Implantable medical device and delivery catheter apparatus system and method

An implantable medical device includes a device housing, a fixation device, a first prong projecting from a proximal end of the device housing and a second prong projecting from the proximal end of the device housing. The second prong is spaced apart from the first prong. The first prong includes a first flange projecting away from a longitudinal axis of the device housing. The second prong includes a second flange projecting away from the longitudinal axis. The first prong and the second prong are configured to extend to a first flange diameter in a relaxed configuration and to extend to a second flange diameter in an expanded configuration.

TECHNICAL FIELD

The present disclosure relates to implantable medical devices. More specifically, the disclosure relates to medical devices and delivery systems for medical devices.

BACKGROUND

Implantable medical devices, such as medical electrical leads, must often be implanted with the aid of an introducer or delivery catheter. The delivery catheter positions the implantable medical device with the aid of a stylet extending through the coil conductor, or similar structure, within the implantable medical device. The implantable medical device is then fixated to tissue with a fixation element, such as a fixation helix, for example. Fixation is typically achieved by rotating the stylet or, in some cases, the coil conductor. The need for the implantable medical device to accommodate the stylet, which can have a diameter as small as 0.20 mm-0.43 mm″, or a coil conductor to be large enough to transmit sufficient torque to activate the fixation element, limits how small the implantable medical device diameter can be. Thus, for example, medical electrical leads are limited to a diameter of from about 1.3 mm-2.0 mm at a minimum.

The human body responds more favorably to smaller implantable medical devices. Thus, there is a need for improvements in implantable medical devices and their delivery systems that allows for smaller implantable medical devices.

SUMMARY

Example 1 is an implantable medical device including a device housing, a fixation device, a first prong projecting from a proximal end of the device housing and a second prong projecting from the proximal end of the device housing. The second prong is spaced apart from the first prong. The first prong includes a first flange projecting away from a longitudinal axis of the device housing. The second prong includes a second flange projecting away from the longitudinal axis. The first prong and the second prong are configured to extend to a first flange diameter in a relaxed configuration and to extend to a second flange diameter in an expanded configuration.

Example 2 is the implantable medical device of Example 1, wherein the device is configured to couple to a delivery catheter when the first prong and the second prong are in the expanded configuration, and to decouple from the delivery catheter when the first prong and the second prong are in the relaxed configuration.

Example 3 is the implantable medical device of Example 1, further including an electrode and an electrical conductor. The electrical conductor includes a proximal end and a distal end. The distal end is electrically coupled to the electrode and the proximal end is configured to electrically couple to a medical electrical device.

Example 4 is the implantable medical device of Example 3, where in the fixation device is the electrode.

Example 5 is the implantable medical device of Example 3 or Example 4, wherein the implantable medical device is a first implantable medical device, and further including a second implantable medical device substantially similar to the first implantable medical device, the proximal end of the electrical conductor of the second implantable medical device electrically coupled to the first implantable medical device.

Example 6 is the implantable medical device of any of Examples 1-5, wherein the first prong further includes a first set of internal threads projecting toward the longitudinal axis and the second prong further includes a second set of internal threads projecting toward the longitudinal axis. The first set of threads and the second set of internal threads are configured to engage a delivery catheter in the expanded configuration and to disengage from the delivery catheter in the relaxed configuration.

Example 7 is an implantable medical device and delivery catheter apparatus system including the implantable medical device according to any of Examples 1-5 and a delivery catheter apparatus. The delivery catheter apparatus includes a delivery catheter, a driver coil and a driver wedge. The delivery catheter forms a catheter lumen extending from a proximal end of the delivery catheter to a distal end of the delivery catheter. The driver coil extends through the catheter lumen. The driver coil forms a driver coil lumen. The driver wedge is disposed at a distal end of the driver coil. The driver wedge is configured to selectively engage the first prong and the second prong to place the first prong and the second prong in the expanded configuration, coupling the device to the delivery catheter, and to disengage from the first prong and the second prong to allow the first prong and the second prong to return to the relaxed configuration, decoupling the device from the delivery catheter.

