MAGNETICALLY COUPLED ABLATION COMPONENTS
20240197426 ยท 2024-06-20
Assignee
Inventors
- Matthew MONTI (Cincinnati, OH, US)
- Kenneth Lance Miller (Hamilton, OH, US)
- Keith Edward Martin (Dayton, OH, US)
- Salvatore Privitera (Mason, OH, US)
- Tamer IBRAHIM (Danville, CA, US)
- Jeremy D. Dando (Plymouth, MN, US)
- Adam Wesley Cates (Minneapolis, MN, US)
- Paighton Anne Schrupp (St. Louis Park, MN, US)
- Sonja Kosir (Cincinnati, OH, US)
- Liam Douglas Malone (Chatteris, GB)
- Joseph Thomas Batley (Impington, GB)
Cpc classification
A61M2025/0681
HUMAN NECESSITIES
A61B2017/00292
HUMAN NECESSITIES
A61B18/00
HUMAN NECESSITIES
A61M25/0068
HUMAN NECESSITIES
International classification
Abstract
An ablation system and method provides for cooperatively transdermally ablating cardiac tissue by cooperating epicardial and endocardial components. The ablation system includes a first ablation component configured to be positioned on a first side of a target tissue. The first ablation component includes a first ablation element and a first magnetic element. The ablation system includes a second ablation component configured to be positioned on a second side of a target tissue. The second side is opposite the first side. The second ablation component includes a second ablation element and a second magnetic element. The first magnetic element and the second magnetic element are configured to cooperate to facilitate positioning at least one of the first ablation component and the second component on the target tissue. The first ablation element and the second ablation element are configured to cooperate to create a lesion in the target tissue.
Claims
1. An ablation system comprising: a first ablation component configured to be positioned on a first side of a target tissue, the first ablation component comprising a first ablation element and a first magnetic element; a second ablation component configured to be positioned on a second side of a target tissue, the second side being opposite the first side, the second ablation component comprising a second ablation element and a second magnetic element; wherein the first magnetic element and the second magnetic element are configured to cooperate to facilitate positioning at least one of the first ablation component and the second component on the target tissue; and wherein the first ablation element and the second ablation element are configured to cooperate to create a lesion in the target tissue.
2.-7. (canceled)
8. A method of creating a lesion, the method comprising: placing a first ablation component on a first surface of a target tissue, the first ablation component comprising a first magnetic element and a first ablation element; placing a second ablation component on a second surface of a target tissue, the second ablation component comprising a second magnetic element and a second ablation element; positioning one or more of the first ablation component or the second ablation component using magnetic cooperation between the first magnetic element and the second magnetic element; and creating a first lesion in the target tissue using the first ablation element and the second ablation element.
9. The method of claim 8, wherein one or more of the first magnetic element or the second magnetic element comprises an electromagnet; and wherein positioning the one or more of the first ablation component or the second ablation component using magnetic cooperation between the first magnetic element and the second magnetic element comprises energizing the electromagnet.
10. The method of claim 8, wherein creating the lesion in the target tissue using the first ablation element and the second ablation element comprises one or more of radiofrequency (RF) energy ablation, pulsed field ablation, cryoablation, ultrasound ablation, or laser ablation.
11. The method of claim 8, further comprising repositioning the one or more of the first ablation component or the second ablation component; and creating a second lesion in the target tissue proximate the first lesion via at least one of simultaneous monopolar ablation and bipolar ablation.
12. The method of claim 8, further comprising, securing one or more of the first ablation component or the second ablation component to the target tissue using a tissue anchor.
13. An ablation system comprising: a first ablation component configured to be positioned on a first side of a target tissue, the first ablation component comprising a first magnetic element; a second ablation component configured to be positioned on a second side of a target tissue, the second side being opposite the first side, the second ablation component comprising a second magnetic element; wherein the first magnetic element and the second magnetic element are configured to cooperate to facilitate positioning at least one of the first ablation component and the second ablation component on the target tissue.
14.-19. (canceled)
20. A method of creating a lesion, the method comprising: placing a first ablation component on a first surface of a target tissue, the first ablation component comprising a first ablation magnetic element; placing a second ablation component on a second surface of a target tissue, the second ablation component comprising a second ablation magnetic element; aligning and compressing the target tissue between the first and second ablation magnetic elements using magnetic attraction; and creating a first lesion in the target tissue using at least one of the first ablation magnetic element and the second ablation magnetic element.
21. The method of claim 20, wherein: at least one of the first ablation magnetic element and the second ablation magnetic element comprises an electromagnet; and aligning and compressing the target tissue between the first and second ablation magnetic elements using magnetic attraction includes energizing the electromagnet.
22. The method of claim 20, wherein creating the first lesion in the target tissue using at least one of the first ablation magnetic element and the second ablation magnetic element includes using at least one of radiofrequency (RF) energy ablation, pulsed field ablation, cryoablation, ultrasound ablation, and laser ablation.
