Perhaps your beta blocker was too strong. I am on BP meds and a beta blocker, Metoprolol. My heart rate is slow most of the time too, in the 60's, but every now and then races to close to 100. I just finished wearing a monitor for 1 month so my insurance would pay for a loop monitor, it goes under skin and is worn for 3 years. I had worn monitors before but this one was different. I put patches on back of sensor and placed on chest in 2 areas. It's 1 piece but patches on each piece. The sensor piece goes more on right and other end goes over heart on left. Had to play around to get it in place to stay during night. It comes with a thing that resembles a phone and when you feel the PVC's, you hit record. I sent an EKG reading to them when I was having an episode couple days before being done. Someone is monitoring them constantly from the main office. Have an appt on 21st to discuss readings.