Programmed electrical stimulation of the heart was performed in a 40-year-old man with documented recurrent, sustained ventricular tachycardia, which had proved refractory to standard medical therapy. In this patient, both the presence of several discontinuities in the atrioventricular (AV-)nodal conduction curves during atrial and ventricular stimulation and the varying time intervals of the AV-nodal echo phenomena suggested the presence of multiple AV-nodal pathways.