Welcome to HealingWell. I was not sure I understood if your Dr. did an ECG looking at your heart or and EEG looking for a neurological problem.
If you had a major heart problem it should show up on an ECG and there are a lot of follow up tests he could have ordered.
Looking at your neurological status Patients may be asked to go to sleep during the test because EEG abnormalities are more likely to show up during sleep.
When you say you black out, do you mean you actually faint ?
I have a few of your symptoms but I know the cause of mine and they are much different from anything to do with the heart.
Be sure to follow up with perhaps referrals to some specialty areas.