A cardiac assist device is provided. The cardiac assist device may comprise a structure surrounding at least a portion of a heart. The cardiac assist device may comprise an inner cup enclosing at least a portion of the structure. The cardiac assist device may comprise an outer cup enclosing at least a portion of the inner cup. The outer cup may comprise an opening. Gas may be conducted into a space between the outer cup and the inner cup, using a pump, to cause a first motion of the structure, associated with a first rotation of a first portion of the heart in a first direction. The gas may be conducted from the space to outside of the outer cup, using the pump, to cause a second motion of the structure, associated with a second rotation of the first portion of the heart in a second direction.