High-resolution (HR) mapping has been used to study gastric slow-wave activation, however the specific characteristics of antral electrophysiology remain poorly defined. This study applied HR mapping and computational modeling to define functional human antral physiology. HR mapping was performed in ten subjects using flexible electrode arrays (128-192 electrodes; 16-24 cm2) arranged from the pylorus to mid corpus. Anatomical registration was by photographs and anatomical landmarks. Slow wave parameters were computed and resultant data incorporated into a computational fluid dynamics (CFD) model of gastric flow to calculate impact on gastric mixing. In all subjects, extracellular mapping demonstrated normal aboral slow-wave propagation and a region of increased amplitude and velocity in the pre-pyloric antrum. On average, the high-velocity region commenced 28 mm proximal to the pylorus and activation ceased 6 mm from the pylorus. Within this region, velocity increased 0.2 mm s-1 per mm of tissue, from mean 3.3 ± 0.1 mm s-1 to 7.5 ± 0.6 mm s-1 (p<0.001), and extracellular amplitude increased from 1.5 ± 0.1 mV to 2.5 ± 0.1 mV (p<0.001). CFD modeling using representative parameters quantified a marked increase in antral recirculation, resulting in an enhanced gastric mixing, due to the accelerating terminal antral contraction. The extent of gastric mixing increased almost linearly with the maximal velocity of the contraction. In conclusion, the human terminal antral contraction is controlled by a short region of rapid high-amplitude slow wave activity. Distal antral wave acceleration plays a major role in antral flow and mixing, increasing particle strain and trituration.
- slow wave
- computational fluid dynamics
- interstitial cell of Cajal
- Copyright © 2016, American Journal of Physiology-Gastrointestinal and Liver Physiology