Radiofrequency (RF) catheter ablation has become the treatment of choice for a variety of supraventricular tachycardias. Autonomic dysfunction may occur during application of RF current; these abnormalities resolve quickly when current delivery is terminated. We present a case of sinus node arrest and AV block in a 69-year-old woman induced by RF catheter ablation of an AV nodal slow pathway. The proposed mechanisms are a Bezold-Jarisch-like phenomenon or paradoxical activation of cardiac C fibres by direct neural sympathetic stimulation or RF-induced myocardial injury. Based on a review of previously published reports, autonomic effects of RF ablation are discussed.