TECHNICAL FIELD

The present invention relates to medical devices and methods for the active fixation of an implantable medical lead. More specifically, the invention relates to devices and methods for active fixation of implantable medical leads for mapping and stimulating the bundle of His in a patient's heart.

BACKGROUND

Cardiac rhythm management systems are useful for electrically stimulating a patient's heart to treat various cardiac arrhythmias. A method of electrically stimulating the heart can include stimulating the His bundle at a location proximate to the tricuspid valve at the interatrial septum in the right atrium of the heart or at a location proximate to the tricuspid valve at the interventricular septum in the right ventricle of the heart. Directly stimulating the bundle of His can simultaneously pace both the right and left ventricles of the heart, potentially avoiding pacing induced dyssynchrony which may occur with right ventricular apex pacing. There is a continuing need for improved His bundle lead designs and assemblies.

SUMMARY

Example 1 is a device for the active fixation of an implantable medical lead. The device includes a housing, a tine assembly, an electrode, and rotatable shaft. The housing includes a proximal end for connecting to the lead and a distal end opposite the proximal end. The housing defines a housing lumen having a longitudinal axis extending between the proximal end and the distal end. The tine assembly is disposed within the housing lumen. The tine assembly includes at least one tine configured to self-bias from a linear configuration within the housing to a curved configuration outside of the housing. The electrode is disposed at the distal end of the housing. The rotatable shaft is connected to the electrode and extends through the housing lumen. The shaft is configured to engage the tine assembly such that rotation of the shaft transitions the at least one tine between the linear configuration and the curved configuration.

Example 2 is the device of Example 1, wherein the housing further includes internal screw threads extending along the housing lumen, and the tine assembly further includes a driver member and a carrier member. The driver member is disposed within the housing lumen. The driver member defines a driver lumen that is coaxial with the housing lumen. The driver member includes a threaded portion having external screw threads engaged with the internal screw threads of the housing, a flange, and a hub connecting the flange to the threaded portion. The carrier member is rotatably disposed around the hub of the driver member. The at least one tine is connected to and projecting from the carrier member. The rotatable shaft extends through the driver lumen. The shaft is configured to engage the driver member such that rotation of the shaft rotates the driver member to transition the at least one tine between the linear configuration and the curved configuration.

Example 3 is the device of Example 2, wherein the flange and the threaded portion of the driver member constrain axial movement of the carrier member.

Example 4 is the device of either of Examples 2 or 3, wherein the housing further defines at least one slot at least partially radially outward from the internal screw threads, the at least one slot extending from the proximal end to the distal end and parallel to the longitudinal axis.

Example 5 is the device of Example 4, wherein the carrier member includes at least one lobe configured to engage the at least one slot to prevent axial rotation of the carrier member relative to the housing while permitting the carrier member to move through the housing lumen while the shaft rotates the driver member, the at least one tine connected to and projecting from the at least one lobe.

Example 6 is the device of any of Examples 2-5, wherein the driver lumen is sized so that the driver member can slide along the shaft while the shaft rotates the driver member.

Example 7 is the device of any of Examples 1-6, wherein rotation of the shaft in a first direction moves the at least one tine out of the housing lumen, transitioning the at least one tine from the linear configuration to the curved configuration to fix the lead to tissue, and rotation of the shaft in a second direction opposite the first direction retracts the at least one tine into the housing lumen, transitioning the at least one tine from the curved configuration to the linear configuration.

Example 8 is the device of any of Examples 1-7, wherein the at least one tine is conductive and the electrode and the shaft are electrically insulated from the at least one tine.

Example 9 is the device of any of Examples 1-8, wherein the at least one tine includes a plurality of tines.

Example 10 is the device of any of Examples 1-9, wherein the electrode includes a conical tip having an axis that is collinear with the longitudinal axis of the housing lumen.

Example 11 is the device of any of Examples 1-10, wherein the shaft is electrically and mechanically connected to the electrode.

