An artificial heart kept an Australian man alive for a record 100-plus days in what doctors are calling an "unmitigated clinical success." As the Guardian reports, the man was given an experimental BiVACOR total artificial heart implant to address heart failure in late November and became the first to walk out of a hospital while using the device in February. He received a donor heart earlier this month, reports CNN. Though some 23 million people globally suffer heart failure, only about 6,000 receive donor hearts. More: