title: Functional physiology of the human terminal antrum defined by high-resolution electrical mapping and computational modeling.
abstract: 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 10 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 were 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 prepyloric 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 per mm of tissue, from the mean 3.3 ± 0.1 mm/s to 7.5 ± 0.6 mm/s (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.
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Aukland, New Zealand.
authors.forename: Rachel
authors.initials: R
authors.lastname: Berry
authors.affiliation: Department of Biomedical Engineering, Tohoku University, Sendai, Japan.
authors.forename: Taimei
authors.initials: T
authors.lastname: Miyagawa
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Aukland, New Zealand.
authors.forename: Niranchan
authors.initials: N
authors.lastname: Paskaranandavadivel
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Aukland, New Zealand.
authors.forename: Peng
authors.initials: P
authors.lastname: Du
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Aukland, New Zealand.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Angeli
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Aukland, New Zealand.
authors.forename: Mark L
authors.initials: ML
authors.lastname: Trew
authors.affiliation: Department of Surgery, University of Auckland, Auckland, New Zealand.
authors.forename: John A
authors.initials: JA
authors.lastname: Windsor
authors.affiliation: School of Engineering, Tohoku University, Sendai, Japan; and.
authors.forename: Yohsuke
authors.initials: Y
authors.lastname: Imai
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Aukland, New Zealand.|Department of Surgery, University of Auckland, Auckland, New Zealand.
authors.forename: Gregory
authors.initials: G
authors.lastname: O'Grady
authors.affiliation: Auckland Bioengineering Institute, University of Auckland, Aukland, New Zealand; l.cheng@auckland.ac.nz.|Department of Surgery, Vanderbilt University, Nashville, Tennessee.
authors.forename: Leo K
authors.initials: LK
authors.lastname: Cheng
mesh_terms: D000328:Adult; D000368:Aged; D003198:Computer Simulation; D055724:Electrophysiological Phenomena / Q000502:physiology; D004594:Electrophysiology; D005260:Female; D005769:Gastrointestinal Motility / Q000502:physiology*; D006801:Humans; D056885:Interstitial Cells of Cajal / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D011706:Pyloric Antrum / Q000502:physiology*
keywords: computational fluid dynamics; electrophysiology; interstitial cell of Cajal; slow wave; stomach