What are the 3 types of atrial septal defects?

What are the 3 types of atrial septal defects?

There are 3 major types of ASDs or interatrial communications: ostium secundum, ostium primum, and sinus venosus (Figure 1A) defects. The ostium secundum is a true defect of the atrial septum and involves the region of the fossa ovalis.

What is ostium primum ASD?

An ostium primum atrial septal defect (ASD), as seen in the image below, is located in the most anterior and inferior aspect of the atrial septum. It is the simplest form of atrioventricular (AV) canal or AV septal defect. These defects are often associated with trisomy 21.

What is septum primum?

The septum primum originally develops as a ridge of muscular tissue that grows toward the endocardial cushion tissue of the developing AV valves. It eventually fuses with the cushion and closes the primordial hole, the ostium primum, between the AV valves and the septum primum.

What do the endocardial cushions form?

The endocardial cushions are two thicker areas that develop into the walls (septum) that divide the four chambers of the heart. They also form the mitral and tricuspid valves. These are the valves that separate the atria (top collecting chambers) from the ventricles (bottom pumping chambers).

Is ostium primum the same as foramen primum?

In the developing heart, the atria are initially open to each other, with the opening known as the primary interatrial foramen or ostium primum (or interatrial foramen primum). The foramen lies beneath the edge of septum primum and the endocardial cushions.

What is primum type ASD?

An ostium primum atrial septal defect (ASD) occurs when then atrial septum near the atrioventricular valves has a communication between the two atrium causing a left to right shunt. This rarely develops into Eisenmenger’s syndrome if pulmonary hypertension develops reversing the direction of the shunt to right to left.