23. The method of claim 20, further comprising repositioning at least one of the first ablation magnetic component and the second ablation magnetic component; and creating a second lesion in the target tissue proximate the first lesion.
24. The method of claim 20, further comprising, securing at least one of the first ablation magnetic component and the second ablation magnetic component to the target tissue using a tissue anchor.
25. An ablation device comprising: a first ablation component configured to be positioned on a first side of a target tissue, the first ablation component comprising a first ablation element and a first magnetic element; a first catheter operatively coupled to the first ablation component; and, a second catheter having a through conduit sized to receive the first ablation component and the first catheter.
26. The ablation device of claim 25, wherein the first ablation element and the first magnetic element are synonymous.
27. The ablation device of claim 25, wherein the ablation device further includes an atraumatic distal tip.
28. The ablation device of claim 27, wherein the atraumatic distal tip comprises at least one of the first ablation element and the first magnetic element.
29.-81. (canceled)
82. A method of monitoring a tissue compression procedure, the method comprising: positioning a first medical device and a second medical device so as to be interposed by tissue, the first medical device including a magnet, the second medical device including at least one of a magnet and a magnetically attractive material, where at least one of the first medical device and the second medical device includes a magnetic sensor; obtaining outputs from the magnetic sensor while the medical devices are interposed by the tissue; estimating at least one of a distance between the first medical device and the second medical device, and a compression force applied to the tissue by at least one of the first medical device and the second medical device.
83. An ablation device comprising: a first ablation component configured to be positioned on a first side of a target tissue, the first ablation component comprising a first ablation element and a first magnetic element; a first tether operatively coupled to the first ablation component; and, a catheter having a through conduit sized to receive the first ablation component and the tether.
84.-88. (canceled)
Description
BRIEF DESCRIPTION OF DRAWINGS
[0026] The description of the examples described herein can be read with reference to the accompanying figures. It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements. Examples incorporating teachings of the present disclosure are shown and described with respect to the figures presented herein, in which:
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DETAILED DESCRIPTION OF THE INVENTION
[0068] The present disclosure contemplates that heart arrhythmias affect millions of people in the United States alone. For example, atrial fibrillation is a heart arrhythmia in which the electrical activity of the heart is disorganized. Common arrhythmias include ventricular tachycardia and/or inappropriate sinus tachycardia.
[0069] The present disclosure contemplates that effective treatments for cardiac arrhythmias may include creating a pattern (maze) of scar tissue (lesions) on a patient's heart to interrupt the errant electrical impulses in the heart tissue. The lesions may be created by cutting the cardiac tissue and sewing it back together. Alternatively, the lesions may be created by ablating the cardiac tissue using a variety of modalities, such as RF energy ablation, pulsed field ablation, cryoablation, ultrasound ablation, and/or laser ablation, for example. As used here, ablation may refer to the removal or destruction of a function of a body part, such as cardiac tissue, regardless of the apparatus or process used to carry out the ablation.
[0070] The present disclosure contemplates that, in some circumstances, it may be desirable for cardiac ablation lesions to span the entire thickness of the heart tissue (a heart transmural lesion). Thus, some ablation apparatus and methods may be configured to create one or more transmural lesions. As used herein, transmural may refer to through the wall or thickness of tissue, such as through the wall or thickness of a hollow organ or vessel.
[0071] The present disclosure contemplates that because RF ablation delivers energy between two electrodes to heat the target tissue, an effective electrode configuration for achieving transmural lesions with RF energy may include ablation electrodes positioned on one or multiple sides of the tissue targeted for ablation. Similar approaches may be utilized with other ablation modalities.
[0072] In the following detailed description of examples of the disclosure, specific examples in which the various aspects of the disclosure may be practiced are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other examples may be utilized and that logical, architectural, programmatic, mechanical, electrical, and other changes may be made without departing from the spirit or scope of the present disclosure. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present disclosure is defined by the appended claims and equivalents thereof. Within the descriptions of the different views of the figures, similar elements are provided similar names and reference numerals as those of the previous figure(s). The specific numerals assigned to the elements are provided solely to aid in the description and are not meant to imply any limitations (structural or functional or otherwise) on the described example. It will be appreciated that for simplicity and clarity of illustration, elements illustrated in the figures have not necessarily been drawn to scale. For example, the dimensions of some of the elements are exaggerated relative to other elements.
[0073] It is understood that the use of a specific component, device and/or parameter names, such as those of the executing utility, logic, and/or firmware described herein, are for illustrations only and not meant to imply any limitations on the described examples. The examples may thus be described with different nomenclature and/or terminology utilized to describe the components, devices, parameters, methods and/or functions herein, without limitation. References to any specific protocol or proprietary name in describing one or more elements, features or concepts of the examples are provided solely on an illustrative basis of one implementation, and such references do not limit the extension of the claimed limitations to examples in which a different element, feature, protocol, or concept name is utilized. Thus, each term utilized herein is to be given its broadest interpretation given the context in which that term is utilized.
