POSITIONING THE PACING ESOPHAGEAL STETHOSCOPE FOR TRANSESOPHAGEAL ATRIAL-PACING WITHOUT P-WAVE RECORDING - IMPLICATIONS FOR TRANSESOPHAGEALVENTRICULAR PACING

This study determined guidelines for positioning a new pacing esophage al stethoscope (PES) used for transesophageal atrial pacing (TEAP) wit hout having to record esophageal P waves. In 44 patients with heights ranging from 142 cm (4'8'') to 193 cm (6'4''), the PES was inserted to a depth of insertion (DOI) of 43 cm. As the PES was withdrawn, TEAP t hresholds were determined at every DOI in 1-cm intervals between 43 an d 25 cm DOI inclusive. TEAP was accomplished in all 44 patients. The m inimum TEAP threshold (mean +/- SD 10.8 +/- 4.0 mA) was less than or e qual to 17 mA in 43 of 44 patients (98%). Except for one patient, TEAP could be accomplished over a 9- to 19-cm (mean +/- SD, 13.7 +/- 2.8 c m) wide range of DOI. Unintentional transesophageal ventricular pacing (TEVP) occurred in 15 of 44 (34%) of patients. TEVP occurred over a 1 - to 7-cm (mean +/- SD, 3.7 +/- 1.7 cm) wide range of DOI; the minimum TEVP threshold averaged 30.4 +/- 6.4 mA. TEAP was consistently accomp lished at DOIs more proximal than where TEVP could occur and with lowe r currents than that required for TEVP. An insertion depth, in centime ters, equal to half of the patient's height, in inches, produced succe ssful TEAP in all 44 patients; the minimum TEAP threshold occurred on average at a DOI 2.6 cm more proximal. Asynchronous TEVP can be avoide d by using lower currents at shallow DOIs.