A 15-year-old girl had had syncope induced by swallowing since infancy. An ECG recorded during food intake revealed SA block with very slow junctional and ventricular escape rhythms. No symptoms or signs of other cardiac disorders or gastrointestinal diseases were present. Activation of a strong vagal reflex, able to inhibit impulse formation and propagation in an otherwise normal heart, is the most likely explanation of the disorder in this patient. Furthermore, ECGs of her close relatives which were recorded during food intake as compared with the findings in a reference group (n = 20), indicated that a genetic factor could be involved.