Leadless cardiac pacemaker device configured to provide his bundle pacing

Abstract

A leadless cardiac pacemaker device is configured to provide HIS bundle pacing and contains a housing having a tip, a first electrode arranged on the housing in the vicinity of the tip, the first electrode being configured to engage with intra-cardiac tissue, and a second electrode arranged on the housing at a distance from the tip of the housing. A processor is enclosed in the housing and operatively connected to the first electrode and the second electrode. The processor is configured to process a reception signal received by at least one of the first electrode and the second electrode and to generate a pacing signal to be emitted using at least one of the first electrode and the second electrode.

Claims

1. A delivery system for placement of a leadless pacemaker device in a human heart, the delivery system comprising: a catheter device for insertion into a human body, said catheter device having a lumen and a distal end to be inserted into the human body, the leadless pacemaker device configured to provide HIS bundle pacing, the leadless pacemaker device being received within said lumen in an area of said distal end of said catheter device; and a first mapping electrode and a second mapping electrode disposed in said area of said distal end of said catheter device for sensing, in a mapping mode, a mapping signal vector in between said first mapping electrode and said second mapping electrode, the mapping signal vector representing an electrogram of cardiac activity, at least one of said first mapping electrode or said second mapping electrode encircling an outer surface of said catheter device, and a distance between said first mapping electrode and said second mapping electrode matching a distance between a first electrode and a second electrode arranged on the leadless pacemaker device for HIS bundle pacing.

2. The delivery system of claim 1, wherein: the leadless pacemaker device has a housing with a tip; the other one of said at least one of said first mapping electrode and said second mapping electrode is disposed either: on said housing in an area of the tip; or on said housing at a distance from said tip; and the leadless pacemaker device has a communication interface for transmitting a communication signal containing information relating to the mapping signal vector from the leadless pacemaker device to an external device outside of the human body.

3. The delivery system according to claim 1, wherein both of said first mapping electrode and said second mapping electrode are disposed on said catheter device.

4. The delivery system according to claim 1, further comprising a mapping wire received within said catheter device, wherein the other one of said first mapping electrode and said second mapping electrode is disposed on said mapping wire.

5. A method for placing a leadless pacemaker device using a delivery system, the delivery system containing a catheter device for insertion into a human body and having a lumen, a distal end to be inserted into the human body, a first mapping electrode and a second mapping electrode disposed in an area of the distal end of the catheter device for sensing, at least one of the first mapping electrode or the second mapping electrode encircling an outer surface of the catheter device, and a distance between said first mapping electrode and said second mapping electrode matching a distance between a first electrode and a second electrode arranged on the leadless pacemaker device for HIS bundle pacing, which method comprises the step of: using the first mapping electrode and the second mapping electrode disposed in the area of the distal end of the catheter device in a mapping mode, for sensing, a mapping signal vector in between the first mapping electrode and the second mapping electrode, the mapping signal vector representing an electrogram of cardiac activity.

6. The delivery system according to claim 1, wherein the other one of said first mapping electrode or said second mapping electrode is disposed on a pin fixed to a housing of the leadless pacemaker device.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

(1) FIG. 1 is a schematic view of a human heart, including a Sinotrial node, an Atrioventricular node, a HIS bundle and a left bundle branch and right bundle branch extending from the HIS bundle;

(2) FIG. 2 is a view of an embodiment of a leadless pacemaker device received within a catheter device, partially deployed for mapping during placement according to the invention;

(3) FIG. 3 is a view of another embodiment of the leadless pacemaker device received within the catheter device;

(4) FIG. 4 is a view of yet another embodiment of the leadless pacemaker device received within the catheter device during placement;

(5) FIG. 5 is a schematic view of the catheter device having electrodes at a tip;

(6) FIG. 6 is a schematic view of another embodiment of the catheter device;

(7) FIG. 7 is a view of an embodiment of the leadless pacemaker device received in the catheter device, a mapping wire being received within the catheter device for mapping;

(8) FIG. 8 is a view of an embodiment of the leadless pacemaker device;

(9) FIG. 9 is a view of another embodiment of the leadless pacemaker device;

(10) FIG. 10 is a view of yet another embodiment of the leadless pacemaker device;

(11) FIG. 11 is a view of yet another embodiment of the leadless pacemaker device;

(12) FIG. 12 is a view of a schematic view of \the leadless pacemaker device;

(13) FIG. 13 is a schematic view of the leadless pacemaker device, indicating signal vectors sensed between different electrodes of the leadless pacemaker device;

(14) FIG. 14 is an illustration of an electrocardiogram signal;

(15) FIG. 15 is a table illustrating an atrial detection algorithm; and

(16) FIG. 16 is a table illustrating a ventricular detection algorithm.

