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CONGENITAL HEART DISEASE
A SIMPLIFIED LOOK
Jennifer Fung, James Gray, Ibrahim Hajjali
Overview
Embryologic Development
Most critical period of fetal heart development is between 3-8 wks gestation
Single heart tube grows rapidly forcing it to bend back upon itself and begin to assume the shape of a four chambered heart
Insults at this time are most likely to lead to CHD
Epidemiology
8/1,000 live births can present with heart murmur, heart failure, or cyanosis
Ventricular septal defect is the most common lesion
The Basics
Embryology
Structures
Truncus Arteriosus -> Great Vessels
Bulbus Cordis -> Outflow Tracts of L and R Ventricles
Primitive Ventricle -> L and R Ventricles
Primitive Atria -> L and R Atria
Left Horn -> Coronary Sinus
Right Horn -> R atrium
Embryology
Embryology
The Septums
Aorticopulmonary Septum:
Relies on migration of neural crest cells.
Failure of migration leads to persistent Truncus Arteriosus, Tetralogy of Fallot, Transposition
Atrial Septum:
Growth of septum is guided by endocardial cushions.
Contains Foramen Ovale, an important shunt in fetal heart circulation.
Upon first breath, increased LA pressures fuse septum secundum and primum, closing the foramen.
Ventricular Septum:
Caudal 2/3 forms muscular septum from the apex.
Cranial 1/3 forms the interventricular foramen, relies on endocardialcushions to close (membranous portion of septum).
Embryology
Before Birth
Fetal lungs bypassed by flow through fetal shunts:
Shunting deoxygenated blood
Ductus arteriosus: connection between pulmonary artery and aorta
Shunting oxygenated blood
Foramen ovale: connection between R and L atria
Ductus venosus: connection between umbilical vein and IVC
Circulation:
Placenta (oxygenated blood) -> umbilical vein -> ductus venosus -> IVC -> R atrium -> oxygenated blood shunted through foramen ovale -> L atrium -> L ventricle -> aorta -> brain/myocardium/upper extremities
Deoxygenated blood returns via SVC to R atrium -> 1/3 of blood entering R atrium does not flow through foramen ovale and flows to the R ventricle -> pulmonary arteries -> ductus arteriosus -> aorta -> systemic circulation -> placenta for re-oxygenation
At Birth
With first breath, lungs open up and pulmonary resistance decreases allowing pulmonic blood flow
Increasing pulmonic flow increases left atrial pressures leading to foramen ovale closure
Increased oxygen concentration in blood after first breath leads to decreased prostaglandins leading to closure of the ductus arteriosus
Upon separation of the placenta, systemic circulation becomes a high resistance system and the ductus venosuscloses
Fetal shunts close and changes in pulmonic/systemic resistance allow for normal adult flow
Before Birth After Birth
Normal Values
Cardiac Examination
History
Start with general health issues:
Feeding difficulties, growth delay, decreased exercise tolerance.
Ask the parent to compare the child to peers of the same age to help in this assessment.
Symptoms that indicate cardiovascular disease include:
periods of cyanosis, sweating, shortness of breath, palpitations, edema, chest pain, and syncope.
Squatting after exercise can indicate a congenital cardiac defect (Tetralogy of Fallot).
Enquire about the prenatal period.
Exposure to medication or drugs: lithium, phenytoin and alcohol.
History of maternal illnesses:
SLE, Diabetes or primary rubella.
Premature births are at an increased risk of having a patent ductus arteriosus.
Don’t forget the family history.
General exam
Hand Hygeine.
Signs of Distress:
pallor, sweating, cyanosis or increased work of breathing.
Level of activity in the patient:
Do they appear comfortable? Are they interacting appropriately with you and their
parent?
Dysmorphic features that may indicate a syndrome associated with congenital heart disease
(refer to table at end).
Trisomy 21, Di George and Turner’s syndrome.
Vital signs:
HR, RR, BP, Height, Weight, and head circumference (<5 yr).
Ideally, the blood pressure should be taken in all four limbs.
Choose the proper cuff size: a small cuff will provide a falsely high blood pressure. Should
be 2/3 the length of the arm.
Be sure to plot the growth on an age appropriate chart.
Inspection
Examine the hands and feet:
Clubbing, splinter hemorrhages.
Cardiac abnormalities normally manifests as respiratory distress. Look for signs of
increased work of breathing:
Tachypnea, intercostal indrawing, tracheal tug,head bobbing and nasal flaring.
Abdominal breathing is normal in the neonate but not in the older child.
