An external defibrillator can have a synchronous shock operating mode and an asynchronous shock operating mode and include a controller to set the defibrillator in the synchronous shock operating mode or the asynchronous shock operating mode. The defibrillator can also include a shock module to cause the defibrillator to deliver shock therapy to the patient according to the operating mode of the defibrillator, and a prompt module to transmit a prompt, after delivery of the shock therapy, that includes the operating mode of the defibrillator.