An electrode arrangement, for the temporary stimulation or defibrillation of the heart includes at least one unipolar electrode configured to be secured on the myocardium of the heart. An indifferent electrode is configured to be secured on the inner wall of the thorax via its supply line and be positioned such that direct contact with the heart is prevented. An external pacemaker is in electronic communication with the at least one unipolar electrode and the indifferent electrode such that negative poles of the indifferent electrode are combined into a single cable.