DETAILED DESCRIPTION OF THE INVENTION

(17) Subsequently, embodiments of the invention shall be described in detail with reference to the drawings. In the drawings, like reference numerals designate like structural elements.

(18) It is to be noted that the embodiments are not limiting for the invention, but merely represent illustrative examples.

(19) In the instant invention it is proposed to provide a leadless pacemaker device providing for HIS bundle pacing.

(20) Referring now to the figures of the drawings in detail and first, particularly to FIG. 1 thereof, there is shown, in a schematic drawing, a 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.

(21) As electrical impulses from the atrioventricular node AVN are transmitted collectively via the HIS bundle H towards the right bundle branch RBB and the left bundle branch LBB for stimulating the right ventricle RV and the left ventricle LV, HIS bundle pacing has the potential to synchronously pace the right ventricle RV and the left ventricle LV, hence avoiding a lack of synchrony in between the left ventricle RV and the right ventricle RV as it may occur for example in a right ventricular pacing.

(22) Whereas common pacemaker devices providing for an HIS bundle pacing use leads extending from the (subcutaneously implanted) pacemaker device transvenously into the heart, it is proposed within the instant invention to use a leadless pacemaker device 1 for implementation into the right atrium RA to provide for an HIS bundle pacing at the HIS bundle H, as schematically indicated in FIG. 1. By means of such leadless pacemaker device 1, stimulation energy is injected into the right atrial wall at the HIS bundle H in order to provide for a pacing at the HIS bundle H.

(23) In another embodiment, the leadless pacemaker is implanted in the high right ventricular septum in order to pace at or near the HIS from the ventricle (rather than from the atrium). This ventricular implant location may be better for patients with small atriums, and may have some implant stability advantages over atrial placement.

(24) Referring now to FIG. 12, in one embodiment a leadless pacemaker device 1 configured to provide for an HIS bundle pacing comprises a housing 10 enclosing electrical and electronic components for operating the leadless pacemaker device 1. In particular, enclosed within the housing 10 is a processor 15 and a communication interface 16 for communicating with an external device 3, such as a programmer wand, wherein in addition electrical and electronic components such as an energy storage in the shape of a battery are confined in the housing 10. In one embodiment the battery casing itself makes up part of the housing 10. The housing 10 provides for an encapsulation of components received therein, the housing 10 having the shape of, e.g., a cylindrical shaft having a length of for example a few centimeters.

(25) In the embodiment of FIG. 12, the leadless pacemaker device 1 comprises different electrodes 11, 12, 13 serving to emit pacing signals towards the HIS bundle H for providing HIS bundle pacing and to sense electrical signals indicative of cardiac activity, in particular indicative of atrial and ventricular contractions.

(26) A first electrode 11 herein is denoted as pacing electrode and is placed close to the HIS bundle H upon implanting the leadless pacemaker device 1. The first electrode 11 is placed at a tip of the housing 10 and is configured to engage with cardiac tissue in order to come to rest close to the HIS bundle H.

(27) A second electrode 12 serves as a counter electrode for the first electrode 11, a signal vector P arising between the first electrode 11 and the second electrode 12 providing for a pacing vector P for emitting pacing signals towards the HIS bundle H. In addition, the second electrode 12 serves as a sensing electrode for sensing signals, in particular relating to atrial and ventricular contractions. The second electrode 12 is placed at a distance from the first electrode 11 and for example has the shape of a ring. The second electrode 12 is for example placed at a distance of about 1 cm from the tip of the housing 10 at which the first electrode 11 is placed.

(28) The leadless pacemaker device 1, in the embodiment of FIG. 12, in addition comprises a third electrode 13 placed at a far end of the housing 10, the third electrode 13 serving as a sensing electrode for sensing signals indicative of cardiac activity. In particular, a signal vector A arises between the third electrode 13 and the second electrode 12, the signal vector A picking up signals being indicative for example of atrial contractions. In addition, a signal vector F arises between the third electrode 13 and the first electrode 11, the signal vector F being indicative for example of ventricular contractions. The signal vector F also is denoted as farfield vector.

(29) The electrodes 11, 12, 13 are in operative connection with the processor 15, the processor 15 being configured to cause the first electrode 11 and the second electrode 12 to emit a pacing signal for stimulating the HIS bundle H for an HIS bundle pacing. The processor 15 furthermore is configured to process signals received via the electrodes 11, 12, 13 to provide for a sensing of cardiac activity, in particular atrial and ventricular contractions. By being able to record both atrial and ventricular activity, the leadless pacemaker device 1 can provide AV synchronous pacing.

