[The case of the "runaway pacemaker"]

A case of a runaway pacemaker is described. Malfunctioning pacemaker produced stimuli with changeable amplitude and fast rate. It was a reason of intermittent capture, producing a variable ventricular rate; periods of life-threatening pacemaker-induced ventricular tachycardia or uneffective stimulation with slow ventricular escape rhythm. Although runaway pacemaker is a rare complication in modern pacemakers, but it still exists. It usually occurs as an emergency situation requiring immediate correction.