HK1196318B - Left ventricular intraseptal stimulation lead - Google Patents

Description

Left ventricle intra-septal stimulation lead

Cross Reference to Related Applications

The benefit and priority of french patent application No.1259760, filed on 12/10/2012, which is incorporated herein by reference in its entirety, is claimed.

Technical Field

The present invention relates to intracardiac leads for left ventricular pacing. The present invention is in the general context of an "active/active implantable medical device" defined by the 90/385/EEC directive, established by the European Union council at 1990, 20, and includes implants to continuously monitor heart rhythm and deliver electrical stimulation, resynchronization or defibrillation pulses to the heart as needed.

Background

Intracardiac "stimulation" leads refer to leads used to deliver low energy pulses for bradycardia or resynchronization therapy. The present invention also applies to intracardiac leads used for cardioversion/defibrillation which are intended to deliver a high energy shock to the heart in an attempt to terminate an irregular tachycardia. A "stimulation lead (or electrode)" or "stimulation/defibrillation lead" may refer to any type of lead used for these or other similar purposes.

To stimulate the right ventricle, it is sufficient to implant an endocardial lead through the right peripheral venous network. However, the situation of stimulating the left ventricle is more complicated. The most commonly used solution is to introduce leads into the coronary mesh instead of stimulation within the cavity, the leads provided with electrodes being applied epicardially against the heart wall and oriented in the direction of the left ventricle. These leads stimulate the myocardium via one or more point electrodes whose position varies with the trajectory of the pre-determined cannulated vein. This type of lead is the status LV mode sold, for example, by Sorin CRM (Clamart, france) and described in EP0993840a 1(ELA Medical company). The introduction of such a guide wire is effected via the coronary sinus because of its opening in the right atrium. The lead is then pushed along the coronary vein mesh and directed to a selected site. Upon reaching the target vein, the surgeon looks for a satisfactory stimulation site and makes good electrical contact of the stimulation electrode against the epicardial tissue. The contact is maintained even with various changes or pressures over time. This implantation technique is not always possible, particularly when the shape of the coronary sinus is too uneven, or in the case of thrombosis. In fact, the precise positioning of the electrode(s) stimulating the left ventricle across the myocardial wall is a critical parameter and is not always able to reach the effective stimulation site.

Another more difficult and invasive technique involves implanting epicardial electrodes on the outer wall of the myocardium at one or more suitable sites facing the left ventricular cavity. A variation of this technique is described in EP2308550a1 (SorinCRM), which involves implantation of an electrode formed by an electrically conductive helical coil of a coil lead via a curved catheter inserted within the pericardial sac. However, these techniques are relatively invasive and are generally irreversible because it is difficult to alter the initially selected implantation site, and if desired, the lead can only be explanted at a later time.

Another method to which the present invention is applicable is by applying pacing pulses to the wall of the ventricular septum (the wall separating the left and right ventricles) to stimulate the left ventricle with the aid of a lead inserted into the right ventricle using conventional methods. This technique involves drilling the atrial or ventricular septum and then introducing a guide wire through the septum until it makes point contact with the left ventricular wall. The stimulation pulse is then applied directly to the selected left endocardial site. One example of a controlled trans-septal/trans-septal (trans) puncture technique may be found in EP1516644a1(ELA Medical), which describes a guide having a fixed spiral with one end near the right septum wall, and in which a puncture stylet is inserted to initiate septum puncture. After withdrawing the piercing stylet, a guide stylet is inserted into the device to form an axial guide, wherein the pacing lead with the electrode is introduced into the left cavity after removal of the device.

Another technique for making a transseptal puncture is described in EP2327366a1(Sorin CRM), which anchors a spiral to the septum wall and then applies radio frequency energy to the spiral to cause it to become progressively recessed into the septum wall until it penetrates the septum wall. The puncture may also be performed by a wire provided with radio frequency energy that is pushed to pass from one side of the septum to the other.

