I had an echocardiogram when I was 7 1/2 months pregnant 18 months ago (after a heart murmur was detected). The results showed a minor abnormality but I could continue with my pregnancy and delived naturally. I was followed up a year later. The echo had shown a right atrial mass and thickening of the wall. I was sent for a further echo (1 year after the first) which the sonographer said showed my heart was normal. The cardio dept have said that the mass has greatly reduced and they are less concerned. However they were surprised about the results as they thought it was a structural defect. In addition, they have no clue what this mass could be. I am scheduled for a transoesphegal echo in a few weeks to see if there is any residue. I am petrified what this could mean. Will this mass grow back?