Example 8 is the system of Example 7, wherein the catheter lumen includes a first lumen diameter at the distal end of the delivery catheter, a second lumen diameter proximal of the first lumen diameter and a third lumen diameter proximal of the second lumen diameter. The first lumen diameter is greater than the first flange diameter and less than the second flange diameter. The second lumen diameter is greater than or equal to the second flange diameter. The third lumen diameter is less than the second flange diameter.

Example 9 is the system of either of Examples 7 or 8, wherein the first prong further includes a first set of internal threads projecting toward the longitudinal axis and the second prong further includes a second set of internal threads projecting toward the longitudinal axis, and the driver wedge further includes a set of external threads configured to selectively engage the first set of internal threads and the second set of internal threads to place the first prong and the second prong in the expanded configuration and to disengage the first set of internal threads and the second set of internal threads to allow the first prong and the second prong to return to the relaxed configuration.

Example 10 is the system of any of Examples 7-9, wherein the driver wedge forms a driver wedge lumen extending through the driver wedge.

Example 11 is the system of Example 10, wherein the delivery catheter apparatus further includes a stylet configured to extend through the driver coil lumen and the driver wedge lumen and engage the fixation device to extend the fixation device from the distal end of the device housing.

Example 12 is the system of any of Examples 7-11, wherein the delivery catheter includes a cone projecting distally and radially outward from the distal end of the delivery catheter.

Example 13 is a method of decoupling a delivery catheter apparatus from an implantable medical device, the implantable medical device including a first prong including a first flange and a second prong including a second flange, the first flange and the second flange engaging an annular recess in a delivery catheter of the delivery catheter apparatus to couple the implantable medical device to the delivery catheter apparatus. The method includes rotating a driver wedge to disengage the driver wedge from the first prong and the second prong; removing the disengaged driver wedge from between the first prong and the second prong to release a compressive force exerted by the first prong and the second prong on the driver wedge, the released compressive force moving the first prong and the second prong toward each other, disengaging the first flange and the second flange from the annular recess; and retracting the delivery catheter proximally to uncouple the delivery catheter apparatus from the implantable medical device.

Example 14 is the method of Example 13, wherein rotating the driver wedge includes rotating a driver coil coupled to the driver wedge.

Example 15 is the method of either of Examples 13 or 14, wherein the implantable medical device is a medical electrical lead.

Example 16 is an implantable medical device including a device housing, a fixation device configured to extend from a distal end of the device housing, a first prong projecting from a proximal end of the device housing and a second prong projecting from the proximal end of the device housing. The second prong is spaced apart from the first prong. The first prong includes a first flange projecting away from a longitudinal axis of the device housing. The second prong includes a second flange projecting away from the longitudinal axis. The first prong and the second prong are configured to extend to a first flange diameter in a relaxed configuration and to extend to a second flange diameter in an expanded configuration.

Example 17 is the implantable medical device of Example 16, wherein the device is configured to couple to a delivery catheter when the first prong and the second prong are in the expanded configuration, and to decouple from the delivery catheter when the first prong and the second prong are in the relaxed configuration.

Example 18 is the implantable medical device of Example 16, where in the fixation device is a fixation helix.

Example 19 is the implantable medical device of Example 16, further including an electrode and an electrical conductor including a proximal end and a distal end, the distal end electrically coupled to the electrode and the proximal end configured to electrically couple to a medical electrical device.

Example 20 is the implantable medical device of Example 19, where in the fixation device is the electrode.

Example 21 is the implantable medical device of Example 19 or Example 20, wherein the implantable medical device is a first implantable medical device, further including a second implantable medical device substantially similar to the first implantable medical device, the proximal end of the electrical conductor of the second implantable medical device electrically coupled to the first implantable medical device.

