Patent Description:
Various physiological functions can be managed utilizing minute, wireless implants that operate individually or as part of a larger system. Wireless implants can provide sensing or stimulating functionality to assist with a person's health. For example, wireless implants have been discussed in association with cardiac management, including wireless electrodes used to stimulate cardiac muscle for assisted cardiac pacing. Wireless implant configuration, deployment, and fixation within the body provide an array of both recognized and yet-to-be realized problems.

For example, <CIT> describes a method and apparatus for implanting a medical device within a living body. The apparatus includes an elongate sleeve positionable with a living body, such as within a blood vessel, and a medical device insertable into the sleeve. During use, the sleeve is retained with the body, and the medical device is sealed within the sleeve.

<FIG> show a transvenously implantable medical device (TIMD) <NUM> where <FIG> is an enlarged view showing the TIMD <NUM> in greater detail. The TIMD <NUM> is adapted to be implanted transvenously at a desired location within the vasculature of the patient. In some embodiments, the TIMD <NUM> is implanted within vasculature of the heart <NUM> to provide cardiac sensing and/or stimulation functionality. For example, the TIMD <NUM> can be used to sense various physiological characteristics of the heart <NUM> and/or to transmit a stimulating pulse of energy to tissue of the heart <NUM>, such as the tissue forming the left ventricle <NUM>.

In some embodiments, the TIMD <NUM> is adapted to be implanted into the right atrium <NUM>, through the coronary sinus ostium <NUM> and into the coronary sinus <NUM> of the heart <NUM>. As is subsequently described, catheter-based implantation is contemplated in association with the TIMD <NUM>. The TIMD <NUM> is implantable within the left marginal vein <NUM> (as shown), or any other branch vein of the coronary sinus <NUM>, including any of those known in the art of cardiac management. For example, the TIMD <NUM> is optionally implanted within the great cardiac vein <NUM>, the middle cardiac vein <NUM>, the left posterior ventricular vein <NUM>, the small cardiac vein <NUM>, or others.

Although the TIMD <NUM> is implanted in vasculature of the heart <NUM> in some embodiments, the TIMD <NUM> can also be implanted at other intravenous locations and/or to perform other functions. For example, the TIMD <NUM> is optionally implanted in vasculature of the neck, such as one of the jugular veins. The TIMD <NUM> can perform various functions from the jugular veins, such as cardiac rhythm management via vagal nerve stimulation, for example. As another example, the TIMD <NUM> is optionally implanted in peripheral vasculature and is adapted for acquiring diagnostic information, blood pressure for example, and then storing the diagnostic information, transmitting the diagnostic information to another implanted medical device (IMD), and/or transmitting the diagnostic information to an external device.

In some embodiments, the TIMD <NUM> is usable with a wireless electrode system <NUM> that includes a control system <NUM> having a transmitter <NUM> for communicating with one or more wireless electrodes, such as the TIMD <NUM>. In one embodiment, the transmitter <NUM> is an inductive coil used to inductively charge the TIMD <NUM> with power and/or trigger delivery of stimulating energy from the TIMD <NUM> to the heart <NUM>. In other embodiments, the transmitter <NUM> is a radiofrequency communication device, an acoustic communication device, or other device for communicating with the TIMD <NUM>.

In some embodiments, the control system <NUM> directly controls stimulation via the TIMD <NUM> from outside of the body (externally, for example worn about the neck) or from within the body (internally, for example implanted similarly to a conventional pacemaker) using inductive communication/power transmission. The control system <NUM> can also use other types of communication to directly control stimulation or sensing functionality administered with the TIMD <NUM> in addition to or as an alternative to inductive transmission. For example, radiofrequency, optical, or acoustic communication between the TIMD <NUM> and the control system <NUM> are also contemplated. Examples of various wireless electrode systems usable in association with the TIMD <NUM> are described in <CIT>, "<NPL>," and <CIT>, "<NPL>," the entire contents of each of which are incorporated herein by reference.

