LEAD FOR AN IMPLANTABLE STIMULATION DEVICE FOR CARDIAC STIMULATION OF A PATIENT

Abstract

A lead for an implantable stimulation device for cardiac stimulation of a patient generally extends along a longitudinal axis. The lead comprises a body section, a distal lead section extending from the body section along the longitudinal axis and forming a distal end, a first electrode device arranged on the distal lead section for at least one of transmitting an electrical pacing signal and sensing an electrical sense signal, the first electrode device being configured for placement in or on intra-cardiac tissue, and a second electrode device arranged on the body section for emitting an electrical defibrillation signal. The distal lead section in at least one portion comprises a reduced bending stiffness with respect to at least a portion of said body section.

Claims

1. A lead for an implantable stimulation device for cardiac stimulation of a patient, the lead generally extending along a longitudinal axis and comprising: a body section, a distal lead section extending from the body section along the longitudinal axis and forming a distal end, a first electrode device arranged on the distal lead section for at least one of transmitting an electrical pacing signal and sensing an electrical sense signal, the first electrode device being configured for placement in or on intra-cardiac tissue, and a second electrode device arranged on the body section for emitting an electrical defibrillation signal, wherein the distal lead section in at least one portion comprises a reduced bending stiffness with respect to at least a portion of said body section.

2. The lead according to claim 1, wherein the distal lead section in at least one portion comprises a reduced bending stiffness with respect to a portion of said body section carrying the second electrode device.

3. The lead according to claim 1, wherein the distal lead section comprises an isodiametric cross-sectional shape.

4. The lead according to claim 1, wherein the body section comprises an isodiametric cross-sectional shape.

5. The lead according to claim 1, wherein the distal lead section comprises a first diameter and the body section comprises a second diameter, wherein the first diameter is smaller than the second diameter.

6. The lead according to claim 1, wherein the distal lead section comprises a length, measured between the distal end and the body section, equal to or larger than 10 mm.

7. The lead according to claim 1, wherein the first electrode device is arranged at the distal end.

8. The lead according to claim 1, wherein the first electrode device is configured to pierce into intra-cardiac tissue for fixing the lead at the distal end to intra-cardiac tissue.

9. The lead according to claim 1, wherein the first electrode device is form by a screw to engage with intra-cardiac tissue.

10. The lead according to claim 1, wherein the first electrode device extends from the distal end by a length, as measured along the longitudinal axis, configured to reach into a left bundle branch of the cardiac conduction system for injecting a pacing signal into the left bundle branch.

11. The lead according to claim 1, wherein the distal lead section comprises at least one drug eluting reservoir.

12. The lead according to claim 1, wherein the second electrode device comprises a helical coil-shape.

13. The lead according to claim 1, wherein the second electrode device comprises at least a first electrode section and a second electrode section, wherein the lead comprises a connection section extending in between the first electrode section and the second electrode section.

14. The lead according to claim 13, wherein the connection section in at least one portion comprises a reduced bending stiffness with respect to a portion of said body section carrying the first electrode section and/or to a portion of said body section carrying the second electrode section.

15. A method for operating an implantable stimulation device for cardiac stimulation of a patient, comprising: providing a lead generally extending along a longitudinal axis, the lead comprising a body section and a distal lead section extending from the body section along the longitudinal axis and forming a distal end, the lead further comprising a first electrode device arranged on the distal lead section for at least one of transmitting an electrical pacing signal and sensing an electrical sense signal and a second electrode device arranged on the body section for emitting an electrical defibrillation signal, using the first electrode device, which is placed on intra-cardiac tissue to reach into a left bundle branch of the cardiac conduction system, to at least one of inject pacing signals into or receive sense signals from the left bundle branch.

