Congenital CV Disease Flashcards
Define congenital heart defects.
Congenital heart defects are problems with the heart’s structure that are present at birth.
What structures of the heart can be affected by congenital heart defects ?
- The interior walls of the heart
- The valves inside the heart
- The arteries and veins that carry blood to the heart or the body
How severe are congenital heart defects ? How tough of treatment do they require ?
They range from simple defects with no symptoms to complex defects with severe, life- threatening symptoms.
Many of these defects are simple conditions that need no treatment or are easily fixed but some babies are born with complex congenital heart defects that require special medical / surgical care soon after birth (but many of the latter survive to adulthood and can live active, productive lives)
Do congenital heart defects affect blood flow through the heart ?
Yes, congenital heart defects change the normal flow of blood through the heart.
How many babies out of 1000 are affected by congenital heart disease ?
8 in 1000
What is the most common type of congenital defect ? What is the congenital defect that causes the most deaths within the first year of life ?
Congenital Heart Defects (CHD) are the most common type of birth defect. Also, complex CHD causes more deaths in the first year of life than any other birth defects.
What are the possible categories of Congenital Heart Defects ?
Non-cyanotic and Cyanotic
What is cyanosis ?
Blue skin colour caused by a lack of oxygen
Identify cyanotic congenital heart defects.
Tetralogy of Fallot Total anomalous pulmonary venous return Transposition of the great vessels Tricuspid atresia Truncus arteriosus (^5 Ts)
Hypoplastic left heart
Pulmonary atresia
Ebstein’s anomaly (severe)
Identify non cyanotic congenital heart defects.
- Ventricular septal defect (VSD)
- Atrial septal defect (ASD)
- Patent ductus arteriosus (PDA)
- Coarctation of the aorta
- Pulmonary stenosis
- Aortic stenosis
- Atrioventricular canal (endocardial cushion defect)
- Ebstein’s anomaly (mild)
How can you further divide cyanotic, and non-cyanotic CHDs into categories ?
With shunt and without shunt (with shunt means there is pattern of blood flow in the heart that deviates from the normal circuit of the circulatory system).
Can also divide them into sub-categories depending on what’s wrong:
1) Cyanotic: Increased pulmonary flow, or obstruction to blood flow the aorta
2) Non-Cyanotic: Decreased pulmonary flow, or mixed blood flow
Rank the most common congenital heart diseases.
- Ventricular Septal Defect 39%
- Atrial Septal Defect 10%
- Patent Ductus Arteriosus 10%
- Coarctation of the aorta 7%
- Pulmonary Stenosis 7%
- Aortic Stenosis 6%
- Fallot’s Tetralogy 6%
- Others 15%
What other types of congenital issues may CHDs be present with ?
Most children with CHD do not have other types of birth defects. However, heart defects may be part of genetic and chromosomal syndromes. E.g. • Down syndrome (Trisomy 21) • DiGeorge syndrome • Edward syndrome (Trisomy 18) • Marfan syndrome • Noonan syndrome • Patau syndrome (Trisomy 13) • Turner syndrome
What proportion of all infants affected by significant CHD are also found to have extra-cardiac anomalies (ECAs) during the first year of life ?
25%
What are ECAs ?
Extracardiac anomalies, abnormalities outside of the heart which may be found alongside congenital heart disease.
Where are ECAs found ?
The most frequent ECA are in the musculoskeletal system or associated with a specific syndrome (one third of the affected infants have some established syndrome)
What is the significance of ECA ?
The presence of an ECA significantly increases the mortality in infants with CHD.
Are ECAs usually present in single or multiple quantities ?
Often the ECA are multiple
What are the main causes of congenital heart diseases ?
- Drugs such as retinoic acid for acne, chemicals, alcohol, and infections (such as rubella) during pregnancy can contribute to some congenital heart problems.
- Poorly controlled blood sugar in women who have diabetes during pregnancy has also been linked to a high rate of congenital heart defects.
- Often, no cause for the heart disease can be found.
What are the symptoms of Congenital Heart Defects ?
• Symptoms depend on the condition.
What is the timeline of the appearance of symptoms in congenital heart disease ?
- Depends on the condition
- Although congenital heart disease is present at birth, the symptoms may not appear right away.
- Defects such as coarctation of the aorta may not cause problems for years.
- Other problems, such as a small VSD, ASD, or PDA may never cause any problems.
Describe the symptoms / signs of heart failure in infants with CHD.
- Cyanosis (> 5g/dl deoxyhaemoglobin)
- Rapid breathing (Tachypnoea)
- Extra work of breathing
- Grunting
- Tachycardia
- Poor blood circulation
- Fatigue (Poor feeding)
- Faltering growth
- Sweating
- Enlarged Liver (Hepatomegaly)
- Murmurs
Identify possible complications of congenital heart disease.
- Faltering growth (previously referred to as “failure to thrive”)
- Paradoxical embolus (embolus from venous to arterial)
- Bacterial endocarditis
- Pulmonary hypertension
- Polycythaemia (high RBCs)
- Haemoptysis (coughing blood)
- Arrhythmias
Describe the main features of ventricular septal defects (VSD).
