Optimization of pacing parameters to entrain slow wave activity in the pig jejunum

Pacing has been proposed as a therapy to restore function in motility disorders associated with electrical dysrhythmias. The spatial response of bioelectrical activity in the small intestine to pacing is poorly understood due to a lack of high-resolution investigations. This study systematically varied pacing parameters to determine the optimal settings for the spatial entrainment of slow-wave activity in the jejunum. An electrode array was developed to allow simultaneous pacing and highresolution mapping of the small intestine. Pacing parameters including pulsewidth (50, 100 ms), pulse-amplitude (2, 4, 8 mA) and pacing electrode orientation (antegrade, retrograde, circumferential) were systematically varied and applied to the jejunum (n = 15 pigs). Pulse-amplitudes of 4 mA (p = 0.012) and 8 mA (p = 0.002) were more effective than 2 mA in achieving spatial entrainment while pulse-widths of 50 ms and 100 ms had comparable effects (p = 0.125). A pulsewidth of 100 ms and a pulseamplitude of 4 mA was determined to be most effective for slow-wave entrainment when paced in the antegrade or circumferential direction with a success rate of greater than 75%. These settings can be applied in chronic studies to evaluate the long-term efficacy of pacing, a critical aspect in determining its therapeutic potential.