These techniques have several disadvantages, mainly because they require a puncture in the septum wall and the diameter of the puncture is sufficient to insert a catheter for establishing communication between the left and right cavities through the wall, followed by insertion of the left endocardial stimulation lead. Since the element that leads to the left ventricular element is a hollow catheter, this results in a significant risk of air emboli. In order to avoid such a risk, it is necessary to take various precautions in operating the hemostatic valve, to meet the decontamination procedure, and the like. However, given the highly invasive nature of this procedure, this uncertainty in behavior will remain in the long-term circulation, which includes anticoagulation to prevent post-operative thromboembolism. Finally, a subsequent removal of the wire is practically impossible, since this would lead to an excessively high risk when passing through the membrane.

In summary, these techniques are difficult to implement and require a high degree of skill on the part of the doctor who must ensure perfect positioning of the piercing needle on the septum wall before passing through the septum, which can only be initiated if the position of the needle is not in any question, in order to avoid accidental cutting of the septum wall due to the abrupt movement of the needle that pierces the septum, specific drilling devices have been developed, such as those described in EP1516644a1 and EP2327366a1 above.

Yet another technique designed to reduce these risks is described by EP2457612a1 and EP2384784 (SorinCRM). The basic idea is to remove the guiding catheter associated with the catheter through the septum and replace it by a conventional guide wire threaded onto the septum of the right ventricular wall, extending the guide wire through a transseptal microcable (microcable), which is partially insulated and pushed into the left ventricle to contact a target located in that ventricle, for example, with the free wall of the left ventricle (i.e., the free wall is on the opposite side of the septal wall).

This technique greatly reduces the risks of the prior related art due to the extremely fine penetration (size of the micro-cable diameter). However, since the microcatheter is freely disposed within the left ventricle, it is difficult to control the delivery of pacing pulses at a particular site, and because of the physical instability of the microcatheter on the free wall caused by the high flexibility of the microcatheter, it is difficult to ensure adequate and sustained contact between the electrode of this free portion and the wall of the left ventricle. Furthermore, transferring the puncture push via a micro cable would be difficult: indeed, the requirement for mechanical life requires a very good flexibility of the micro-cable, but the flexibility is incompatible with the necessary requirements for "pushability" (ability to transmit axial thrust applied from the proximal end) during the puncturing step.

Disclosure of Invention

The basic idea of the present invention is to overcome the above drawbacks and limitations by extending the helical lead fixed to the right wall of the ventricular septum with a very thin telescopic needle to achieve minimal invasion. The needle is extended to pierce the septum thickness but with little or no exposure of the left sidewall. The helix is in principle passive/inactive (it has only a mechanical function) but the tip is active/active (active), with one or more electrodes that can reach the left branch of the his bundle accurately: the branch is in fact a fast-conducting line and the stimulation of the left ventricle is effective without delay, even in the case of, for example, a local left block. It can be seen that the lead is provided with means for fine adjustment of the penetration depth to reach the desired target area according to a completely gentle and controlled method, except for the inclusion of conventional surgical procedures common to physicians.

By the above techniques such as those taught by EP2457612a1 and EP2384784 described above, it is intended to implant a micro cable that is pushed through the septum into the left ventricle to contact against a target in the ventricle (e.g. against the free wall of the ventricle, which is on the opposite side of the septum wall), which however cannot be achieved with current intra-septal (intraseptal) stimulation needles, rather than transseptal (transseptal) stimulation needles.

In fact, as long as the stimulation has to take place at the membrane, the position of the needle tip needs to be precisely adjusted, i.e. the active part with the stimulation electrode(s), which after implantation has to be within the thickness of the membrane. This technique is not possible by simply pushing the micro-cable in the sheath, which is not sufficient to ensure the millimeter accuracy required for intra-septal implantation.

WO2012/073097a2 and u.s.2001/0023367a1 describe needle insertion mechanisms in different contexts that do not involve cardiac pacing.