[0074] As further described below, implementation of the functional features of the disclosure described herein is provided within processing devices and/or structures and can involve use of a combination of hardware, firmware, as well as several software-level constructs (e.g., program code and/or program instructions and/or pseudo-code) that execute to provide a specific utility for the device or a specific functional logic. The presented figures may illustrate both hardware components and software and/or logic components.
[0075] Those of ordinary skill in the art will appreciate that the hardware components and basic configurations depicted in the figures may vary. The illustrative components are not intended to be exhaustive, but rather are representative to highlight essential components that are utilized to implement aspects of the described examples. For example, other devices/components may be used in addition to or in place of the hardware and/or firmware depicted. The depicted examples are not meant to imply architectural or other limitations with respect to the presently described aspects and/or the general invention. The description of the illustrative examples can be read in conjunction with the accompanying figures. Examples incorporating teachings of the present disclosure are shown and described with respect to the figures presented herein.
[0076] Unless specifically indicated, it will be understood that the description of the structure, function, and/or methodology with respect to any illustrative example herein may apply to any other illustrative example. More generally, it is within the scope of the present disclosure to utilize any one or more features of any one or more examples described herein in connection with any other one or more features of any other one or more other example(s) described herein. Accordingly, any combination of any of the features or examples described herein is within the scope of this disclosure.
Permanent Magnet Coupled Ablation Components
[0077] Examples according to the present disclosure may be described and illustrated to encompass devices, methods, and techniques relating to medical procedures. Of course, it will be apparent to those of ordinary skill in the art that the examples discussed below are exemplary and may be reconfigured by removing and/or adding elements of other examples without departing from the scope and spirit of the present disclosure. It is also to be understood that variations of the examples contemplated by one of ordinary skill in the art shall concurrently comprise part of the instant disclosure. However, for clarity and precision, the examples as discussed below may include optional steps, methods, and/or features that one of ordinary skill should recognize as not being a requisite to fall within the scope of the present disclosure.
[0078] The present disclosure encompasses, among other things, medical instruments and devices and related methods, and, more specifically, devices for ablating tissue and related methods. Some examples according to at least some aspects of the present disclosure may be useful in connection with ablation of cardiac tissue, such as to treat cardiac arrhythmias like atrial fibrillation, ventricular tachycardia, and/or inappropriate sinus tachycardia. Some examples according to at least some aspects of the present disclosure may be configured to deliver ablation energy, such as through a heart wall to create an efficient lesion (that may be transmural), while minimizing collateral tissue trauma.
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[0080] For example, the first ablation component 102 may be configured to be positioned on an epicardial (exterior) surface 12 of the heart 10. The second ablation component 104 may be configured to be positioned on an endocardial (interior) surface 14 of the heart 10.
[0081] The first ablation component 102 may include at least one ablation element 106, such as an electrode, and the second ablation component 104 may include at least one ablation element 108, such as an electrode. The ablation elements 106, 108 may be configured to cooperate to create a lesion 16 in the target tissue, such as a transmural lesion extending through the full thickness of the heart wall 18.
[0082] The first ablation component 102 may include at least one magnetic element 110 and the second ablation component 104 may include at least one magnetic element 112. The magnetic elements 110, 112 may be configured to cooperate to facilitate positioning the first ablation component 102 and/or the second ablation component 104. For example, the magnetic elements 110, 112 may be utilized to align the ablation elements 106, 108 across the heart wall 18 to create the lesion 16 at the desired location. Some examples may utilize selective coupling and/or uncoupling of the magnetic elements 110, 112 to facilitate positioning the electrodes as well as for subsequent repositioning to nearby target tissues for subsequent ablations. Some example ablation components 102, 104 may be configured to at least partially compress tissue therebetween. For example, the magnetic elements 110, 112 may be configured to cooperate to compress the target tissue (e.g., heart wall 18) between the ablation components 102, 104, which may improve ablation outcomes in some circumstances.
[0083] The example ablation system 100 may include a control unit 114. The control unit 114 may be operable to control the operation of the ablation components 102, 104. In some examples, the control unit 114 may be configured to selectively provide ablation energy (e.g., RF energy from an electrosurgical generator) to electrodes comprising the ablation elements 106, 108. In some examples, the control unit 114 may be configured to control the operation of the magnetic elements 110, 112. For example, the control unit 114 may be configured to selectively apply electrical current through one or more electromagnets comprising one or more of the magnetic elements 110, 112. The ablation components 102, 104 may include respective connecting elements 116, 118, which may operatively couple aspects of the ablation components 102, 104 such as, without limitation, the ablation elements 106, 108 and/or the magnetic elements 110,112, to the control unit 114. The connecting elements 116, 118 may include or be used in connection with one or more electrical conductors, fluidic conduits, mechanical force transmission components, catheters, wires, steerable portions, sheaths, trocars, hemostatic components, etc.