In some embodiments, the control system <NUM> and the TIMD <NUM> are optionally deployed in a satellite-planet configuration, where the control system <NUM> acts as a planet device and the TIMD <NUM>, or a plurality of devices similar to the TIMD <NUM>, act as one or more satellite device(s). The TIMD <NUM> and control system <NUM> can have varying degrees of control over sensing/stimulating operation of the TIMD <NUM>. In some embodiments, the TIMD <NUM> is programmed to manage cardiac stimulation for a substantial period of time. Examples of wireless, implanted electrodes that are programmable to control stimulating or sensing functionality, as well as examples of satellite-planet device configurations are described in previously-incorporated <CIT>.

<FIG> is a schematic view of the TIMD <NUM> in an unassembled state. The TIMD <NUM> includes a control module <NUM> and an electrical lead <NUM> providing means for fixating the control module <NUM> within vasculature. The control module <NUM> includes a housing <NUM> and various electrical components, including a signal management component <NUM>, a power component <NUM>, and a communication component <NUM>. Various components of the control module <NUM>, including components <NUM>, <NUM>, <NUM> can be arranged as discrete devices, combined devices having shared circuits and/or processing capabilities, or according to other arrangements.

The housing <NUM> is adapted for transvenous delivery and implantation in human vasculature, including vasculature associated with the heart <NUM>. The housing <NUM> is formed of metallic, polymeric, or other biocompatible materials. In one embodiment, the housing <NUM> is substantially oblong and forms a terminal connector <NUM> adapted to be secured to the lead <NUM>, a hermetically sealed interior compartment <NUM> adapted to house and protect the components <NUM>, <NUM>, <NUM>, and an inner lumen <NUM> (shown in dotted lines) extending longitudinally through the housing <NUM>. The inner lumen <NUM> is generally adapted to facilitate implantation of the TIMD <NUM>, as described subsequently in greater detail. In some embodiments, the housing <NUM> includes drug delivery features, e.g., a steroid collar, drug eluting coating, or other therapeutic agents, or others. The housing <NUM> also optionally includes stimulating and/or sensing features, e.g., one or more electrodes associated with the housing <NUM>.

The signal management component <NUM> includes circuitry for managing operation of the TIMD <NUM>. In some embodiments, the signal management component <NUM> controls delivery of stimulating energy from the TIMD <NUM>. The signal management component <NUM> is optionally adapted to be programmed to execute various stimulation or sensing programs. In other embodiments, the signal management component <NUM> is a hardwired circuit configured to deliver set stimulation or sensing programs upon initiation by a remote controller, such as the control system <NUM> (<FIG>).

The power component <NUM> operates to provide power to the signal management component <NUM> and/or the communication component <NUM>. In various embodiments, the power component <NUM> is a battery, a coil for receiving a charge through inductance, or other type of power source for providing energy to the TIMD <NUM>. In some embodiments, power is transmitted to the control module <NUM> from an outside source, including those internal or external to the body, such as the control system <NUM> (<FIG>). If desired, the power component <NUM> is optionally integrated with the communication component <NUM> and data being transmitted to and received by the control module <NUM> is encoded into the power transmission as a modulation of the power signal from the control system <NUM>. Examples of integrated power/communication arrangements are described in previously incorporated <CIT>.

The communication component <NUM> serves to provide a communication link between the TIMD <NUM> and one or more other devices, such as the control system <NUM> (<FIG>), that are internal and/or external to the patient. The communication component <NUM> includes circuitry and/or other structures for providing communication between the chronically-implanted device and another device using radio-frequency (RF) waves, acoustics, or inductance, for example. In some embodiments, the communication component <NUM> includes an acoustic transmitter for transmitting an acoustic signal to another device, such as the control system <NUM>. For example, the control system <NUM> is optionally an implanted cardiac stimulus device, such as a pacemaker and the communication component <NUM> is adapted to provide bidirectional communication between the TIMD <NUM> and the control system <NUM>.

