Ambulatory gastric mucosal slow wave recording for chronic experimental studies

Dysrhythmic bioelectric slow wave activity have been implicated in major functional motility disorders such as gastroparesis and chronic unexplained nausea and vomiting, but its correlation to symptoms is still unclear. For patients with severe gastroparesis, high-frequency gastric stimulation is offered as a therapy in some centers. Temporary gastric electrical stimulation has also been proposed an approach to screen patients who would benefit from the implantation of a permanent stimulator. In this study we introduced novel methods for recording slow wave activity from the gastric mucosa during the entire temporary stimulation phase of 5 days, in 3 patients. An ambulatory recording system was applied to record 3 channels of mucosal slow wave activity, as well as three axis accelerometer data to monitor when the patient was mobile. Techniques were developed to detect large movements and these time periods were excluded from analyses of mucosal slow waves. The frequency and amplitude of the slow waves was calculated in a 5 min segment, with 75% overlap, for the entire duration. In feasibility studies, the slow wave frequency and amplitude for the patients were 3.0±0.96 cpm and 1.43±1.75 mV. Large variations in slow wave amplitude were seen in comparsion to slow wave frequency, which were concordant with previous studies. The use of the ambulatory system will allow for investigation of pathophysiology, correlation of electrophysiology data to patient symptoms and to determine the effects of post-prandial and noctural slow wave patterns. We anticipate that future use of slow wave information alongside patient symptoms may allow improved selection of patients for stimulaton techniques.