Spontaneous noncardiac chest pain. Evaluation by 24-hour ambulatory esophageal motility and pH monitoring.

Noncardiac chest pain can be a diagnostic dilemma because patients rarely experience spontaneous chest pain in the laboratory. Therefore, we studied 24 patients with chronic, daily, substernal chest pain with a prototype 24-h ambulatory esophageal motility and pH system. Spontaneous chest pain episodes were correlated with pH less than 4 and abnormal motility changes (mean amplitude and duration, maximum amplitude and duration, or percentage of abnormal peristalsis) defined as exceeding the patient's normal esophageal motility pattern. Twenty-two patients experienced a total of 92 spontaneous chest pain episodes. Eleven chest pain episodes (12%) occurred during abnormal motility, whereas 18 episodes (20%) were associated with pH less than 4 and four episodes (4%) had both abnormalities. The majority of chest pain episodes, 59 events (64%), did not have any association with motility or pH. Abnormal maximum duration and amplitude were the motility changes most frequently associated with chest pain. Overall, 13 of 22 patients (59%) had at least one chest pain episode correlating with abnormal motility or pH (range 33%-100%). Therefore, we conclude that ambulatory esophageal motility and pH monitoring is useful in the evaluation of noncardiac chest pain. pH abnormalities (20%) are more commonly associated with chest pain than motility abnormalities (12%). However, the majority of chest pain episodes (64%) did not correlate with either abnormality and may be the result of lowered esophageal pain threshold for distention, i.e., the "irritable esophagus."