Example 22 is the implantable medical device of any of Examples 17-21, wherein the first prong further includes a first set of internal threads projecting toward the longitudinal axis and the second prong further includes a second set of internal threads projecting toward the longitudinal axis. The first set of thread and the second set of internal threads are configured to engage the delivery catheter in the expanded configuration and to disengage from the delivery catheter in the expanded configuration.

Example 23 is an implantable medical device and delivery catheter apparatus system including an implantable medical device and a delivery catheter apparatus. The implantable medical device includes a device housing, a fixation device configured to extend from a distal end of the device housing, a first prong projecting from a proximal end of the device housing and a second prong projecting from the proximal end of the device housing. The second prong is spaced apart from the first prong. The first prong includes a first flange projecting away from a longitudinal axis of the device housing. The second prong includes a second flange projecting away from the longitudinal axis. The first prong and the second prong are configured to extend to a first flange diameter in a relaxed configuration and to extend to a second flange diameter in an expanded configuration. The delivery catheter apparatus includes a delivery catheter, a driver coil and a driver wedge. The delivery catheter forms a catheter lumen extending from a proximal end of the delivery catheter to a distal end of the delivery catheter. The driver coil extends through the catheter lumen. The driver coil forms a driver coil lumen. The driver wedge is disposed at a distal end of the driver coil. The driver wedge is configured to selectively engage the first prong and the second prong to place the first prong and the second prong in the expanded configuration to couple the device to the delivery catheter, and disengage from the first prong and the second prong to allow the first prong and the second prong to return to the relaxed configuration to decouple the device from the delivery catheter.

Example 24 is the system of Example 23, wherein the implantable medical device further includes an electrode and an electrical conductor. A distal end of the conductor is electrically coupled to the electrode and a proximal end of the conductor is configured to electrically couple to a medical electrical device.

Example 25 is the system of Example 24, where in the fixation device is the electrode.

Example 26 is the system of Example 24 or Example 25, wherein the implantable medical device is a first implantable medical device and delivery catheter apparatus is a first delivery catheter apparatus. The system further includes a second implantable medical device substantially similar to the first implantable medical device and a second delivery catheter apparatus substantially similar to the first delivery catheter apparatus. The proximal end of the electrical conductor of the second implantable medical device is electrically coupled to the first implantable medical device.

Example 27 is the system of any of Examples 23-26, wherein the catheter lumen includes a first lumen diameter at the distal end of the delivery catheter, a second lumen diameter proximal of the first lumen diameter and a third lumen diameter proximal of the second lumen diameter. The first lumen diameter is greater than the first flange diameter and less than the second flange diameter. The second lumen diameter is greater than or equal to the second flange diameter. The third lumen diameter is less than the second flange diameter.

Example 28 is the system of Example 27, wherein the second lumen diameter forms an annular recess, the first flange and the second flange are disposed at least partially within the annular recess in the expanded configuration and are not disposed within the annular recess in the relaxed configuration.

Example 29 is the system of any of Examples 23-28, wherein the first prong further includes a first set of internal threads projecting toward the longitudinal axis and the second prong further includes a second set of internal threads projecting toward the longitudinal axis. The driver wedge further includes a set of external threads configured to selectively engage the first set of internal threads and the second set of internal threads to place the first prong and the second prong in the expanded configuration and to disengage the first set of internal threads and the second set of internal to allow the first prong and the second prong to return to the relaxed configuration.

Example 30 is the system of Examples 23-29, wherein the driver wedge forms a driver wedge lumen extending through the driver wedge.

Example 31 is the system of Example 30, wherein the delivery catheter apparatus further includes a stylet configured to extend through the driver coil lumen and the driver wedge lumen and engage the fixation device to extend the fixation device from the distal end of the device housing.

Example 32 is the system of any of Examples 23-31, wherein the delivery catheter includes a cone projecting distally and radially outward from the distal end of the delivery catheter.

