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 postprandial 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 distensions of an endoscopically introduced intragastric balloon. Dysrhythmias were consistently induced in all five 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 postprandial stomach and electrophysiological effects of gastric interventions.NEW & NOTEWORTHY This study presents the discovery of temporary dysrhythmic ectopic pacemakers in the distal stomach caused by localized gastric distension. Distension-induced dysrhythmias are an interesting physiological phenomenon that can inform the design of new interventional and electrophysiological protocols for both research and the clinic. The observation of distension-induced dysrhythmias also contributes to our understanding of stretch-sensitivity in the gut and may play an important role in normal and abnormal postprandial physiology.