Thank you for sharing this! I'm into endurance cycling and had similar issues. I'm diagnosed with PVC as well and rely on medication to keep it from happening. I nearly fainted while driving a car, so it is not without "harmful effect".
In my case, the PVC disappears during exercise and comes back when I take a rest after exercising. I just wonder if you had any comparisons between rest vs. elevated heart rate scenarios. Now I'm super curious how elevated heart rate might change the clock rates for those nodes.