Example 33 is a method of decoupling a delivery catheter apparatus from an implantable medical device, the implantable medical device including a first prong including a first flange and a second prong including a second flange, the first flange and the second flange engaging an annular recess in a delivery catheter of the delivery catheter apparatus to couple the implantable medical device to the delivery catheter apparatus. The method includes rotating a driver wedge to disengage the driver wedge from the first prong and the second prong; removing the disengaged driver wedge from between the first prong and the second prong to release a compressive force exerted by the first prong and the second prong on the driver wedge, the released compressive force moving the first prong and the second prong toward each other, disengaging the first flange and the second flange from the annular recess; and retracting the delivery catheter proximally to uncouple the delivery catheter apparatus from the implantable medical device.

Example 34 is the method of Example 33, wherein rotating the driver wedge includes rotating a driver coil coupled to the driver wedge.

Example 35 is the method of Example 33 or Example 34, wherein the implantable medical device is a medical electrical lead.

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

DETAILED DESCRIPTION

A more complete understanding is available by reference to the following detailed description of numerous aspects and embodiments of the disclosure. The detailed description which follows is intended to illustrate but not limit the disclosure.

In accordance with various aspects of the disclosure, an implantable medical device is understood to be completely introduced, surgically or medically, into the human body or by medical intervention into a natural orifice, and which is intended to remain after, at least temporarily, after the procedure. It is understood that the various embodiments can be implemented in any suitable medical device implanted in a patient by a delivery catheter and held in place, by a fixation mechanism. It is further understood that in embodiments can include tissue anchors, medical electrical leads, or other such devices. In embodiments in which embodiments include medical electrical leads, it is understood that such leads may be electrically coupled to medical electrical devices, such as, and without limitation, cardiac rhythm management (CRM) systems (e.g., a cardioverter-defibrillator (ICD) system, a pacemaker system, or a cardiac resynchronization system), implantable cardiac monitors, neurostimulation systems (e.g., a spinal cord stimulation system, a deep brain stimulation system, an overactive bladder system, a hypoglossal nerve stimulation system, or a vagus nerve stimulation system), implantable incontinence systems and implantable erectile dysfunction systems, for example.

Embodiments of the disclosure separates the need for some implantable medical device elements, such as coil conductors or retrieval tethers, for example, to serve as a portion of the delivery system or to activate a fixation element. The separation permits the medical device element, such as a coil conductor to be much smaller, as it need not accommodate a stylet or supply torque to activate a fixation element. The separation also allows for significant design flexibility in the position and orientation of the implantable medical device element.

FIG. 1is a side view of an implantable medical device10, according to some embodiments of the disclosure. As shown inFIG. 1, the implantable medical device10includes a device housing12, a fixation device14, a first prong16, and a second prong18. In some embodiments, the device housing12can be formed from a biocompatible non-conductive polymer such as, for example, an aromatic polyether-based thermoplastic polyurethane, polyether ether ketone, a polycarbonate based polyurethane, silicone rubbers, or a hybrid material composed of silicones and polyurethanes, for example.

The fixation device14is illustrated as a fixation helix. The fixation device14can be formed of any biocompatible material, such as platinum, platinum alloys, palladium, palladium alloys, titanium, cobalt-chromium-nickel alloys, nickel-cobalt-chromium-molybdenum alloys or stainless steel, for example. The fixation device14may be conductive, or non-conductive, depending the function of the implantable medical device10. The fixation device14can be deployed by rotating a threaded structure (not shown) within the device housing12. Although the fixation device14is illustrated as a fixation helix, it is understood that embodiments include other fixation devices, such as tines, for example.

In some embodiments, the first prong16and the second prong18are integrally formed with the device housing12and thus be composed of the same material as the device housing12. In some other embodiments, the first prong16and the second prong18are formed of a different material coupled to the device housing12. In some embodiments, the first prong16and the second prong18can be joined to the device housing12by laser welding, radio-frequency bonding, adhesive bonding or solvent bonding, for example.