In order to achieve the objects outlined above, the present invention provides a wire of the general type disclosed in EP2457612a1 mentioned above, i.e. comprising: a lead body having a flexible hollow sheath that isolates a central lumen that receives an inner conductor that moves axially and rotatably within the lumen; an electrical connector at a proximal side thereof connected to a generator of an active implantable medical device, the connector having at least one center pin connected to an inner conductor; a lead at its distal end having a tubular body integral with the sheath and extending distally by extending a fixed helical thread integral with the lead body.

The lead extends into the lumen of the right ventricle and the anchoring helix pierces the right ventricular septum wall under the influence of helical motion of the sheath of the lead from the proximal end of the lead.

The lead further includes a stimulation needle electrically connected to the inner conductor and including an active free portion at a distal end thereof, the active free portion having at least one stimulation electrode for applying stimulation pulses. The stimulation needle is a retractable needle that is axially movable between a retracted position inside the tubular body and a fully or partially deployed position in which an active free portion of the needle is exposed outside the tubular body.

The invention is typically capable of intra-septal stimulation by a needle, wherein the pulse is applied to an area of the septum proximate to a left wall area of the septum, the lead further comprising an actuation mechanism that provides controlled movement of the needle from its retracted position to its fully or partially extended position under relative rotational movement of the connector pin with respect to the lead body, the movement being transmitted from the pin to the proximal end of the lead. The actuation mechanism comprises a guide core rotationally and translatably fixed to the needle and rotationally and translatably movable within the tubular body, and means coupling the core to the tubular body for converting relative rotational movement of the core with respect to the tubular body into axial translational movement of the core within the tubular body.

According to various embodiments:

the coupling means may be in the form of a nut and screw having an internal helically threaded tubular body member fitted with coupling elements engaging the threads of the tubular body, in particular the helical threads carried by the outer surface of the core;

the inner conductor screw is a helical conductor arranged in the peripheral region of the hollow sheath;

the amplitude of the axial translational movement of the core inside the tubular body may be between 10 and 15 mm;

the length of the projecting portion of the needle in the extended position may be between 0 and 15mm and the diameter is 1.5 french (0.5 mm);

the outer surface of the needle may be electrically insulated except for at least one exposed area located at an active free portion forming the at least one stimulation electrode;

the active free portion may comprise at least one exposed area extending not more than 6mm from the free distal end of the needle;

the wire may comprise a plurality of distinct exposed regions, which extend successively along the active free portion and are separated by unexposed insulating spacers;

the total area of the exposed region(s) of the active part may not exceed 6mm²；

At its proximal portion, the needle may extend through a stem integral therewith, and wherein the stem is welded to the inner conductor;

the fixed screw and/or the tubular body may be electrically inactive/non-electrically active.

Drawings

Further features, characteristics and advantages of the present invention will become apparent to those of ordinary skill in the art from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings, wherein like reference numerals represent like elements, and wherein:

fig. 1 is a schematic cross-sectional view of a myocardium showing the different cavities and major conductive paths of the myocardium.

Figures 2 to 3 are cross-sectional views of the lead in the retracted and extended positions of the stimulation needle, respectively.

Figures 4a-4e illustrate various stages of implantation of the lead of the present invention into the wall of the ventricular septum.

Detailed Description

Fig. 1 is a schematic cross-sectional view of a myocardium 10 having a right ventricle 12 and a left ventricle 14 separated by a ventricular septum 16. Which is typically about 10 to 15mm thick and constitutes a significant portion of the heart's mass.

The depolarization wave originating from the sinoatrial node 18 is transmitted to the atrioventricular node 20 and the his bundle 22. the his bundle 22 is divided into two branches extending along the septum 16, a straight branch 24 in the region of the right septal wall 26 and a left branch 28 in the region of the left septal wall 30.

