A dilatable cardiac electrode arrangement for implantation in particular in the coronary sinus of the heart is provided with a defibrillator electrode of the type of a stent and of an expandable, electrically conductive structure; with annular pacemaker electrodes; with insulation zones between the pacemaker electrodes on the one hand and the defibrillator electrode on the other; and with electric lines for the defibrillator and pacemaker electrodes.