| 摘要 |
Apparatus for assisting the heart in the pumping of blood comprising a resilient umbrella-like member positioned within the aorta and adapted to permit the flow of blood in a normal direction and being moved to an open or expanded position to perform a pumping action and to prevent retrograde flow. The umbrella-like member may be combined for use with an intra-aortic balloon or may comprise a stand-alone pumping assembly. The umbrella-like member is preferably mounted upon a catheter for insertion in the desired location. The umbrella-like member is designed to be non-occlusive or occlusive, depending on design, when open. When used alone, operating means are provided, which means are coupled to the umbrella-like member normally maintains the umbrella in its operative, expanded position. Electromechanical control means coupled to the umbrella-like member through a control member is designed to urge the umbrella assembly to its open or closed position, depending on the direction of the control force. The umbrella assembly may also be provided with stiffener members to normally maintain the umbrella in the open position. Umbrella members of a "parachute" design and of a double conical design are disclosed. An alternative assistive assembly employs a spherical member filled with either a non-toxic gas such as, for example, air, or a saline liquid. When filled with a gas, the assembly may be inserted in a patient sitting generally in the upright position. The pumping assembly is pulled downwardly during systole and is capable of at least partially rising by itself during diastole in order to help perfuse coronaries. A drive system comprising a linear stepping motor is used to impart reciprocating movement to the control wire utilized to open and close the umbrella assembly, as well as linearly moving the umbrella assembly in a reciprocating fashion. An electronic controller operates the linear stepping motor under control of an electrocardiogram signal coupled to the controller by a three-wire circuit.
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