Prior sensitization of esophageal mucosa by acid reflux predisposes to reflux-induced chest pain
Esophageal acid exposure is believed to be a major source of unexplained chest pain; but, individual episodes of reflux in pH study are not consistently associated with chest pain. Our aim was to discover whether prior sensitization of esophageal mucosa by acid reflux predisposes to reflux-induced chest pain. Ambulatory pH studies of patients referred to our laboratory from January 1991 to November 1996 with noncardiac chest pain was reviewed. We compared the frequency of esophageal acid exposure in the 30 minutes preceding chest pain episodes with a positive symptom/reflux association (+SRA) to reflux with the frequency of acid exposure in the 30 minutes preceding those chest pain episodes that were not associated with reflux negative symptom/reflux association (-SRA). We analyzed the time esophageal pH <4, symptom index (SI) defined as percentage of chest pain episodes associated with reflux in the preceding 5 minutes, and amount of reflux in the 30 minutes preceding each chest pain episode. Of 104 patients, 52 had chest pain during their pH study, 10 had high SI (> or =50%), and 42 had low SI (<50%). Those with a high SI were significantly more likely to have an abnormal pH study (p = 0.015). Chest pain associated with reflux in proceeding 5 minutes (+SRA) was strongly associated (p < 0.002) with additional reflux episodes in the preceding 25-minute period. Chest pain related to reflux is associated with sensitization of the esophageal mucosa by prior reflux events.