Sometimes, when I was watching various artificial heart experiments in the basement of the Texas Heart Institute, I wondered if I was experiencing something akin to Thomas Edison’s housekeeper. That is, someone with only a tenuous reason to be in a place where history was being made—or was made today, when it was announced by the Texas Heart Institute that a new total artificial heart, the BiVacor TAH, had kept a Houston man alive for several days. It is, as one of its developers likes to say, the cardiac equivalent of a successful moon landing, a medical breakthrough that could change the way the millions currently suffering from heart failure are treated. If the device is proven to go the distance, it could spell freedom for…