I Am A 55 Year Old Female Who Had A

I am a 55 year old female who had a heart attack 6 years ago. I also have PKD. In the last year, just as a I doze off at night, my heart starts beating really fast and I can't go to sleep. It lasts for several minutes, then I get clammy and it is hard to go to sleep after that. I end up getting up and stay up for a while and try to go back to bed, sometimes it happens again. The only time this seems to happen is when I am trying to go to sleep. This is very disturbing to my sleep and I wake up very tired the next morning to go to work. I am up now because of this. Any idea what is causing this and what I can do about it?
Barbara