Runaway pacemaker inhibited by external overdrive stimulation: a case report.

A case is described of runaway pacemaker ( Stimulith ) which could be inhibited by external chest-wall overdrive. This pulse generator had been implanted for four years before runaway occurred; the runaway rate was 140/min with capture of the ventricles. Using external chest-wall stimulation at a rate of 170/min, we were able to achieve almost complete inhibition of the faulty generator, while preparing for emergency replacement.