Atrial Septum Defects Flashcards
What is a true ASD?
An abnormal opening in the atrial septum allowing blood to flow either way.
How are ASDs discovered?
By a surface echo, a TEE, or a bubble study.
Which way does blood primarily shunt through ASDs?
From left to right.
What are the 4 types of ASDs?
- Ostium Secundum
- Sinus Venosus
- Ostium Primum
- Common Atrium
Which ASD is the most common type?
Ostium Secundum ASD
With an ostium secundum ASD what goes wrong in fetal development?
The proliferations that form in the septum secundum become exaggerated and most of the septum primum disappears, and the foramen ovale never closes.
What is the surgical correction for an Ostium Secundum ASD?
Patches to close the ASD.
With a large ASD what happens to the right atrium and ventricle?
They both dilate and become hypertrophic due to the volume overload. This causes pulmonary blood flow to increase and pulmonary arteries to dilate.
What negative effects do ASDs have on the left heart?
Blood flow in the left atrium is increased, and the left ventricle becomes hyperdynamic to maintain cardiac output. Systemic blood flow is diminished.
Where is a Sinus Venosus ASD located?
It is located high within the IAS, near or at the level of the SVC and pulmonary veins.
What are other congenital lesions associated with Sinus Venosus ASDs?
- Abnormal pulmonary veins
- Ventricular septal defects
- Abnormal drainage from pulmonary veins
What are the surgical corrections for Sinus Venosus ASDs?
Pericardial patch to reroute the anomalous venous return and close the ASD.
What causes an Ostium Primum ASD?
The septum primum does not meet the endocardial cushion in fetal development.
What can an Ostium Primum be associated with?
A membranous VSD.
Which ASD involves the complete absence of the IAS?
Common Atrium ASD.
What goes wrong during fetal development leading to a Common Atrium ASD?
The truncus is not finished over the roof of the atria and the sinus venosus fails to produce folds.
Why may there be low O2 sats associated with Common Atrium ASD?
Because there is arterial and venous blood mixing. The atria act as one chamber causing slight arterial desaturation.
What Sx may be present in a Pt with a hemodynamically significant ASD?
- SOB
- Pulmonary HTN
- increased HR & BP
- Right heart failure
- Venous congestion & distended neck veins
- Neonates experience nausea, restlessness, and loss of appetite
What murmurs may a Pt with an ASD have?
Murmurs are heard at atrial contraction (if it is a large defect), and an ejection murmur in the PA due to an increased amount of blood passing through the PA valve.
What will a Pt with an ASD chest X-ray look like?
It will show signs of pulmonary congestion, a dilated right heart, pulmonary infiltrates, a dilated PA, and/or a primary left heart defect.
How does an ASD effect the heart?
- dilated right heart
- incompetent tricuspid valve
- pulmonary HTN
- venous congestion
- LV compression
- Low return to left heart
- Left heart becomes hyperdynamic to maintain stroke volume.
