The septum in question is a wall that separates the left and right atria (upper two chambers) An atrial septal aneurysm is an abnormal dilatation of the atrial septum with bulging of the septum at least half the distance to the left atrial wall. There is variation in the anatomical definition, but in general, the basal width of an atrial septal aneurysm should be more than 15mm and the excursion of the aneurysm beyond the plane of the residual atrial septum should be at least 10 or 15mm. Apparently your aneurysm does not fit the definition.
For some insight: Many fetuses have a recognizable flap (Septum Primum flap) that projects into the left atrium. However, this flap shows little mobility during the cardiac cycle, and has limited extension: it is a flap, NOT an aneurysm. An atrial septal ANEURYSM (redundant atrial septal tissue) is very mobile, and may extend across to the far left atrial wall, or even herniate through the mitral valve! The defect, which involves the septum primum , can be seen antenatally as a bulge exceeding half the diameter of the left atrium on the four-chamber view. An ASD occurs during fetal life, when the septum between the upper chambers of the heart does not form properly. And this condition may present a hole in the heart.
Your test ruled out a hole in the heart. If there were a hole between the upper two chambers, some blood would flow from the left atrium to the right atrium rather than go into circulation. Some individuals go through a lifetime without any progression or medical problem with a small hole between the chambers. If there is a medical problem, there can ber effective treatment.
but why would my septum be redundant? i mean what does that mean and do i need to look further into it?
It is a congenital anomaly...the upper chamber of septal wall has not formed properly. If there is a medical problem, your doctor should advise. A hole in the septal wall as been ruled out!. The anomaly, if a problem, would be the size of the flap herniating into the mitral valve.