Borum SE, Bittenbinder TM, Buckley CJ. Department of Anesthesiology, Scott & White Clinic and Memorial Hospital, Texas A&M University System Health Science Center, College of Medicine, Temple 76508, USA. J Cardiothorac Vasc Anesth 14(3):277-80, 2000. OBJECTIVE: To determine whether transesophageal atrial pacing reduces phenylephrine requirement for blood pressure support during general anesthesia for carotid endarterectomy. DESIGN: Prospective randomized clinical study. SETTING: University hospital. PARTICIPANTS: Thirty-six patients undergoing elective carotid endarterectomy under general anesthesia. INTERVENTIONS: Adults of either sex (n = 36) received general anesthesia using a standardized anesthetic regimen for elective carotid endarterectomy. Phenylephrine requirements were measured in patients having carotid endarterectomy and randomized to phenylephrine infusion (group 1, 19 patients) or phenylephrine infusion plus transesophageal atrial pacing (group 2, 17 patients) to maintain systolic blood pressure within +/-20% of baseline systolic blood pressure. MEASUREMENTS AND MAIN RESULTS: Measurements included (1) the amount of phenylephrine required in each group, (2) the variance of systolic blood pressure outside the desired range, and (3) the occurrence of postoperative electrocardiogram or myocardial enzyme changes suggesting myocardial ischemia. The average requirement for phenylephrine was less for group 2 (0.28+/-0.16 microg/kg/min) than for group 1 patients (0.46+/-0.23 microg/kg/min) (p = 0.02 by t-test). CONCLUSIONS: Under controlled conditions of general anesthesia for carotid endarterectomy, transesophageal atrial pacing reduced by 40% the amount of phenylephrine needed for blood pressure support and helped in the treatment of disadvantageous sinus bradycardia.