16. The lead according to claim 1, wherein the distal lead section comprises a length, measured between the distal end and the body section, equal to or larger than 50 mm.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] An idea of the present invention shall subsequently be described in more detail with reference to the embodiments shown in the figures. Herein:

[0034] FIG. 1 shows a schematic view of the human heart, including the Sinoatrial node, the Atrioventricular node, the HIS bundle and the left bundle branch and right bundle branch extending from the HIS bundle;

[0035] FIG. 2 shows a view of an embodiment of a lead placed in the right ventricle of the heart for providing for a left bundle branch pacing as well as a defibrillation therapy;

[0036] FIG. 3 shows an embodiment of a lead combining electrodes for a left bundle branch pacing and a defibrillation therapy;

[0037] FIG. 4 shows a front view of a distal end of the lead;

[0038] FIG. 5 shows a view of another embodiment of a lead placed in the right ventricle of the heart; and

[0039] FIG. 6 shows an embodiment of an electrode device arranged on a distal end of a distal lead section.

DETAILED DESCRIPTION

[0040] Subsequently, embodiments of the present invention shall be described in detail with reference to the drawings. In the drawings, like reference numerals designate like structural elements.

[0041] It is to be noted that the embodiments are not limiting for the present invention, but merely represent illustrative examples.

[0042] FIG. 1 shows, in a schematic drawing, the human heart comprising the right atrium RA, the right ventricle RV, the left atrium LA and the left ventricle LV, the so-called sinoatrial node SAN being located in the wall of the right atrium RA, the sinoatrial node SAN being formed by a group of cells having the ability to spontaneously produce an electrical impulse that travels through the heart's electrical conduction system, thus causing the heart to contract in order to pump blood through the heart. The atrioventricular node AVN serves to coordinate electrical conduction in between the atria and the ventricles and is located at the lower back section of the intra-atrial septum near the opening of the coronary sinus. From the atrioventricular node AVN the so-called HIS bundle H is extending, the HIS bundle H being comprised of heart muscle cells specialized for electrical conduction and forming part of the electrical conduction system for transmitting electrical impulses from the atrioventricular node AVN via the so-called right bundle branch RBB around the right ventricle RV and via the left bundle branch LBB around the left ventricle LV.

[0043] In the embodiment of FIG. 1, an implantable medical device 1 in the shape of a stimulation device, such as a CRT device, is implanted in a patient, the implantable medical device 1 comprising a generator 12 connected to leads 10, 11 extending from the generator 12 through the superior vena V into the patient's heart. By means of the leads 10, 11, electrical signals for providing a pacing action in the heart shall be injected into intra-cardiac tissue potentially at different locations within the heart, and sense signals may be received. In addition, a defibrillation therapy may be performed by an electrode arrangement arranged on one or both of the leads 10, 11.

[0044] In an embodiment shown in FIG. 2, a lead 10 is implanted into the heart such that it extends into the right ventricle RV of the heart and, at a distal end 102, is arranged on intra-cardiac tissue at the septum M in between the right ventricle RV and the left ventricle LV of the heart. At the distal end 102 herein an electrode device 14 in the shape of a screw is arranged, the electrode device 14 being screwed into intra-cardiac tissue for injecting electrical signals into the intra-cardiac tissue or for receiving sense signals from the intra-cardiac tissue.

[0045] An embodiment of such a lead 10 is shown in FIG. 3. The lead 10 comprises a body section 100 having a tube shape and forming, for example, an inner lumen. The body section 100 carries an electrode device 13 which comprises a coil shape and is wound about or embedded in the body section 100, the electrode device 13 serving as a shock electrode for providing for a defibrillation function in an implanted state of the lead 10. A distal lead section 101 extends from the body section 100 distally from the electrode device 13, the distal lead section 1 carrying, at a distal end 102, the electrode device 14 in the shape of the screw to be engaged with intra-cardiac tissue for fixing the lead 10 into intra-cardiac tissue at the distal end 102.

[0046] In one embodiment, both the body section 100 and the distal lead section 101 comprise an iso-diametric cross-section, as this is visible, e.g., from FIG. 4. Herein, the distal lead section 101 comprises a reduced bending stiffness in that the diameter D1 of the distal lead section 101 is reduced in comparison to the diameter D2 of the body section 100. Hence, the distal lead section 101 with the electrode device 14 arranged thereon may be flexibly bent, a stiffness along the length L2 of the distal lead section 101 being reduced with respect to the body section 100, in particular the portion of the body section 100 carrying the electrode device 13.

