Baseline Impedance Measured during High-resolution Esophageal Impedance Manometry in Patients with Rumination Syndrome is as Abnormal as in Patients with GERD

Goals and Background: Baseline impedance measured during high-resolution impedance manometry (HRIM) can distinguish patients with gastroesophageal reflux disease (GERD) from controls, presumably due to differences in esophageal acid exposure. The characteristics of regurgitation and reflux in rumination syndrome and GERD are very different, and thus we investigated whether baseline esophageal impedance would differ in these 2 patient groups compared with controls. Study: We compared 20 patients with rumination syndrome with 20 patients who had GERD and 40 controls. Baseline impedance was measured over 15 seconds during the landmark period of HRIM in all 18 impedance sensors on a HRIM catheter. Results: The mean distal baseline impedance measured in ohms during HRIM was 1336 Ω [95% confidence interval (CI)=799, 1873) in patients with GERD, 1536 Ω in rumination syndrome (95% CI=1012, 2061), and 3379 Ω in controls (95% CI=2999, 3759) (P<0.0001). Proximal impedance was significantly lower in the GERD and rumination groups compared with controls; rumination syndrome (2026; 95% CI=1493, 2559 Ω), GERD (2572; 95% CI=2027, 3118 Ω), and controls (3412; 95% CI=3026, 3798 Ω) (P<0.001). Conclusions: Baseline impedance measured during HRIM in patients with rumination syndrome is significantly lower than controls and appears similar to patients with GERD both in the proximal and distal esophagus. These findings suggest that the postprandial regurgitation in rumination syndrome alters both the distal and proximal esophageal mucosal barrier.