22-09-22 – Congenital Cardiovascular Disease Flashcards
Learning outcomes
- Describe the common congenital cardiovascular abnormalities.
- Understand the difference between a foetal circulation and that of an adult.
- Describe the functional consequences of common congenital cardiovascular abnormalities.
- Describe the ways in which congenital cardiovascular disease can present.
- Demonstrate a basic understanding of the management of congenital cardiovascular disease.
What are congenital heart defects (CHD)?
What is cyanosis?
What are 6 acyanotic CHDs?
What are 7 cyanotic CHDs?
- Congenital heart defects (CHD) are problems with the heart’s structure that are present at birth
- Cyanosis is where the skin or lips turn blue due to inadequate oxygen supply to tissues
- Acyanotic CHDs (dont affect blood in the body):
1) Ventricular septal defect (VSD) – hole in ventricular septum between the ventricles
2) Atrial septal defect (ASD) – hole in atrial septum
3) Pulmonary stenosis (aka pulmonary valve stenosis) – narrowing of pulmonary valve, which doesn’t fully open
4) Aortic stenosis (aka aortic valve stenosis) - narrowing of aortic valve, which doesn’t fully open
5) Coarctation of the aorta - birth defect causing aorta to be narrower than usual
6) Patent ductus arteriosus (PDA) - Ductus arteriosus fails to close after birth
- Cyanotic CHDs:
1) Tetralogy of Fallot (TOF) – combination of 4 birth defects
2) Total anomalous pulmonary venous return – oxygen rich blood returns to right side of heart and mixes with deoxygenated blood
3) Transposition of the great vessels (TGA) – pulmonary trunk and aorta positions are switched
4) Tricuspid atresia (tricuspid valve atresia) – tricuspid valve doesn’t form, leading to no blood getting from the right atrium to the right ventricle
5) Truncus arteriosus – one large vessel leads out of heart instead of 2. Ventricular septal defect normally present also
* The above 5 CHDs are referred to as the 5 Ts
6) Hypoplastic left heart – left heart doesn’t develop properly
7) Pulmonary atresia (pulmonary valve atresia) – pulmonary valve doesn’t form correctly, leading to difficulty with blood going to the lungs. In atresia, the valve lacks a hole for blood to go through
What are left to right shunts?
What are they associated with?
Are they typically cyanotic or acyanotic?
What are 4 examples of left-to-right shunt CHDs?
What are right to left shunts?
What are they associated with?
What are 6 examples of right to left shunt CHDs?
What are examples of obstructive valvular and non-valvular lesions?
- Left -to -right shunts Lesions that allow blood to shunt from the left to the right side of the heart.
- They are associated with varying degrees of increased pulmonary blood flow and are typically acyanotic.
- Examples of left-to-right shunt lesions include:
1) Ventricular septal defect (VSD) – hole in septum between ventricles
2) Atrial septal defect (ASD) – hole in atrial septum
3) Atrioventricular septal defect (AVSD) – atrial and ventricular hole
4) Patent ductus arteriosus (PDA) - Ductus arteriosus fails to close after birth
- Right-to-left shunts are lesions that result in deoxygenated blood reaching the aorta and are associated with an increased or decreased pulmonary blood flow
- Examples of right-to-left shun lesions:
1) Tetralogy of Fallot (TOF) – combination of 4 CHDs
2) Transposition of the great arteries (TGA) - – pulmonary trunk and aorta positions are switched
3) Pulmonary valve atresia with or without a VSD (pulmonary atresia) – pulmonary valve doesn’t form correctly, leading to difficulty with blood going to the lungs
4) Truncus arteriosus - one large vessel leads out of heart instead of 2. Ventricular septal defect normally present also
5) Tricuspid Atresia - (tricuspid valve atresia) – tricuspid valve doesn’t form correctly, leading to no blood getting from the right atrium to the right ventricle
6) Total anomalous pulmonary venous return - oxygen rich blood returns to right side of heart and mixes with deoxygenated blood
- Examples of Obstructive valvular and non-valvular lesions
1) Pulmonary stenosis (aka pulmonary valve stenosis) – narrowing of pulmonary valve, which doesn’t fully open
2) Aortic stenosis (aka aortic valve stenosis) - narrowing of aortic valve, which doesn’t fully open
3) Coarctation of the aorta - birth defect causing aorta to be narrower than usual
What are the most common congenital heart lesions? (Order this lecture will follow)
What are the 5 categories?
