Embryological Basis of Atrial Septal Defects Introduction: Atrial septal defect (ASD) is a type of congenital heart anomaly that occurs when there is a hole in the wall (septum) between the two upper chambers (atria) of the heart. ASDs have an incidence of approximately 6-6.4 per 10,000 live births, with a sex ratio of 2:1 in females to males. There are four types of ASDs, including ostium primum defects, ostium secundum defects, complete absence of the atrial septum, and ASDs related to sinus venosus defects. Embryological Basis of ASDs: 1. Ostium Primum Defects: - In this type of defect, the atrial septum and the formation of the atrioventricular wall are affected. - The endocardial cushion, which contributes to the formation of the interatrial septum, is involved. - The fusion between the lower part of the septum primum and the endocardial cushion does not occur, resulting in the persistence of the foramen primum or ostium primum. - This defect is not isolated and is always associated with a ventricular septal defect (VSD) of the membranous type. - The AV valve defect, particularly the involvement of the tricuspid valve, is also present. 2. Ostium Secundum Defects: - The ostium secundum is the area above the lower part of the septum primum, and it is overlapped by the septum secundum. - There are two varieties of ostium secundum defects based on the size of the opening. - If the septum primum is shorter in size, the ostium secundum enlarges, leading to a large opening between the right and left atria. - If the septum secundum is shorter in size, it cannot completely overlap the developing ostium secundum, resulting in a persistent opening. - In both cases, considerable intra-cardiac shunting may occur from left to right due to higher pressure in the left atrium after birth. 3. Complete Absence of the Atrial Septum: - This condition is characterized by the complete absence of both the septum primum and septum secundum. - A single atrial chamber is formed due to the fusion of the right and left atria. - This defect is associated with other serious congenital heart defects. - It is also known as trilocular biventricular heart, as there are three chambers (two ventricles and one atrium). 4. Premature Closure of Foramen Ovale: - The foramen ovale is a normal fetal opening between the atria that allows blood to bypass the lungs. - If the fusion between the lower end of the septum secundum and the upper end of the septum primum occurs prematurely, it leads to the closure of the foramen ovale before birth. - This abnormality results in massive hypertrophy of the right atrium and right ventricle due to increased pressure in the right side of the heart. - The underdevelopment of the left side of the heart occurs due to decreased oxygen supply. - Infants with this condition may experience immediate death after birth. Conclusion: In summary, the different types of atrial septal defects have distinct embryological bases. Understanding these helps in comprehending the anatomical and functional abnormalities associated with ASDs. The severity and clinical implications of ASDs vary depending on the specific defect and associated complications.
Hello Sir which app do you use to explain anatomy sir where in you remove structures one by one! It will be of much help if u told the name of the app.
Good evening sir Age 27 years female Cyanotic CHD Avsd, Single atrium, Large sub aortic vsd, Mild TR pasp 107 Kya ilaz ho sakta hai or hoga toh kaha possible hai or kitna costly hai?
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Embryological Basis of Atrial Septal Defects
Introduction:
Atrial septal defect (ASD) is a type of congenital heart anomaly that occurs when there is a hole in the wall (septum) between the two upper chambers (atria) of the heart. ASDs have an incidence of approximately 6-6.4 per 10,000 live births, with a sex ratio of 2:1 in females to males. There are four types of ASDs, including ostium primum defects, ostium secundum defects, complete absence of the atrial septum, and ASDs related to sinus venosus defects.
Embryological Basis of ASDs:
1. Ostium Primum Defects:
- In this type of defect, the atrial septum and the formation of the atrioventricular wall are affected.
- The endocardial cushion, which contributes to the formation of the interatrial septum, is involved.
- The fusion between the lower part of the septum primum and the endocardial cushion does not occur, resulting in the persistence of the foramen primum or ostium primum.
- This defect is not isolated and is always associated with a ventricular septal defect (VSD) of the membranous type.
- The AV valve defect, particularly the involvement of the tricuspid valve, is also present.
2. Ostium Secundum Defects:
- The ostium secundum is the area above the lower part of the septum primum, and it is overlapped by the septum secundum.
- There are two varieties of ostium secundum defects based on the size of the opening.
- If the septum primum is shorter in size, the ostium secundum enlarges, leading to a large opening between the right and left atria.
- If the septum secundum is shorter in size, it cannot completely overlap the developing ostium secundum, resulting in a persistent opening.
- In both cases, considerable intra-cardiac shunting may occur from left to right due to higher pressure in the left atrium after birth.
3. Complete Absence of the Atrial Septum:
- This condition is characterized by the complete absence of both the septum primum and septum secundum.
- A single atrial chamber is formed due to the fusion of the right and left atria.
- This defect is associated with other serious congenital heart defects.
- It is also known as trilocular biventricular heart, as there are three chambers (two ventricles and one atrium).
4. Premature Closure of Foramen Ovale:
- The foramen ovale is a normal fetal opening between the atria that allows blood to bypass the lungs.
- If the fusion between the lower end of the septum secundum and the upper end of the septum primum occurs prematurely, it leads to the closure of the foramen ovale before birth.
- This abnormality results in massive hypertrophy of the right atrium and right ventricle due to increased pressure in the right side of the heart.
- The underdevelopment of the left side of the heart occurs due to decreased oxygen supply.
- Infants with this condition may experience immediate death after birth.
Conclusion:
In summary, the different types of atrial septal defects have distinct embryological bases. Understanding these helps in comprehending the anatomical and functional abnormalities associated with ASDs. The severity and clinical implications of ASDs vary depending on the specific defect and associated complications.
pls upload lectures on development of eyes and ear and nervous system too
Hello Sir
which app do you use to explain anatomy sir where in you remove structures one by one!
It will be of much help if u told the name of the app.
Good evening sir
Age 27 years female
Cyanotic CHD Avsd,
Single atrium,
Large sub aortic vsd,
Mild TR pasp 107
Kya ilaz ho sakta hai or hoga toh kaha possible hai or kitna costly hai?