Association between gastric rhythm and gastroesophageal reflux defined by simultaneous body surface gastric mapping and 24-hour pH testing

Background Abnormal gastric myoelectrical function may contribute to gastroesophageal reflux disease (GERD). We assessed if myoelectrical abnormalities measured using body surface gastric mapping were correlated with reflux measured by 24 hr pH testing, and symptom severity.

Gastric Alimetry® was performed simultaneously on patients undergoing 24 hr pH testing for investigation of reflux symptoms, with a standardised 4.5 hr test and validated symptom logging. Data were segmented into 15-minute epochs. Correlations between myoelectric activity, reflux events, and symptoms were assessed, including temporal correlations adjusted for repeated measures.

Forty subjects were recruited (mean age 46.5 years, 60% female): 20 undergoing pH testing (12 with GERD and 8 symptomatic patients without), and 20 controls. GERD patients displayed less stable Gastric Alimetry® Rhythm-Index (GA-RI) compared with controls (p=0.011), but not with non-GERD patients (p=0.605). Decreasing GA-RI was associated with esophageal acid exposure (DeMeester score; r=-0.46, p=0.042). Periods of decreased GA-RI were not temporally correlated with reflux (r=0.08, p=0.182), or heartburn severity (r=0.04, p=0.309), but were correlated with nausea (r=-0.22, p<0.001) and excessive fullness (r=-0.28, p<0.001).

Gastric rhythm instability is associated with increased symptom severity and overall acid exposure in GERD patients, although no temporal link to heartburn was found. Reduced rhythm stability was temporally associated with increased nausea and fullness. GA-RI offers an emerging biomarker of gastric dysfunction in patients with GERD symptomatology. What is known ● Heartburn is common and often medically refractory ● Gastric conduction and motility abnormalities may contribute to symptoms but the temporal relationship is unknown What is new here ● Gastric rhythm abnormalities measured by Gastric Alimetry® are correlated with increasing reflux burden and symptom severity ● There is no temporal association between gastric rhythm and reflux events ● Gastric rhythm abnormalities may predispose patients to worse reflux, but there is no direct temporal correlation Competing Interest Statement Greg OGrady and Armen Gharibans hold grants and intellectual property in the field of gastrointestinal electrophysiology and are the co-founders at Alimetry Ltd. William Xu, Sam Simmonds, Daphne Foong, Chris Varghese, Christopher N Andrews, Gabe Schamberg, Armen Gharibans, Stefan Calder are members of Alimetry Ltd. The remaining authors have no conflicts of interest to declare. Funding Statement This study was supported by a New Zealand Health Research Council Program Grant. Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethical approval for reporting was obtained from the Auckland Health Ethics Research Ethics Committee and Western Sydney Human Research Ethics Committee (ref: AH1130, H15157). All patients provided informed consent. I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Data Availability All data produced in the present study are available upon reasonable request to the authors