Clinical Correlates - Heart Embryology Flashcards
What does sudden infant death syndrome (SIDS) refer to?
The unexpected death of a seemingly healthy infant, typically within the first year of life.
SIDS is a diagnosis of exclusion, meaning it is identified only after ruling out other explanations.
What are some suggested causes of SIDS?
- Abnormalities in brainstem development
- Abnormalities in neuroregulation of cardio-respiratory control
- Abnormalities of the heart’s electrical conducting system
What is dextrocardia?
A condition where the heart is located more to the right with the apex pointing right, and all vessels are reversed.
This occurs due to the heart tube bending to the left instead of right.
What is ectopia cordis?
A very rare congenital condition where the heart is located outside of the thoracic cavity.
This condition results from failure of lateral folds to fuse during development.
What is an atrial septal defect (ASD)?
A defect that allows left to right shunting of blood from the left atrium to the right atrium.
This can lead to mixing of oxygenated and poorly oxygenated blood.
What is the most common type of ASD?
Patent foramen ovale.
What are the four clinically significant types of ASDs?
- Ostium secundum defect
- Ostium primum defect
- Sinus venosus defect
- Common atrium
What are some symptoms of ASD?
- Shortness of breath on exertion
- Easy fatigability
- Edema of the lower limb or abdomen
- Frequent respiratory infections
- Palpitations
How does an ASD affect heart sounds?
It causes a widely split and fixed second heart sound (S2).
What is a ventricular septal defect (VSD)?
The most common type of congenital heart defect, accounting for approximately 25% of cases.
What is a patent ductus arteriosus (PDA)?
A condition where the ductus arteriosus fails to close after birth, creating a left to right shunt.
What is Eisenmenger syndrome?
A condition that results from an uncorrected left to right shunt, leading to pulmonary artery hypertension and right-to-left shunting.
What is persistent truncus arteriosus?
A condition where the truncal ridges fail to separate the truncus arteriosus into the aorta and pulmonary trunk.
What occurs in transposition of the great arteries?
The aorta arises from the right ventricle and the pulmonary trunk arises from the left ventricle.
What is unequal division of the truncus arteriosus?
A condition that creates one large artery and one small artery, leading to misalignment and potential VSD.
What is tricuspid atresia?
A condition where the tricuspid valve is absent or fused, blocking blood flow from the right atrium to the right ventricle.
What are the four cardiac anomalies associated with Tetralogy of Fallot?
- Pulmonary infundibular stenosis
- An overriding aorta
- Ventricular septal defect (VSD)
- Right ventricular hypertrophy
What is total anomalous pulmonary venous return?
A condition where pulmonary veins drain into the right atrium instead of the left.
What causes aortic stenosis?
Fusion of the edges of the aortic valve leaflets, forming a dome and reducing the opening for blood flow.
What percentage of congenital heart diseases does congenital aortic stenosis account for?
3-6%.
What happens to the aortic valve leaflets in aortic stenosis?
The aortic valve leaflets fuse, forming a dome and reducing the opening through which blood can flow.
What is the consequence of aortic stenosis on the left ventricle?
The left ventricle must work harder to force blood into the aorta, leading to left ventricular hypertrophy.
What percentage of congenital heart diseases does congenital aortic stenosis account for?
3-6% of congenital heart diseases.
What is subaortic stenosis?
A ring of fibrous tissue narrows the aorta just below the valve.
What is aortic atresia?
Aortic atresia occurs when the aortic valve or part of the aorta itself is completely obstructed.
What type of heart murmur is associated with aortic stenosis?
A systolic crescendo-decrescendo heart murmur.
What is coarctation of the aorta?
A constriction of the aorta seen in 10% of patients with congenital heart diseases.
What are the two main classifications of coarctations?
- Infantile (preductal) * Adult (postductal)
What occurs in infantile coarctations?
The aortic arch proximal to the ductus arteriosus is hypoplastic, resulting in narrowing of the aorta.
What is the consequence of narrowing in infantile coarctation?
Reduced pressures in the aorta after the coarctation, allowing poorly oxygenated blood to enter systemic circulation.
What tissue forms in adult coarctations?
A ridge of tissue made up of smooth muscle and elastic fibers constricts the aorta.
What is the typical presentation of severe coarctation in infants?
Tachypnea, systolic murmurs, and palpable thrills.
How does coarctation of the aorta affect blood flow between upper and lower extremities?
There is a discrepancy in blood flow and blood pressure, with diminished and delayed pulses below the coarctation.
What is congenital long QT syndrome?
An inherited disorder characterized by a prolonged QT-interval on an electrocardiogram.
What does a prolonged QT-interval indicate?
Increased time for cardiac muscle to repolarize between heartbeats.
What can congenital long QT syndrome lead to?
Polymorphic ventricular tachycardia called Torsades de pointes, potentially leading to sudden cardiac death.
What are the two types of congenital long QT syndrome?
- Jervell and Lange-Nielsen syndrome * Romano-Ward syndrome
What is Brugada syndrome?
A condition where the heart’s normal rhythm is disrupted, leading to irregular heartbeats.
What is a common ECG finding in Brugada syndrome?
A pseudo-right bundle branch block with ST segment elevations in leads V1-V3.
What is Ebstein’s anomaly?
An abnormality of the right heart, characterized by a downward displacement of the tricuspid valve.
What is the most common clinical presentation of Ebstein’s anomaly?
Exertional dyspnea, palpitations, and cyanosis.
What can fetal exposure to lithium during pregnancy cause?
Ebstein’s anomaly in the infant.
What are the classical features of congenital rubella infection?
- Cataracts * Rash of bluish spots * Sensorineural deafness
What is the most common cardiac anomaly associated with congenital rubella?
Patent ductus arteriosus (PDA).
What virus causes congenital rubella infection?
Rubella virus, a togavirus.
