Abstract: Disclosed is a device for assisting cardiac function having the following atures:at least one half-shell is provided, the interior and exterior contours of which are designed in such a manner that it can be inserted into the human thorax in such a manner that it at least partially surrounds the heart with the exception of the arteries leading to and away from the heart,in or at the half-shell respectively half-shells is situated at least one filling chamber which can be inflated with gas and is propped by the shell,a control unit controls a pneumatic drive which fills and empties the individual filling chambers in such a manner that said filling chambers press at least on the left ventricle synchronously with cardiac activity in such a manner that blood is pressed into the aorta.