ablation procedure and vasovagal syncope

Hello all.  I've considered ablation or at least having an EP map done to locate the source of my PVC's and infrequent SVT.  So, here's my question.  Does the catheterization cause problems with vasovagal syncope?  I have suffered from severe fainting spells since I was about 15 and have posted here before about my situation.  While the fainting spells no longer scare me abnormally, as I am aware of what to do and their benign overall effect, I do worry about various activities and procedures.  For instance, I cannot go to the dentist for a tooth extraction, I CANNOT give blood, and I cannot have an IV placed in my hand without passing out and therefore take action to avoid or modify those procedures (dental surgery, donate $$ instead of blood and IV in seam of elbow instead of hand).  

Since they do not sedate you completely during catheterizations/ep mapping/ablations the chances of me passing out on the table seem nearly 100%.  And, when I pass out I have a mild seizure (due to very low heart rate) which can't be good for the system when you have a catheter fed through your body.

Have any of you dealt with this?  And if so, what did your doctor do for you?