Make sure they do a good anemia screen, including ferritin levels. I've had rapid pulse for the past few months, and a couple of instances of very very high heart rate (had it all my life--dxed as "short P-R interval, benign" but it used to be just 30 seconds at a time--these last two times were 20 minutes each.) Turns out I was anemic. Unfortunately, they only ran the basic anemia screen, so it didn't provide full info on the type. So I'm treating it with iron and cast iron pans, and will draw blood again in 3 weeks, this time with the ferritin too. My pulse has dropped 20 beats per minute since supplementing, so I'm pretty confident that was the issue for me.
Zone diet on and off for several years....worked, but too much focus on exact meal composition
Primal since July 2010...skinniest I've ever been and the least stressed about food