Anesth Analg 80: SCA78, 1995. Introduction: Transvenous or endocardial pacing has been considered a standard technique for treating intra-operative bradycardia in cardiac patients. Recently, transesophageal atrial pacing (TAP) has become available with a modified transesophageal stethoscope. Because TAP is left atrial pacing and transvenous is right atrial pacing, we compared the efficacy and hemodynamics of each. We postulated that the time required to institute esophageal pacing is shorter than the time to institute transvenous pacing, even in those patients in whom an appropriately placed A-V paceport PA line is already in place. Methods: Twenty consecutive patients undergoing cardiac surgery were enrolled if they had a resting heart rate < 60 BPM. An A-V paceport PA line without the atrial pacing wire was placed in each patient. After induction with fentanyl and vecuronium, non-paced hemodynamics were recorded using pulse, BP, cardiac output, PA pressure, pcwp and cvp. Before incision, the patient was paced consecutively either transvenously or with TAP in random order. Each patient served as his/her own control. We recorded the time from when pacing was desired to the initiation of pacing. We also noted thresholds, depths to capture, efficacy/complications and hemodynamics. Results: