( Still scientific evidence does not ye...)For one Stanford doctor, the beat goes on during open-heart surgery

Still, scientific evidence does not yet conclusively show its benefits, said Robbins, addding that he wants to see more research done before he's convinced.

"It's just so difficult," explained Robbins, who first used the procedure when it was developed a decade ago and now uses it only occasionally. "I don't have the time to devote to it. You need to do it often to be good at it."

Which is exactly what Ihnken plans to do. He's completed more than 130 of the surgeries and does all his bypass work off-pump. "I really want to build Stanford as an off-pump center," he said, before scrubbing up for surgery on that afternoon earlier this year. "I want patients sent here from everywhere."

Ihnken would spend the next three-and-a-half hours intricately stitching new blood vessels onto the beating heart of his patient. When he lifted the heart out of the chest, a tricky step in the beating-heart procedure, the doctors and nurses and technologists in the room turned suddenly quiet. The beat, beat, beat of the heart monitor filled the air. Ihnken, head tilted, found the spot he was searching for on the heart's backside and, finally, looked up.

"Everything OK out there?" Ihnken asked the anesthesiologist breaking the tense silence.

"Really stable, really stable," the anesthesiologist answered. "He's tolerating it really, really well."