New Hi-Tech Images Guide Surgeons' Hands
"It's trial and error, trial and error," says Douglas Packer, a cardiac electrophysiologist at Mayo. "I'm standing there moving these catheters with my hands, and I'm looking at one screen that shows their position on a murky two-dimensional fluoroscopy image, and another that shows some details of the heart" using ultrasound. He's also building up a map, on another screen, of points that represent different aspects of the heart's electrical activity. "I have to combine all of this information in my head and hold it there. So it's hard to find your way around. I'm pretty good at it, but it takes hours to find the trouble spots and treat them."
Working with Packer, Robb has devised a system to show all of this complicated stuff on one computer screen. Three-dimensional ultrasound captures the movement of the heart while fluoroscopy or another technology tracks the electrodes, which, along with a standard electrocardiogram, provide an ongoing stream of data about electrical activity. This information is all mapped onto a detailed anatomic image, taken by computed tomography or CT, that changes as the heart beats–and can be manipulated on the fly to show different parts of the heart from different angles.
"The result is like actually being in the heart," Packer says. "I see things as they happen, and where they happen." In animal tests, and computerized re-creations of procedures using actual patient data, the technique has cut errors and hours way down. Later this year, Robb and Packer intend to start a trial on actual heart patients. The moment will be a long way from the one about 30 years ago, Robb recalls, "when a surgeon said to me, 'If I can see it, I can fix it.'" These new views eliminate a lot of blind spots, and for patients that means more and better repairs.
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