no idea, but you can pick up a basic heart monitor for about $60 at a sporting goods store. i have a polar hr monitor, and it's great. it'll calculate calories, beep to let you know you are slacking, and lets you customize your training goals. mine was about $100, i think.
i got it when i realized that the only reason i went to the gym was for the heart rate monitor machines, so having it let me cancel a gym membership in favor of exercise outdoors.
another benefit i discovered is that certain machines will sync with my monitor, so i don't have to constantly grip the monitor things when i use a cardio machine.