REDUCTION IN ENERGY PACING THRESHOLDS BY OVERLAPPING BIPHASIC STIMULATION VERSUS CONVENTIONAL BIPOLAR PACING

Overlapping biphasic (OLBI) stimulation is a new pacing waveform consi sting of two simultaneous monophasic pulses of opposite polarities app lied to a bipolar electrode. The goal of this prospective study was to compare, using conventional pacing leads, the acute energy pacing thr esholds, measured at 0.5-ms pulse duration, associated with bipolar ve rsus OLBI (mode 7 and mode 8) pulse delivery. Results: Thirty one lead s were tested in 20 patients. Of these leads, 7 (23%) were implanted c hronically, 12 (39%) were in atrial positions, and 19 (61%) in ventric ular positions. Energy pacing thresholds were significantly lower (-25 .6 +/- 25.6%, P = 0.005) in OLBI mode 8 (1.30 +/- 3.96 mu J) compared to bipolar (1.55 +/- 4.37 mu J) pacing, regardless of the pacing site qr length of service of the leads. In contrast, OLBI mode 7, which has an anodal component, at the tip electrode was associated with higher energy pacing thresholds (3.65 +/- 6.48 mu J; +358.3 +/- 219.4%, P = 0 .002). Conclusions: Mode 8 OLBI pacing is associated with lower acute energy pacing thresholds when used with bipolar leads in contact with the myocardium. OLBI pacing may increase pacemaker longevity by reduci ng long-term energy consumption.