Example 12 is an implantable medical lead including a flexible, tubular lead body including a proximal end and a distal end, a connector assembly disposed at the proximal end, an electrical conductor extending from the connector assembly to the distal end, and a device for the active fixation of the implantable medical lead according to any of Examples 1-11. The device is disposed at the distal end of the lead body. The electrical conductor is mechanically and electrically connected to the shaft.

Example 13 is a method of making a device for the active fixation of an implantable medical lead. The method includes attaching at least one tine to a carrier member, inserting a hub extending from a threaded portion of a driver member through the carrier member such that the carrier member is rotatable about the hub, forming a flange at an end of the hub opposite the threaded portion of the driver member, inserting the at least one tine into a proximal end of a longitudinal slot of a housing lumen of a housing to place the at least one tine in a linear configuration contained by the housing, threading the threaded portion of the drive member into a threaded portion at a proximal end of the housing, inserting a shaft through the a driver lumen of the driver member at the proximal end of the housing and through the housing lumen to a distal end of the housing, and connecting an electrode to the shaft at the distal end of the housing. The tine is self-biasing to a curved configuration. The flange and the threaded portion of the driver member restrain the axial movement of the carrier member.

Example 14 is the method of Example 13, further including placing a seal around the shaft at the distal end of the housing before connecting the electrode to the shaft.

Example 15 is the method of either of Examples 13 or 14, wherein forming the flange at the end of the hub includes heating the end of the hub until it softens and flanging the heated hub outward to form the flange.

Example 16 is a device for the active fixation of an implantable medical lead into tissue. The device includes a housing, a tine assembly, and a rotatable shaft. The housing includes a proximal end for connecting to the lead and a distal end opposite the proximal end. The housing defines a housing lumen having a longitudinal axis extending between the proximal end and the distal end. The tine assembly is disposed within the housing lumen. The tine assembly includes at least one tine configured to self-bias from a linear configuration within the housing to a curved configuration outside of the housing. The rotatable shaft extends through the housing lumen. The shaft is configured to engage the tine assembly such that rotation of the shaft transitions the at least one tine between the linear configuration and the curved configuration.

Example 17 is the device of Example 16, wherein rotation of the shaft in a first direction moves the at least one tine out of the housing lumen, transitioning the at least one tine from the linear configuration to the curved configuration to fix the lead to tissue, and rotation of the shaft in a second direction opposite the first direction retracts the at least one tine into the housing lumen, transitioning the at least one tine from the curved configuration to the linear configuration to release the lead from tissue.

Example 18 is the device of either of Examples 16 or 17, wherein the at least one tine includes a plurality of tines.

Example 19 is the device of any of Examples 16-18, further including an electrode disposed at the distal end of the housing, the rotatable shaft connected to the electrode

Example 20 is the device of Example 19, wherein the electrode includes a conical tip having an axis that is collinear with the longitudinal axis of the housing lumen.

Example 21 is the device of either of Examples 19-20, wherein the shaft is electrically and mechanically connected to the electrode.

Example 22 is the device of any of Examples 16-21, wherein the housing further includes internal screw threads extending along the housing lumen, and the tine assembly further includes a drive member and a carrier member. The driver member is disposed within the housing lumen. The driver member defines a driver lumen that is coaxial with the housing lumen. The driver member includes a threaded portion having external screw threads engaged with the internal screw threads of the housing, a flange, and a hub connecting the flange to the threaded portion. The carrier member is rotatably disposed around the hub of the driver member. The at least one tine is connected to and projecting from the carrier member. The rotatable shaft extends through the driver lumen. The shaft is configured to engage the driver member such that rotation of the shaft rotates the driver member to transition the at least one tine between the linear configuration and the curved configuration.

Example 23 is the device of Example 22, wherein the flange and the threaded portion of the driver member constrain axial movement of the carrier member.

Example 24 is the device of either of Examples 22 or 23, wherein the housing further defines at least one slot at least partially radially outward from the internal screw threads, the at least one slot extending from the proximal end to the distal end and parallel to the longitudinal axis.

Example 25 is the device of Example 24, wherein the carrier member includes at least one lobe configured to engage the at least one slot to prevent axial rotation of the carrier member relative to the housing while permitting the carrier member to move through the housing lumen while the shaft rotates the driver member, the at least one tine connected to and projecting from the at least one lobe.

