Abstract: A method and apparatus as described herein for substantially, but not entirely, blocking back-flow through a blood pump when the blood pump is not pumping blood wherein the method and apparatus can operate passively or actively if the blood pump stops pumping in order to provide a limited back-flow through the blood pump to prevent clot formation.

Abstract: A back flow limiting valve member which substantially, but not entirely, blocks reverse blood flow through a blood pump, such as when the blood pump is not pumping blood or pumping below a predetermined rate. The valve member can operate passively or actively in order to provide a limited back-flow through the blood pump to prevent clot formation. The back flow check valve may also be employed to restrict reverse blood flow through a blood flow conduit or blood vessel rather than in a blood pump.

Abstract: A blood pump having rotor and/or stator touch down zones to prevent pump failure or hemolysis which can occur if the rotor comes into contact with the stator due to power failure or mechanical shock. The touch down zones can include forming, or coating, portions of adjacent surfaces of the stator and rotor which can come into contact if a rotor touch down occurs. The materials used to form or coat the touch down zones can have properties which ensure that no consequential damage to the contacting surfaces occurs.

Abstract: A ventricular assist device for a heart includes a compression band-stay-pad assembly for encircling substantially the heart perimeter and comprising an elongated band member or chain disposed in a sealed protective structure filled with a lubricating medium. The band member may be fixed at one end and wound upon, or unwound from, a rotatable spool by a drive motor through a speed reducer. Force-transmitting support or stay assemblies are disposed in the protective structure between the band member and a resilient pad assembly for encircling the heart and promoting heart tissue ingrowth therein. The force-transmitting stay assemblies are biased circumferentially, and thus radially outward, by compression return springs disposed therebetween.

Abstract: A ventricular assist device for a heart includes a compression band-stay-pad assembly for encircling substantially the entire heart perimeter and comprising an elongated band member or chain disposed in a sealed protective structure filled with a lubricating medium. The band member may be fixed at one end and wound upon, or unwound from, a rotatable spool by a drive motor through a speed reducer. Force-transmitting support or stay assemblies are disposed in the protective structure between the band member and a resilient pad assembly for encircling the heart and promoting heart tissue ingrowth therein. The force-transmitting stay assemblies are biased circumferentially, and thus radially outward, by compression return springs disposed therebetween.

Abstract: A ventricular assist device may include a cardiac compression assembly which comprises a gel-filled pad of generally concave configuration, mounted on a pressure plate with peripheral portions of the pad extending beyond the periphery of the plate, to preclude damage to the heart by the peripheral edges of the plate. The gel-filled pad may have undulating opposite sides formed by intersecting rows of raised dimples. The pad also includes portions for suturing the pad to a heart ventricle, and at least some of the dimples on the side of the pad facing the heart ventricle are provided with ventricle tissue growth-promoting islands. An electrode, in the form of a grid having intersecting strips which define dimple-receiving openings therebetween, also may be mounted on the venticle side of the pad. As many as eight circumferentially arranged cardiac compression assemblies, having lower ends pivotally mounted on a support member adapted to be located adjacent the apex of a heart ventricle, may be provided.