Reversible prolonged pacemaker failure due to electrocautery.

Despite improved technology, permanent pacemakers remain susceptible to electromagnetic interference, including electrocautery. We describe sudden, apparently irreversible output loss in a pacemaker associated with the use of electrocautery, despite standard precautionary measures. When tested by the manufacturer several weeks later, pulse generator function was normal and it was functioning in the "reset" mode. We postulate that pacemaker failure was related to current drain causing "lockout" of the voltage control oscillator, the mechanism responsible for regulating pulse width. Further reduction in battery voltage, due either to exposure to cold temperatures while the device was being transported to the manufacturer or to further use of electrocautery during device explanation, may have allowed it to reach the "reset" level, permitting normal function to resume.