Giving up in the face of emotional arousal and psychologic uncertainty are conditions conducive both to vasodepressor syncope and sudden death. Under such circumstances there may be simultaneous activation of two emergency biologic regulatory systems, flight-fight and conservation-withdrawal. In the healthy person this may result in vasodepressor syncope, benign arrhythmias, or both. In the presence of factors lowering the threshold for conduction disturbances, dangerous arrhythmias and sudden death rather than, or as well as, vasodepressor syncope may result. Although active myocardial damage by itself may provide the necessary and sufficient conditions for lethal arrhythmias, psychic uncertainty must be considered an additional risk factor. The implications of this concept for patient care and prevention of sudden death are a challenge for future research.