What primary signs/symptoms is each category associated with?
- Most common congenital heart lesions (Order this lecture will follow):
- Left-to-right shunts (associated with breathlessness):
1) Ventricular septal defect (VSD) – 30% OF CHDs
2) Persistent/patent ductus arteriosus (PDS) – 12% of CHDs
3) Atrial septal defect – 7% - Right-to-left shunts (patient turning blue)
1) Tetralogy of Fallot (TOH) – 5%
2) Transposition of the great vessels/arteries – 5% - Common mixing (breathless and blue)
1) Atrioventricular septal defect – 2% - Outflow obstruction in a well child (asymptomatic with a murmur)
1) Pulmonary stenosis – 7%
2) Aortic stenosis – 5% - Outflow obstruction in a sick neonate (collapsed with shock)
1) Coarctation of the aorta – 5% CHDs
Left-to-right shunts (breathless) - Ventricular Septal defects (VSDs):
* Anatomical manifestation
* Clinical signs and symptoms
* Treatment
- Left-to-right shunts (breathless) - Ventricular septal defect (VSD)
1) Manifestation
* VSDs can be small, medium, or large.
* Small VSDs don’t cause problems and may close on their own.
* Medium VSDs are less likely to close on their own and may require treatment.
* Large VSDs allow a lot of blood to flow from the left ventricle to the right ventricle.
* As a result, the left side of the heart must work harder than normal.
* Extra blood flow increases blood pressure in the right side of the heart and the lungs.
* The heart’s extra workload can cause heart failure and poor growth.
* If the hole isn’t closed, high blood pressure can scar the arteries in the lungs leading to the dreaded complication of Pulmonary Hypertension and irreversible damage leading to shunt reversal (blood from shunt goes in opposite direction) and Eisenmenger’s Syndrome (associated with pulmonary hypertension and shunt reversal)
2) Clinical signs and symptoms
* With VSDs, we have a pan systolic murmur, a loud second heart sound, and heart failure
3) Treatment
* Medium and large VSDs that need treatment can be repaired using a catheter procedure or open-heart surgery.
Left-to-right shunts (breathless) - Persistent/patent ductus arteriosus (PDS)
* Anatomical manifestation
* Clinical signs and symptoms
* Treatment
- Left-to-right shunts (breathless) - Persistent/patent ductus arteriosus (PDS)
1) Anatomical manifestation
* PDA is a persistent communication between the descending thoracic aorta and the pulmonary artery that results from failure of normal physiological closure of the foetal ductus.
* Left to right shunt the blood flows from the aorta to the pulmonary trunk
2) Clinical signs and symptoms
* Continuous murmur as the pressure in the pulmonary artery is lower than in the aorta throughout the cardiac cycle
3) Treatments
* In a new born, therapy is usually prudent if significant respiratory distress or impaired systemic oxygen delivery is present.
* Intravenous indomethacin or ibuprofen is frequently effective in closing a PDA if administered in the first 10-14 days of life.
* Older children, closure is recommended to avoid the risk of infective endocarditis - options are catheter closure and surgical ligation.
Left-to-right shunts (breathless) - Arterial septal defects (ASDs)
* Anatomical manifestation
* Clinical signs and symptoms
* Treatment
- Left-to-right shunts (breathless) - Atrial septal defects (ASDs)
1) Manifestation
* ASDs can be small, medium, or large.
* Small ASDs allow only a little blood to leak from one atrium to the other.
* They don’t affect how the heart works and don’t need any special treatment.
* Many small ASDs close on their own as the heart grows during childhood.
* Medium and large ASDs allow more blood to leak from one atrium to the other and are less likely to close on their own
2) Clinical signs and symptoms
* Associated with No symptoms/recurrent chest infections
* Signs – ejection systolic murmur, ULSB (upper left sternal border) Split P2 (pulmonary closure sound – makes up S2 heart sound)
3) Treatment
* About half of all ASDs close on their own over time.
* Medium and large ASDs that need treatment can be repaired using a catheter or open-heart surgery
Right-to-left shunt (blue) - Tetralogy of Fallot (TOF)
* Anatomical manifestation
* Clinical signs and symptoms
* Treatment
- Right-to-left shunts (blue) - Tetralogy of Fallot (TOF):
1) Clinical manifestation:
* Manifests as a combination of 4 CHDs:
1) Pulmonary valve stenosis.
