The new pacemaker uses three wires, or leads, which are threaded into both sides of the heart to help it pump more efficiently.

CNN: Pacemakers found to help heart failure patients

After undergoing another surgery to replace Medtronic leads--wires connecting the pacemaker to the heart--with ones from Guidant, Davis sued both the hospital system and Haugland, charging medical malpractice and complaining that the second surgery could have been prevented.

FORBES: Unintended Consequences

This time I had a "brain pacemaker" installed, which uses wires and a battery source to stimulate deep parts of the brain with electric currents.

CNN: 'I had brain surgery while I was awake'