Cardio-oesophageal reflex in humans as a mechanism for 'linked angina'

The aim of this study was to investigate the hypothesis thatoesophageal acid stimulation reduces coronary blood flow inhumans as a result of the presence of a cardiooesophageal reflexwhich may provide a mechanism for ‘linked angina’.We studied the effect of oesophageal acid stimulation on coronaryblood flow in 35 syndrome X patients and 24 heart transplantpatients. A line tube was positioned into the patient's distaloesophagus. An intracoronary Doppler catheter was positionedin the proximal left anterior descending coronary artery forcoronary blood flow measurements. Oesophageal instillation of0·1 M hydrochloric acid was performed (60 ml over 5 min)and the measurements were repeated. The coronary blood flowwas significantly reduced by acid oesophageal stimulation inthe syndrome X group [pre-acid 78·9 ± 36·ml . min^–1, post-acid 50·8 ± 32·9ml . min^–1 (P=0·0001)]. However, coronary bloodflow in the heart transplant group, in whom the heart is denervated,was unaffected by acid infusion. We conclude that oesophagealacid stimulation can produce angina and significantly reducecoronary blood flow in humans. The lack of any significant effectin the heart transplant group, in whom the heart is denervated,suggests a neural reflex. (Eur Heart J 1996; 17: 407–413)