Subcardial 24-h wireless pH monitoring in gastroesophageal reflux disease patients with and without hiatal hernia compared with healthy subjects

OBJECTIVES: After meals, highly acidic gastric juice is present in the subcardial region, the so-called acid pocket. Patients with gastroesophageal reflux disease (GERD) have a higher frequency of acidic reflux. Our aim was to investigate the possible differences in subcardial pH in GERD over 24 h and the role of hiatal hernia (HH), using a wireless capsule. METHODS: A total of 14 healthy volunteers (4 men, 24-60 years), 10 GERD patients without HH (4 men, 25-68 years), and 11 GERD patients with HH >or=3 cm (2 men, 46-74 years) underwent 24-h wireless pH monitoring 2 cm below the squamocolumnar junction. All patients had increased 24-h acid reflux. A standardized lunch was given to all study subjects. RESULTS: No capsule detached during the 24-h recording. Median 24-h pH was similar in healthy subjects, and in patients without and with HH, median: 1.4 (interquartile range: 1.2 -1.9), 1.5 (1.3 -1.7), and 1.4 (1.3 -1.7), respectively. Similar results were seen in the supine period. Median pH after the standardized meal was often highly acidic, 2.7 (1.5 - 3.2), 1.9 (1.6 - 2.3), and 2.5 (1.6 - 3.2), respectively. The first minute with a median pH <2 occurred 14 min (4 - 49), 14 min (6 - 25), and 20 min (4 - 43), respectively, P=NS, after the end of the meal. Similar data were observed on pooling all meals together. CONCLUSIONS: Subcardial pH is confirmed to be highly acidic early after meals, but it is similar over 24 h in healthy subjects and GERD patients independent of the presence of HH.