Oscillating Esophageal Acid Sensitivity in Symptomatic Reflux Hypersensitivity and Functional Heartburn

BACKGROUND In previous analyses of recordings of esophageal pH and symptom occurrence in subjects with nonerosive esophageal reflux disease, all of whom had increased esophageal exposure, I found that the lower the value of esophageal acid exposure, the higher the probability of a symptom. This finding could be explained by esophageal acid sensitivity oscillating between longer periods of high esophageal acid sensitivity, and shorter periods of low esophageal acid sensitivity. To examine whether these oscillations also occur in symptomatic subjects with normal esophageal acid exposure, I analyzed data from subjects with Reflux Hypersensitivity and subjects with Functional Heartburn, to examine relationships between esophageal acid exposure and the probability of symptoms.  METHODS For each subject I calculated interval esophageal acidity that measures esophageal acid exposure that precedes each symptom and cumulative interval esophageal acidity. RESULTS In each group of subjects there was a negative relationship between the probability of a symptom and interval esophageal acid exposure indicating that the lower the value of esophageal acid exposure, the higher the probability of a symptom. The time course of symptoms and cumulative esophageal indicated that esophageal acid exposure oscillates between longer periods of high esophageal acid sensitivity, and shorter periods of low esophageal acid sensitivity. CONCLUSIONS The present analyses of subjects with Reflux Hypersensitivity or Functional Heartburn in conjunction with previous analyses of subjects with nonerosive esophageal reflux indicate that oscillating esophageal acid sensitivity is a characteristic feature of symptomatic gastroesophageal reflux disease.