title: Dynamic characteristic of gastro-oesophageal reflux in ambulatory patients with gastro-oesophageal reflux disease and normal control subjects.
abstract: 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.
mesh_terms: D000328:Adult; D000368:Aged; D000465:Algorithms; D016022:Case-Control Studies; D004943:Esophagogastric Junction / Q000503:physiopathology; D004947:Esophagus / Q000503:physiopathology; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D011187:Posture / Q000502:physiology