2) A large VSD.
3) An overriding aorta
- The aorta is located between the left and right ventricles, directly over the VSD.
- As a result, oxygen-poor blood from the right ventricle can flow directly into the aorta instead of the pulmonary artery.
4) Right ventricular hypertrophy.
2) Clinical signs and symptoms
* Most are diagnosed:
* Antenatally (prior to birth) or following the identification of a murmur in the first two months of life.
* Cyanosis at this stage may not be apparent, although a few presents with severe cyanosis in the first few days of life.
* A loud, harsh ejection systolic murmur at the left sternal edge from day 1 of life (VSD)
* Leads to a boot shaped heart
3) Treatment
* Palliative (end of life care)
* Infants who are very cyanosed in the early neonatal period require a shunt to increase pulmonary blood flow.
* This is usually done by the surgical placement of an artificial tube between the subclavian artery and the pulmonary artery (a modified Blalock–Taussig shunt).
* This redirects a large portion of the partially oxygenated blood leaving the heart for the body into the lungs, increasing flow through the pulmonary circuit and greatly relieving symptoms in patients.
- Corrective Surgery for TOF
- The Blalock-Thomas-Taussig procedure, initially the only surgical treatment available for tetralogy of Fallot, was palliative but not curative.
- It involves closing the VSD and relieving right ventricular outflow tract obstruction, sometimes with an artificial patch which extends across the pulmonary valve
- Total repair on infants has had success since 1981.
- Tetralogy of Fallot must be repaired with open-heart surgery, either soon after birth or later in infancy.
- The timing of the surgery will depend on how narrow the pulmonary artery is
- Early definitive repair of tetralogy of Fallot is now advocated, with an actuarial survival rate of almost 90% at 30 years.
- Survival into adulthood is both expected and of high quality.
- The large majority of patients who undergo corrective surgery within the first two years of life lead normal lives without significant cardiac or vascular symptoms.
- However, patients with repaired tetralogy of Fallot (TOF) experience increased mortality and morbidity rates in adulthood.
- RV hypertrophy, ventricular dysfunction and atrial tachyarrhythmias are risk factors for sudden cardiac death in adults with repaired TOF
- The quality of surgical correction affects long-term susceptibility to sudden death, with residual outflow obstruction and pulmonary regurgitation of particular importance.
Right-to-left shunts (blue) – Transposition of great arteries
* Anatomical manifestation
* Clinical signs and symptoms
* Treatment
- Right-to-left shunts (blue) - Transposition of great arteries
1) Anatomical manifestation
* The pulmonary arteries are supplied by the left ventricle and the aorta by the right ventricle.
* This, of course, is the opposite of the normal arrangement.
* Infants can only survive if there is a shunt between the two sides of the heart.
* Fortunately, some naturally occurring associated anomalies, e.g. VSD, ASD and PDA, can achieve this mixing
2) Clinical signs and symptoms
* Cyanosis is always present.
* The second heart sound is often loud and single.
* Usually, no murmur.
3) Treatment
* In the sick cyanosed neonate, the key is to improve mixing
* Maintaining the patency of the ductus arteriosus with a prostaglandin infusion is mandatory
* A balloon atrial septostomy may be a life-saving procedure and needs to be performed in 20% of patients
* A catheter with an inflatable balloon at its tip is passed through the umbilical or femoral vein and then through the right atrium and foramen ovale
* The balloon is inflated within the left atrium and then pulled back through the atrial septum
* This tears the atrial septum, renders the flap valve of the foramen ovale incompetent, and allows the mixing of the systemic and pulmonary venous blood within the atrium.
* Patients with transposition of the great arteries will require an operation, usually the arterial switch procedure in the neonatal period.
* This operation is performed in the first few days of life.
* The pulmonary artery and aorta are transected above the arterial valves and switched over.
Common mixing (breathless and blue) – Atrioventricular septal defect
* Anatomical manifestation
* Clinical signs and symptoms
* Treatment
- Common mixing (breathless and blue) – Atrioventricular septal defect
1) Anatomical manifestation
* An AVSD is a heart defect in which there are holes between the chambers of the right and left sides of the heart, and the valves that control blood flow between these chambers may not be formed correctly.
* This condition is also called an atrioventricular canal (AV canal) or endocardial cushion defect.