In particular, the left branch 28 is a fast longitudinal conductive line (arrow 32) with a speed of about 4 m/s. However, conventional techniques for implementing telescoping helical leads can stimulate the right wall 26, so in order to stimulate the left ventricle 14, the depolarization wave must pass through the septum 16 (arrow 34), but the speed of cross conduction is relatively low, on the order of 0.4 m/s. This results in a delay of approximately 30ms between the application of the pulse on the right lateral portion 26 and the stimulation of the left branch 28 causing contraction of the left ventricle 14.

Moving the stimulation point of the right wall of the septum (conventional technique) to the left wall of the septum, near the left branch 28 of the his bundle (inventive technique) can significantly help to reduce the time between pulse application and actual contraction of the left ventricle, and/or mitigate the effects of local left-side block.

In accordance with the present invention, a lead 36 implanted in the right lumen in a conventional manner is employed for this purpose, having a lead head 38 secured against the right wall 26 of the septum 16. The lead is extended by a telescopic needle, the distal end 40 of which carries the stimulation electrodes. Gentle and controlled puncture of the septum allows the tip 40 of the needle to be placed near the left wall 30 without penetrating the septum, or just opening the left wall, to just directly stimulate the left branch 28 of the his bundle in the fast conduction region, thereby providing direct and rapid stimulation of the left ventricle.

Figures 2 and 3 show in more detail the structure of the lead head 38 at the distal end of the lead 36 and intended to abut against the right septum wall, in the retracted and extended positions of the telescopic needle, respectively.

The lead body 42 includes an insulative flexible hollow sheath 44, for example of a material such as polyurethane which has good slip properties when the sheath is inserted into a delivery catheter, and has "torquability", the ability to transmit torque from the proximal end of the lead to the distal end. The lumen of the hollow sheath 44 houses one or more internal conductors, such as, as shown in the example, a helical conductor 46 disposed in a peripheral region of the hollow sheath, so as to leave a vacant central space, particularly for inserting a guiding and/or stiffening stylet in the sheath. This configuration would advantageously be "coaxial" if the sheath had multiple inner conductors, where two (or more) conductors are insulated conductors in the peripheral region of the lumen of the hollow sheath 44 and form a side-by-side helix of a single radius coil having one particular thickness.

The sheath 44 of the lead extends to its distal end through a tubular body 48 having an outer diameter of about 7 French (2.33 mm). The tubular body 48 carries a helical anchoring helix 50 at its distal end, which extends for about 2mm in axial length. The helical screw is secured to the tubular body 48 and is secured at its opposite proximal end to the hollow sheath 44 at location 52. Thus, any rotational movement of the lead body under the influence of a specific torque applied by the physician from the proximal end of the lead will be fully transmitted through the tubular body 48 to the helical helix 50, these three elements being integral with one another.

Implanted lead screws similar to those already described are typically used as the detection/stimulation lead after the screw is secured to the endocardial stimulation site.

This is not the case in the present invention: the function of the spiral here is to support and guide the stimulating needle penetrating into the septal wall. For embodiments of the present invention, the helix 50 and the tubular body 48 are not (or need not be) electrically active elements.

In the retracted position (fig. 2), the tubular body 48 houses a retractable stimulation needle 54, which retractable stimulation needle 54 is axially translatable relative to the tubular body 48 between a retracted position in fig. 2 and an extended position in fig. 3. The telescoping needle 54 extends proximally through an axial stem 56, and for operation, the stem 56 is welded proximally to the distal end of the inner conductor 46 so that any axial or rotational movement of the inner conductor 46 is fully transmitted to the needle 54. In addition, the pin 54 is not only mechanically connected to the inner conductor 46 but also electrically connected to the inner conductor 46.

In particular, the proximal end of the inner conductor 46 is connected to a pin 58 of a connector 60 for connecting to the pulse generator housing. This IS, for example, an IS-1 standard connector or similar connector having a pin 58 that IS rotationally movable relative to a connector body 60 to allow a pin-driving operation in which a physician holds the connector body 60 (integral with the sheath 44 of the lead body 42) in one hand and applies rotation to the pin 58 of the connector by the other hand, either directly or via a tool. The pin 58 is integral with the axial conductor 46 and is free to rotate within the hollow sheath 44, the movement of the pin being transmitted directly to the mandrel 56 and the retractable needle 54.

