An implantable electrode device designed for heart stimulation and/or cardioversion/defibrillation in connection with a pacemaker or a defibrillator. The electrode device comprises a large-surface area indifferent reference electrode pole permanently implanted in the atrial septum and in electrical communication with a pacemaker or defibrillator. The electrode pole is made from biocompatible metal braiding and has a tube like opening. The electrical communication is positioned from the pacemaker/defibrillator via the right atrium of the heart through the indifferent electrode pole into the left atrium via the opening. Thus allowing electrical pulses to be delivered to the electrode pole and stimulating the heart.
