The device (100) has a dislocation detection unit indirectly or directly connected to two sensing electrode poles, where the dislocation detection unit evaluates detection times at sensing electrode poles, and the detection times are ascribable to a particular cardiac event. The dislocation detection unit generates dislocation signal if relative time relationship of detection times is changed beyond a predetermined value. The dislocation detection unit comprises an evaluation unit. An atrial stimulation electrode pole is placed in an atrium of a heart.