[0084] In some examples, the exemplary ablation system 100 may be configured to access the target tissue (e.g., heart wall 18) via a surgical approach (open-chest and/or minimally invasive) and/or via the patient's vascular system. For example, the first ablation component 102 may be positioned on the epicardial surface 12 via a percutaneous or surgical sub-xiphoid or intercostal access or incision 120, such as through the chest wall 20. The second ablation component 104 may be positioned on the endocardial surface 14 via a blood vessel 22 (e.g., the femoral vein). In various circumstances, the routes used to obtain access to the epicardial and endocardial surfaces may be determined based at least in part upon factors such as the portion of the heart wall 18 that comprises the target tissue for the ablation, the patient's potential anatomical variations, previous surgeries, etc. In some examples, either or both of the first ablation component 102 and the second ablation component 104 may access the target tissue by any suitable route, such as open chest, thoracotomy, sub-xiphoid, trans-diaphragmatic, and/or vascular access.
[0085] In some examples, one or more of the ablation components 102, 104 may include and/or may be configured to operate in connection with a device configured to selectively and/or releasably attach to the target tissue, such as a tissue anchor. For example, the first ablation component 102 may include a vacuum anchor 122, which may be configured to selectively and/or releasably secure the first ablation component 102 to the epicardial surface 12. In some such examples, the connecting element 116 may include a vacuum line and/or the control unit 114 may include a vacuum pump and/or related control apparatus.
[0086] Generally, some examples may be operated as follows. Appropriate access to the epicardial 12 and endocardial 14 surfaces may be obtained. The first ablation component 102 may positioned at a desired location on the epicardial surface 12. The vacuum anchor 122 may be operated (e.g., vacuum may be applied) to secure the first ablation component 102 in position on the epicardial surface 12. The magnetic elements 110, 112 may be utilized (e.g., magnetically coupled) to position and/or secure the second ablation component 104 on the endocardial surface 14. For example, the magnetic element 110 of the first ablation component 102 may magnetically attract the magnetic element 112 of the second ablation component 104. The ablation elements 106, 108 may be operated to ablate the target tissue and create the lesion 16. The magnetic elements 110, 112 may be uncoupled. In some examples, the magnetic elements 110, 112 may be reconfigured into a magnetically repulsive arrangement, such as to disengage one or more of the first ablation component 102 and/or the second ablation component 104 from the target tissue and from one another. The vacuum anchor 122 may be released. The first and second ablation components 102, 104 may be withdrawn from the patient.
[0087] In some examples, an ablation component may be passively oriented and/or located on the target tissue. For example, the ablation component may be generally positioned on the target tissue, such as by direct imaging and/or through a medical scope. The ablation component may be releasably attached to the target tissue, such as by a vacuum anchor or other tissue anchor. Related elements associated with the ablation component may include a single lumen sheath, a multilumen sheath, and/or an inflatable element, such as a space-making element. In some examples, an ablation component may be oriented and/or located on the target tissue using an image guided catheter. For example, the ablation component and/or the cooperating ablation component may comprise guidance features. In some examples, an ablation component may include sensing features and/or stimulation features and/or may be used in connection with a cooperating ablation component including sensing features and/or stimulation features.
[0088] Some examples may provide sensing capabilities for various parameters. For example, tissue impedance may be sensed between ablation electrodes, such as to assess the extent of an ablation. In some examples, measurements of magnetic fields may be utilized, such as to determine a distance between certain components. In some example, one or more temperatures may be measured.
[0089] The foregoing description of the example ablation system 100 provides context for various examples described below. The various examples described below may comprise components of the example ablation system 100, or may be utilized in alternative systems. Any feature or component of any example described herein may be utilized in connection with any other example, and repeated description of components is omitted for brevity.
[0090] The ablation elements 106, 108 and magnetic elements 110, 112 are illustrated as separate elements in
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[0092] In some examples, the ablation component 200 may be positioned on the endocardial surface 14 to act as a second ablation component 104 as described above with reference to
[0093] In some examples, the ablation component 200 may be introduced via the pericardial space. The ablation component 200 may be delivered through the heart wall 18 via a needle or through a hollow needle 206, such as a small bore (e.g., 21 gauge) needle. In some examples, the hole created by delivering the ablation component 200 in this manner may be small enough not to require hemostasis during ablation and/or suture upon removal.
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[0099] The ablation element 706 may comprise a generally cylindrical ring electrode. In alternative examples, two or more magnetic elements 702, 704 may be positioned distally or proximally relative to the ablation element 706. The magnetic elements 702, 704 and the ablation element 706 may be positioned substantially adjacent (e.g., minimal or no gaps therebetween), or may be spaced apart by longitudinal distances 708, 710. The magnetic elements 702, 704 may be generally diametrically magnetized. In some examples, there is a sequence of magnet-electrode-magnet-electrode-magnet etc., and/or may be incorporated on a straight axis, as shown in
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[0101] The magnetic element 802 and the ablation element 804 may be disposed proximate a distal end of a shaft 806. In some examples, the shaft 806 may be substantially straight. In some examples, the shaft 806 may be curved and/or may be flexible and/or malleable. In some examples, the shaft 806 may be articulable, such as to allow repositioning (e.g., steering) of the magnetic element 802 and/or the ablation element 804 relative to the target tissue.
