What is a leadless pacemaker?

Leadless pacemakers, which are no bigger than a multivitamin pill, are far less prone to complications that traditional pacemakers, which have long leads (wires). These wires may become infected, dislodged, frayed, or broken. Scar tissue or blood clots can form around the leads, which may hinder blood flow and cause pain and swelling. Thanks to recent advances, most people who need pacemakers may now be candidates for leadless devices. However, doctors have less experience with what happens with leadless pacemakers over the long term—and they cost two to three times as much as a traditional pacemaker.