* AVSD is common in babies with Down syndrome, a genetic condition that involves an extra chromosome 21 (also called trisomy 21).
2) Clinical signs and symptoms
* Antenatal ultrasound screening or routine echocardiography screening in a new born infant with Down syndrome
* Cyanosis at birth or heart failure at two weeks to 3 weeks of life
* No murmur heard
3) Treatment
* Treat heart failure medically (as for large VSD) and surgical repair at three months to 6 months of age
What are the 3 CHDs that affect valves of the heart?
What are signs of each?
- 3 CHDs that affect valves of the heart:
1) Atresia.
* This defect occurs if a valve doesn’t form correctly and lacks a hole for blood to pass through.
* Atresia of a valve generally results in more complex congenital heart disease.
2) Stenosis.
* This defect occurs if the flaps of a valve thicken, stiffen, or fuse. As a result, the valve cannot fully open.
* Thus, the heart has to work harder to pump blood through the valve.
3) Regurgitation.
* This defect occurs if a valve doesn’t close tightly.
* As a result, blood leaks back through the valve.
Outflow obstruction in a well child (asymptomatic with a murmur) – pulmonary stenosis:
* Anatomical manifestation
* Clinical signs and symptoms
* Treatment
- Outflow obstruction in a well child (asymptomatic with a murmur) – pulmonary stenosis:
1) Anatomical manifestation
* The most common valve defect is pulmonary valve stenosis, which is a narrowing of the pulmonary valve.
* This valve allows blood to flow from the right ventricle into the pulmonary artery.
* The blood then travels to the lungs to pick up oxygen.
* Pulmonary valve stenosis can range from mild to severe.
* Most children with this defect have no signs or symptoms other than a heart murmur.
* Treatment isn’t needed if the stenosis is mild
2) Clinical signs and symptoms
* Most are asymptomatic
* An ejection systolic murmur is best heard at the upper left sternal edge
* A small number of neonates with critical pulmonary stenosis have duct- dependent pulmonary circulation and present in the first few days of life with cyanosis.
* In babies with severe pulmonary valve stenosis, the right ventricle can get overworked trying to pump blood to the pulmonary artery.
* These infants may have signs and symptoms of heart failure
3) Treatment
* Pulmonary valve stenosis is treated with a catheter procedure - balloon dilatation is the treatment of choice in most children.
Outflow obstruction in a well child (asymptomatic with a murmur) – aortic stenosis:
* Anatomical manifestation
* Clinical signs and symptoms
* Treatment
- Outflow obstruction in a well child (asymptomatic with a murmur) – aortic stenosis:
1) Anatomical manifestation
* Aortic valve stenosis results from minor to severe degrees of aortic valve maldevelopment.
* This stenosis causes mild to severe left ventricular outflow obstruction that may be associated with other left heart obstructive lesions, varying degrees of left heart hypoplasia, or extracardiac malformations, including genetic disorders.
* An estimated 10-15% of patients with aortic valve stenosis present with the condition when they are younger than one year due to severe stenosis.
* The remainder of patients may present later in childhood or adulthood due to progressive obstruction.
2) Clinical signs and symptoms
* Most present with an asymptomatic murmur.
* Those with severe stenosis may present with reduced exercise tolerance, chest pain on exertion, or syncope.
* Small volume, slow rising pulses
* Carotid thrill (always)
* Ejection systolic murmur maximal at the upper right sternal edge radiating to the neck
* Delayed and soft aortic second sound
* Apical ejection click - Ejection clicks are high-pitched sounds that occur at the moment of maximal opening of the aortic or pulmonary valves.
* They are heard just after the first heart sound.
* In the neonatal period, those with critical aortic stenosis and a duct-dependent systemic circulation may present with severe heart failure leading to shock.
3) Treatment
* In children, regular clinical and echocardiographic assessment is required to assess when to intervene.
* Children with symptoms on exercise or who have a high resting pressure gradient (>64 mmHg) across the aortic valve will undergo balloon valvotomy.
* Balloon dilatation in older children is generally safe and uncomplicated, but in neonates, this is much more difficult and dangerous.
* Most neonates and children with significant aortic valve stenosis requiring treatment in the first few years of life will eventually require aortic valve replacement.
* Early treatment is, therefore, palliative and directed towards delaying this for as long as possible.
Outflow obstruction in the sick infant.
What is the most common cause of heart failure in a week-old infantry?