The lead <NUM> defines a central longitudinal axis X and includes a lead body <NUM> extending from a terminal connector end <NUM> to a distal end <NUM>. <FIG> shows a cross-section of a portion of the lead <NUM> along the line <NUM>-<NUM> shown in <FIG>. As shown in <FIG>, the lead body <NUM> includes an outer, insulating sheath <NUM>, an inner, conductive core <NUM>, an inner, insulating sheath <NUM>, and one or more electrodes <NUM>. The electrodes <NUM> include a plurality of ring electrodes <NUM> disposed circumferentially about the lead body <NUM> and a tip electrode <NUM> located at the distal end <NUM>.

The conductive core <NUM> is sandwiched between the outer and inner insulating sheaths <NUM>, <NUM> and is optionally of a coiled design. The inner sheath <NUM> defines a lumen <NUM> that is open at the terminal connector end <NUM>. As shown, the electrodes <NUM> are positioned along the lead body <NUM>. The electrodes <NUM> are in electrical communication with the conductive core <NUM>, providing an electrical pathway between the electrodes <NUM> and the control module <NUM>. In some embodiments, the core <NUM> is a coiled core, although other configurations are contemplated. For example, in other embodiments, the core <NUM> is a cable or ribbon conductor. The conductive core <NUM> can be made of any electrically conductive materials.

In some embodiments, the lead <NUM> includes no lumens or greater number of lumens <NUM>, a non-coiled conductive core <NUM>, or other features associated with electrical leads. For example, in some embodiments, a steroid collar is employed with the lead <NUM> to help ensure proper pacing and/or as a therapeutic agent, including anti-inflammatories, antithrombogenics, antiproliferatives, or other types of therapeutic agents. Examples of various electrical lead features contemplated for use with the lead <NUM> are described in <CIT>, "<NPL>," the entire contents of which are incorporated herein by reference.

The electrodes <NUM> can be substantially the same as known electrodes for pacing and/or defibrillation leads. The electrodes <NUM> are formed of an electrically conductive material such as an alloy of platinum and iridium which is highly conductive and highly resistant to corrosion. In operation, the conductive core <NUM> carries electrical current between the control module <NUM> and the electrodes <NUM>. As shown, the lead <NUM> is unipolar with a single conductor. In other embodiments, the lead <NUM> is bipolar where one or more of the electrodes <NUM> are each in electrical communication with a plurality of separate conductors (not shown).

The lead <NUM> is pre-biased to define a first shape in an expanded state (<FIG>) and can be transitioned, or collapsed, to define a second shape in a collapsed state (<FIG>). As shown in <FIG> and <FIG>, the lead <NUM> has a substantially larger maximum outer dimension in the expanded state than in the collapsed state. In different terms, the lead <NUM> defines a larger profile relative to the central longitudinal axis X of the lead <NUM> when the lead is in the expanded state in comparison to when the lead <NUM> is in the collapsed state.

As shown in <FIG>, in the expanded state, the lead <NUM> naturally extends though an arcuate path to define a substantially helical, or coiled shape. As will be described in greater detail, other expanded state shapes are also contemplated, including generally arcuate shapes, undulating shapes, sinusoidal shapes, circular shapes, and others. The lead <NUM> is pre-formed, or otherwise pre-biased to the shape exhibited in the expanded state via heat-setting, materials selection, plastic deformation of the conductive core <NUM>, or using another technique known in the art.

As shown in <FIG>, the lead <NUM> is straighter, or more linear, in the collapsed state than in the expanded state according to some embodiments. Various collapsed state shapes are contemplated, including helical shapes having a smaller transverse profile than in the expanded state.