[0102] The ablation component 800 may be positioned on the epicardial surface 12 of a patient's heart 10, such as via a sub-xiphoid or intercostal incision or access device. In some examples, the ablation component 800 may comprise the first ablation component 102 described above with reference to
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[0104] Ablation component 900 may include one or more magnetic elements 910, 912, 914, which may each be associated with a respective pair of electrodes 902A, 902B, 904A, 904B, 906A, 906B and/or which may be disposed within the pad 908. In some examples, an individual magnetic element 910, 912, 914 may be inserted into a port extending within the pad 908 and associated with one of the pairs of electrodes 902A, 902B, 904A, 904B, 906A, 906B. In some examples, the magnetic elements 910, 912, 914 may be movable (e.g., longitudinally) along at least a portion of the length of the electrodes 902A, 902B, 904A, 904B, 906A, 906B. In
[0105] For example, ablation component 900 may be positioned on the epicardial surface 12 of a patient's heart 10, such as via a sub-xiphoid or intercostal incision or access device and/or may comprise the first ablation component 102 described above with reference to
[0106] The pad 908 may be disposed proximate a distal end of a shaft 920. In some examples, the shaft 920 may be substantially straight. In some examples, the shaft 920 may be curved and/or may be flexible and/or bendable. In some examples, the shaft 920 may be articulable, such as to allow repositioning of the pad 908 relative to the target tissue. The ablation component 900 may include a handle 922 positioned generally proximally on the shaft 920. The handle 922 may include and/or may be operatively coupled to one or more actuators 924, which may be configured to control various aspects of the operation of the ablation component 900, such as steering. The ablation component 900 may include a connecting component 926, which may be operatively coupled to the control unit 114. In some examples, the ablation component 900 may comprise the second ablation component 104 described above with reference to
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[0108] In some examples, the pad 1002 may be configured to curl about a generally longitudinal/axial axis so that it can be delivered and recovered through a catheter 1004. In some examples, the deployed (uncurled, unfurled, and/or unfolded) lateral width of the pad 1002 may be substantially greater than the internal diameter of the catheter 1004. Some example ablation devices 1000 may be positioned on the epicardial surface 12 of a patient's heart 10, such as via a sub-xiphoid or intercostal incision or access device and/or may comprise the first ablation component 102 described above with reference to
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[0110] In some examples, the inflatable elements 1102, 1152 may be configured to move between a deflated configuration and an inflated configuration. For example, a fluid (e.g., gas or liquid such as saline solution) may be directed into and/or withdrawn from the interior of the inflatable elements 1102, 1152 from a pressure source (e.g., syringe 1154). In some examples, the inflated size of the inflatable element 1102, 1152 may be substantially larger than the internal diameter of a device used to direct the inflatable element 1102, 1152 to the ablation site (e.g., a catheter). Some example ablation devices 1100, 1150 may be positioned on the epicardial surface 12 of a patient's heart 10, such as via a sub-xiphoid or intercostal incision or access device and/or may comprise the first ablation component 102 described above with reference to
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Electromagnet Coupled Ablation Components
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[0119] The first ablation component 102 may include at least one ablation element 106, such as an electrode, and the second ablation component 104 may include at least one ablation element 108, such as an electrode. The ablation elements 106, 108 may be configured to cooperate to create a lesion 16 in the target tissue, such as a transmural lesion extending through the full thickness of the heart wall 18.
[0120] The first ablation component 102 may include at least one magnetic element 110 and the second ablation component 104 may include at least one magnetic element 112. The magnetic elements 110, 112 may be configured to cooperate to facilitate positioning the first ablation component 102 and/or the second ablation component 104. For example, the magnetic elements 110, 112 may be utilized to align the ablation elements 106, 108 across the heart wall 18 to create the lesion 16 at the desired location. Some examples may utilize selective coupling and/or uncoupling of the magnetic elements 110, 112 to facilitate positioning the electrodes as well as for subsequent repositioning to nearby target tissues for subsequent ablations. Some example ablation components 102, 104 may be configured to at least partially compress tissue therebetween. For example, the magnetic elements 110, 112 may be configured to cooperate to compress the target tissue (e.g., heart wall 18) between the ablation components 102, 104, which may improve ablation outcomes in some circumstances. Some examples may be configured to control the damping force, such as to provide sufficient, but not excessive, compression of the target tissue.
