Pacemaker runaway following intermittent output failure

A case with a mixed pattern of pacemaker failure is presented, “Runaway” pacemaker with ventricular capture at 250 beats per minute occurred three days after the development of syncope associated with intermittent loss of pacing artifact. Presumed protection by placement of a temporary pacemaker upon admission was unfounded. This case argues for rapid diagnosis of pacemaker failure, followed by prompt surgical exploration and repair of the pacing system.