I don't think its doing actual damage to my heart, otherwise I would be shooting myself straight into emergency. What I think is happening is the poison is stressing my heart and nervous system. I took Targin long acting painkiller and it settled my heart flippety flops very well and allowed me to get some long needed sleep. I just wish I would have figured that out last night and not gone through hell.
I will mention it again to my oncologist and my GP next visit. They didn't sound very concerned last time so it must be a little bit par for the course. Still, not nice though.