Gastric electrical stimulation with long pulses in humans and animals: can data obtained in animals be replicated in humans?

Aims: The aim of this study was to investigate and compare effective parameters for gastric electrical stimulation (GES) to modulate gastric muscle functions in different species. Methods: Four species: Pigs, dogs, rats, and mice implanted with two pairs of electrodes on the serosal surface of the stomach were studied, respectively. Experiment 1 was designed to entrain/pace gastric slow waves and included a series of 5-min periods with long-pulse GES of different pulse widths and frequencies. Experiment 2 was designed to induce gastric dysrhythmia with long-pulse GES of different frequencies. Gastric slow waves were recorded during the entire experiment. Results: 1) The minimum pulse width for GES to completely entrain the slow waves was similar (100-400 msec) in all four species. 2) With fixed amplitude (4 mA) and pulse width (400 msec), the highest frequency at which slow waves could be paced was similar (about 10-60% higher than the intrinsic slow wave frequency) in all species. 3) With fixed pulse width of 400 msec and amplitude of 6 mA, GES with nine to 18 cycles per min (cpm) was able to induce dysrhythmia in dogs. In addition, there was no significant difference among these frequencies of 9-18 cpm. 4) GES with 400 msec, 6 mA, and 9 cpm was able to induce dysrhythmia in all species. These effective GES parameters in results 1-4 were similar to those used in humans in the literature. Conclusions: There is no significant difference in stimulation parameters when GES is applied to alter gastric slow waves in different animal models. Furthermore, the effective parameters for GES to alter slow waves are similar between the humans and various animal models. These findings suggest that stimulation parameters obtained from animal studies are applicable in humans.