Pacemaker-mediated tachycardia induced by intraoperative somatosensory evoked potential stimuli

Abstract

Permanent cardiac pacing is reliable and effective form of therapy for a variety of slow and fast dysrhythmias. In addition to being relatively long-lived and trouble free, newer generations of these increasingly sophisticated devices have been designed to provide greater programmable and telemetric capabilities. Such advances have supported the increased use of the more complex dual chamber and rate responsive pacemakers, which not only ensure a minimum heart rate but attempt to optimize the patient's hemodynamic status by varying the pacing rate in accordance with metabolic needs. Performing appropriately they offer considerable benefits. Should aberrations in function occur, however, adverse results may be profound unless there is early recognition and prompt corrective action. The operating room and other anesthetizing areas present several unique opportunities for pacemaker dysfunction, (e.g., cautery, muscle tremor, inadvertent damage to leads or generator) of which the anesthesiologist must be aware. Whereas in many instances the pacemaker problems encountered in this setting are readily identified by a transient or prolonged decrease in heart rate, we report a case in which an acceleration of the ventricular rate occurred in association with profound hypotension.