Example 26 is the device of any of Examples 22-25, wherein the driver lumen is sized so that the driver member can slide along the shaft while the shaft rotates the driver member.

Example 27 is an implantable medical lead including a flexible, tubular lead body including a proximal end and a distal end, a connector assembly connector disposed at the proximal end, an electrical conductor extending through the tubular body from the connector assembly to the distal end, and a device for the active fixation of the implantable medical lead. The device is disposed at the distal end of the lead. The device includes a housing, a tine assembly, an electrode, and a rotatable shaft. The housing includes a proximal end for connecting to the distal end of the lead body and a distal end opposite the proximal end. The housing defines a housing lumen having a longitudinal axis extending between the proximal end and the distal end. The tine assembly is disposed within the housing lumen. The tine assembly includes at least one tine configured to self-bias from a linear configuration within the housing to a curved configuration outside of the housing. The electrode is disposed at the distal end of the housing. The rotatable shaft is connected to the electrode and extends through the housing lumen. The shaft is configured to engage the tine assembly such that rotation of the shaft transitions the at least one tine between the linear configuration and the curved configuration. The shaft mechanically and electrically connects the electrical conductor to the electrode.

Example 28 is the lead of Example 27, wherein the at least one tine is conductive and the electrode and the shaft are electrically insulated from the at least one tine.

Example 29 is the lead of Example 28, further including at least one tine conductor extending through the tubular body from the connector assembly to the at least one tine.

Example 30 is the lead of any of Examples 27-29, wherein the housing further includes internal screw threads extending along the housing lumen, and the tine assembly further includes a driver member and a carrier member. The driver member is disposed within the housing lumen. The driver member defines a driver lumen that is coaxial with the housing lumen. The driver member includes a threaded portion having external screw threads engaged with the internal screw threads of the housing, a flange, and a hub connecting the flange to the threaded portion. The carrier member is rotatably disposed around the hub of the driver member. The at least one tine is connected to and projects from the carrier member. The rotatable shaft extends through the driver lumen. The shaft is configured to engage the driver member such that rotation of the shaft rotates the driver member to transition the at least one tine between the linear configuration and the curved configuration. The flange and the threaded portion of the driver member constrain axial movement of the carrier member.

Example 31 is the lead of Example 30, wherein the housing further defines at least one slot at least partially radially outward from the internal screw threads. The at least one slot extends from the proximal end to the distal end and parallel to the longitudinal axis. The carrier member includes at least one lobe configured to engage the at least one slot to prevent axial rotation of the carrier member relative to the housing while permitting the carrier member to move through the housing lumen while the shaft rotates the driver member. The at least one tine is connected to and projects from the at least one lobe.

Example 32 is a method of making a device for the active fixation of an implantable medical lead. The method includes attaching at least one tine to a carrier member, inserting a hub extending from a threaded portion of a driver member through the carrier member such that the carrier member is rotatable about the hub, forming a flange at an end of the hub opposite the threaded portion of the driver member, inserting the at least one tine into a proximal end of a longitudinal slot of a housing lumen of a housing to place the at least one tine in a linear configuration contained by the housing, threading the threaded portion of the drive member into a threaded portion at a proximal end of the housing, inserting a shaft through the a driver lumen of the driver member at the proximal end of the housing and through the housing lumen to a distal end of the housing, and connecting an electrode to the shaft at the distal end of the housing. The flange and the threaded portion of the driver member restraining the axial movement of the carrier member. The tine self-biasing to a curved configuration.

Example 33 is the method of Example 32, further including placing a seal around the shaft at the distal end of the housing before connecting the electrode to the shaft.

Example 34 is the method of either of Examples 32 or 33, wherein forming the flange at the end of the hub includes heating the end of the hub until it softens and flanging the heated hub outward to form the flange.

Example 35 is the method of either of Examples 32 or 33, wherein forming the flange at the end of the hub includes connecting the flange to the end of the hub.

While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.

