I Have Been On Xanax For Approx. 3 Years, I

I have been on Xanax for approx. 3 years, I have a Medtronic implant in my left upper chest. I am out of town working and my physician is out of the country. I went to a Dr and he took me off of Xanax and put me on Ativant. Would like to know the difference between the two. And if there is any side effects different for Ativan then for Xanax. I took 1 Xanax in the morning and one at bedtime. My Dr had me on them 3X per day. But I only took them twice a day. I have terrible anxiety attacks.