Eyes:
Scleral icterus, pallor.
Mouth:
Signs of central cyanosis, mucous membranes to assess the volume status.
JVP assessment not routinely performed if under 8 years of age.
Chest:
Shape, symmetry, precordial bulge (right-sided cardiac enlargement), skeletal
deformity (pectus carinatum or excavatum), scars.
Peripheral Palpation
Younger children may need to be examined in their parents arms, be flexible.
Capillary refill, preferably over sternum
Pulses:
Radial, brachial , femoral, dorsalis pedis, and posterior tibial
Rate, rhythm, volume, brachial-femoral delay
Precordium Palpation
Apex beat, heaves, thrills
Palpate all four auscultatory areas.
Palpation of the liver:
Indication of right-sided heart function.
normal liver may be felt up to 2 cm below the costal margin.
Assess for edema in the limbs and sacral area.
Often the best assessment of whether edema is present is by asking the child’s parent whether they think the child appears puffy.
Auscultation
Same landmarks as aduts
Be sure to listen to the back.
The murmur of aortic coarctation is sometimes only found here and will be missed if not
specifically listened for.
If a murmur is heard:
area the murmur is loudest
Timing in the cardiac cycle,
Radiation, including both the axilla and the back.
Remember that more than 50% of children will have a murmur at some point, but congenital
heart disease is present in less than 1%. Learning to distinguish pathologic from benign
murmurs is extremely important and takes practice.
Don’t forget the lungs:
Crepitations may be a late sign of pulmonary congestion secondary to congestive heart
failure.
CYANOTIC VS. ACYANOTIC
Toronto Notes, 2012. page P20
CYANOTIC VS. ACYANOTIC
Cyanotic heart disease:
cyanosis: blue mucous membranes, nail beds, and skin secondary to an absolute concentration of deoxygenated hemoglobin of at least 3 g/dL
(i.e. R to L shunt) blood bypasses the lungs -> no oxygenation occurs -> high levels of deoxygenated hemoglobin enters the systemic circulation -> cyanosis
Acyanotic heart disease:
(i.e. L to R shunt, obstruction occurring beyond lungs) blood passes through pulmonic circulation -> oxygenation takes place -> low levels of deoxygenated blood in systemic circulation -> no cyanosis
Cyanotic Congenital Heart Disease
Cyanotic Heart Disease
Some of the systemic venous return re-enters arterial circulation without re-oxygenation by the lungs
Arterial oxygen saturation <75%
“Right-to-left” shunt
Hyperoxic test helps differentiate between respiratory and cardiac causes of hypoxia
Obtain ABG on room air
Repeat ABG after 100% oxygen for 10 minutes
If PaO2 improves to >20 kPa, cyanosis less likely cardiac in origin
Survival depends on mixing via shunts (e.g. ASD, VSD, PDA)
Important to keep in mind that pressure and flow through embryological openings can keep them open after birth
Five T’s
Five cyanotic heart diseases starting with T:
Truncus arteriosus
Transposition of the great arteries
Tricuspid atresia
Tetralogy of Fallot
Total anomalous pulmonary venous return
Ebstein’s anomaly is often cyanotic
Hypoplastic left heart syndrome
Truncus arteriosus
Blood is pumped from
both ventricles into a
single trunk, which then
gives rise to the aorta
and pulmonary
arteries
VSD
Truncus arteriosus:
Presentation
Presents within the first weeks of life
Cyanosis is the first sign (often not clinically evident)
Respiratory distress appears days to weeks later (due
to pulmonary congestion and heart failure)
Ejection click and systolic ejection murmur (often
impossible to appreciate)
Usually diagnosed by echocardiography
postnatally
Sometimes detected in utero
Truncus arteriosus:
Management
Supportive medical management to stabilize for
surgical repair
Surgery is definitive
Pulmonary arteries are mobilized from the truncus and
attached to the RV
Truncus is patched
VSD is patched
Dextro-transposition of the great
arteries
Aorta arises from RV
Pulmonary trunk arises from LV
Can be associate with other anomalies (“complex TGA”)
ASD
VSD
LV outflow tract obstruction
D-TGA:
Presentation
Severity is determined by the mixing of the two
circulations and the presence of other cardiac
anomalies
The presence and size of an ASD is the most important
determinant of severity
Most present in the first 30d of life
Cyanosis (not always clinically evident)
Tachypnea without evidence of respiratory distress
