriosus; PS =
pulmonic stenosis; RVOT = right ventricular outflow tract = TGA, transposition of the great arteries; VSD = ventricular septal defect; BE, = bacterial
endocarditis; COA = coarctation of the aorta; LV/LA – left ventricle/left atrium; RV/RA: right ventricle/right atrium;
L-to-R = left-to-right shunting; R-to-L = right to left shunting
FETAL HEART DEFECTS, CLASSIFICATION, & TYPES
DEFECTS RELATED TO AN ↑ IN PULMONARY BLOOD FLOW
Characteristics: mixing of blood from the pulmonary + systemic circulations in heart chambers; fully saturated systemic blood mixes w/ desaturated pulmonary
blood flow (causes a systemic blood flow that has less O2)
Pathophysiology
-Abnormal opening between atria
- L-to-R shunt (high to low)
-blood in L Atrium shunt to R Atrium
-↑ flow of oxygenated blood to R side of heart
Complications: risk for atrial dysrhythmias,
pulmonary vascular obstructive disease, embolism
Signs/Symptoms
Treatment
Asymptomatic (early on)
Surgical TX:
Surgical patch closure
Open repair cardiopulmonary
bypass
HF (develop after awhile)
Systolic/diastolic murmur
(w/ fixed split 2nd heart sound)
Nonsurgical treatment:
Amplatzer Septal Occluder
Enlarged RA
Most close spontaneously
Atrial Septal Defect
-Abnormal opening between L & R ventricles
-L-to-R shunting occurs
-blood in L ventricle shunt to R ventricle
-more resistance in systemic than pulmonary
-co-occur w/ other defects (pulmonary stenosis,
transposition of great vessels, ductus arteriosus, atrial
defects, coarct of aorta)
(during 1st yr of life)
Enlarged RV
HF
loud holosystolic murmur
- ↑ blood volume forced into lungs (↑ resistance)
Ventricular Septal Defect
Complications: risk for Endocarditis, pulmonary
obstructive disease
-ductus arteriosus don’t fully close in 1st weeks of life
-causes L-to-R shunting
-blood continues flow from aorta →pulmonary artery
-severity depends on size of ductus & pulmonary
resistance
Complications: injury to laryngeal nerve/thoracic, left
diaphragm paralysis
(heard best at L sternal border)
Asymotomatic
HF
Machinery-like murmur
R Ventricle hypertrophy
Pulmonary Congestion
Widened pulse presure
Bounding pulses
Surgical TX:
Pulmonary artery banding
Complete Repair
Sutures (small defects)
Knitted Dacron patch (large defect)
Medication TX:
Indomethacin
(Prostaglandin inhibitor)
Surgical TX:
Thoracotomy
(Division of ductus arteriosus)
Non-Surgical TX:
Coils to occlude/close ductus
FETAL HEART DEFECTS, CLASSIFICATION, & TYPES
DEFECTS RELATED TO A ↓ PULMONARY BLOOD FLOW
Characteristics: obstruction of pulmonary blood flow + an anatomic defect (ASD or VSD) between the right and left sides of the heart
Pathophysiology
-includes total of FOUR defects: Ventricular septal defect, pulmonary
stenosis, overriding aorta & RV hypertrophy
- pressures may be equal in the R & L ventricles
- shunt direction depends on difference between pulmonary & systemic
resistance
-R-to-L shunt occurs if pulmonary resistance is higher
Tetralogy of Fallot
-L-to-R shunt occurs if systemic resistance is higher
-Anoxic spells: occur usually during crying or after feeding. Infant’s O2
needs exceed the blood supply available. Increases risk for emboli,
seizures, loss of consciousness or sudden death after an anoxic spell
- tricuspid valve fails to develop
-no communication between R atrium to R ventricle
-Blood flows through ASD or foramen ovale to the left side of the
heart and through a VSD to the right ventricle and out to the lungs
- often co-occur w/ PS + TGA
- deoxy + oxyg blood of left side of heart mixes
Tricuspid Atresia
Postoperative complications: dysrhythmias, HTN, pleural/pericardial
effusions, ventricular dysfunction, protein-losing enteropathy, atrial
dysrhythmias, late ventricular dysfunction, developmental delays
Signs/Symptoms
Treatment
Cyanotic at birth
Surgical tx:
Mild cyanosis that
worsens
Blalock-Taussig shunt
operation
Complete repair
systolic murmur
(moderate)
Blue spells/tet
(acute episodes of cyanosis &
hypoxia)
Anoxia
Cyanosis
Tachycardia
Dyspnea
Hypoxemia
(acute or chronic)
