I am on 200mgs of extended release Seroquel. I was on 300mgs for a year and I was tapered down to 200mgs in March 2018. I had to go on Propranolol for irregular heart beat in June 2018. I am wondering if the Seroquel caused it. I have had irregular heartbeat before Seroquel so it's hard to say. Do you mind if i ask how old are you? I am 72. The Seroquel scares me.