Prospective study on prevalence of esophageal chest pain in patients referred on an elective basis to a cardiac unit for suspected myocardial ischemia. The prevalence of esophageal chest pain was studied prospectively in patients referred on an elective basis to a cardiac unit for suspected myocardial ischemia. A group of 248 consecutive patients without previously documented heart disease was admitted for elective diagnostic coronary angiography. The clinical history classified 185 patients as having anginal pain and the coronary angiogram was normal in 48 of them. In 37 of these 48 patients full esophageal testing was performed including 24-hr intraesophageal pH and pressure recordings with indication of chest pain episodes as well as a number of esophageal provocation tests, ie, acid perfusion, edrophonium stimulation, balloon distension, and ergonovine stimulation, all performed under continuous esophageal manometric and electrocardiographic monitoring. In 19 of these 37 patients, the familiar chest pain could be reproduced by esophageal provocative testing without ischemic ST-T segment alterations; six of these 19 patients had also a positive 24-hr pH and pressure recording. These data strongly suggest an esophageal origin of chest pain in half the patients with typical angina and a normal coronary angiogram. 