| 摘要 |
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portion (42) is chosen to have an edge configuration which will deflect chordae tendonae as the conductive tip is withdrawn from the heart wall for either removal or relocation.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. |
