Some tachycardia (heart racing) is very common in response to smoking. It's worse w/ sativas than indicas, and it's a response that happens routinely after smoking of anything because the heart's having to work harder to pump oxygenated blood around the body when you're inhaling lungsful of smoke to compete with your air intake.

In the post below, my husband outlined a fairly tried-and-true method for slowing the heart rate down if it's dire enough to require some sort of treatment. Good luck w/ that.

http://boards.cannabis.com/medicinal...ml#post1790562