Pentafluorosulfanylbenzoylguanidines of the formula I and II ##STR00001## in which R1 to R4 have the meanings stated in the claims, are suitable as antiarrhythmic medicaments with a cardioprotective component for the prophylaxis of infarction and treatment of infarction and for the treatment of angina pectoris. They also inhibit preventively the pathophysiological processes associated with the development of ischemia-induced damage, especially in the triggering of ischemia-induced cardiac arrhythmias.