The telescopic needle 54 is a solid needle so no hollow element is provided in the left ventricle in case the needle penetrates the septum and therefore no risk of any air emboli is created.

The guiding and deployment of the telescopic needle 54 is controlled by a movable element 62, which movable element 62 is inside the tubular body 48 and forms the guiding and driving core. The core 62 integral with the stem 56 is coupled to the tubular body, for example by means of the cooperation of an external thread 64 integral with the core 62 and an internal thread 66 integral with the tubular body 44. Thus, relative axial rotational movement of rod 56 relative to tubular body 48 (caused by corresponding relative rotational movement of pin 58 relative to connector 60 (proximal)) results in axial translation of drive core 62 and retractable needle 54 relative to tubular body 48.

The magnitude of this axial displacement is typically about 10 to 15mm and has a value significantly greater than conventional deployment mechanisms for the helix of the retractable helical wire.

Flexible bearings 68 and 70 are provided distal and proximal of the tubular body 48 for guiding the needle and for sealing the interior volume of the tubular body and the lumen of the sheath 44, respectively.

In the retracted state (fig. 2), the needle 54 is completely housed inside the tubular body 48, from which only the helical fixing screw 50 protrudes, the screw 50 being fixed with respect to the tubular body 48.

In the fully deployed state (fig. 3), the retractable needles 54 are exposed from the tubular body for a length of about 15 mm.

In a method adjustable by the physician, the needle can be retracted between any of these extreme positions in a controlled manner, thus extending and retracting in a length between 0 and 15 mm.

The retractable needle 54 is made of a conductive material and has a general diameter of 1 french (F) (0.33 mm). In particular, the material may be a stainless steel alloy, such as MP35N, or consist of a composite structure, for example MP35N in the core and a biocompatible and radiopaque coating, such as a platinum or platinum alloy coating, around its periphery.

Alternatively, the intraseptal stimulation needles 54 may be made of micro-cables having a diameter of about 1.5F (0.5 mm), which allows them to benefit from the relative flexibility of the micro-cable and thus have better fatigue resistance than a monofilament configuration of the same diameter. Such a micro-cable may include a core of a plurality of composite wires stranded together, such as a central wire bundle surrounded by six peripheral wire bundles. Each composite bundle is itself made up of wires, the core of which is platinum iridium (for radiation protection) surrounded by a plurality of composite wires providing the required mechanical and electrical properties, for example a silver core (for electrical conductivity) wrapped in nitinol (for mechanical stress resistance characteristics). These various electrical wires are available, for example, from Fort Wayne Metals Company inc, Fort Wayne, usa, and are used in the medical field, particularly in the manufacture of defibrillation conductors.

The retractable stimulation needle 54 is wrapped with an electrically insulating material, such as parylene. To form the active free portion 40, the insulating coating of the needle is partially removed to form one or more ablation regions 72 separated by insulating regions 74. Advantageously, the active free portion 40 has an ablation area 72 extending over a length of about 6mm, the surface of the ablation area being at most 6mm²To limit the stimulation surface.

Having a plurality of electrodes 72 over a relatively significant length (6 mm) provides the possibility of compensating for variations in the thickness of the diaphragm, which contracts during the heart cycle and thus maintains a tissue-facing stimulation surface.

From an electrical point of view, the fixed screw 50 and the tubular body 48 are in principle inactive and coated with an insulating material, such as parylene, over their entire surface. In a particular configuration, however, it is possible to make the fixation screw 50 and/or all or part of the tubular body 48 electrically active, for example to allow simultaneous stimulation at the fixation screw (right wall of the septum) and the active free portion 40 of the telescopic needle (left wall of the septum).

A method of implanting the above-described lead will now be described with reference to fig. 4a to 4 e.

