I'm sorry but this just doesn't sound right to me. From what I understand, you should be off your medication if you are doing a tilt table test and holter. What's the point of testing you if the medication masks your symptoms. Does the SSRI help with the fainting? And pre syncope episodes? In the Changes video on you tube they explain the reason ssri works is not because of an anxiety/depressive disorder but rather it affects the same neurotransmitters that are misfiring. I just saw a neuro on autonomic disorders and he scoffed at the diagnosis of anxiety. In my opinion the anxiety is a natural reaction to your body taking on so much physical stress trying to maintain homeostasis, hence your inability to handle external stresses as you had previously. Well good luck, I hope all goes well!