Editor,—I enjoyed the prospective study by Cooke et al ( Gut 1998; 42 :323–329) on the relation between oesophageal abnormalities and chest pain in patients with normal coronary angiograms and with angina pectoris. This study confirms the findings of previous studies1 2 that the oesophagus is responsible for chest pain in a high percentage of patients with coronary artery disease, and that an episode of gastro-oesophageal reflux nearly always triggers this pain. However, no explanation for this unexpected finding has been given. The tentative proposition that it is the result of a decreased angina threshold3 and a reflex coronary ischaemia, both induced …