A heart pump including a casing internally defining a substantially spherical cavity (10) housing: a rotating shutter (12) secured to the cavity (10) so as to be rotatable about a rotation axis; an oscillating shutter (14) secured to the rotating shutter (12) and rotatable relative to the latter about a rotation axis transverse to the rotation axis of the rotating shutter relative to the casing; a guide ring (18) secured to the oscillating shutter (14) such that the latter can rotate relative to the ring. The guide ring is arranged to move within a seal formed in the substantially spherical cavity (10) while lying in a substantially slanting plane relative to the rotation axis of the rotating shutter (12) and thereby making the rotating shutter rotate. This allows constructing an artificial heart of very small size that can be driven either by a motor member or by an induced muscle contraction.