Well done on being proactive after seeing the webinar, @Maree72? I am guessing you didn't have any Pain or palpitations previously? I know it really scared me, when I started having mine! :(
I was diagnosed with an abnormal heartbeat a couple of years ago, 4 years after my BC surgery - I didn't have chemo. But my father had heart problems as well and passed away at age 51 (possibly caused by/made worse by an injury during the WW2) .. I am now 71, so, so far, so good!! I am now on a small dose beta blocker to control the wonky beat .... and I've not had a recurrence (even tho I forget to take the tablets .... oooops!)
It sounds like you are doing everything right in your life, so well done YOU!! Roughly what age are you? It could well be an age related thing too ... I think mine is.
take care & all the best for your ongoing treatment xx