Esophageal hypersensitivity may be a major cause of heartburn

OBJECTIVE: Little is known about esophageal nociceptive thresholds in chronic heartburn sufferers with normal clinical findings. The aim of this study was to evaluate and to characterize the pathogenesis of heartburn in subjects who chronically use antacids and had not sought medical attention. METHODS: Subjects (N = 152) with chronic heartburn of greater than or equal to 3 months duration underwent endoscopic grading of the esophagus, esophageal manometry, Bernstein testing, intraesophageal balloon distention (IEBD), and 24-h esophageal pH monitoring. RESULTS: Normal acid contact time (ACT less than or equal to 6%) was observed in 43% of these subjects with recurrent heartburn. Of subjects with normal ACT, 64% had normal LES pressure (greater than or equal to 10 mm Hg), 79% had normal esophageal endoscopy, 89% developed heartburn during Bernstein acid infusion, and 52% perceived IEBD as painful. CONCLUSIONS: Approximately 30% of individuals chronically using antacids for heartburn had esophageal sensitivity to mechanical or chemical stimuli despite negative endoscopy and pH monitoring. Our findings suggest that a significant subset of typical heartburn sufferers have a lower threshold for esophageal sensation and pain, which may influence options for pharmacological intervention in such subjects. (Am J Gastroenterol 1999;94:628-631. (C) 1999 by Am. Cell. of Gastroenterology).