[0121] The example ablation system 100 may include a control unit 114. The control unit 114 may be operable to control the operation of the ablation components 102, 104. In some examples, the control unit 114 may be configured to selectively provide ablation energy (e.g., RF energy from an electrosurgical generator) to electrodes comprising the ablation elements 106, 108. In some examples, the control unit 114 may be configured to control the operation of the magnetic elements 110, 112. For example, the control unit 114 may be configured to selectively apply electrical current through one or more electromagnets comprising one or more of the magnetic elements 110, 112. The ablation components 102, 104 may include respective connecting elements 116, 118, which may operatively couple the ablation elements 106, 108 and/or the magnetic elements 110, 112 to the control unit 114. The connecting elements 116, 118 may include or be used in connection with one or more electrical conductors, fluidic conduits, mechanical force transmission components, catheters, wires, steerable portions, sheaths, trocars, hemostatic components, etc.
[0122] In some examples, the ablation system 100 may be configured to access the target tissue (e.g., heart wall 18) via a surgical approach (open-chest and/or minimally invasive) and/or via the patient's vascular system. For example, the first ablation component 102 may be positioned on the epicardial surface 12 via a percutaneous or surgical sub-xiphoid or intercostal access or incision 120, such as through the chest wall 20. The second ablation component 104 may be positioned on the endocardial surface 14 via a blood vessel 22 (e.g., the femoral vein). In various circumstances, the routes used to obtain access to the epicardial and endocardial surfaces may be determined based at least in part upon factors such as the portion of the heart wall 18 that comprises the target tissue for the ablation, the patient's potential anatomical variations, previous surgeries, etc. In some examples, either or both of the first ablation component 102 or the second ablation component 104 may access the target tissue by any suitable route, such as open chest, thoracotomy, sub-xiphoid, trans-diaphragmatic, and/or vascular access.
[0123] In some examples, one or more of the ablation components 102, 104 may include and/or may be configured to operate in connection with a device configured to selectively and/or releasably attach to the target tissue, such as a tissue anchor. For example, the first ablation component 102 may include a vacuum anchor 122. Which may be configured to selectively and/or releasably secure the first ablation component 102 to the epicardial surface 12. In some such examples, the connecting element 116 may include a vacuum line and/or the control unit 114 may include a vacuum pump and/or related control apparatus.
[0124] Generally, some examples may be operated as follows. Appropriate access to the epicardial 12 and endocardial 14 surfaces may be obtained. The first ablation component 102 may positioned at a desired location on the epicardial surface 12. The magnetic elements 110, 112 may be utilized (e.g., magnetically coupled) to position and/or secure the second ablation component 104 on the endocardial surface 14. For example, the magnetic clement 110 of the first ablation component 102 may magnetically attract the magnetic element 112 of the second ablation component 104. The ablation elements 106, 108 may be operated to ablate the target tissue and create the lesion 16. The magnetic elements 110, 112 may be uncoupled. The first and second ablation components 102, 104 may be withdrawn from the patient.
[0125] Some examples may provide sensing capabilities for various parameters. For example, tissue impedance may be sensed between ablation electrodes, such as to assess the extent of an ablation. In some examples, measurements of magnetic fields may be utilized, such as to determine a distance between certain components.
[0126] The ablation elements 106, 108 and magnetic elements 110, 112 are illustrated as separate elements in
[0127] Various examples according to at least some aspects of the present disclosure may include one or more magnetic elements. For example, each ablation component may comprise one or more magnetic elements. Magnetic elements may comprise, for example, any combination of one or more permanent magnets, electromagnets, and/or ferromagnetic materials. Individual magnetic elements mentioned above may comprise one or more constituent subcomponents, which may be shaped, arranged, configured, combined, and/or controlled to achieve desired magnetic and/or mechanical characteristics. In some examples, electromagnets may be energized (with constant or varying electrical current) to attract and/or repel other magnetic elements, such as by reversing current direction to reverse magnetic polarity and/or varying current flow to adjust magnetic field strength. For example, the current supplied to an electromagnet may be constant direct current (DC) and/or may be pulsed to change the attractive and/or repulsive forces. In some examples, magnetic elements (such as permanent magnets) may be repositioned (e.g., translated and/or reoriented) to vary the arrangement of the magnetic field. In some drawings and descriptions herein, magnetic poles of various magnetic elements may be described as north (N) and south (S), however, it should be understood that these descriptions are illustrative and generally represent opposite polarities. Generally, opposite polarities (N-S or S-N) attract each other, and identical polarities (S-S or N-N) repel each other.
[0128] Magnetic elements and associated technologies according to at least some aspects of the present disclosure, as well as any feature, characteristic, or methodology relating thereto, may be used in connection with any medical or surgical device. For example, magnetic elements and associated technologies according to at least some aspects of the present disclosure may be utilized in connection with any ablation system (or component thereof) employing magnetic elements and/or magnetic coupling of ablation components. In various examples described herein, repeated description of the ablation or other components, elements, or systems may be omitted for brevity. However. it will be understood that any magnetic element described herein may be utilized in connection with any ablation or other element, component, or system according to the present disclosure and/or may be paired or combined with any other magnetic element according to the present disclosure.
