An automated cardio pulmonary resuscitation device comprises a front structure with first and second movable unit arranged to move back and forth along said front structure, a compression element for compressing a patients chest, two arms coupled to the chest pad, one end of each of the arms being coupled to a respective one of the first and second movable units, driving means arranged for, when in operation, driving the first and second movable unit back and forth. The front structure comprises a transmission system including a driving pulley and a transmission rope, the transmission rope being arranged to be driven by the driving pulley, and said first and second movable units being coupled to the transmission rope so as to move back and forth in a translational motion along the front structure.