Prior to this, the wire is inserted into a conventional catheter 76 for pre-positioning the wire head against the compartment wall. The catheter has an outer diameter of substantially 9 french (3 mm). The use of a catheter allows the fixation screw 50 (not a retractable screw) to be protected during transvascular and tricuspid valve passage. Examples of suitable catheters allowing access to the right wall of the compartment are described in, for example, EP2135638a1 (pre-shaped catheter, which is self-adjusting in the direction of the septum wall) and FR2932688a1 (bi-material catheter, the ends of which are optionally adaptable), both of which applications belong to Sorin CRM s.a.s. company, formerly elamedia company.

The first stage is to confirm the fixation site by manipulating the guide wire assembly for introduction into the superior vena cava, right atrium, and right ventricle 12 until it abuts the right wall 26 of the interventricular septum 16.

Figure 4a illustrates the configuration achieved when the conduit 76 is brought against the right wall of the diaphragm 16 with the lead 38 located inside the conduit 76 and adjacent the wall 26.

The next step illustrated in figure 4b is to apply a rotational motion (arrow 78) to the sheath 44 of the lead body from the proximal end of the lead body. This rotation causes the screw 50 to penetrate the tissue of the septum 16 to a relatively small depth (about 2 mm), thereby securing the tubular body 48 integral with the screw against the right wall 26 of the septum. Full screwing is tactilely detected by the doctor through the resistance to rotation.

The reached part is confirmed according to different impact forces through radiographic detection; if the position is not satisfactory, the physician can unscrew the lead and move to another point under control and test a new site.

The physician rotates the pins 58 of the connector 60 so long as the tubular body 48 is secured to the septum wall. Rotation (arrow 80 of fig. 4 c) transmitted through the inner conductor 46 is applied to the lever 56, thus causing the telescoping stimulation needle 54 to progressively penetrate the thickness of the septum 16 from the lead body, while the sheath 44 and the tubular body 48 remain stationary during this deployment.

This operation is performed under fluoroscopy to visualize the position of the active portion 40 relative to the septum wall (which may optionally be visualized by injecting contrast media through the catheter 76). The physician may also map or electrically measure at this stage to verify the effectiveness of the selected site in order to determine the optimal location of the active portion 40 of the needle, that is, the extent of its deployment.

If the initially selected location is not satisfactory, one or more repositioning may be performed. In fact, the use of the fixation of the helix 50 with a relatively small thickness (about 2mm for a typical chamber spacing of 10 to 15 mm) and the removal of the guide wire with a small diameter (about 0.3mm because of the small diameter of the needle 55) does not result in irreversible damage to the septum, and therefore has a smaller tolerance than conventional septum penetration access due to its remaining penetration dimension (corresponding to the diameter of the catheter, typically greater than 9 french or 2.3 mm).

A more or less important deployment of the telescopic needle 54 allows not only to take into account the variation of the thickness of the septum according to the implanted area, but also reflects the fact that the guide wire can be positioned in a position more or less perpendicular to the septum wall (with a convex shape, seen in cross section).

Once the final site and degree of deployment of the retractable needle is selected, the physician removes the catheter 76, resulting in the final configuration of the wire guide.

In the configuration shown in figure 4d, the distal end 54 of the needle (with active portion 40) does not exit the left wall 30 of the septum.

However, as shown in fig. 4, it may be of interest to fully penetrate the septum to position the free end 40 of the needle 54 so that it is slightly exposed within the cavity of the left ventricle. This avoids the effect of the tip of the needle peeling away from the target tissue, which would cause damage to the tissue and loss of capture during pacing.

Those skilled in the art will appreciate that the present invention can be practiced by other than the specific embodiments disclosed herein, which are presented for purposes of illustration and not of limitation.