As shown inFIG. 1, the device housing12has a proximal end20end and a distal end22opposite the proximal end20. The device housing12also has a longitudinal axis A extending between the proximal end20and the distal end22. The fixation device14is disposed at the distal end22. The first prong16and the second prong18each project from the proximal end20. The first prong16includes a first flange24. The first flange24is spaced apart from the device housing12and projects away from the longitudinal axis A. Similarly, the second prong18includes a second flange26. The second flange26is spaced apart from the device housing12and projects away from the longitudinal axis A.

InFIG. 1, the first prong16and second prong18are shown in a relaxed configuration. That is, there the first prong16and second prong18are in a neutral state, not subject to any forces that would cause the first prong16or second prong18to flex. Together, the first flange24and the second flange26extend to a first flange diameter F1in the relaxed configuration.

The implantable medical device10can be quite small. In some embodiments, a diameter of the implantable medical device10can be as small as 1.5 mm, 1.6 mm, 1.7 mm, 1.8 mm, 1.9 mm or 2.0 mm, or as large as 2.2 mm, 2.4 mm, 2.6 mm, 2.8 mm or 3.0 mm, or may be within any range defined between any two of the foregoing values, such as 1.5 mm to 3.0 mm, 1.6 mm to 2.8 mm, 1.7 mm to 2.6 mm, 1.8 mm to 2.4 mm, 1.9 mm to 2.2 mm, 2.0 mm to 2.2 mm, 1.8 mm to 2.0 mm, or 1.7 mm to 2.0 mm, for example.

FIG. 2is a side cross-sectional view of a portion of the implantable medical device10ofFIG. 1, according to some embodiments of the disclosure.FIG. 2shows that the first prong16further includes a first set of internal threads28and the second prong18further includes a second set of internal threads30. The first set of internal threads28and the second set of internal threads30each project toward the longitudinal axis A. Together, the first set of internal threads28and the second set of internal threads30are disposed to provide a single threaded connection.

Although the embodiment ofFIGS. 1 and 2is shown with two prongs projecting from the proximal end20of the device housing12, it is understood that embodiments include more than two prongs, such as three prongs, four prongs, or even more prongs, so long that the flanges projecting from the prongs extend to the first flange diameter F1and that the internal threads projecting from the prongs are disposed to provide a single threaded connection.

FIG. 3is a side cross-sectional view of portion of a delivery catheter apparatus32, according to some embodiments of the disclosure. As shown inFIG. 3, the delivery catheter apparatus32includes a delivery catheter34, a driver coil36and a driver wedge38. For clarity and understanding, only a portion of the length of the delivery catheter34and of the driver coil36are shown. The delivery catheter34includes a distal end40and a proximal end (not shown) configured to extend outside of the patient when in use. The delivery catheter34is a tubular structure forming a catheter lumen42which extends from the distal end40to the proximal end (not shown). The catheter lumen42includes a first lumen diameter D1, a second lumen diameter D2and a third lumen diameter D3. The first lumen diameter D1is disposed at the distal end40. The second lumen diameter D2is disposed proximal of the first lumen diameter D1. The third lumen diameter D3is disposed proximal of the second lumen diameter D2. Together, the first lumen diameter D1, the second lumen diameter D2and the third lumen diameter D3for an annular recess44. In some embodiments, the third lumen diameter D3may extend from the second lumen diameter D2to the proximal end (not shown) of the delivery catheter34. The delivery catheter34may be formed of a flexible, biocompatible polymer such as polyether polyurethanes, silicones, polyurethane silicone blends and polyesters, fore example.

The driver coil36includes a distal end46and a proximal end (not shown) configured to extend outside the patient when in use. The driver coil36forms a driver coil lumen48which extends from the distal end46to the proximal end (not shown). The driver coil36can be formed of platinum, palladium, titanium, cobalt-chromium-nickel alloys, nickel-cobalt-chromium-molybdenum alloys, nickel-titanium alloys, stainless steel or tantalum, for example.

