We conducted a survey of all defibrillators currently on the European market that offer synchronized cardioversion. The mode after cardioversion can be classed into one of four categories: (1) remain in synchronized mode; (2) defer to asynchronized mode; (3) 'intelligent'; and (4) configurable. The different modes and the lack of standardization present a potential hazard because they cause confusion among the user of the defibrillator. Uniformity should be obtained after broad agreement between clinicians and manufacturers of defibrillators.