Nobody has talked much about artificial hearts in recent years, and no wonder. It took Washington dentist Barney Clark 112 miserable days to die after being fitted with the Jarvik-7 heart back in 1982--four months of suffering that included convulsions, kidney failure, respiratory problems, a wandering mind and, finally, multi-organ system failure. In the aftermath of that debacle, the New York Times nicknamed artificial-heart research the "Dracula of Medical Technology."
But Dracula has risen again. About a dozen companies and academic research centers have been working without fanfare on devices that can replace all or part of a failing heart. Getting...