interatrial septum aneurysmal

i am a 45 yr female. i had an echocardiogram and dx w/ interatrial septum-aneurysmal. the cardiologist wants me to have a  transesphogeal echo. to determine if a PFO or small ASD is there as well. Do i need to take ASA daily if i have both the aneurysmal and PFO? what's the research say on this?  if i have just the aneursymal do i need the ASA?  i do not smoke, drink  or eat relatively healthy. i know i need to exercise more and have recently increased this. this has been a shock since i am healthy otherwise. i am concerned of the risk of Stroke which was mentioned to me. i was told ASA would prevent a stroke ...i also have trace-mild mitral regurgitation, mild tricuspid regurgitation... this is all very upsetting , i am very concerned about the  future of my heart and how my heart will continue to function over time. is exercise the best medicine along w/ taking an ASA? should i be panicked by these dx?