Lead locking device and method

#1. Field of the Invention

#This invention pertains to lead locking devices and methods for locking onto a lead, and more particularly to lead locking devices and methods for locking onto and removing a lead, such as a pacemaker lead, from a patient's body.

#2. Description of Related Art

#These and other objects and advantages of the invention will become more apparent and more readily appreciated from the following detailed description of the presently preferred exemplary embodiments of the invention, taken in conjunction with the accompanying drawings, of which:

#FIG. 1 illustrates a lead locking device according to a first embodiment of the invention;

#FIG. 2 is a schematic illustration of the lead locking device according to the first embodiment of the invention;

#Reference numeral 10 in FIG. 1 generally represents a lead locking device according to a first embodiment of the invention. The lead locking device 10 has a lead engaging member 12, a mandrel 14, a loop handle 16 and a press-fit type of latching mechanism 18. The lead engaging member 12 has a proximal end 20 and a distal end 22. FIG. 1 shows a section of the lead engaging member 12, between the proximal end 20 and the distal end 22, with the center portion cut away for illustration purposes. Consequently, FIG. 1 does not illustrate the scaled length of the lead engaging member 12. Preferably, the lead engaging member 12 is at least about 65 cm long. However, the length of the lead engaging member 12 may be selected according to the intended application. As one may see illustrated schematically in FIG. 2, the lead engaging member 12 defines a lumen extending between the proximal end 20 and distal end 22. The mandrel 14 is disposed in the lumen defined by the lead engaging member 12 and attached to the distal tip 24 of the lead engaging member 12. In a preferred embodiment, the lead engaging member 12 is a braided sheath. The lead engaging member 12 is soldered to the mandrel 14 at the distal tip 24 in a first embodiment. The solder at the distal tip 24 is preferably a radiopaque solder. Suitable materials for the radiopaque solder are alloys of gold and tin. More preferably, the solder at the distal tip 24 is about 80% gold and about 20% tin.

#In a preferred embodiment, the press-fit type of latching mechanism 18 has at least a portion 26 attached to the proximal end 20 of the lead engaging member 12 and a crimped portion 28 of the mandrel 14. Preferably, the portion of the press-fit mechanism 26 attached to the proximal end 20 of the lead engaging member 12 has an inner hypotube 30 and an outer hypotube 32 concentrically arranged to sandwich the proximal end 20 of the lead engaging member 12 therebetween. Preferably, the inner hypotube 30 and outer hypotube 32 are crimped to become mechanically fixed to the lead engaging member 12. The inner hypotube 30 and outer hypotube 32, which are preferably rigidly fixed with respect to each other and to a proximal end 20 of the lead engaging member 12, is slidable along the mandrel 14 disposed in the lumen defined by the lead engaging member 12. The crimped section 28 in the mandrel 14 is constructed at a position relative to the proximal end 20 of the lead engaging member 12 such that the inner hypotube 30 and outer hypotube 32 attached to the proximal end 20 of the lead engaging member 12 overlaps the crimped section 28 of the mandrel 14 when the lead engaging member 12 is in a stretched configuration. More preferably, the inner hypotube 30 and outer hypotube 32 attached to the proximal end 20 of the lead engaging member 12 sets in a stable condition, thus being held or “latched” in place, approximately in the center of the crimped section 28 when the lead engaging member 12 is in a stretched configuration. In the preferred embodiment, the inner hypotube 30 and outer hypotube 32 attached to the proximal end 20 of the lead engaging member 12 is beyond the most distal end 34 in the distal direction when the lead engaging member 12 is in a substantially relaxed configuration.

#As one may see illustrated in FIG. 1, the loop handle 16 of the lead locking device 10 preferably has a proximal loop 36 and an end portion 38 which is further twisted around the most proximal end 40 of the mandrel 14. In the preferred embodiment, a proximal loop hypotube 42 is disposed over the twisted end 38 of the loop handle 16 and crimped to mechanically attach the loop handle 16 to the mandrel 14. Preferably, the proximal loop hypotube 42 is crimped, thereby forming a solid mechanical attachment of the loop handle 16 to the mandrel 14.