RESUMO
OBJECTIVES: Gastroesophageal reflux disease (GERD) has overlapping symptoms with functional disorders such as functional heart burn. Twenty-four-hour pH with impedance monitoring is useful for differentiation. The intraluminal impedance change with meal in distal esophagus is not investigated. METHODS: We performed a retrospective investigation of clinical files, 24-hour pH with intraluminal impedance monitoring in patients with GERD and functional disorders. The post-reflux swallow induced peristaltic wave (PSPW) index as well as the impedance in distal esophagus before the first meal and 30 min and 60 min after the meal were measured and analyzed. RESULTS: A significant decrease of intraluminal impedance in distal esophagus was noted at 30 min (ΔI30min -301.5 [747.5] Ω, p = 0.018) and recovered at 60 min (ΔI60min -194.6 [766.0] Ω, p = 0.126) after meals in GERD patients. On the other hand, there was no significant change of impedance in patients with functional disorders. There were positive correlations between ΔI30min and PSPW index (correlation = 0.232, p = 0.038). Comparing GERD to functional disorders, the best cut-off value for ΔI30min was -212Ω with 74.4% sensitivity and 60.5% specificity. CONCLUSIONS: The intraluminal impedance in distal esophagus was lowered after meals in GERD patients other than functional disorders. This impedance change was correlated with PSPW index and could help differentiate GERD from functional disorders.