VOLTAGE DIP IN PACEMAKER BATTERY SUPPLY - A NEW CAUSE OF PACEMAKER MEDIATED TACHYCARDIA

A new cause of pacemaker mediated tachycardia was observed in a patien t equipped with a Vitatron(R) Quintech 931 DDD pacemaker. In this type of pacemaker the microprocessor is switched off during the atrial ref ractory period. Beyond the recommended replacement time, the internal resistance of the battery may increase to such an extent that switchin g on and off the microprocessor may cause voltage dips. Those voltage dips are erroneously interpreted as P waves by the atrial sensing ampl ifier, which may cause self-triggering of the pacemaker and initiate a pacemaker mediated tachycardia.