Editor,—I enjoyed the prospective study by Cooke et al (Gut1998;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 …