Electrogastrographic impact of multi-site functional gastric electrical stimulation

Microprocessor-controlled multi-site functional gastric electrical stimulat ion using synchronized higher frequency (above 25 Hz) bipolar voltages has been suggested as a possible new avenue towards efficient artificial contro l of gastric motility. However, the effect of this sequential stimulation o n gastric electrical activity is unknown. Because of the substantial streng th of the invoked sequential contractions, using implanted electrodes to as sess gastric electrical activity (GEA) in experimental animals is difficult , if not impossible. Electrogastrography (EGG) the non-invasively obtained recording of GEA, provides an excellent opportunity to study the changes as sociated with the multi-site functional stimulation. In this study, we inve stigated 4 unconscious dogs with 4 circumferential sets of subserosally-imp lanted stimulating electrodes and 4 force transducers attached close to eac h stimulating electrode set at operation. The abdominal cavity of each dog was closed after the electrode implantations and 3 standard neonatal electr ocardiographic electrodes were attached overlying the abdominal projection of the gastric arts. Two-channel EGG recordings were obtained for 1/2 h bef ore any electrical stimulation and during 1/2 h of intensive sequential sti mulation. Significant changes were observed in the EGG pattern during stimu lation. These changes were quantified and compared to the basal recordings. Our findings indicate that the interrelation between spectral changes in c utaneous EGG and mechanical activity of the stomach could be far more compl ex than previously speculated.