An electrode assembly for temporary cardioversion/defibrillation and/or for temporary stimulation of the heart after open heart surgery consisting of two defibrillation electrodes with at least one indifferent pole each and an elastic section is disclosed. Each defibrillation electrode in the operating position is positioned on the right and left atrium. The defibrillation electrodes each distally comprise a fixation member and each end in a protective tube to protect the epicardium at a proximal end. The fixation members are elastic and enable reversible fastening of the defibrillation electrodes in the pericardium on the right and left side. The protective tubes are preferably fed together into a guide tube, where the guide tube is slidable along the longitudinal axis. The stimulation electrodes (different electrode poles) for stimulation of the atria are designed appropriately together with the defibrillation electrode in one piece.
