New Foundations for Pacing the Stomach

Abstract

The use of electrical pacing and high-resolution (HR) mapping continues to advance our understanding of gut motility in health and disease. However, the efficacy and effectiveness of gastric pacing remains limited in clinical practice. In the stomach, omnipresent bioelectrical events known as slow-waves are responsible for coordinating motility that aids digestion. Functional motility diseases, such as gastroparesis, chronic unexplained nausea and vomiting, and functional dyspepsia, are associated with slow-wave dysrhythmias. The use of external electrical impulses to correct disordered cardiac rhythms is well established. Similar techniques have been assessed in the gastrointestinal (GI) field, from low energy/high-frequency (stimulation) to high energy/low frequency (pacing) protocols. High-frequency stimulation targets the neural pathways. Enterra (Medtronic, Minneapolis, MN) is the only clinical device currently available for gastric stimulation that uses high-frequency neuromodulation protocols, but does not correct dysrhythmias. Pacing is an attractive therapeutic approach to revert slow-wave abnormalities. However, there are currently no clinical gastric pacing devices in active use. Unlike cardiac pacing the application and performance of electrical pacing in the GI tract are not well understood and not widely used in clinical practice. A wide range of methods and protocols have been utilised in clinical research without the optimisation of pacing parameters, such as electrode type, location, and impulse properties. One of the barriers to the standardisation, optimisation, and development of gastric electrical pacing is that most previous gastric pacing studies utilised low-resolution recording techniques to assess the slow-wave responses to the different combinations of pacing parameters, where few recording electrodes were sparsely placed around the pacing site. Although sparse recording provides local measurements of slow-wave frequency and amplitude, it is unable to track, classify, and quantify the slow-wave activation sequences in spatiotemporal detail. Therefore, this approach may not have been sufficiently accurate to evaluate the effect of gastric pacing on the entrainment and propagation of the slow-waves. In the last decade, HR mapping techniques have been utilised to quantify and classify normal and abnormal slow-wave propagation patterns. The joint application of pacing and HR mapping provides a new analytical framework to investigate dysrhythmia and evaluate the benefits of gastric pacing as a potential therapeutic device.....