Temporary endocardial pacing is a technically demanding invasive procedure requiring sterile precautions and access to fluoroscopy. External (transcutaneous) pacing requires high current for capture and is poorly tolerated in the conscious patient. An esothoracic pacing system has been developed capable of reliable ventricular capture. The flexible gastroesophageal electrode is passed into the stomach. The distal 6 cm is angled to 90 degrees with an internal pulley system, positioning the tip of the gastroesophageal electrode in the fundus of the stomach. Ventricular pacing is performed with a spherical electrode (cathode) mounted on the gastroesophageal electrode tip in conjunction with a chest pad (anode) positioned medial to the cardiac apex. Of 91 subjects in which esothoracic pacing was attempted, 86 (94.5%) demonstrated successful ventricular capture at the maximum pulse duration used (40 msec). Threshold current for ventricular capture ranged from 22.5 ± 8.1 mA at a pulse duration of 40 msec to 29.9 ± 8.6 mA at a pulse duration of 10 msec. Esothoracic pacing was compared with external pacing in a subgroup ( n = 30) of patients. Ventricular capture with the gastroesophageal electrode was more common when compared with the external approach (27 [90%] of 30 vs 13 [43.3%] of 30, p < 0.001). In those subjects in whom ventricular capture was obtained with both methods, threshold current for capture was significantly lower with the esothoracic approach. This gastroesophageal electrode may be useful in the emergency management of acute bradyarrhythmias. (Am Heart J 1997;133:674-80.)