As shown inFIG. 3, the driver wedge38is disposed at the distal end46of the driver coil36. The driver wedge38includes a set of external threads50. The driver wedge38forms a diver wedge lumen52extending through the driver wedge38as shown inFIG. 2. The driver wedge38can be formed of any biocompatible, rigid material, such as polyether ether ketone, platinum, palladium, titanium, cobalt-chromium-nickel alloys, nickel-cobalt-chromium-molybdenum alloys, nickel-titanium alloys, stainless steel or tantalum, for example. The driver wedge38can be coupled to the distal end46of the driver coil36by methods know in the art, such as welding, swaging, or an adhesive, for example. Alternatively, the driver wedge38can be formed of swaged and/or welded portions of the driver coil36.

The driver coil36and driver wedge38are configured to be disposed within the catheter lumen42to guide the delivery catheter34and to selectively couple and decouple the delivery catheter apparatus32from the implantable medical device10, as described below. The catheter lumen42is sized to accommodate the driver coil36and driver wedge38so that they can move along the delivery catheter34.

FIG. 4is a side view of an implantable medical device and delivery catheter apparatus system54, according to some embodiments of the disclosure. The implantable medical device and delivery catheter apparatus system54includes the implantable medical device10and the delivery catheter apparatus32, as described above. InFIG. 4, the implantable medical device10is coupled to the delivery catheter apparatus32. So configured, the implantable medical device and delivery catheter apparatus system54can deliver the implantable medical device10to a site within a patient's body.

FIG. 5is an enlarged side view of the portion of the implantable medical device and delivery catheter apparatus system54ofFIG. 4where the implantable medical device10couples to the delivery catheter apparatus32, according to some embodiments of the disclosure. InFIG. 5, the external threads50of the driver wedge38engage the first set of internal threads28of the first prong16and the second set of internal threads30of the second prong18(FIG. 2). So engaged, the driver wedge38acts as a wedge, flexing the first prong16and the second prong18, forcing the first prong16and the second prong18apart from each other into an expanded configuration. Together, the first flange24and the second flange26extend to a second flange diameter F2in the expanded configuration.

The first lumen diameter D1is greater than the first flange diameter F1(FIG. 1) and less than the second flange diameter F1. The second lumen diameter is greater than equal to the second flange diameter F2. The third lumen diameter D3is less than the second flange diameter F2. Thus, the second flange diameter F2is sized such that the first flange24and the second flange26extend into the annular recess44of the delivery catheter34. So configured, the implantable medical device10is coupled to the delivery catheter apparatus32because the second flange diameter F2is greater than the first lumen diameter D1and the third lumen diameter D3, trapping the first flange24and the second flange26within the annular recess44.

FIG. 6is a side view of the implantable medical device and delivery catheter apparatus system54ofFIG. 4with the fixation device14deployed to implant the implantable medical device10, according to some embodiments of the disclosure. The implantable medical device10is coupled to the delivery catheter apparatus32with the first prong16and the second prong18in the expanded configuration with the first flange24and the second flange26engaging the annular recess44, as shown inFIG. 5. In the embodiment shown inFIG. 6, the delivery catheter apparatus32further includes a stylet56. The stylet56is configured to extend through the driver coil lumen48and the driver wedge lumen52(FIG. 3) and within the device housing12along the longitudinal axis A (FIG. 1) to engage the fixation device14. A distal tip (not shown) of the stylet56has a shape configured to engage the fixation the fixation device14, such as hexagonal, flat blade, cross-shaped, or a multi-point star-shaped pattern, for example. Once the implantable medical device10is in a location suitable for fixation and pressed against tissue T, the stylet56is rotated to extend the fixation device14out of the distal end22of the device housing12and into the tissue T to implant the implantable medical device10, as shown inFIG. 6. Once the implantable medical device10is implanted, the stylet56can be withdrawn from the catheter lumen42(FIG. 3).