[0129] The present disclosure contemplates that magnetic elements utilized in ablation systems may be subject to certain design considerations, such as the magnitudes and directions of forces exerted by the magnetic elements and the dimensions and package sizes of the magnetic elements. For example, some ablation components may be configured to contact a target tissue following delivery through a cannula, catheter, or similar device. Some example ablation components, such as those used endocardially, may be delivered through a catheter having an internal diameter of about 5 mm or less. Some example ablation components, such as those used epicardially, may be delivered through a cannula having an internal diameter of about 10 mm or less. Some example ablation components may have a longitudinal length of about 20-30 mm, excluding the connecting elements, though the foregoing exemplary dimensions may be exceeded or reduced in certain instances.
[0130] The present disclosure contemplates that the force between two magnetic elements may be given by the following equation, in which F is the force, m.sub.1 is the magnetic moment of a first magnetic element, m.sub.2 is the magnetic moment of a second magnetic element, x is the center-to-center distance between the first magnetic element and the second magnetic element, and ?.sub.0 is the free space permeability:
[0131] The force may be increased by, for example, increasing the moment of the first magnetic element and/or the second magnetic element, ensuring collinear alignment of the magnetic elements, and/or reducing the distance between the magnetic elements,
[0132] The present disclosure contemplates that the magnetic moment of a ferromagnet may be given by the following equation, in which m is the magnetic moment, M is the magnetization, V is the volume of the magnetic element, B.sub.r is the flux density, and ?.sub.0 is the free space permeability:
[0133] The magnetic moment may be increased by, for example, increasing the volume of the magnetic element and/or increasing the flux density by utilizing a different material.
[0134] The present disclosure contemplates that the flux density of some example materials may differ as indicated in the table below:
TABLE-US-00001 B.sub.r Tesla Material (T) S.sub.rFe.sub.12O.sub.19 0.42 Alnico 5 1.25 SmCo5 0.88 Sm.sub.2Co.sub.17 1.08 Nd.sub.2Fe.sub.14B 1.28
[0135] The present disclosure contemplates that an electromagnet generally comprises a core wrapped with a wire (e.g., a coil) through which electrical current is directed. The magnetic moment of an electromagnetic coil with a soft magnetic core may be given by the following equation, in which m the magnetic moment, ?.sub.eff is the effective permeability of the core, N is the number of turns of the wire in the coil, I is the current through the wire, and A is the coil loop area:
[0136] The effective permeability of the core may depend on the core materials, relative permeability and/or the core shape. Generally, it is within the scope of the disclosure to optimize characteristics of electromagnets (e.g., shape, coil wire cross section, winding geometry, and/or materials (e.g., washers)) to increase current density in the coil, which may increase the magnetic moment of an electromagnet.
[0137] The present disclosure contemplates that the more stray flux a shape has, the harder it may be to align the internal moments, thus producing a low ?.sub.eff. Generally, long and thin magnetic elements may have relatively low stray flux. They may be a low energy shape and may have a relatively higher effective permeability. Generally, short and wide magnetic elements may have relatively high stray flux. They may be a high energy shape and may have a relatively lower effective permeability.
[0138] The present disclosure contemplates that a generally U-shaped magnetic element may be referred to as a horseshoe magnet. Generally, horseshoe magnetic elements may reduce stray flux and may increase effective permeability as compared to other shapes.
[0139] The descriptions herein of various example magnetic elements focuses on the differences between various example configurations. Description of aspects or features common among several examples may not be repeated for brevity. Accordingly, it should be understood that various aspects, features, and characteristics described in connection with any example may also pertain to other examples, whether or not explicitly noted.
[0140]
[0141]
[0142]
[0143]
[0144]
[0145]
[0146] Magnetic element 2500 may comprise a double horseshoe electromagnet 2502. The double horseshoe magnet 2502 may include a double horseshoe (e.g., generally E-shaped) core 2504 wound with a coil 2506. As illustrated in
[0147] Magnetic element 2540 (
[0148] Magnetic element 2570 (
[0149]
[0150]
[0151]
[0152]
[0153]
[0154]
[0155]
[0156] Magnetic element 3250 may comprise an axially oriented electromagnet 3252, which may include two or more coils 3254, 3256 disposed about an axially oriented, generally cylindrical core 3258. In some examples, the coils 3254, 3256 may be at least partially concentrically disposed about the core 3258. In some examples, the inner coil 3254 may be disposed about the core 3258 for most or all of the axial length of the core 3258 and/or the outer coil 3256 may be disposed concentrically about the inner core 3254 for substantially less than the axial length of the core 3258. In an alternative example, the inner coil 3254 may be shorter than the outer coil 3256 and/or the outer coil 3256 may extend for most or all of the axial length of the core 3258.
