Gastric longitudinal shortening may occur during gastric phase III activities in man.

Background and Aim:  The aim of this study was to determine whether the gastric longitudinal shortening occurs during the gastric phase III in man. Methods:  Intragastric pH and gastroduodenal motility were simultaneously measured by means of a 24-h ambulatory recording system in 14 healthy volunteers. In nine subjects (group A), the catheter assembly was endoscopically clipped to the gastric mucosa with the middle transducer and the distal pH sensor in the antrum. In the remaining five subjects (group B), measurements were performed without securing the assembly. Results:  In 23 of the 25 gastrointestinal interdigestive migrating complexes in group A, the distal and middle transducers showed characteristic duodenal contractions (11–12 c.p.m.). Neutralization was noted at the distal pH sensor. Similar phenomena were observed during all 15 gastrointestinal interdigestive migrating complexes in group B. The catheter assemblies escaped into the duodenum despite the fact that they were secured to the stomach. This may be explained by gastric longitudinal shortening during gastric phase III activities. Conclusions:  Studies of intragastric physiology with test catheters must take the effect of gastric longitudinal shortening during phase III into consideration.