Hi Beauty,
I applied for SSDI in 2009 and was approved. I had the help of Julie. In the 12 months before I applied, which is the period they look at, I had been hospitalized 3 times (on 3-4 weeks of IV antibiotics with each), had a sinus surgery, a port placed, and a bronchoscopy. My FEV1 had dipped into the 40s during a couple exacerbations. I was lucky that my case was pretty clear cut.
I really hate to be a Debbie Downer here, but based on your posts I would say getting approved based on CF, or even CF in some combination with heart problems is unlikely. If you read the link Jaimers provided, they look at things like hospitalizations, IV antibiotic use, nebulized antibiotic use, and FEV1. I know you have mentioned previously that you don't take antibiotics or do treatments. So that would take any IV antibiotic and nebulized antibiotic use out of the equation for you. With an FEV1 of 78, you would not meet that criteria either. Also, one of the things Julie has her clients do is create an activity log that shows how much time you spend per day doing treatments, washing/sterilizing nebulizer cups etc. if you are still currently not taking meds or doing treatments, you wouldn't be able to submit that for evidence either. I also think that Social Security would just in general question how severe and limiting your CF is if you do not do treatments or take antibiotics. The criteria they have for the hemoptysis episodes is also quite specific, and since your episodes would be undocumented, they wouldn't count either.
With all that said, I know nothing of your heart issues so I think your best bet would be to request your medical records for the past 12 months and see if you can get a free consultation with a lawyer who specializes in SSD. They could look at records and tell you your odds based on that. As someone mentioned previously, often times you don't pay anything unless your case is won. You can also try Julie, but I know her resources are spread thin and she is unfortunately having to be very choosy with the cases she takes on.
Sorry for sounding negative. I just wanted be honest based on my experience and what I know they are looking for. I'm no expert, so take my opinion with a grain or two of salt. I really hope you are able to find a solution so you can go back to school and get a job that's better for your health!
Take Care, Autumn