Doctors in Lexington have successfully implanted an artificial heart, marking the first time the procedure was performed in Kentucky. The SynCardia Freedom Driver beats a steady rhythm that’s keeping 20-year-old Zack Poe alive. It powers the Total Artificial Heart doctors implanted in February. “The device is a polyurethane device. It has two pumps, each driven by its own drive line, and it has four mechanical valves," says Dr. Mark Plunkett, chief of Cardiothoracic Surgery at the University of Kentucky.