(30) One challenge in implanting a leadless pacemaker device 1 at the HIS bundle H is to provide for a mapping in order to correctly place the leadless pacemaker device 1 with its pacing electrode 11 in close proximity to the HIS bundle H. Within a mapping technique, the HIS bundle H shall be located by electrophysiological measurements in order to ensure that the leadless pacemaker device 1 is correctly placed at the HIS bundle H in order to provide for an effective HIS bundle pacing.

(31) Referring now to FIG. 2, in one embodiment the leadless pacemaker device 1 in a mapping mode is configured to sense a real-time electrogram in between the first electrode 11 and the second electrode 12 during placement of the leadless pacemaker device 1 in the human heart. For placement, the leadless pacemaker device 1 is received within a lumen of a catheter device 2 forming part of a delivery system, the leadless pacemaker device 1 being received at a distal end 20 of the catheter device 2 in order to deliver the leadless pacemaker device 1 into the human heart.

(32) For mapping, the leadless pacemaker device 1 in one embodiment is partially deployed from the distal end 20 of the catheter device 2, as illustrated in FIG. 2, such that the first electrode 11 and the second electrode 12 are exposed for sensing electrical cardiac signals in order to record a real-time electrogram. By means of the communication interface 16 as illustrated in FIG. 12 a recorded electrogram can be transferred to an external device 3 such as a programmer wand, such that the electrogram may be monitored and assessed in order to determine whether the HIS bundle H has been reached.

(33) In the embodiment of FIG. 2, the first electrode 11 is placed on a pin at a tip 100 of the housing 10 of the leadless pacemaker device 1. Upon implant, the first electrode 11 is inserted into cardiac tissue, in particular the right atrial wall (or in one embodiment, the high RV septum), such that via the first electrode 11 during actual pacing operation stimulation after implant energy may be transmitted towards the HIS bundle H for HIS bundle pacing. Because, in the mapping mode, sensing signals are received via the first electrode 11 and the second electrode 12, the leadless pacemaker device 1 during placement sees, in terms of electrical coupling to the HIS bundle H, what the device 1 will see after implant during actual pacing operation. If during placement a HIS bundle capture is picked up via the first electrode 11 and the second electrode 12, it is ensured that also during actual pacing operation after implant stimulation energy can effectively be injected into the HIS bundle H.

(34) As the electrogram recorded via the first electrode 11 and the second electrode 12 during placement is communicated towards the outside via the communication interface 16, the electrogram may be monitored and may be assessed in order to evaluate whether correct placement has been achieved. The communication interface 16 herein may be configured to provide for a communication by inductive coupling, by MICS, by a BLE, by acoustic communication, or by E-field communication. Signals indicative of a recorded real-time electrogram hence are transmitted using telemetry from the leadless pacemaker device 1 towards an external device 3 outside of the human body in the mapping mode.

(35) Referring now to FIG. 3, in another embodiment the catheter device 2 comprises a window 22 in the region at which the second electrode 12 is placed when the leadless pacemaker device 1 is received within the catheter device 2 for placement in the human heart. In this embodiment, no partial deployment of the leadless pacemaker device 1 for placement is necessary, but the leadless pacemaker device 1 can remain seated in the catheter device 2, hence potentially easing the placement of the leadless pacemaker device 1 in the right atrium RA as the leadless pacemaker device 1 does not stick out from the catheter device 2 during placement. By means of the window 22 the second electrode 12 is exposed in order to sense signals, wherein in addition the electrode 11 at the tip 100 of the housing 10 of the leadless pacemaker device 1 is exposed at the distal end 20 of the catheter device 2 such that a sensing vector can be picked up in between the electrodes 11, 12 for mapping.

(36) Referring now to FIG. 4, in another embodiment mapping electrodes 23, 24 are arranged on the catheter device 2, a first mapping electrode 23 for example being placed immediately at a distal end 20 of the catheter device 2, and a second mapping electrode 24 being placed at a distance from the distal end 20 and hence from the first mapping electrode 23. The shape, size and distance of the electrodes 23, 24 herein, preferably, resembles the shape, size and distance of the electrodes 11, 12 of the leadless pacemaker device 1, such that an electrogram picked up via the mapping electrodes 23, 24 during placement resembles what the electrodes 11, 12 of the leadless pace maker device 1 will see during actual pacing operation after implant.

(37) Referring now to FIG. 5, different shapes and arrangements of the electrodes 23, 24 on the catheter device 2 are conceivable. For example, multiple first mapping electrode elements 230 may be circumferentially spaced with respect to each other at the distal end 20 of the catheter device 2, for example by an angle of 90° between neighboring electrode elements 230. The second mapping electrode 24 may for example have the shape of a ring circumferentially extending about the catheter device 2, wherein it is also conceivable that multiple second electrode elements making up the electrode 24 are present. By using multiple electrode elements it may be possible to pick up different mapping signal vectors, allowing for example to derive information indicative of a direction of signal reception, hence further facilitating the placement and mapping for arranging the leadless pacemaker device 1 at the HIS bundle H.

(38) Referring now to FIG. 6, it also is conceivable to provide multiple electrodes 23, 24, 25 on the catheter device 2, the electrodes 23, 24, 25 being axially spaced apart and for example being shaped as rings extending about the catheter device 2. By means of such ring electrodes 23, 24, 25 nearfield and farfield vectors may be picked up, hence allowing to detect both a nearfield response and a farfield response.

(39) In one embodiment, one or multiple of the electrodes 23, 24, 25 of the catheter device 2 are also used as flouro markers for additional visibility during implant.

(40) Referring now to FIG. 7, in another embodiment a mapping wire 26 is received in a side lumen of the catheter device 2 separate from the main lumen. The mapping wire 26 is angled towards the center of the catheter device 2 at the distal end 20, the mapping wire 26 carrying mapping electrodes 260 at its angled end, the electrodes 260 allowing to sense a mapping signal during implant of the leadless pacemaker device 1.

(41) In another embodiment, a regular mapping catheter received in the main lumen is used for mapping when implanting the leadless pacemaker device 1.

(42) The leadless pacemaker device 1, in one embodiment, is to be placed in the right atrium RA, as this schematically as illustrated in FIG. 1. For the implant, the leadless pacemaker device 1 is to be fixed to the atrial wall, hence requiring a fixation device providing for a reliable and permanent fixture of the leadless pacemaker device 1 in the right atrium RA.

(43) As the atrial wall of the right atrium RA typically is comparatively thin and more delicate than for example the ventricular wall, a fixation device is to be configured such that a penetration of the atrial wall and a damage of the nerve structure near the HIS bundle H is prevented.

(44) Referring now to FIG. 8, in one embodiment, a fixation device 14 at the tip 100 of the housing 10 of the leadless pacemaker device 1 comprises a multiplicity of curved fixation elements 140 being formed by wires in the shape of nitinol tines, the fixation elements 140 having for example a radius of curvature smaller than 1.5 mm in order to ensure that the fixation elements 140 do not penetrate deeply into the cardiac wall.

(45) In the embodiment of FIG. 8, the first electrode 11 is placed on a pin 110, the pin 110 engaging the atrial wall at the HIS bundle H during implant such that the electrode 11 comes to rest in close proximity to the HIS bundle H. The pin 110 has a pointed shape and has a length of for example in between 1 mm and 3 mm, for example approximately 2 mm.

(46) The second electrode 12, in the embodiment of FIG. 8, has a ring shape and circumferentially extends about the housing 10 of the leadless pacemaker device 1, the housing 10 having a generally cylindrical shape. A third electrode 13 is placed at a far end 101 of the housing 10 opposite the first electrode 11.

(47) Referring now to FIG. 9, in one embodiment multiple (here: three) first electrodes 11 are placed on multiple pins 110 at the tip 100 of the housing 10 of the leadless pacemaker device 1. During implant the pins 110 engage with cardiac tissue, the processor device 15 for example being configured to select one or a group of the first electrodes 11. In this way an electrode of the first electrodes 11 may be chosen which is arranged closest to the HIS bundle H and hence has the strongest electrical coupling with the HIS bundle H. Because multiple first electrodes 11 are available for selection, a potential need for repositioning the leadless pacemaker device 1 during implant at least can be reduced.

(48) Referring now to FIG. 10, in one embodiment the fixation device 14 comprises a screw anchor 141, the screw anchor 141 serving to screw into cardiac tissue in order to fix the leadless pacemaker device 1 within the right atrium RA. The first electrode 11 herein is placed at a tip of the screw anchor 141, such that by engagement of the screw anchor 141 in cardiac tissue the electrode 11 comes to rest in close proximity to the HIS bundle H. The screw anchor 141 may for example have a diameter equal to or smaller than 2 mm in order to minimize the risk for damaging the nerve structure near the HIS bundle H during implant.

(49) In one embodiment, the screw anchor 141 may comprise multiple arms to form a double or triple helix, each arm for example carrying a first electrode 11 such that—similar to the embodiment of FIG. 9—the processor 15 may be configured to select one or a group of the electrodes 11 for operation in order to select such electrode 11 which is closest and best coupled to the HIS bundle H. In another embodiment a single screw anchor 141 contains multiple electrodes along its length, each individually selectable by the processor 15.

