Medical electrode lead with atrial electrode at the distal and ventricular electrode between the distal and proximal ends

In an electrode system for implantation in a heart, both the atrium and ventricle electrically interact with a medical apparatus. The electrode system has a single electrode lead having an atrial electrode at a distal end for implantation in the atrium before the electrode lead is advanced deeper into the heart so that a ventricular electrode in-line with and preceding the atrial electrode along the lead, is connectable in the ventricle of the heart. The electrode lead has a first curvature near the ventricular electrode and a second curvature near the atrial electrode in order to facilitate implantation of the electrode system and reduce mechanical loads on the heart after implantation. The electrode system can also be equipped with defibrillation electrodes and/or physiological sensors, thereby becoming multi-functional.