High‐resolution electrical mapping of porcine gastric slow‐wave propagation from the mucosal surface

Abstract

Background Gastric motility is coordinated by bioelectrical slow-waves, and gastric dysrhythmias are reported in motility disorders. High-resolution (HR) mapping has advanced the accurate assessment of gastric dysrhythmias, offering promise as a diagnostic technique. However, HR mapping has been restricted to invasive surgical serosal access. This study investigates the feasibility of HR mapping from the gastric mucosal surface. Methods Experiments were conducted in-vivo in 14 weaner pigs. Reference serosal recordings were performed with flexible-printed-circuit (FPC) arrays (128-192 electrodes). Mucosal recordings were performed by two methods: 1) FPC array aligned directly opposite the serosal array, and 2) cardiac mapping catheter modified for gastric mucosal recordings. Slow-wave propagation and morphology characteristics were quantified and compared between simultaneous serosal and mucosal recordings. Key Results Slow-wave activity was consistently recorded from the mucosal surface from both electrode arrays. Mucosally-recorded slow-wave propagation was consistent with reference serosal activation pattern, frequency (P≥0.3), and velocity (P≥0.4). However, mucosally-recorded slow-wave morphology exhibited reduced amplitude (65-72% reduced, P<0.001) and wider downstroke width (18-31% wider, P≤0.02), compared to serosal data. Dysrhythmias were successfully mapped and classified from the mucosal surface, accorded with serosal data, and were consistent with known dysrhythmic mechanisms in the porcine model. Conclusions & Inferences HR gastric electrical mapping was achieved from the mucosal surface, and demonstrated consistent propagation characteristics with serosal data. However, mucosal signal morphology was attenuated, demonstrating necessity for optimized electrode designs and analytical algorithms. This study demonstrates feasibility of endoscopic HR mapping, providing a foundation for advancement of minimally-invasive spatiotemporal gastric mapping as a clinical and scientific tool.

Intra‐operative high‐resolution mapping of slow wave propagation in the human jejunum: Feasibility and initial results

“…The methods developed in this study can now be further usefully applied and expanded to investigate slow wave characteristics in the human intestine in more detail, for example, by expanding to other regions of the intestine to quantitate velocity and pacemaking gradients along the intestinal length, investigate the spatiotemporal occurrence and significance of “waxing and waning,” and expand to states of disease and/or surgical intervention, as has been usefully achieved in the stomach . The use of minimally invasive approaches in future studies, like laparoscopic or endoscopic mapping, would enable greater patient recruitment and minimize intestinal handling and exposure, which may help to clarify the issue of the occurrence and cause of disordered propagation. Non‐invasive approaches for recording small intestine slow wave activity, including electroenterography and magnetoenterography, also hold promise and could be better informed by the spatial analysis provided by HR mapping …”

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

“…The human analyses performed here were a comprehensive re‐analysis of previously collected slow wave mapping studies from two control cohorts. This is ethically appropriate, because human HR mapping studies must currently be performed invasively during surgery meaning that such data are difficult to obtain, although less‐invasive approaches are now emerging . This limitation meant that only a relatively restricted range of slow wave periods could currently be examined, particularly in the corpus.…”

“…This is ethically appropriate, because human HR mapping studies must currently be performed invasively during surgery meaning that such data are difficult to obtain, 19,20 although less-invasive approaches are now emerging. 38,39 This limitation meant that only a relatively restricted range of slow wave periods could currently be examined, particularly in the corpus. Frequencyvelocity relationships were therefore approximated using linear regression, whereas simulations and animal data would predict a non-linear relationship to be more appropriate over an extended data range.…”

Improved Visualization of Gastrointestinal Slow Wave Propagation Using a Novel Wavefront-Orientation Interpolation Technique

“…The algorithms developed in this study were limited to gastric data obtained from 2-dimensional (2D) electrode arrays with uniform electrode spacing, applied via open surgery [5], [6], [23]. Minimally-invasive methods of endoscopic and laparoscopic mapping hold great promise as a diagnostic tool for gastric dysrhythmias, but endoscopic mapping employs non-uniform, 3D electrode arrays [27], and some laparoscopic approaches also use non-uniform arrays [28]. The principles and techniques developed in this study could likely be adapted in future for application to non-uniform and 3D electrode arrays, intestinal slow wave propagation [29]–[31], and spike propagation [32], [33].…”