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

Gastroesophageal reflux disease (GERD) is common and often medically refractory. Abnormal gastric myoelectrical function may contribute to pathogenesis. This prospective observational study with matched controls assessed if myoelectrical abnormalities measured using body surface gastric mapping were correlated with reflux measured by 24-h pH testing and symptom severity. Gastric Alimetry was performed simultaneously on patients undergoing 24-h pH testing for investigation of reflux symptoms, with a standardized 4.5-h test and validated symptom logging. Data were segmented into 15-min epochs. Forty subjects were recruited (mean age 46.5 yr, 60% female): 20 undergoing pH testing (12 with GERD and 8 symptomatic patients without) and 20 controls. Patients with GERD displayed lower gastric rhythm stability measured by the Gastric Alimetry Rhythm Index (GA-RI) when compared with controls (<i>P</i> = 0.011), but not with patients without GERD (<i>P</i> = 0.605). Lower gastric rhythm stability measured by GA-RI was associated with increased esophageal acid exposure (DeMeester score; <i>r</i> = -0.46, <i>P</i> = 0.042). Periods of decreased gastric rhythm stability measured by GA-RI were not temporally correlated with reflux (<i>r</i> = 0.08, <i>P</i> = 0.182) or heartburn severity (<i>r</i> = 0.04, <i>P</i> = 0.309) but were correlated with nausea (<i>r</i> = -0.22, <i>P</i> < 0.001) and excessive fullness (<i>r</i> = -0.28, <i>P</i> < 0.001). We demonstrated that gastric rhythm instability is associated with increased symptom severity and overall acid exposure in patients with GERD. Although there was no temporal link between rhythm instability and heartburn, rhythm instability was temporally associated with increased nausea and fullness. GA-RI therefore offers an emerging biomarker of concurrent gastric neuromuscular dysfunction in patients with GERD.<b>NEW & NOTEWORTHY</b> Gastroesophageal reflux disease (GERD) is common and often medically refractory. We assessed whether gastric myoelectrical function contributes to pathogenesis by simultaneously measuring myoelectrical activity with Gastric Alimetry and reflux events on 24-h pH testing in patients. We demonstrated that gastric rhythm instability is associated with increased symptom severity and acid exposure in patients with GERD. Although there was no temporal link between rhythm instability and heartburn found, rhythm instability was temporally associated with dyspepsia.