Electrical activity recorded from abdominal surface before and after gastric surgery in man.

To explain the role of the different portions of the stomach in the genesis of electrical signal obtained from abdominal surface (Electrogastrography, EGG), the EGG was recorded in 6 patients with gastric cancer and 7 with duodenal ulcer before and after total gastrectomy or Billroth II gastric resection, respectively. Eight patients undergoing cholecystectomy entered the study as controls. The spectral frequency components were subdivided into ranges, and the dominant frequency and power were calculated for each range before and after surgery. The power profile, expressed as difference in power percentages before and after surgery for each frequency range, was obtained. The power profile from total gastrectomy or gastric resection was clearly different from that resulting from cholecystectomy in the 2.6-3.5 cycles per minute range (cholecystectomy vs gastric resection, P = 0.009; cholecystectomy vs gastrectomy, P = 0.012). No difference in power profile between total gastrectomy and gastric resection was demonstrated. Since total and partial gastrectomized patients showed a similar power profile, EGG signal corresponded to the electrical activity of the distal two third of the stomach.