(50) In the embodiments of FIGS. 8 to 11, the pin 110 respectively the screw anchor 141 may comprise an electrically insulating coating, such that only the electrode 11 is electrically exposed. This may help to reduce the risk of accidental atrial capture.

(51) During an actual pacing operation, the processor 15 may switch between a sensing mode and a stimulation mode in order to sense signals indicative of cardiac activity and to generate pacing signals for stimulating the HIS bundle H in an alternating fashion.

(52) In particular, in a first phase of the cardiac cycle, atrial contractions may be sensed for example by a signal vector A in between the second electrode 12 and the third electrode 13 as illustrated in FIGS. 12 and 13. Following an atrial capture, in a second phase of the cardiac cycle a pacing signal is emitted by means of a pacing vector P in between the first electrode 11 and the second electrode 12 in order to inject stimulation energy at the HIS bundle H, the pacing signal being injected with adequate timing after the atrial capture in order to provide for atrial to ventricular (A to V) synchrony. After injection of the pacing signal, the processor 15 may switch back into a sensing mode in order to sense an evoked response by picking up ventricular contractions via the farfield vector F in between the first electrode 11 and the third electrode 13.

(53) Different sensing algorithms for obtaining atrial and ventricular captures and different pacing algorithms for capturing the HIS bundle may be used. An atrial sensing algorithm may for example be similar to an atrial DX algorithm. For sensing ventricular signals an increased amplification may be required as for the leadless pacemaker 1 ventricular contractions occur in the farfield and hence require a stronger amplification.

(54) In order to provide for a pacing at the HIS bundle H, an automated capture algorithm may be used. Within the capture algorithm the QRS waveform in the ECG as illustrated in FIG. 14 may be examined, a short QRS waveform indicating a capture of the HIS conduction pathway without recruitment of surrounding cardiac tissue. An automated capture algorithm herein may include a periodic search, for example once per hour, by increasing and decreasing the pacing threshold and by monitoring a QRS response. The processor 15 may then for example be configured to choose the pacing amplitude having the smallest QRS width, wherein for the further pacing operation the pacing amplitude determined in this way may be used.

(55) An embodiment of an atrial sensing algorithm is illustrated in the table of FIG. 15.

(56) In case atrial activity has not been sensed for an extended period of time the processor 15 may be configured to attempt to synchronize with atrial activity that is present but not detected. For this, the timing of the pacing may be adapted. For example, if a previous intrinsic distance between ventricular signals (V-V) has been X milliseconds, the next pacing signal should be injected earlier than the intrinsic V-V of the previous cycle by some value, for example by 10% or 10 ms (third row in the table of FIG. 15). This causes a shortening of the A/V. When in this mode, the processor 15 should be configured to periodically check the intrinsic V-V by allowing intrinsic conduction, for example once in a minute or once every 5 minutes.

(57) In FIG. 16, an embodiment of a ventricular sensing algorithm to capture an evoked response is illustrated.

(58) Since the leadless pacemaker device 1 is placed in the right atrium RA, it can sense the atrial signal with its atrial dipole in between the second electrode 12 and the third electrode 13. If the device should detect that the patient is in a state of atrial fibrillation (AF), the processor is configured to drive the ventricle by pacing the AF rate as set by the clinician. Driving the ventricle during the state of AF is desirable because it will continue to provide LV-RV synchrony, which may not be present in intrinsic beats.

(59) 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 teaching. 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.

(60) When reading the claim language, the following definitions apply. When the claim language recites A and/or B it means A alone, B alone or A and B. When the claim language recites at least one of A and B it means A alone, B alone or A and B. When the claim language recites at least one of A or B it means A alone, B alone or A and B.

LIST OF REFERENCE NUMERALS

(61) 1 Leadless pacemaker device 10 Housing 100 Tip 101 Far end 11 First electrode (pacing electrode) 110 Pin 12 Second electrode (pacing ring) 13 Third electrode 14 Fixation device 140 Fixation element (wire) 141 Fixation element (screw) 15 Processor 16 Communication interface 2 Catheter device 20 Distal end 22 Window 23 Electrode 230 Electrode element 24 Electrode 25 Electrode 26 Mapping wire 260 Electrodes 3 External device (programmer wand) A Atrial vector AVN Atrioventricular node F Farfield vector H HIS bundle LA Left atrium LBB Left bundle branch LV Left ventricle M Intra-cardiac tissue (myocardium) P Pacing vector RA Right atrium RBB Right bundle branch RV Right ventricle SAN Sinoatrial node