For connecting a cardiac biventricular assist means including a dual-chamber pumping device, and an electrically powered compressor means provided between the two chambers (12, 15) a partially flexible one-part or multi-part adapter (20) is provided with two through-passageways (21, 22; 34, 35) each separate from the other, said adapter being securely held, on the one hand, in a port (4a) in the apical portion of the septum (4) and, on the other, in a port (2a) in/at the apex of the left ventricle (2) so that the through-passageway (22; 35) extending into the left ventricle (2) is connected directly or by means of a first flexible tube (11) to the inlet (12a) of the one chamber (12) and the other through-passageway (21; 34) extending into said right ventricle (3) is connected directly or by means of a second flexible tube (14) to the inlet (15a) of the other chamber (15).