I was diagnosed yesterday with IST. The nurse just called and told me that is what the results are from the 48 hour holter monitor and that the Dr. wants to put me on perafirmil??? I have been trying to read as much as I can about IST but I am more confused. I have been told over the course of the last 8 months that I have been having panic attacks, I am having anxiety, etc. I am a little depressed (not uncommon for me my whole life) but panic attack and anxiety, I really don't think I am. I have the same everyday normal stresses that I have always had and I am just the type of person that lets things go and don't get upset too easily. Am I just in denial and really do have an anxiety issue or is the IST a real problem that can be caused by other things other than stress and anxiety? I have not been sick other than having some back problems. L4L5S1 discs are slipped and I have had 2 ESI injections since July. Is IST something that will get worse over time, better or just stay the same? It got worse for me over the last few months which made me go see the Cardiologist. Thank you for any information!