Buh-bum. Buh-bum. Buh-bum. We all have our own interpretations of what a heartbeat sounds like but here is what it looks like during heart surgery. It looks like it's rolling in place inside your chest. Pretty amazing.
BoingBoing said that this footage was taken during Toronto's Sunnybrook Hospital's live-tweeting of a coronary artery bypass graft done to prevent a heart attack. It's hypnotic to watch (if you can stomach it).