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 cm) 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.

Relationships between gastric slow wave frequency, velocity, and extracellular amplitude studied by a joint experimental‐theoretical approach

“…Human data for this study were collated from previous intra‐operative recordings performed in two cohorts of control subjects with healthy stomachs (22 patients total); however, all analyses were novel and unique to this study. Patients with motility disorders and those taking medication known to alter gastrointestinal motility had been excluded.…”

“…The velocity, amplitude, and period were calculated and averaged for all data points within each slow wave cycle for use in parameter comparisons and statistical analyses. In human data, analyses of velocity vs period parameters were performed separately for corpus and antral propagation in view of the marked propagation differences normally occurring between these gastric regions …”

“…In human data, analyses of velocity vs period parameters were performed separately for corpus and antral propagation in view of the marked propagation differences normally occurring between these gastric regions. 19,20 Statistical analyses were performed in Prism v5.0 (GraphPad, San Diego, USA), using regression analyses and a threshold of P<.05.…”

“…• These relationships contribute to the regulation of normal gastric motility and these findings will help to inform diagnostic advances for gut electrophysiological disorders. stomachs (22 patients total); 19,20 however, all analyses were novel and unique to this study. Patients with motility disorders and those taking medication known to alter gastrointestinal motility had been excluded.…”

Advances in the physiology of gastric emptying

“…That serve to set the pace for the phasic contraction and have been called pace-setter potentials. The pylorus exhibits nearly simultaneous and strong slow waves that are associated with forceful contractions 83. Slow waves recorded by surface electrodes in vivo have often been assumed to represent phasic contractions.…”