Scientists have directly controlled animals before, but these approaches tend to either require surgery or only work with critters at certain stages in their lives. Researchers might have a more powerful technique in store, however: they've managed to control fruit flies' heartbeats through laser pulses. The approach relies on optogenetics, or modifying the genes of animals to produce materials that respond to light. In this case, the team tweaked flies' heart cells to produce light-sensitive proteins. After that, it was just a matter of zapping the hearts to make them beat on command, whether the flies were larvae or full-grown insects.
Right now, this concept wouldn't be very practical for humans. You aren't about to see people with these kinds of genetic modifications, and human bodies are simply too thick for light to reach very far. It isn't an impossible concept, though. Near-infrared light would work, and you could augment cells with the right proteins to achieve similar effects. Eventually, you could see optical pacemakers that sit outside your body and easily adapt to your needs over time.