On a recent spring day William Cohn, a surgeon at the Texas Heart Institute, waited for a call he hoped would not come. In an operating room near his office doctors worked to extract wires that had been threaded through a 55-year-old female patient’s blood vessels from her pacemaker to her heart. The wires had broken, as happens all too often with pacemaker leads, and now they had to be removed without damaging the patient’s blood vessels. Cohn was on call in case damage did occur and had to be patched in a hurry.
