I had an SVT ablation done about a year ago. I'm not a medical professional, but I was told that it was not uncommon to experience some of the same symptoms after the ablation (elevated heart rate), because there is healing process involved. You should contact your electrophysiologist's office and tell them about the side effects that you are experiencing from the beta-blocker. There are many things that can cause your heart rate to elevate, anything over 100 bpm is considered tachycardia, but it could be related to stress, caffeine, etc. My doctor told me to be concerned if mine reaches 150, and stays that way for a 1/2 hour or more.