The present invention relates generally to medical devices for electrode positioning during implantation procedures. A cardiac signal measuring device measures cardiac signals sensitive to inherent differences between cardiac tissue and blood using at least one electrode of a medical lead arranged at a distal tip of the medical lead and at least a second electrode arranged at a distance from the distal electrode and being connectable to the measuring unit. An analyzing module acquires cardiac signals measured during predetermined measurement sessions. The analyzing module determines at least one cardiac signal value based on the cardiac signals for each measurement session and analyzes changes of the cardiac signal values between different measurement sessions to determine a position of the electrode relative a tissue border. A maximum of the change of the cardiac signal values between two successive measurement sessions indicates that the electrode has reached the tissue border.