D-TGA:
Diagnosis and management
Difficult to diagnose in utero
Usually diagnosed with echocardiography post-
natally
Management
Prostaglandin E1 to maintain PDA
Consider balloon atrial septostomy if severely hypoxic
Surgery: arterial switch operation
Levo-transposition of the great arteries
Tricuspid atresia
Absence of tricuspid valve
RA and RV do not communicate
ASD: R to L shunt
Usually VSD or a single hypoplasticventricle
Cyanosis in neonatal period
Tricuspid atresia:
Management
Medical:
Prostaglandin E1 to maintain PDA
Surgical:
Shunt is usally required in the first year of life
Systemic circulation to pulmonary circulation
Fontan procedure after 4y of age
Connects RA to the pulmonary arteries
Excludes RV
Close ASD
Tetralogy of Fallot
Overriding aorta
RV outflow
obstruction
VSD
Right ventricular
hypertrophy
Tetralogy of Fallot:
Presentation
Severe stenosis: a newborn with profound cyanosis
Moderate stenosis: elective evaluation for a
murmur
Mild stenosis: congestive heart failure (dyspnea on
exertion, clubbing)
“Pink variant”: rarely, the stenosis can be so mild
as to be asymptomatic for years
Tetralogy of Fallot:
Physical exam
If cyanotic, found in nailbeds and lips
Often worse while crying
Harsh, ejection systolic crescendo-decrescendo
murmur (due to right outflow obstruction)
The worse the obstruction, the quieter the murmur
“Tet spells”: severe hypercyanotic spells
Often a vicious circle of crying/anxiety which worsens
the cyanosis
Knee-to-chest position: increases SVR
Tetralogy of Fallot:
Diagnosis and management
Diagnosis:
Echocardiography is diagnostic
Boot-shaped heart on CXR
Surgical management:
Severely cyanotic newborns may require
prostaglandins to maintain a PDA
Intra-cardiac repair is gold standard (patch closure of
VSD, widening of RVOT)
Preferably within the first year of life
Total anomalous pulmonary venous
return
All four pulmonary veins fail to connect to LA
All pulmonary venous blood drains into the systemic venous system
Neonatal cyanosis (life preserved by ASD or PFO)
Surgery: connect the pulmonary veins to the LA
Ebstein’s anomaly
Malformation of the tricuspid valve and the RV (highly variable)
The tricuspid valve is partly attached the annulus and partly to the RV
The proximal RV is “atrialized” because of the large valve
The distal RV is normal
Ebstein’s anomaly
Pathogenesis is multifactorial
Occurs at increased rate with maternal lithium use
Multiple associated cardiac anomalies
ASD and PFO (80%, results in cyanosis)
VSD
Pulmonary outflow obstruction
PDA
Coarctation of the aorta
Ebstein’s anomaly:
Presentation
Highly variable and depends on degree of
displacement of the valve leaflets and their
functional status
Fetuses: abnormal scan
Neonates: cyanosis
Infants: heart failure
Children: murmur
Adolescents/adults: arrhythmia
Ebstein’s anomaly:
Diagnosis and management
Echocardiography is best for diagnosis
Medical management:
Prostaglandin E1 if severely hypoxic at birth
Arrhythmias can be managed medically but if surgery is undertaken, consider ablation or Maze procedure
Surgical management:
Tricuspid repair/replacement
Neonates: only if severely cyanotic or severe tricuspid regurg
Older patients: symptomatic, cyanosis, paradoxical embolism, progressive cardiomegaly
Hypoplastic left heart syndrome
Small left ventricle
Usually an ASD
RV is forced to supply
systemic circulation via
PDA
Fatal if untreated
(only 65% survive with
surgical repair)
HLHS:
Diagnosis and management
Diagnosis:
Early cyanosis (critically ill at birth if no ASD)
Respiratory distress
Echocardiography
Medical management:
Prostaglandin E1 to maintain PDA
Surgical management:
Complicated 3-stage procedure (neonate, 4-6mos, 18-30mos)
Does not restore a biventricular system
Acyanotic Congenital Heart Disease
Atrial Septal Defects
Atrial Septal Defect
Three types of ASD:
Secundum
Primum
Sinus Venosus
Embryology
Septation of the
atria begins in the
5th week of
gestation
The foramen
ovale in the fetus
is kept open by a
pressure gradient
Atrial Septal Defects
Symptoms and Signs
Commonly asymptomatic
Recurrent chest infections/wheeze
Heart failure
Arrhythmias
S2 heart sound (fixed and widely split)
Ejection systolic murmur heard best at upper left sternal border
Apical pansystolic murmur (seen in partial AV valve involvement)
Atrial Septal Defect
Investigations
