Temporal relationships between episodes of non-cardiac chest pain and abnormal oesophageal function

Analysis of the association between symptoms and abnormal oesophageal function is a central part of 24 hour oesophageal pressure and pH recording in patients with non-cardiac chest pain. Such studies have used different time windows including a period after the onset of pain. Since stress and pain can induce oesophageal motor abnormalities and transient lower oesophageal sphincter relaxations, a proportion of the motor abnormalities and the reflux episodes observed after the onset of pain may be a consequence rather than the cause of that pain. This study aimed to assess this possibility in patients with chest pain that was presumed to be of oesophageal origin by comparing the results of analysis using time windows before and after the onset of pain. Forty eight patients experienced a total of 166 spontaneous chest pain episodes during 24 hour ambulatory monitoring. A time window beginning two minutes before and ending at the onset of pain (-2/0) was compared with a window beginning at the onset of pain and ending two minutes afterwards (0/+2). The percentage of episodes related to reflux, abnormal oesophageal motility, or neither were 22.9%, 24.7%, and 52.4% in the -2/0 time window and 9.0%, 22.3%, and 68.7% in the 0/+2 time window, respectively. However, 11 of the 37 episodes associated with abnormal motility in the 0/+2 time window were preceded by a reflux episode, and 19 of these 37 episodes had abnormal motility in the -2/0 time window. Consequently, in only seven of the 166 chest pain episodes (4.2%) in two patients were the findings consistent with secondary oesophageal motor disorders provoked by pain. Likewise, only six of the 166 chest pain episodes (3.6%) were consistent with reflux provoked by pain. These findings indicate that in patients with non-cardiac chest pain, gastro-oesophageal reflux and oesophageal motor abnormalities are rarely a consequence of the pain.