I am one year post and still have the heart palpitations. I had all sorts of tests ran and nothing wrong with the heart. I notice it is worse around period time and ovulation. I just had a bad case this last couple of weeks. I had gone quite a few months with very little. I guess a one year crash? My pulse always seems to be on the high side since Mirena. around 100 bpm. Just hope with time, it keeps improving, til one day I am normal again.