 Instead of your normal heartbeat going at 60 to 100 beats a minute, you could be going at the top can be going to 400 to 600 beats a minute. But then that gatekeeper, the AV node, is the one that communicates between the top and the bottom, and it's the one that says, hey, back off. I'm not going to let all of you come down to the bottom chamber because that would be sudden death if the bottom chamber goes at 400, 600 beats a minute. Gotcha.