I also have a very high HR with my RSD. My drs have always just chalked it up to my body dealing with the very high pain levels. I've had several full work ups for it and they find nothing. I've gone to the ER for other reasons before and have had a difficult time getting them to focus on my reason for being there because they get so distracted by my elevated HR. I also have a BP that fluctuates significantly like that...though mine tends to the lower end most of the time with random spikes and drops thrown in for fun. Gotta love that dysfunctional sympathetic nervous system and all the havoc it causes on the rest of the body...