Other

William A McArthur

Lynn D Crawford

Thomas M Soukup

A syringe which can be used only once. The syringe includes a body having a fluid chamber, a plunger reciprocally movable within the chamber and a handle for moving the plunger within the chamber. Following the injection cycle, the handle automatically disconnects from the plunger rendering the device useless.

Non-reusable syringe

An electrode tip (14) of a tissue-stimulating lead provides active fixation of the tip of body tissue. Tissue attachment means (34), within the electrode tip, are selectively extended so as to protrude from the tip upon application of an external force. Otherwise, biasing means (40), also within the electrode tip, urge the tissue attachment means to a retracted position within the tip. Extension and retraction of the tissue attachment means are realized through the use of a carrier bobbin (44), to one end of which the tissue attachment means are affixed. The carrier bobbin is movably inserted into a barrel (30) of the tip. An O-ring (38) placed around the circumference of the carrier bobbin, sized so as to make sealable contact with the inside barrel wall, seals the back end of the barrel and prevents fluids from flowing therein. This O-ring also rolls along the surface of the carrier bobbin and barrel wall as the bobbin moves within the barrel, thereby reducing friction associated with the movement of the bobbin. The carrier bobbin moves to its extended position upon application of an axial force. This axial force is selectively supplied by a stylet (20) that passes through a lume (56) of the lead.

Tissue-stimulating electrode having sealed, low-friction

An improved fixation structure for an endocardial lead (10), the lead (10) having an elongated electrical conductor (12) encased in an encasing material (14) and terminating in an exposed electrically conductive tip (16). The fixation structure includes at least one fin (20) which defines an upper edge (28), a first trailing edge portion (40), and a second trailing edge portion (42). The fin upper edge (28) defines an acute angle with respect to the longitudinal axis (22) of the lead (10). The first trailing edge portion (40) defines a ninety degree angle with respect to the longitudinal axis (22) of the electrical conductor (12) and the second trailing edge portion (42) extends backward and downward from a point (A) on the first trailing edge portion (40), until it intersects the encasing material (14) at a point (C). In one embodiment, the edge between point A and point C defines an arc. Point A begins at a point twenty percent of the distance from the encasing material (14) to the top of the first trailing edge portion (40). Thus, the fixation structure disclosed engages the heart trabeculae in substantially the same manner as other types of fixation structures. However, the second trailing portion (42) is chosen to have an edge configuration which will deflect chordae tendonae as the conductive tip is withdrawn from the heart wall for either removal or relocation. Thus, an improved endocardial fixation structure is disclosed which has the advantages of existing structures with respect to engaging heart trabeculae while at the same time facilitates tip removal in the presence of chordae tendonae in the heart.

Fixation means for an endocardial electrode

An implantable stimulation electrode having differing stiffness characteristics along its length. An endocardial electrode (20) is disclosed which includes a spirally-wound, unifilar, continuous portion (50) extending the entire length of the electrode and a stiffening portion (52) which extends for only a portion of the electrode length. The spirals of the stiffening portion (52) and the continuous portion (50) are interleaved in a juxtapositional relationship with respect to each other to form a bifilar section (26), the remainder of the electrode being a unifilar section (28). In the bifilar section (26), each spiral is wound at twice the pitch of the spirals in the unifilar section (28). The bifilar section (26) has a greater stiffness than the unifilar section. In a specific embodiment disclosed, an atrial J electrode is formed in which the bifilar section includes the J portion of the electrode where stiffness is needed. Thus, more flexibility is provided for most of the electrode length where stress concentrations occur, whereas the J portion has additional stiffness for maintaining the electrode in a desired location within the heart atrium (36). A further feature of the disclosed electrode (20) is that the diameter of the bifilar and unifilar sections can be chosen so that the overall electrode has essentially the same diameter as the unifilar section, thus resulting in an electrode having substantially the same cross-sectional profile over its entire length.

Growing community of inventors

Saugus, CA, United States of America

William A McArthur