One manner of assembling the control module <NUM> to the lead <NUM> is described with reference to <FIG>, and <FIG>. In particular, the control module <NUM> is assembled to the lead <NUM> by securing the terminal connector end <NUM> of the lead <NUM> to the terminal connector <NUM> of the control module <NUM>. Upon assembly, the conductive core <NUM> (<FIG>) of the lead <NUM> is placed in electrical communication with the components of the control module <NUM> such that the signal management component <NUM> (<FIG>) of the module <NUM> can send a stimulation signal to, or receive a sensing signal from, the electrodes <NUM> through the conductive core <NUM> of the lead <NUM>. Additionally, the inner lumen <NUM> (<FIG>) of the lead <NUM> is coaxially aligned to the inner lumen <NUM> (<FIG>) of the control module <NUM> to form a longitudinal passageway through the control module <NUM> into the lead <NUM>. In one embodiment, the lead <NUM> has specific biases to facilitate placement and retention of the lead <NUM> in the coronary sinus <NUM> (<FIG>) or a branch vessel thereof.

<FIG> are illustrative of one embodiment method of transvenously implanting the TIMD <NUM> in a blood vessel <NUM> having a vessel wall <NUM>. <FIG> shows the TIMD <NUM> with the lead <NUM> in a collapsed state. In particular, a straightening member <NUM>, such as a stylet or a guidewire having sufficient stiffness to straighten and maintain the lead <NUM> in the collapsed state, is inserted through the inner lumen <NUM> of the control module <NUM> into the lead <NUM> to collapse the lead <NUM>.

The TIMD <NUM> and straightening member <NUM> are delivered to a desired transvenous implantation site, for example in the coronary sinus <NUM> (<FIG>) or a branch vein thereof. In some embodiments, the TIMD <NUM> and the straightening member <NUM> are delivered through a guide catheter <NUM> as shown in <FIG>. When the guide catheter <NUM> is used, the TIMD <NUM> is deployed from the guide catheter <NUM> once the TIMD <NUM> is delivered proximate a desired location within the blood vessel <NUM>. In other embodiments, the TIMD <NUM> is delivered directly to the desired implantation site using the straightening member <NUM> and in the absence of the guide catheter <NUM> in a manner substantially similar to an over-the-wire lead delivery technique.

The straightening member <NUM> is then removed from the TIMD <NUM>. If desired, a secondary member <NUM> can be deployed over the straightening member <NUM> to press against the TIMD <NUM> to assist with deployment of the TIMD <NUM> from the guide catheter <NUM> and/or removal of the straightening member <NUM> from the TIMD <NUM>. In some embodiments, the secondary member <NUM> is catheter-like in construction and formed according to catheter-based manufacturing methods.

As the straightening member <NUM> is removed, the lead <NUM> transitions from the collapsed state to the expanded state shown in <FIG> to contact the vessel wall <NUM>. The lead <NUM> provides means for anchoring or fixating the TIMD <NUM> in the blood vessel <NUM>. In particular, the maximum outer dimension of the lead <NUM>, for example the transverse diameter defined by the helical shape of the lead <NUM>, is selected such that the lead <NUM> will mechanically engage the vessel wall <NUM>. The mechanical engagement between the lead <NUM> and the vessel wall <NUM> is used to place one or more of the electrodes <NUM> in electrical communication with the vessel wall <NUM> and to anchor or otherwise fixate the TIMD <NUM> in position within the blood vessel <NUM>. In various embodiments, the lead <NUM> includes coatings, e.g., fibrosis encouraging coatings, or surface features to enhance frictional engagement with the vessel wall <NUM>. In other embodiments, the lead <NUM> includes anti-fibrosis coatings or treatments to discourage fibrosis and facilitate lead extraction. As shown in <FIG>, upon expansion the TIMD <NUM> defines a central passage <NUM> through the expanded shape of the TIMD <NUM>. In some embodiments, the central passage <NUM> facilitates blood flow past the TIMD <NUM>.

