Dynamic Characteristics of Gastro-oesophageal Reflux in Ambulatory Patients with Gastro-oesophageal Reflux Disease and Normal Control Subjects

BACKGROUND: The aim of the study was to investigate the dynamic characteristics of pathologic gastro-oesophageal reflux. METHODS: Five-channel ambulatory 24-h oesophageal pH monitoring was performed in 19 gastro-oesophageal reflux disease patients (age, 21-74 years) and in 19 healthy volunteers (age, 21-64 years). The pH was recorded at 3, 6, 9, 12, and 15 cm from the lower oesophageal sphincter (LOS), using a sample frequency of 4 Hz for each channel. Automated analysis included calculation of the ascending velocity of the refluxate and duration and extent (cm above the LOS) of all individual reflux episodes. RESULTS: In the patients more upright reflux episodes reached the proximal sensor than in the controls (20% and 11%, respectively, P < 0.01). The duration of the reflux episodes (measured at 3 cm above the LOS) was longer in the patients than in controls (P < 0.0001). This effect was independent of the proximal extent of the reflux episodes. Ascending velocities of upright acid reflux were higher in controls (1.8 to 2.7 cm/sec) than in patients (0.7 to 2.2 cm/sec; P = 0.01). CONCLUSIONS: The dynamic characteristics of pathologic reflux differ significantly from those of physiologic reflux.