Kitahata H, Tanaka K, Kimura H, Kawahito S, Oshita S. Department of Anesthesiology, Tokushima University School of Medicine, Japan. hiroshi@clin.med.tokushima-u.ac.jp Anesth Analg 89(1):21-5, 1999. We evaluated whether ventricular pacing is possible using pacing electrodes attached to a transesophageal echocardiography (TEE) probe in 20 patients undergoing elective cardiovascular surgery. A bipolar pacing lead was fixed with silicone adhesive anteriorly to the TEE probe with the distal electrode 25 mm from the TEE probe tip. The TEE probe was positioned to obtain a transgastric short-axis view of the left ventricle. The distal or proximal electrode on the TEE probe was the cathode; the chest electrode placed at the V5 lead position was the anode. Gastrothoracic ventricular pacing (GVP) was performed at 100 bpm at 30- or 50-ms pulse duration. Transgastric ventricular pacing (TVP) was also attempted using both TEE probe electrodes alternately as cathode/anode. Maximal generator output was 32 mA. GVP with the distal electrode as cathode was successful in 75% and 80% of patients at 30- and 50-ms pulse durations and 23.3+/-5.8 mA and 22.6+/-5.8 mA threshold currents, respectively. However, success rates (20% and 25%, respectively) were significantly lower with the proximal electrode as cathode using the same pulse durations and 14.4+/-5.3 mA and 16.7+/-6.8 mA threshold currents. The TVP success rate was significantly lower than that for GVP. With optimization, this system could become an available technique for intraoperative emergency ventricular pacing. IMPLICATIONS: Using an endocardial pacing lead attached to a transesophageal echocardiography probe, gastrothoracic ventricular pacing can be performed successfully without complications in 75%-80% of patients undergoing cardiovascular surgery.