Once disposed within the blood vessel <NUM>, the TIMD <NUM> is used for sensing or stimulation according to various embodiments. For example, the blood vessel <NUM> is optionally the coronary sinus <NUM> (<FIG>) or one of the branch vessels thereof. The electrodes <NUM> of the TIMD <NUM> can then be used to transmit a pulse of stimulating energy through the vessel wall <NUM> to surrounding tissue of the heart <NUM>.

According to some methods of transvenous implantation, the TIMD <NUM> is re-collapsible following transvenous implantation to remove or reposition the TIMD <NUM>. For example, the secondary member <NUM> can be used to grip the control module <NUM> following implantation of the TIMD <NUM>. In some embodiments, a vacuum is applied through the secondary member <NUM>, which secures the control module <NUM> to the secondary member <NUM>. The control module <NUM> optionally includes a proximal seal <NUM> that is able to be engaged by the secondary member <NUM>. In one embodiment, the proximal seal <NUM> facilitates coupling of the control module <NUM> to the secondary member <NUM> via application of negative pressure through the secondary member <NUM> by forming a better seal between the control module <NUM> and the secondary member <NUM>.

In other embodiments, the secondary member <NUM> includes gripping elements (not shown), somewhat like jaws of a pliers, for gripping the control module <NUM> or associated structures. In still other embodiments, the control module <NUM> includes a wire loop (not shown) and the secondary member <NUM> includes a hook (not shown) for grasping the loop. Other means for securing the control module <NUM> relative to the secondary member <NUM> are also contemplated, including detents, magnets, adhesives, male and female threads, and others.

Once the secondary member <NUM> is secured to the control module <NUM>, the straightening member <NUM> is reinserted into the lumen <NUM> of the lead <NUM> through the inner lumen <NUM> of the control module <NUM>. As the straightening member <NUM> is reintroduced into the lead <NUM>, the lead <NUM> transitions to the collapsed state, and out of mechanical engagement with the vessel wall <NUM>. Once the lead <NUM> has been partially or fully collapsed, the TIMD <NUM> is able to be removed or repositioned as desired.

<FIG> show another TIMD <NUM>. The TIMD <NUM> includes a control module <NUM> and an electrical lead <NUM> providing means for fixating the control module <NUM> within vasculature. In some embodiments, the control module <NUM> and the lead <NUM> include substantially similar components as the control module <NUM> and the lead <NUM> of the TIMD <NUM>. The lead <NUM> extends through an arcuate path and is curved or biased, being adapted to expand from a collapsed state (not shown), for example substantially straight, to an expanded state, for example having the curvatures shown in <FIG>. Similarly to the TIMD <NUM>, the lead <NUM> of the TIMD <NUM> defines a substantially larger maximum outer dimension in the expanded state than in the collapsed state.

As shown in <FIG>, the curvature of the lead <NUM> is primarily in two dimensions, or within a single plane. As shown in <FIG>, the curvature of lead <NUM> also includes a non-planar component, with a second bend or curve in a second plane. The lead <NUM> is pre-formed, or otherwise pre-biased to the expanded state via heat-setting, materials selection, plastic deformation, or others. In some embodiments, the lead <NUM> is constructed and arranged for fixation in the coronary sinus <NUM>, and is pre-biased to facilitate placement and retention in the coronary sinus <NUM>, or a branch vessel thereof. Various examples of structures and methods for providing such pre-biased, curved shapes are described in co-pending <CIT>, and entitled "Left Ventricular Lead Shapes," the entire contents of which are incorporated herein by reference.

In some embodiments, the TIMD <NUM> is transvenously implanted in a similar manner to the TIMD <NUM>, for example using the guide catheter <NUM> (<FIG>), the secondary member <NUM> (<FIG>), and/or the straightening member <NUM> (<FIG>) as previously described. Once implanted, the lead <NUM> is transitioned from the collapsed state to the expanded state to contact the vessel wall <NUM> (<FIG>). The maximum outer dimension of the lead <NUM>, for example the outer diameter defined by the arcuate shape of the lead <NUM>, is selected such that the lead <NUM> will mechanically engage the vessel wall <NUM> to anchor the TIMD <NUM> in the blood vessel <NUM>. The TIMD <NUM> can also be removed from the blood vessel <NUM> in a similar manner to that described in association with the TIMD <NUM> according to some embodiments.

