Unipolar recording and pacing using a conductive introducer sheath as the indifferent electrode.

Unipolar recording has been shown to have advantages over bipolar techniques in certain clinical settings. Unipolar recording and pacing, however, require an indifferent electrode to complete the circuit. Current options for the indifferent electrode require additional hardware or special recording capabilities. A novel percutaneous unipolar conductive introducer sheath (PUCIS) was developed for unipolar electrophysiological recording and pacing. This article describes the development of this sheath, in vitro testing results, and initial animal data using the PUCIS as the indifferent electrode. The current silver/gold coating has acceptable mechanical and electrical properties. Electrogram appearance and amplitude, pacing thresholds, and impedances were comparable to currently used alternatives. The PUCIS sheath may therefore serve as a convenient standard as the indifferent electrode for unipolar electrophysiology.