Cardiac Pacemaker Induced Ventricular Fibrillation during Surgical Diathermy

Abstract

Two demand pacemakers were observed to repeatedly fibrillate the heart during clinical surgery employing diathermy. Marked hypotension associated with a rapid, irregular ventricular action was observed in another patient who had a fixed rate pacemaker implanted. Pacemakers were tested with function generators over a range of frequencies and some increased their rate to between 200–600 impulses/min. Animal experiments confirmed that, contrary to manufacturers advice, surgical diathermy produces myocardial fibrillation in the presence of some pacemakers. Mechanisms of these effects and their clinical significance are discussed.