In some other embodiments, the fixation device14may be driven in to the tissue T by other mechanisms, such as by rotating the delivery catheter34, and/or the driver coil36, for example.

FIG. 7is the side view of the embodiment ofFIG. 6, illustrating decoupling of the delivery catheter apparatus32from the implantable medical device10, according to some embodiments of the disclosure. InFIG. 7, the driver wedge38is rotated to disengage the driver wedge38from the first prong16and the second prong18. Specifically, as the driver wedge38is rotated, the external threads50disengage the internal threads28of the first prong16and the internal threads30of the second prong18. In the embodiment shown inFIG. 7, the driver wedge38is rotated by rotating the driver coil36. In some other embodiments, the driver wedge38may be rotated by a stylet similar to the stylet56, but configured to engage the driver wedge38.

Once the driver wedge38is disengaged from the first prong16and the second prong18, the driver wedge38is removed from between the first prong16and the second prong18, releasing a compressive force exerted by the first prong16and the second prong18on the driver wedge38. The released compressive force moves the first prong16and the second prong18toward each other to the relaxed configuration. In the relaxed configuration, the first flange24and the second flange26extend to the first flange diameter F1. The first flange diameter F1is less than the first lumen diameter D1. Thus, in the relaxed configuration, the first flange24and the second flange26are not disposed within the annular recess44. As the delivery catheter apparatus32is retracted proximally, the first flange24and the second flange26pass out of the catheter lumen42through the first lumen diameter D1to uncouple the delivery catheter apparatus32from the implanted implantable medical device10, as shown inFIG. 7.

FIG. 8is a side view of an implantable medical device60implanted in the tissue T of a patient, according to some embodiments of the disclosure. The implantable medical device60is substantially similar to the implantable medical device10described above in reference toFIGS. 1, 2 and 4-7, except that it is specifically configured as a medical electrical lead. Thus, the implantable medical device60includes an electrode62and a conductor64. In some embodiments, the electrode62can be the fixation device14, such as the fixation helix shown inFIG. 8. In some other embodiments, the electrode62can be a conductive band or coil disposed about the device housing12. In some other embodiments, the electrode62can be a conductive ring or plate disposed the distal end22of the device housing12. Although the embodiment ofFIG. 8is shown with a single electrode62, it is understood that embodiments may include more than one electrode62including any of the described electrodes in any combination.

The conductor64includes a distal end66and a proximal end68opposite the distal end66. The distal end66is electrically coupled to the electrode62. The proximal end68is configured to electrically couple to a medical electrical device (not shown) by means know in the art, such as a lead terminal or an electrical feed-thru, for example. The conductor64may exit the device housing12at the proximal end20, or along the side of the device housing12between the proximal end20and the distal end22, as shown inFIG. 8.

Advantageously, the conductor64can have a smaller diameter than typical electrical leads because it does not serve as a portion of the delivery catheter apparatus32or to activate the fixation device14. In some embodiments, a diameter of the conductor64can be as small as 0.1 mm, 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm or 0.6 mm, or as large as 0.7 mm, 0.8 mm, 0.9 mm, 1.0 mm, 1.1 mm or 1.2 mm, or may be within any range defined between any two of the foregoing values, such as 0.1 mm to 1.2 mm, 0.2 mm to 1.1 mm, 0.3 mm to 1.0 mm, 0.4 mm to 0.9 mm, 0.5 mm to 0.8 mm, 0.6 mm to 0.7 mm, 0.3 mm to 0.7 mm, 0.2 mm to 0.6 mm, or 0.7 mm to 1.1 mm, for example.

In some embodiments, the conductor64can consist of a single insulated wire. In other embodiments, the conductor64can include multiple wires in straight or twisted arrangements. In some other embodiments, the conductor64can include a coiled conductor, such as U.S. Pat. No. 9,199,077, entitled “MRI conditionally safe lead with multi-layer conductor”.

