Gastric slow-wave morphology in health and disease

Underlying bioelectrical slow waves are critical for regulating gastric motility, and abnormal spatiotemporal slow-wave dysrhythmias are associated with a range of gastrointestinal disorders. However, the definition and role of the morphology of gastric slow-wave signals have remained limited. This study aimed to define gastric slow-wave morphology in cases of health and disease.

Data were repurposed from a study where, following ethical approval, a control cohort ( $n=9$ ) and a pathological cohort of patients with chronic unexplained nausea and vomiting (CUNV; $n=8$ ) underwent intra-operative high-resolution serosal electrical mapping (96-256 electrodes, 4.0-5.2 mm spacing). Slow waves were identified using validated software, and spatiotemporally averaged waveforms were compared between cohorts. These waveforms were replicated in a computational model of gastric slow-wave propagation to explore potential functional implications.

The slow-wave morphology of the CUNV cohort exhibited a more gradual recovery stroke compared to controls, which manifested as an increase in the normalized recovery stroke area [0.206 (95% CI 0.169-0.247) vs. 0.134 (95% CI 0.106-0.166); $p=0.011$ ]. Computational modeling showed that these morphological differences could drive spatial slow-wave dysrhythmias. Considering the evident functional importance of gastric slow-wave morphology, we highlighted the three typical morphological features: (1) rapid, brief upstroke, (2) downstroke, and (3) biphasic recovery stroke.

Altogether, this study presents a physiological basis of gastric slow-wave morphology in health and disease and lays a foundation for the standardization of future slow-wave morphology research.