Electrosurgery and cardiac pacemakers.

There are two basic types of cardiac pacemakers: (1) Fixed-rate pacemakers stimulate the heart at a regular rate independent of the intrinsic heart rate. (2) Demand pacemakers sense the heart's spontaneous rhythm. They are more commonly used because they are noncompetitive with the heart. There are two varieties of demand pacemakers: ventricular-inhibited and ventricular-triggered. Their responses to electrical interference are quite different. Potential pacemaker interference is a consideration with high-frequency electrosurgery. The problems with electrosurgical interference have occurred primarily with early pacemaker models. Recent improvements in electrical shielding and filtering systems have made pacemakers very resistant to outside electrical influence. Simple electrodesiccation of small lesions on relatively healthy pacemaker patients poses negligible risks. Caution is advised for marginal patients undergoing extensive electrosurgical procedures. The potential risks are further minimized by proper attention to patient history, monitoring, proper grounding, the avoidance of cutting current, and the use of proper technic.