Atrial fibrillation is a rhythm problem in the top chamber of the heart, where the top chamber develops a whole bunch of short-circuits all zipping around the top chamber simultaneously. Top chamber is beating electrically about 300 to 350 times a minute. It's beating so fast it's not even really beating. It's sort of quivering. It can cause the heart to race, and it can cause people to feel really poorly. About 70 percent of the time atrial fibrillation develops in one of the four veins in the top chamber of the heart. And somewhere in one of those veins there's a site that starts to fire very, very rapidly. And that electricity penetrates into the top chamber of the heart and it puts the top chamber into atrial fibrillation. All of these short-circuits all of zipping around. The way we can cure that is by electrically isolating those veins off from the rest of the heart. The way that we have done that traditionally is to use a catheter to burn point-by-point around each of those veins. That can take a long time, it can be very tedious and it can do damage to other structures near the heart. A newer technique to cure atrial fibrillation is to avoid burning altogether, and using a catheter that has a balloon on it that gets advanced into each of those veins. And we blow up the balloon with liquid nitrogen oxide and it freezes around all those veins in one shot. It's a lot faster, it's a lot easier, patients are under general anesthesia up for last time and it may be safer from that point of view.
