Who implanted the first fully internal artificial pacemaker in 1958?

Åke Senning implanted the first fully internal artificial pacemaker in 1958.

Senning, a Swedish cardiac surgeon, performed the implantation at the Karolinska Institute in Stockholm. The device had been designed by engineer Rune Elmqvist and was tested in patient Arne Larsson, who suffered from a severe heart-rhythm disorder.

The first pacemaker failed after only a few hours, but Larsson received a replacement and went on to live for decades with successive devices. He eventually outlived both Senning and Elmqvist and received more than two dozen pacemakers during his lifetime.

The key distinction is between the designer and the surgeon: Elmqvist built the pacemaker, while Senning implanted it. Earlier external pacemakers existed, but Senning’s operation introduced a device placed inside the body, a major step toward modern cardiac pacing.