Medication
IV infusion prostaglandin E1
at 0.1 mcg/kg/min
Surgical
Shunt placement
atrial septostomy
(if ASD is small)
pulmonary artery banding (if
clubbing
blood to lung increases)
FETAL HEART DEFECTS, CLASSIFICATION, & TYPES
OBSTRUCTIVE DEFECTS
Pathophysiology
Signs/Symptoms
Treatment
- narrowing near insertion of ductus arteriosus
- Cause increased pressure in upper extremity/head
-decreases pressure in lower extremities
- defect is outside the heart and pericardium
- best to get elective surgery for in 1st 2 years of life
↑BP w/ bounding pulses in upper
extremities
Non-surgical
Balloon angioplasty
(for older kids/adults)
**15% - 30% risk for recurrence in patients who got
surgery as infants underwent surgical repair as
infants ***
Coarctation of Aorta
Complications: HTN, ruptured aorta, aortic
aneurysm, stroke, recoarctation of aorta
- Narrowing of aortic valve
-causes resistance to blood flow in LV
-resists the LV trying to pump blood out of heart
-causes HTN in pulmonary system
***2 Types***
1. Valvular aortic stenosis: most common type;
caused by malformed bicuspid valve ; (1) obstruction
is progressive; (2) sudden MI/ischemia occurs (or low
cardiac output) can result in sudden death; (3)
surgical repair rarely end w/ normal valve
*NO strenuous physical activity*
Aortic Stenosis
2. Subvalvular aortic stenosis: stricture caused by a
fibrous ring
Complications: ↓ cardiac output, MI, pulmonary HTN,
scarred LV muscles (causes mitral insufficiency)
↓ BP w/ weak pulses in lower extremities
Infants: signs of HF
Sever acidosis
Surgical
1st line for infants under 6mo
Percutaneous balloon
angioplasty
dizziness, headaches, fainting, nose bleeds
(epistaxis)
↓ cardiac output
left ventricular hypertrophy
(end-diastolic pressure)
pulmonary vascular congestion
Pulmonary HTN
Infant S/S: hypotension, faint pulses,
tachycardia, poor feeding
Children: exercise intolerance, chest pain,
dizziness w/ prolonged standing; systolic
ejection murmur
VALVULAR STENOSIS
Surgical Repair: catheterization
balloon dilation (1st Line
treatment), Aortic valvotomy
(Rarely used), Aortic valve
replacement (if they’ve had a
valve before)
Non-Surgical Repair: balloon
angioplasty dilation
SUBVALVULAR STENOSIS
Surgical Repair: cut the
fibromuscular ring, patch the
LV, valve replacement
FETAL HEART DEFECTS, CLASSIFICATION, & TYPES
MIXED DEFECTS
Characteristics: Defects impede blood flow out of the ventricles ; blood exiting the heart meets a narrowed area (stenosis) that cause obstruction to blood flow
Pathophysiology
Signs/Symptoms
Medication
IV prostaglandin E1
- The pulmonary artery switches place with Aorta
Severely cyanosis
NORMAL Heart Circulation
Aorta: carries blood from LV → rest of body
Pulmonary Artery: carries blood from RV → lungs
ABNORMAL Transposition of Great Artery
Aorta: carries blood from RV → lungs
Pulmonary Artery: carries blood from LV → rest of body
Transposition of Great
Arteries/Vessels
Treatment
Depressed function at birth
(to keep ductus arteriosus open,
keep oxygen saturation 75% or
higher & maintain cardiac output)
Symptoms of HF
Surgical Repair
Arterial Switch
Cardiomegaly
(best 1st few weeks of life)
Rastelli procedure
-There is no communication between systemic &
pulmonary circulations
(For infants w/ TGA, VSD, severe PS)
- failure of pulmonary veins to join L atrium
- pulmonary veins instead connect to systemic
circulation via the R atrium OR other veins (like
superior vena cava)
Cyanosis in early life
- more pulmonary blood = less cyanosis
Total Anomalous Pulmonary
Venous Connection
End Result:
-mixed blood returns to R atrium
- R-to-L shunting from R atrium to L atrium
-O2 saturation of both heart chambers is equal
- R atrium receives all the blood that normally
flow into the L atrium
-Causes R side of heart to hypertrophy while
left side remain small
Asymptomatic if no obstruction
present
HF symptoms
Surgical Repair
Corrective Repair
(Links pulmonary vein back to
L atrium, closes ASD)
FETAL HEART DEFECTS, CLASSIFICATION, & TYPES
MIXED DEFECTS (cont.)