What can occur if the lesion is severe?
What would closure of the ductus arteriosus mean in these circumstances?
What are the 3 duct dependent lesions associated with left sided heart failure in the first week?
- Outflow obstruction in the sick infant:
- In the first week of life, heart failure usually results from left heart obstruction.
- If the obstructive lesion is very severe, arterial perfusion may be predominantly by right-to-left blood flow via the arterial duct, so-called duct-dependent systemic circulation.
- Closure of the duct under these circumstances rapidly leads to severe acidosis, collapse and death unless ductal patency is restored
- 3 duct dependent lesions associated with left sided heart failure in the first week:
1) Duct dependent coarctation of the aorta
2) Interruption of the aortic arch
3) Hypoplastic Left Heart Syndrome (HLHS)
Outflow obstruction in a sick infant (collapsed with shock) – duct dependent coarctation of the aorta:
* Anatomical manifestation
* Clinical signs and symptoms
* Treatment
- Outflow obstruction in a sick infant (collapsed with shock) – duct dependent coarctation of the aorta:
1) Anatomical manifestation
* This is due to arterial duct tissue encircling the aorta at the duct’s insertion point.
* When the duct closes, the aorta also constricts, causing severe obstruction to the left ventricular outflow.
* This is the most common cause of collapse due to left outflow obstruction
2) Clinical signs and symptoms:
* Examination on the first day of life is usually normal.
* Neonates usually present with acute circulatory collapse at about two days of age when the duct closes.
* A sick baby with severe heart failure
* Absent femoral pulses
* Severe metabolic acidosis – The build-up of acid in the body due to kidney disease or kidney failure
3) Treatment
* No matter what age the defect is diagnosed, the narrow aorta will need to be widened once symptoms are present.
* This can be done with surgery or a procedure called balloon angioplasty, which is done during a cardiac catheterization
Outflow obstruction in a sick infant (collapsed with shock) – Hypoplastic left heart syndrome (HLHS)
* Anatomical manifestation
* Clinical signs and symptoms
* Treatment
- Outflow obstruction in a sick infant (collapsed with shock) – Hypoplastic left heart syndrome (HLHS):
1) Anatomical manifestation
* Babies with this condition may appear normal at birth.
* Foetuses are nourished by oxygen-rich blood from their mothers, so they don’t breathe and don’t use their lungs.
* Babies with hypoplastic left heart syndrome may seem normal at birth because the patent ductus arteriosus is still open, allowing blood to continue circulating directly into the aorta and out to the rest of the body.
* Once the ductus closes a few days after birth, blood flows to the lungs and then to the left side of the heart, where it is blocked and can’t circulate through the rest of the body.
* It is at this time that these babies show symptoms.
2) Clinical signs and symptoms
* Cyanosis, or a grayish (in dark-skinned people) or bluish (in light-skinned people) discoloration of skin, lips and nails.
* Difficulty breathing.
* Difficulty feeding.
* Lack of energy (lethargy).
* Rapid heartbeat.
* Sweaty, clammy or cool skin.
* Weak pulse.
3) Treatment
* HLHS is treated with surgery.
* This can involve either a series of heart surgeries or, less commonly, heart transplantation.
* In some instances, a hybrid procedure involving surgery and cardiac catheterisation may be used to treat the child in place of the first in a series of 3 surgeries.
What maternal disorders are linked with increased frequency of CHDs?
- Maternal disorders linked with increased incidence of CHDs
1) Maternal rubella infection – Peripheral pulmonary stenosis and PDA (frequency of 30-35%)
2) Maternal Systemic Lupus erythematosus (SLE) – Complete heart block (electrical impulses between atria and ventricles are disrupted – frequency of 35%)
3) Maternal Diabetes mellitus – increased risk of CHD overall (frequency of 2%)
What are extracardiac anomalies (ECAs) ?
How often do cardiac anomalies occur in infants with significant CHD?
Where are they most frequently found?
What do ECAs increase?
- Extracardiac anomalies (ECAs) are those that occur outside of the heart
- Extracardiac anomalies (ECA) occur in 25% of infants seen during the first year of life for significant cardiac disease.
- Often the ECA are multiple and one third of the affected infants have some established syndrome.
- The most frequent ECA are in the musculoskeletal system or associated with a specific syndrome.
- The presence of an ECA significantly increases the mortality in infants with CHD.
Summary of CHD
Summary of CHD
