Localized gastric distension disrupts slow wave entrainment leading to temporary ectopic propagation: A high-resolution electrical mapping study.

Gastric distension is known to affect normal slow wave activity and gastric function, but links between slow wave dysrhythmias and stomach function are poorly understood. Low--resolution mapping is unable to capture complex spatial properties of gastric dysrhythmias, necessitating the use of high-resolution mapping techniques. Characterizing the nature of these dysrhythmias has implications in the understanding of post-prandial function and the development of new mapping devices. In this two‑phase study, we developed and implemented a protocol for measuring electrophysiological responses to gastric distension in porcine experiments. In vivo, serosal high-resolution electrical mapping (256 electrodes; 36 cm2) was performed in anaesthetized pigs (n = 11), and slow wave pattern, velocity, frequency, and amplitude were quantified before, during, and after intragastric distension. Phase I experiments (n = 6) focused on developing and refining the distension mapping methods using a surgically inserted intragastric balloon, with a variety of balloon types and distension protocols. Phase II experiments (n = 5) used barostat‑controlled 500 mL isovolumetric distension of an endoscopically introduced intragastric balloon. Dysrhythmias were consistently induced in 5 of 5 gastric distensions, using refined distension protocols. Dysrhythmias appeared 23 s (SD = 5 s) after the distension and lasted 129 s (SD = 72 s), which consisted of ectopic propagation originating from the greater curvature in the region of distension. In summary, our results suggest that distension disrupts gastric entrainment, inducing temporary ectopic slow wave propagation. These results may influence the understanding of the post‑prandial stomach and electrophysiological effects of gastric interventions.