Characteristics (cont.): Pressure in the ventricles & great artery before the obstruction is increased, and the pressure in the area beyond the obstruction is decreased ; location of
the narrowing is usually near the valve ; obstruction on L side of heart causes HF symptoms; Severe obstruction on R side = cyanosis
Pathophysiology
Signs/Symptoms
Treatment
-The two major arteries (aorta + pulmonary artery) fail
to separate, leaving one large artery space (AKA the
truncus arteriosus)
moderate to severe HF
Surgical Repair
Corrective Repair &
Homograph: occurs 1st month
of life; closes the VSD so
truncus arteriosus gets blood
flow from the L ventricle ;
remove pulmonary arteries
from aorta and attach them to
R ventricle via of homograft
-Blood from both L + R ventricles empty into the
truncus arteriosus
variable cyanosis
poor growth
activity intolerance
-This causes systemic & pulmonary blood to mix =
overall blood becomes desaturated = hypoxemia
-pulmonary blood flow ↑; systemic blood flow ↓
Truncus Arteriosus
-Pulmonary vascular disease develops at an early age in
patients with truncus arteriosus.
- Underdevelopment of the left side of the heart,
resulting in a hypoplastic (small size than normal)
left ventricle and aortic atresia.
-blood from L atrium flows across the patent
foramen ovale to the R atrium & R ventricle, and out
the pulmonary artery. The descending aorta receives
blood from the PDA supplying systemic blood flow
HYPOPLASTIC BLOOD FLOW:
Hypoplastic Left Heart
Syndrome
L atrium blood (saturated) mixes w/ R atrium blood
(desaturated) →R ventricle → pulmonary artery→
lungs → ductus arteriosus → aorta → to rest of the
body
**Hypoplastic = smaller size than normal**
- coronary + cerebral vessels receive blood by retrograde
flow through the hypoplastic ascending aorta
diastolic /holosystolic/L sternal
murmur
35% of patients have 22q11 gene
deletion
mild cyanosis
-Will need to replace as child
grows
Surgical Repair
Multi stage repair (Norwood
& Glenn shunt procedure
signs of HF
decreased cardiac output
fatal in the first months of life
without intervention
Long-term problems w/ repair:
worsening ventricular function,
tricuspid regurg, recurrent aortic
arch narrowing, dysrhythmias,
developmental delays
Heart Transplantation
Mechanical ventilation
Medication
IV prostaglandin E1
(to maintain ductal patency &
adequate systemic blood flow)
FETAL HEART DEFECTS, CLASSIFICATION, & TYPES
GENERAL BACKGROUND INFO
Increased Pulmonary Blood Flow:
-Blood flow from higher-pressure L side of heart to lower-pressure R side (left-to-right shunt); Can cause HF symptoms ; Increased
blood volume on the right side of the heart increases pulmonary blood flow at the expense of systemic blood flow.
Decreased Pulmonary Blood Flow: Result in cyanosis
Obstructive Defects:
Mixed Defects: Can lead to hypoxemia (with or w/out cyanosis) & HF; Hypoxemia & HF usually co-occur with these defects
PRENATAL CIRCULATION
POSTNATAL CIRCULATION
FETAL HEART DEFECTS, CLASSIFICATION, & TYPES