- Definition
- Incidence (as a proportion of all CHDs)
- Does it require treatment
- Consequences of it on the heart/circulation
- Incidence: 39% of all cases of congenital heart disease
- Definition: “a hole in the wall of the heart (septum) that separates LV from RV. This allows blood to flow from the left ventricle to the right ventricle instead of entering the aorta for distribution”
- Do they require treatment ? 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.
- Consequences of larger VSD: 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 and Eisenmenger’s Syndrome.
How may VSDs be closed ?
- Surgically
- Interventional radiology, through trans-arterial devices (less invasive)
Describe the main features of atrial septal defects (ASD).
- Definition
- Incidence (as a proportion of all CHDs)
- Does it require treatment
- Consequences of it on the heart/circulation
- Incidence: 10%
- Definition: Hole in the wall separation RA and LA
- Do they require treatment ? 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. About half of all ASDs close on their own over time. Medium and large ASDs allow more blood to leak from one atrium to the other. They’re less likely to close on their own.
- Consequences of ASD: If there is a longstanding significant left to right shunt through the ASD the increased blood flow through the lungs can scar the arteries in the lungs leading to the dreaded complication of Pulmonary Hypertension.
How may medium and large ASDs which require treatment be closed ?
Medium and large ASDs that need treatment can be repaired using a catheter procedure or open-heart surgery.
Describe the main features of Patent Ductus Arteriosus including
- Definition
- Incidence (as a proportion of all CHDs)
- Does it require treatment
- Consequences of it on the heart/circulation
- Incidence: 10%
- Definition: persistent communication between the descending thoracic aorta and the pulmonary artery that results from failure of normal physiological closure of the foetal ductus.
- Does it require treatment: If significant respiratory distress or impaired systemic oxygen delivery is present, therapy is usually prudent.
- Consequences: possibly, significant respiratory distress or impaired systemic oxygen delivery
How may Patent Ductus Arteriosus be treated ?
- Intravenous indomethacin or ibuprofen is frequently effective in closing a PDA if it is administered in the first 10-14 days of life.
- Other options are catheter closure and surgical ligation.
What is the ductus arteriosus ?
During foetal life, the ductus arteriosus is a normal structure that allows most of the blood leaving the right ventricle to bypass the pulmonary circulation and pass into the descending aorta.
In fetal circulation, how much of the right ventricular output passes through the pulmonary vascular bed ? Where else does it go ?
Typically, only about 10% of the right ventricular output passes through the pulmonary vascular bed. Through Foramen Ovale, Ductus Arteriosus.
Explain the transition from fetal to neonatal circulation.
FETAL CIRCULATION
- Blood enters the right atrium, the chamber on the upper right side of the heart. When the blood enters the right atrium, most of it flows through the foramen ovale into the left atrium.
- Blood then passes into the left ventricle (lower chamber of the heart) and then to the aorta
- From the aorta, blood is sent to the heart muscle itself in addition to the brain. After circulating there, the blood returns to the right atrium of the heart through the superior vena cava. About two thirds of the blood will pass through the foramen ovale as described above, but the remaining one third will pass into the right ventricle, toward the lungs.
- In the fetus, the placenta does the work of breathing instead of the lungs. As a result, only a small amount of the blood continues on to the lungs. Most of this blood is bypassed or shunted away from the lungs through the ductus arteriosus to the aorta. Most of the circulation to the lower body is supplied by blood passing through the ductus arteriosus.
- This blood then enters the umbilical arteries and flows into the placenta. In the placenta, carbon dioxide and waste products are released into the mother’s circulatory system, and oxygen and nutrients from the mother’s blood are released into the fetus’ blood.
NEONATAL CIRCULATION
At birth, the umbilical cord is clamped and the baby no longer receives oxygen and nutrients from the mother. With the first breaths of life, the lungs begin to expand. As the lungs expand, the alveoli in the lungs are cleared of fluid. An increase in the baby’s blood pressure and a significant reduction in the pulmonary pressures reduces the need for the ductus arteriosus to shunt blood. These changes promote the closure of the shunt. These changes increase the pressure in the left atrium of the heart, which decrease the pressure in the right atrium. The shift in pressure stimulates the foramen ovale to close.
The closure of the ductus arteriosus and foramen ovale completes the transition of fetal circulation to newborn circulation.
Define Patent F. Ovale.
Flaplike opening between the atrial septa primum and secundum at the location of the fossa ovalis that persists after age 1 year.
How does the foramen ovale normally close ?
- Immediately after birth, pressure in the right side of the heart and pulmonary vascular resistance diminish abruptly as the pulmonary alveoli fill.
- This, together with greater pressure in the left atrium due to increased venous return, produces functional closure of the foramen ovale which in 75% of people closes structurally in infancy.
What is the incidence of PFO in the population ?
Approx 25% of people have a PFO.