<FIG> show another TIMD <NUM> and are illustrative of one method of transvenously implanting the TIMD <NUM>. The TIMD <NUM> includes a control module <NUM> and an electrical lead <NUM> providing means for fixating the control module <NUM> within vasculature. The lead <NUM> is adapted to transition between a collapsed state and an expanded state. In some embodiments, the control module <NUM> and the lead <NUM> include substantially similar components as the control module <NUM> and the lead <NUM> of the TIMD <NUM>. The control module <NUM> optionally includes one or more electrodes <NUM> for performing sensing and/or stimulating functions similar to those previously described. In some embodiments, the electrode <NUM> is used in conjunction with one or more electrodes of the lead <NUM>.

As shown in <FIG>, the control module <NUM> has a proximal end <NUM> and distal end <NUM> and the lead <NUM> has a first end <NUM> and a second end <NUM>. The first end <NUM> of the lead <NUM> is secured to the proximal end <NUM> of the control module <NUM> while the second end <NUM> of the lead <NUM> is secured to the distal end <NUM> of the control module <NUM>. The lead <NUM> extends through an arcuate shape from the proximal end <NUM> to the distal end <NUM> of the control module <NUM>.

<FIG> shows the lead <NUM> in the collapsed state, where the lead <NUM> has been pressed into a more compact, linear shape than in the expanded state (<FIG> shows the lead <NUM> in the expanded state, where the lead <NUM> defines a greater height, or outer diameter in the expanded state than in the collapsed state. In different terms, in the expanded state the lead <NUM> has a substantially larger maximum outer dimension than in the collapsed state. The lead <NUM> is pre-formed, or otherwise pre-biased to the shape exhibited in the expanded state via heat-setting, materials selection, plastic deformation to impart a curvature, or others.

One method of transvenously implanting the TIMD <NUM> is also generally illustrated in <FIG>. As shown in <FIG>, the lead <NUM> is maintained in the collapsed state within a catheter <NUM>. The catheter <NUM> is guided to a desired position within the blood vessel <NUM>. Once the TIMD <NUM> is positioned proximate to the desired position for implantation, a pusher <NUM> is used to eject the TIMD <NUM> from the catheter <NUM>. Once the external force of the catheter <NUM> is removed from the TIMD <NUM>, the TIMD <NUM> transitions to the expanded state as shown in <FIG> to engage the vessel wall <NUM> and anchor the TIMD <NUM> in place. Although the TIMD <NUM> is shown oriented "sideways" within the blood vessel <NUM>, other orientations are also contemplated. For example, the TIMD <NUM> is optionally transvenously implanted as shown in <FIG>, where the TIMD <NUM> is oriented substantially coaxially with the blood vessel <NUM>.

<FIG> shows another exemplary TIMD <NUM>. The TIMD <NUM> includes a control module <NUM>, a first electrical lead <NUM>, and a second electrical lead <NUM>, the first and second leads <NUM>, <NUM> providing means for fixating the control module <NUM> within vasculature. The first and second leads <NUM>, <NUM> are adapted to transition between a collapsed state and an expanded state. In some embodiments, the control module <NUM> and the leads <NUM>, <NUM> generally include substantially similar components as the control module <NUM> and the lead <NUM> of the TIMD <NUM> (<FIG>).