Chest X-Ray
ECG
Echocardiogram
Atrial Septal Defect
Management
Spontaneous closure mostly likely to occur in defects <7
mm and with younger age at diagnosis
For significant, symptomatic ASDs, treatment is needed
usually between 3-5 years of age
Secundum ASDs
Cardiac catheterisation with insertion of an occlusion device
Partial AVSD
Surgical correction
Ventricular Septal Defect
Ventricular Septal Defect
Most common congenital heart defect, occurring in almost 50% of patients with congenital heart disease
Can occur with other defects, such as in the atrioventricular canal, tetralogy of Fallot, and transposition of the great arteries
VSDs can occur at any part of the interventricularseptum
Most common are membranous defects (close to the tricuspid valve)
The size of the VSD can affect the symptoms, signs, and management
Small VSDs
Clinical presentation
Usually asymptomatic
Thrill at lower sternal edge
Loud pansystolic murmur at lower left sternal edge
Quiet pulmonary second sound (P2)
Investigations
CXR and ECG normal
Echo can show the anatomical defect
Management
75% will close spontaneously within 2 years
Prevention of bacterial endocarditis with good dental hygiene
Large VSDs
Signs
Failure to thrive
Symptoms of heart failure
Cardiac murmur
Recurrent chest infections
Symptoms
Low-pitched pansystolic murmur best heard at left mid-to-lower sternal border
Apical mid-diastolic murmur
Loud P2
Large VSDs
Investigations
CXR
ECG
Echo
Management
Medical
Diuretics and ACE-
inhibitors
Surgery
Patent Ductus Arteriosus
The ductus arteriosus is a connection between the pulmonary artery to the descending aorta
A patent ductusarteriosus occurs when the connection fails to close completely after birth
Makes up 5-10% of all congenital heart defects
Patent Ductus Arteriosus
Clinical Features
Continuous machine-like murmur in the left infraclavicular
region
Collapsing or bounding pulse
Exercise intolerance
Signs of heart failure
Failure to thrive
Poor feeding
Respiratory distress
Patent Ductus Arteriosus
Investigations
Echo Doppler UIltrasound
Management
Medical management
Surgical ligation
Percutaneous catheter occlusion
Complications
Heart failure, infective endocarditis, pulmonary hypertension
and Eisenmenger syndrome
Eisenmenger Syndrome
A pulmonary vascular disease that develops in
patients with initial left-to-right shunts that then
reverse to become right-to-left
Triad of systemic-to-pulmonary cardiovascular
communication, pulmonary arterial disease, and
cyanosis
Can occur in congenital heart defects such as VSD,
ASD, and PDA
Eisenmenger Syndrome
Clinical Features
Central cyanosis
Digital Clubbing
Palpable P2 on
precordial palpation
Prominent “A” wave in
the JVP
Progressive heart failure
can cause peripheral
edema, hepatomegaly,
and ascites
Eisenmenger Syndrome
Management
Avoid high risk situtations such as pregnancy, isometric
exercise, high altitudes, or surgery
Advanced therapy for pulmonary hypertension
Bosentan, epoprostenol, sildanafil
Heart and lung transplantation with intracardiac repair
for severely symptomatic
Down Syndrome
Most common autosomal abnormality
40% have cardiac defects
Most are atrioventricular septaldefects (endocardialcushion defects)
Can also present with ASD, VSD, or TOF
Turner Syndrome
Cardiac
malformations can
include coarctation
of the aorta and a
bicuspid aortic valve
Patients should
receive echo and
ECG to screen for
these defects
Noonan Syndrome
An autosomal
dominant disorder that
affects males and
females
Similar phenotype to
Turner`s
Can present with
pulmonary stenosis
and ASD
DiGeorge Syndrome
Caused by abnormal development of the
pharyngeal pouch
Can present with cyanotic congenital heart disease
(80%)
Truncus arteriosus
Tetralogy of Fallot
Interrupted aortic arch
CHARGE Syndrome
Autosomal dominant disorder characterized by coloboma, heart anomalies, choanalatresia, growth retardation and development, and genital and ear anomalies
Cardiac abnormalities include tetralogy of Fallot, ASD, VSD
The End!
Investigations
Foundational Investigations
echo, ECG, CXR
Characteristic Chest X-Ray Findings in Congenital Heart Disease
Boot-Shaped Heart - Tetralogy ofFallot, Tricuspid Atresia
Egg-Shaped Heart - Transposition of
Great Arteries
"Snowman" Heart - Total Anomalous Pulmonary Venous Return
Any screening programs in Ireland? How are these managed here?