[0047] This allows, as this is shown in FIG. 2, to arrange the lead 10 in the right ventricle RV such that the electrode device 14 on the distal end 102 formed by the distal lead section 101 comes to rest on the septum M in the range of the right bundle range RBB and the left bundle range LBB. Herein, the electrode device 14 in the shape of the screw, in addition to its electrical function, provides a fixation means which may be screwed into the septum M such that the electrode device 14 provides for a fixation within the septum M. By means of the electrode device 14 the lead 10 at its distal end 102 hence is fixed to the septum M and held in place on the septum M.

[0048] As visible from FIG. 2, the electrode device 14 may be inserted into the septum M such that it reaches, from the right ventricle RV, towards the left bundle branch LBB and engages with the left bundle branch LBB for injecting stimulation signals into the left bundle branch LBB for providing for a pacing using the left bundle branch LBB. In addition or alternatively, sense signals may be received from the left bundle branch LBB.

[0049] Referring now to FIG. 6, the electrode device 14, in one embodiment, comprises the shape of a screw extending over a length L1 from the distal end 102, as measured along a longitudinal axis L along which the lead 10 generally extends. The length L1 herein is chosen such that the electrode device 14 may be inserted into the septum M such that it reaches into a depth at which the left bundle branch LBB is placed, such that a left bundle branch pacing or sensing may be achieved by means of the lead 10.

[0050] As visible from FIG. 6, the electrode device 14 in one embodiment may comprise a body 140 formed by an electrically conductive core 141 which extends along the electrode device 14 and in portions is covered by an insulating layer 142. For example, the core 141 is exposed towards the outside only at a distal end 143 forming a contact section for electrically contacting intra-cardiac tissue. In this way it can be achieved that the electrode device 14 extends across the right bundle branch RBB, as visible from FIG. 2, towards the left bundle branch LBB, but electrically contacts only the left bundle branch LBB for providing a pacing and/or sensing at the left bundle branch LBB.

[0051] In an alternative embodiment, the electrode device 14 may be electrically conducting and exposed along its entire length L1 and may contact electrically with intra-cardiac tissue along its entire length L1. In such embodiment, for example, a synchronous pacing at the right bundle branch RBB and the left bundle branch LBB by means of the electrode device 14 may be achieved.

[0052] Referring now again to FIG. 3, a reservoir 15 may be formed in the region of the distal end 102 of the distal lead section 101, the distal lead section 101, for example, comprising a drug reservoir such as a steroid eluting reservoir to be emitted towards intra-cardiac tissue for reducing or preventing a rise of a stimulation threshold after implantation.

[0053] As visible from FIG. 3 and FIG. 4, the electrode device 14 in the shape of a screw has a diameter which is only slightly smaller than the diameter of the distal lead section 101. This may allow to screw the electrode device 14 into the septum M such that also at least a portion of the distal end section 101 is introduced into the septum M, bringing the reservoir 15, for example, into contact with intra-cardiac tissue.

[0054] Referring now again to FIG. 2, because the distal lead section 101 comprises an increased bending flexibility with respect to the body section 100 of the lead 10, the lead 10 may be arranged in the right ventricle RV such that a loop is formed, the electrode device 13 serving as a shock electrode being placed in the region of the vertex of the right ventricle RV. Because the distal lead section 101 is substantially flexible, the distal end 102 formed by the distal lead section 101 may be placed on the septum M in the region of the left bundle branch LBB, the distal lead section 101 assuming a rather tight bending radius allowing the electrode device 13 to come to rest in the region of the vertex of the right ventricle RV and hence allowing for an efficient defibrillation action.