In use, therapy may be provided from the medical electrical device to the tissue T by way of the conductor64and the electrode62. Alternatively, or additionally, electrical measurements of the activity around the tissue T may be provided to the medical electrical device by way of the electrode62and the conductor64. The implantable medical device60poses significantly less risk of perforation or dislodgement from the tissue T due to the small mass of the implantable medical device60and the low stiffness of the conductor64.

FIG. 9is a side view of an implantable medical device70implanted in the tissue T of a patient, according to some embodiments of the disclosure. The implantable medical device70includes a first implantable medical device72and a second implantable medical device74. The first implantable medical device72is configured as a medical electrical lead and is substantially similar to the implantable medical device60described above in reference toFIG. 8, except that it is also electrically coupled to the second implantable medical device74by another conductor76. The conductor76may be substantially similar to the conductor64, as described above. The conductor76includes a proximal end78and a distal end80opposite the proximal end78. The proximal end78of the conductor76is electrically coupled to the first implantable medical device72.

In use, therapy may be provided from the medical electrical device to the tissue T by way of the conductor64and the conductor76. In some embodiments, the electrode62of the first implantable medical device72may sense an electrical impulse from one area of tissue T and transmit that impulse along the conductor76to the second implantable medical device74, where it is provided to another are of the tissue T by the electrode62of the second implantable medical device74. In this way, the implantable medical device70may be used to bridge a damaged portion of a conductor pathway between the two tissue T areas. As with the embodiment ofFIG. 8, the small mass of the implantable medical device70and the low stiffness of the conductors64and76pose significantly less risk of perforation or dislodgement from the tissue T.

FIG. 10is a side view of an implantable medical device82implanted in the tissue T of a patient, according to some embodiments of the disclosure. The implantable medical device82includes a first implantable medical device84, a second implantable medical device86and a tether88. The first implantable medical device84and the second implantable medical device86are each substantially similar to the implantable medical device10described above in reference toFIGS. 1, 2 and 4-7. The first implantable medical device84and the second implantable medical device86are each tissue anchors. The tether88mechanically couples the first implantable medical device84and the second implantable medical device86together, as shown inFIG. 10.

In use the first implantable medical device84and the second implantable medical device86may be anchored in portions of the tissue T that need mechanical support to shore up a weakness. The mechanical connection provided by the tether88can provide additional mechanical support. As with the embodiments described above, the small mass of the implantable medical device82poses significantly less risk of perforation or dislodgement from the tissue T.

FIG. 11is a side view of an implantable medical device and delivery catheter apparatus system90, according to some embodiments of the disclosure. The implantable medical device and delivery catheter apparatus system90includes the implantable medical device10, as described above, and with a delivery catheter apparatus92. The delivery catheter apparatus92is substantially similar to the delivery catheter apparatus32described above in reference toFIG. 3, except that the delivery catheter34is replace by a delivery catheter94. The delivery catheter94is substantially similar to the delivery catheter34, except that it further includes a cone96. The cone96is a cone-shaped extension of the delivery catheter34projecting distally and radially outward from the distal end40of the delivery catheter94. The cone96may be formed by flaring an extension of the delivery catheter94.

Should it become necessary to remove any of the implantable medical devices described above once implanted, such as the implantable medical device10, the delivery catheter apparatus92may be recoupled to the implantable medical device10, and the fixation device14removed from the tissue T by reversing the process described above in reference toFIG. 7. The cone96facilitates the recapture of the first prong16and the second prong18, and the re-engagement of the driver wedge38with the first prong16and the second prong18.

As used herein, the phrase “within any range defined between any two of the foregoing values” literally means that any range may be selected from any two of the values listed prior to such phrase regardless of whether the values are in the lower part of the listing or in the higher part of the listing. For example, a pair of values may be selected from two lower values, two higher values, or a lower value and a higher value.