The invention relates to an apparatus for exchanging material between blood and a gas/gas mixture, comprising a chamber (1) through which blood can flow and in which a plurality of material-permeable fiber tubes is provided, the gas/gas mixture being flowable through the fiber tubes, blood being flowable around the fiber tubes. At least one deformable element (9) is provided in the chamber (1) in addition to the fiber tubes, through which the gas/gas mixture can flow, this deformable element being deformable and restorable, in particular compressible out of a relaxed shape and restorable to a relaxed shape by pressure fluctuations acting on the at least one element (9) externally, in particular pressure fluctuations transmitted by the blood in the chamber (1).

A blood pump comprising a cartridge, the cartridge comprising a first recess therein, said first recess having a surface, and a flexible diaphragm closing said first recess, the first recess and the flexible diaphragm defining a first pump chamber, said first pump chamber having an inlet and an outlet wherein the flexible diaphragm of the first pump chamber is movable between a first position, separated in use from the surface of the first recess, in which said first pump chamber has a maximum volume, and a second position, substantially adjacent to the surface of the first recess, in which said first pump chamber has a minimum volume a pump driver arranged to interface with the cartridge, said pump driver operable to move the flexible diaphragm of the first pump chamber in a first direction into said first recess to, in use, pump blood from the chamber and to move the flexible diaphragm of the first pump chamber in a second direction away from the first recess to, in use, draw blood into said first pump chamber, wherein the pump driver controls the movement of the flexible diaphragm of the first pump chamber such that the flexible diaphragm of the first pump chamber moves toward said first position at a first speed and moves toward said second position at a second speed, said second speed being greater than said first speed.

A method of operating an implantable blood pump and a pacing device, the method includes determining an end diastolic volume (EDV) and ejection fraction of one from the group consisting of the right ventricle and the left ventricle at a predetermined pump set speed. An average flow rate based on the predetermined pump set speed is determined. A target heart rate based at least in part on the determined EDV, ejection fraction, and average flow rate is determined. A lower rate for the pacing device is determined, the pacing device being in electrical communication with a chamber of the heart. The chamber of the heart is paced when a measured heart rate drops below the lower rate.

A method of operating an implantable blood pump and a pacing device, the method includes determining an end diastolic volume (EDV) and ejection fraction of one from the group consisting of the right ventricle and the left ventricle at a predetermined pump set speed. An average flow rate based on the predetermined pump set speed is determined. A target heart rate based at least in part on the determined EDV, ejection fraction, and average flow rate is determined. A lower rate for the pacing device is determined, the pacing device being in electrical communication with a chamber of the heart. The chamber of the heart is paced when a measured heart rate drops below the lower rate.