Claims (15)

1. A pacing lead, comprising:

a lead body comprising a hollow sheath containing an inner conductor, wherein the inner conductor is axially rotatably movable within the hollow sheath, wherein the inner conductor terminates at a distal end of the hollow sheath, and the lead body has an electrical connector at a proximal end for coupling the inner conductor to a generator of an active implantable medical device;

the lead body further comprises a tubular body having a proximal end and a distal end, wherein the proximal end of the tubular body receives the distal end of the hollow sheath;

a helical fixation screw extending from the distal end of the tubular body, integral with the tubular body, wherein the helical fixation screw is configured to penetrate a wall of a target tissue under rotational motion of the lead body from the proximal end of the lead;

a stimulation needle electrically coupled at a proximal end thereof to the distal end of the inner conductor and including an active free portion at a distal end thereof, the active free portion providing at least one stimulation electrode for applying pacing pulses to the target tissue;

wherein the stimulating needle is axially movable between a retracted position inside the tubular body and a deployed position in which the active free portion of the stimulating needle is exposed outside the tubular body; and

an actuation mechanism providing controlled movement of the stimulation needle from its retracted position to its deployed position under the effect of rotational movement relative to the tubular body;

the actuation mechanism includes a core coupled to a proximal portion of the stimulation needle and is rotationally and translatably secured in the tubular body by at least one coupling member and rotationally and translatably movable relative to the tubular body.

2. The lead of claim 1, wherein the coupling member includes external threads that mate with corresponding internal helical threads of the tubular body.

3. The lead of claim 1, wherein the rotational motion relative to the lead body is transmitted from a proximal end of the inner conductor coupled to the stimulation needle.

4. The lead of claim 1, wherein the inner conductor is a helical conductor disposed in a peripheral region of the hollow sheath.

5. The lead of claim 1, wherein the core has an axial translation range of between 10mm to 15mm inside the tubular body.

6. The lead of claim 1, wherein the stimulation needle in the deployed position extends a length between 0 and 15mm beyond the proximal end of the tubular body.

7. The lead of claim 1, wherein the stimulation needle has a diameter of at most 1.5 french, 0.5 mm.

8. The lead of claim 1, wherein the stimulation needle includes an outer surface that is electrically insulated except for at least one exposed area located in the active free portion and forms at least one stimulation electrode.

9. The wire of claim 8, comprising a plurality of distinct exposed regions extending sequentially along the active free portion and separated by an insulated intermediate region.

10. The lead of claim 1, wherein the electrical connector includes at least one center pin connected to the inner conductor.

11. The lead of claim 1, wherein the proximal end of the stimulation needle extends through a rod integral therewith, and wherein the rod is welded to the inner conductor.

12. The lead of claim 1, wherein the helical set helix is electrically passive.

13. The lead of claim 1, wherein the tubular body is electrically passive.

14. The lead of claim 1, wherein the lead is a left ventricular pacing lead within a heart comprising the helical fixation helix for piercing a ventricular septum having a right wall and a left wall and the at least one stimulation electrode, wherein the lead pierces the right wall and the at least one stimulation electrode is for applying pacing pulses to the ventricular septum in a region adjacent to the left wall of the ventricular septum.

15. A wire, comprising:

a lead body comprising a hollow sheath containing an inner conductor, wherein the inner conductor is axially rotatably movable within the hollow sheath, and wherein the inner conductor terminates at a distal end of the hollow sheath and the lead body has a proximal end;

the lead body further comprises a tubular body having a proximal end, wherein the proximal end of the tubular body receives the distal end of the hollow sheath;

a helical fixation helix extending from a distal end of the lead body;

a stimulation needle electrically coupled at a proximal end thereof to the distal end of the inner conductor and including an active free portion at a distal end thereof providing at least one stimulation electrode for applying pacing pulses to a target tissue;

wherein the stimulating needle is axially movable between a retracted position inside the tubular body and a deployed position in which the active free portion of the stimulating needle is exposed outside the tubular body; and

an actuation mechanism providing controlled movement of the stimulating needle from its retracted position to its deployed position under the influence of rotational movement relative to the lead body.