[0055] To allow the distal lead section 101 to flexibly bend such that the electrode device 13 may reach into and come to rest in the region of the vertex of the right ventricle RV, the length L2 of the distal lead section 101 may be equal to or larger than 10 mm, preferably equal to or larger than 20 mm, more preferably equal to or larger than 30 mm, even more preferably equal to or larger than 40 mm or even 50 mm. The distal lead section 101 hence comprises a length L2 allowing the electrode device 13 to be arranged at a substantial distance from the left bundle branch LBB to which the distal end 102 of the distal lead section 101 with the electrode device 14 arranged thereon is connected.

[0056] Referring now again to FIG. 3, the lead 10, at a proximal end, comprises a connector 16 having contacts 160 for electrically contacting with a connector block of the generator 12. The connector 16 may, for example, have the shape of a (standardized) DF4 connector.

[0057] In the embodiment of FIGS. 2 and 3, the electrode device 13 serving as a shock electrode for a defibrillation therapy extends over a length L3 on the body section 100, the electrode device 13 being formed by a continuously wound coil.

[0058] In another embodiment shown in FIG. 5, the electrode device 13 is divided into two electrode sections 13A, 13B which are spatially separated from one another and each are formed as a wound coil. In between the electrode sections 13A, 13B a connection section 103 extends, the connection section 103 having a reduced bending stiffness such that the lead 10 may flexibly bend at the connection section 103 and in particular may assume a rather tight bending radius. Hence, the sections 13A, 13B of the electrode device 13 may be arranged at a sharp angle with respect to one another, which facilitates the arrangement of the electrode device 13 in the region of the vertex of the right ventricle RV, as visible from FIG. 5.

[0059] Both in the embodiment of FIG. 2 and in the embodiment of FIG. 5 the electrode device 13 may extend from the right ventricle RV into the right atrium RA.

[0060] In either embodiment, the body section 100 may form an inner lumen into which, for example, a locking stylet may be inserted in order to facilitate an explantation of the lead 10. By means of the locking stylet a pulling force may be exerted on the distal lead section 101, the locking stylet preventing an axial deformation of the electrode device 13.

[0061] Electrical conductors may be embedded within the body section 100 and the distal lead section 101 in order to electrically connect the electrode device 13 of the electrode device 14 to the connector 16 for connection to the generator 12.

[0062] The idea of the present invention is not limited to the embodiments described above, but may be implemented in an entirely different manner.

[0063] One or multiple leads may be used on a generator. The leads herein may provide for a pacing and/or sensing of electrical signals at different locations within the heart. One or multiple leads, in addition to a pacing and/or sensing electrode, may comprise a defibrillation (shock) electrode such that, using a single lead, a pacing function as well as a defibrillation function may be provided.

[0064] It will be apparent to those skilled in the art that numerous modifications and variations of the described examples and embodiments are possible in light of the above teachings of the disclosure. The disclosed examples and embodiments are presented for purposes of illustration only. Other alternate embodiments may include some or all of the features disclosed herein. Therefore, it is the intent to cover all such modifications and alternate embodiments as may come within the true scope of this invention, which is to be given the full breadth thereof. Additionally, the disclosure of a range of values is a disclosure of every numerical value within that range, including the end points.

LIST OF REFERENCE NUMERALS

[0065] 1 Implantable medical device [0066] 10 Lead [0067] 100 Body section [0068] 101 Distal lead section [0069] 102 Distal end [0070] 103 Connection section [0071] 11 Lead [0072] 12 Generator [0073] 13 Electrode device [0074] 13A, 13B Electrode section [0075] 14 Electrode device [0076] 140 Screw body [0077] 141 Conducting core [0078] 142 Insulation layer [0079] 143 Contact section (free end) [0080] 15 Reservoir [0081] 16 Connector [0082] 160 Contact elements [0083] AVN Atrioventricular node [0084] D1, D2 Diameter [0085] H HIS bundle [0086] L Longitudinal axis [0087] L1, L2, L3 Length [0088] LA Left atrium [0089] LBB Left bundle branch [0090] LV Left ventricle [0091] M Intra-cardiac tissue (myocardium) [0092] RA Right atrium [0093] RBB Right bundle branch [0094] RV Right ventricle [0095] SAN Sinoatrial node [0096] V Superior vena