Seminario Origgi MA, Alves de Godoy R. Departamento de Clinica Medica, Universidad de Sao Paulo, Brasil. Arch Inst Cardiol Mex 1992 Nov-Dec;62(6):547-55. The objective of the present study was to employ a transesophageal atrial pacing (TAP) technique that would permit the use of the lowest possible currents for consistent atrial capture (CAC) and a more accurate recording system. An electrode catheter containing five poles (E1 to E5) spaced 22 mm apart was constructed, with pole E1 being the most cranial one. The catheter was introduced nasally into the esophagus of eleven adult healthy volunteers, and five unipolar intraesophageal leads were recorded and analyzed until the tracings obtained with E2, E3 and E4 showed P waves of the highest potentials, when the catheter was fixed in place. An electric generator specially constructed for TAP was used. CAC was attempted with each of the 20 stimulating bipoles formed by the permutations of the five poles of the fixed catheter. The least voltage needed for CAC in each individual was always detected in at least one of the six stimulating bipoles formed by the permutations involving poles E2, E3 and E4. Thus, in the population studied as a whole, the minimum voltage range needed to obtain TAP was between 5 and 15 V (mean 11.2 +/- 3.0 V), which was tolerated quite well by the individuals. Pulse durations of more than 10 ms did not lead to use of significantly lower voltages for CAC. Six simultaneous tracings were used during and after TAP, and at least one of them recorded intraesophageal or esophago-thoracic bipolar leads.