I didn’t experience heart palpitations, but others have mentioned it as a die-off symptom.
If you can afford to not work, it might be a good option to look into. I don’t work much, as I said, but the looming threat of work probably stressed me out more than the time I actually spent there. I’d worry about how I’d feel/do when I actually got called in, and worrying is pretty counterproductive during this treatment. Just a thought.
Good luck with everything! Stay focused.