As shown in <FIG>, the control module <NUM> has a proximal end <NUM> and distal end <NUM>. The first lead <NUM> has a first end <NUM> and a second end <NUM>. The second lead <NUM> has a first end <NUM> and a second end <NUM>. The first ends <NUM>, <NUM> of the leads <NUM>, <NUM> are secured to the proximal end <NUM> of the control module <NUM> while the second ends <NUM>, <NUM> of the leads <NUM>, <NUM> are secured to the distal end <NUM> of the control module <NUM>. The first and second leads <NUM>, <NUM> extend through opposing, arcuate paths relative to the control module <NUM> to define a pair of semi-circular shapes.

The leads <NUM>, <NUM> are transitionable between an expanded state and a more compact, collapsed state. <FIG> shows the leads <NUM>, <NUM> in the expanded state. As described in association with other embodiments, the leads <NUM>, <NUM> are pre-biased to the expanded state such that they will expand outwardly to the shape shown generally in <FIG>. The leads <NUM>, <NUM> are sufficiently flexible to be compressed to a collapsed state where the leads <NUM>, <NUM> define a more linear, compact shape. In particular, the leads <NUM>, <NUM> are pressed inwardly toward the control module <NUM> in the collapsed state. As described in association with other embodiments, the leads <NUM>, <NUM> define a greater height, or overall outer diameter in the expanded state than in the collapsed state. The leads <NUM>, <NUM> are pre-biased to the expanded state shape via heat-setting, materials selection, plastic deformation, or others.

The TIMD <NUM> can also include means for transitioning the TIMD <NUM> to the collapsed state. In some embodiments, the TIMD <NUM> includes a filament <NUM> that can be tensioned to collapse the first and second leads <NUM>, <NUM> toward the control module <NUM>. The filament <NUM> includes a loop <NUM> at the proximal end <NUM> of the control module <NUM>. The filament <NUM> extends from the loop <NUM> through the control module <NUM> and splits into a first leg <NUM> and a second leg <NUM>. The first leg <NUM> is secured to the first lead <NUM> while the second leg <NUM> is secured to the second lead <NUM>. In operation, the loop <NUM> is pulled, which in turn tensions the first and second legs <NUM>, <NUM>, collapsing the leads <NUM>, <NUM>.

The TIMD <NUM> is transvenously implanted in a similar manner as that described in association with the TIMD <NUM>. For example, the catheter <NUM> is optionally used to maintain the TIMD <NUM> in the collapsed state. The pusher <NUM> is then optionally used to eject the TIMD <NUM> from the catheter <NUM>. Once the external force of the catheter <NUM> is removed from the TIMD <NUM>, the TIMD <NUM> transitions to the expanded state as shown in <FIG> to engage the vessel wall <NUM> and anchor the TIMD <NUM> in place.

Claim 1:
A system including a transvenously implantable medical device (<NUM>; <NUM>; <NUM>; <NUM>) and a straightening member (<NUM>), the transvenously implantable medical device (<NUM>; <NUM>; <NUM>; <NUM>) comprising:
an electrical lead (<NUM>; <NUM>; <NUM>; <NUM>, <NUM>) including one or more electrodes (<NUM>, <NUM>, <NUM>; <NUM>);
a control module (<NUM>; <NUM>; <NUM>; <NUM>) mechanically secured to and in electrical communication with the electrical lead, the control module including a signal management component (<NUM>) and a power component (<NUM>) disposed in a hermetically sealed housing (<NUM>) adapted for implantation into a blood vessel such that blood in the blood vessel can flow past the control module between the housing (<NUM>) and an internal wall of the blood vessel, the control module adapted for at least one of stimulating and sensing a physiologic response using the one or more electrodes of the electrical lead; and
wherein the electrical lead further includes a lumen (<NUM>) extending therethrough configured to accommodate the straightening member within the lumen in order to adapt the electrical lead for transvenous implantation, the electrical lead is pre-biased to expand from a collapsed state to an expanded state to mechanically engage the internal wall of the blood vessel upon removal of the straightening member so as to anchor the electrical lead and the mechanically connected control module in the blood vessel.