The threat that the fusion of humans and medical machines may leave patients vulnerable to the hackers and bugs of the digital world is beginning to resonate with device makers.

Karen Sandler was 31 years old, working at a non-profit organization providing free legal help to computer programmers, when she was diagnosed with an enlarged heart and informed that she'd need a machine to help keep her alive.
Her mother accompanied her the day a doctor recommended that Sandler undergo surgery to implant a medical device into her chest. He handed Sandler a pager-sized machine called a cardioverter defibrillator – a miniature, implantable equivalent of having EMTs follow her around all day with defibrillator paddles should her heart stop.