Ablating Persistent Atrial Fibrillation [pics]

I once held traction during a 7-hour “Whipple” procedure. This was longer than that. The concept is fairly easy to grasp. Atrial fibrillation is classically thought to be triggered by one or more ectopic foci that decide they aren’t going to listen to the SA node anymore. These foci can be all over the place, but statically most of these bad guys are found to originate near the os of a pulmonary vein entering the left atrium. In its most basic sense, the procedure involves creating a barrier around the os of each pulmonary vein in an attempt to block the bad guys from sending out their ectopic signals. The “How” is what makes this procedure difficult.

Electrophysiologists use catheters with electrodes to map the inside of the heart, specifically the left atrium in this case. They combine this data with data from a recent CT to construct a 3D real-time representation of the atrium. They use this real-time 3D representation in conjunction with fluoroscopy to guide an ablation catheter around the left atrium and systematically “burn” a wall around each os. The ablation process is quite tedious because the catheter can be very difficult to control. Furthermore, it is not simply “drawing a line” around each os. Each 30-second ablation is one in a series of spot “burns” all the way around (as you can see in the second picture). I liken it to a person with Parkinson disease trying Pointillism.

Once the electrophysiologists believe they have completed the circles, they use electrodes on another catheter in the left atrium to evaluate the EKG for “leaks” in the barriers. If they find a leak, where signal is still managing to get past their barrier, they will perform further ablations in that area until the leaks are plugged.

There’s much much more that could be said, but that’s it for me. It’s a tedious, complicated process with a success rate around 70% (at least at our hospital). I’m glad that I was able to see one, but I’m also glad that I’m not going to be doing one in the future.

Enjoy the pictures. I snapped them with my iPhone during the procedure.

To get your bearings, the lowest catheter with many black electrodes is sitting in the coronary sinus and mapping the activity. The looped, or “spiral”, catheter sits in one of the pulmonary veins and monitors activity. The lone catheter with a dark tip somewhat near the spiral catheter is the ablation catheter that does all the… well…ablating.  And the dark tube in the middle is your esophagus. You don’t want to ablate that.