Ectopic jejunal pacemakers and enterogastric reflux after Roux gastrectomy: effect of intestinal pacing

The aims of this study were to determine whether ectopic pacemakers are present in the Roux limb of dogs after vagotomy and Roux gastrectomy, whether these pacemakers lead to enterogastric reflux, and whether abolishing the pacemakers with electric pacing might correct such reflex, were it to occur. In five dogs that had undergone gastric vagotomy and Roux gastrectomy and five dogs that had undergone gastric vagotomy and Billroth I gastrectomy (controls), myoelectric activity of the Roux limb or duodenum was recorded during saline infusion (154 mmol/L NaCl) or nutrient (Meritene) infusion into the limb or the duodenum. Reflux of infusate into the stomach was determined via a gastric cannula. Tests in Roux dogs were done with and without limb pacing. Roux dogs showed ectopic pacemakers in the Roux limb that drove the pacesetter potentials of the limb in a reverse, or orad, direction during 76% of the recordings; Billroth dogs rarely had such pacemakers (p less than 0.001). Enterogastric reflux occurred in both groups of dogs but was greater during phase III of the interdigestive migrating myoelectric complex in Roux dogs (12% +/- 6%) than in Billroth dogs (3% +/- 1%; p less than 0.05). Pacing abolished the ectopic pacemakers in the Roux dogs and reduced enterogastric reflux from 12% +/- 6% to 3% +/- 2% when phase III was present (p less than 0.05). In conclusion, the Roux limb was driven by ectopic pacemakers that contributed to, but were not solely responsible for, jejunogastric reflux. Pacing abolished the ectopic pacemakers and decreased reflux when phase III was present in the limb.