Anesthetic implications for patients with rate-responsive pacemakers.

One hundred thousand adults and children in the United States receive pacemakers each year, of which 85% are rate-responsive pacemakers (RRPs). Recent advances in the fields of computer programming and computer chip technology have led to the myriad development of RRPs, which contain sensors that automatically adjust the pacing rate to match the physiologic changes that occur during physical exertion. Because patients with RRPs may experience heart rate changes in the operating room due to ''normal'' sensor function, anesthesiologists must be aware of the new developments in RRP sensor technology to properly manage these patients. Increases in respiratory rate and tidal volume as well as the use of electrocautery have been reported to accelerate the paced rate of pacemakers with minute ventilation sensors. Likewise, patient movement and saws that produce vibrations can accelerate the paced rate of patients with piezoelectric crystal sensors. This paper discusses the history of pacemaker development, reviews the currently used RRP sensors, and recommends procedures for the perioperative management of these patients. Knowledge of sensor type and factors that stimulate them will help the anesthesiologist understand the cause of these changes so that he will be able to manage clinically significant hemodynamic changes due to RRP sensor activation.