[0157] In some examples, the coils 3254, 3256 may be separately energized and/or controlled, such as by the control unit 114 (see
[0158]
[0159] Magnetic element 3350 may act as a horseshoe magnet, with opposite poles at opposite circumferential ends. In some examples, the core 3358 may include generally flattened tissue facing surfaces 3360, 3362, which may be arranged generally opposite corresponding generally flat surfaces of magnetic element 3300. In some alternative examples, the magnetic element 3300 may be replaced by a diametrically magnetized cylindrical permanent magnet, such as one having the form of a right circular cylinder.
[0160] Although some examples are described herein with reference to RF ablation, it is within the scope of the disclosure to utilize alternative and/or additional ablation modalities in various alternative examples according to at least some aspects of the present disclosure. Namely, examples may utilize pulsed field ablation, cryoablation, ultrasound ablation, and/or laser ablation and may include ablation elements appropriately configured for such modalities in addition to or in place of electrodes described herein.
[0161] Various examples according to at least some aspects of the present disclosure may include one or more magnetic elements. Magnetic elements may comprise, for example, any combination of one or more permanent magnets, electromagnets, and/or ferromagnetic materials. Individual magnetic elements mentioned herein may comprise one or more magnetic subcomponents, which may be shaped, arranged, configured, combined, and/or controlled to achieve desired magnetic and/or mechanical characteristics. In some examples, electromagnets may be energized (with constant or varying electrical current) to attract and/or repel other magnetic elements, such as by reversing current direction to reverse magnetic polarity and/or varying current flow to adjust magnetic field strength. In some examples, magnetic elements (such as permanent magnets) may be repositioned (e.g., translated and/or reoriented) to vary the arrangement of a given or varied magnetic field.
[0162] Generally, any ablation component described herein may be utilized epicardially and/or endocardially, such as in cooperation with any other ablation component described herein. Examples may utilize magnetic coupling between magnetic elements associated with each ablation component. In some examples, if a magnetic element of the one ablation component comprises a permanent magnet, then a magnetic element of the other ablation component may comprise a ferromagnetic material, a permanent magnet, and/or an electromagnet. In some examples, if a magnetic element of one ablation component comprises an electromagnet, then a magnetic element of the other ablation component may comprise a ferromagnetic material, a permanent magnet, and/or an electromagnet.
[0163] Some examples may be configured to utilize substantially constant magnetic coupling forces. Some examples may be configured to vary force with separation distance between magnetic elements. For example, the distance between magnetic elements may be measured by imaging, measured by distance sensors (e.g., magnetic field sensors), and/or by measured by initial impedance.
[0164] Some examples may be configured to vary forces in connection with ablation cycles. For example, force may be increased and/or decreased as the ablation elements get closer (e.g., separation distance decreases). In some examples, forces may be increased and/or decreased as impedance through tissue changes. In some examples, magnetic polarity may be reversed (e.g., from an attractive arrangement to a repulsive arrangement), such as when it may be desired to disengage one or both of the ablation components from the tissue. For example, the direction of current flow through an electromagnet may be reversed and/or a movable permanent magnet may be rotated.
[0165] Some examples may be configured to facilitate user driven force changes. For example, some magnetic elements (e.g., permanent magnets) may rotatable to facilitate disengagement from tissue. Some examples may provide the ability for a user to selectively shield a magnetic element to increase and/or decrease forces. Some examples may provide the ability for a user to move a magnetic element closer to and/or farther from a cooperating magnetic element to increase and/or decrease forces.
[0166] In some examples, power delivery to ablation elements, such as for RF ablation, may be impedance controlled. In some examples, power delivery based on impedance may be independent of magnetic forces, magnetic forces may be used to modify an impedance calculation, and/or magnetic forces may be used to assess contact before and/or during an ablation.
[0167] In some examples, power delivery to ablation elements, such as for RF ablation, may be power controlled. In some examples, the power control may be substantially independent of magnetic forces, magnetic forces may be used to adjust power, magnetic forces may be used to modify a voltage calculation, and/or magnetic forces may be used to assess contact before and/or during ablation.
[0168] In some examples, energy delivery to ablation elements, such as for RF ablation, may be continuous, pulsed, and/or switched.
[0169] The following patent references are hereby incorporated by reference in their entireties: US20050187545A1, WO2005081868A3, WO2005081868A2, US20070239155A1, U.S. 8,419,729B2, US20110152860A1, U.S. Pat. Nos. 9,072,522B2, 9,173,705B2, US20110313286A1, US20120123411A1, U.S. Pat. No. 9,474,574B2, US20130172864A1, U.S. Pat. No. 9,101,364B2, 9,445,864B2, US20150366605A1, US20160242750A1, U.S. Pat. No. 10,610,208B2, WO2016138008A1, US20160242788A1, EP3261514A1, EP3261514A4, U.S. Pat. No. 10,548,611B2, US20170354457A1, U.S. Pat. No. 10,398,495B2, US20170258520A1, U.S. Pat. No. 10,251,699B2, US20190247113A1, US20200000511A1, US20200261096A1, and US20200205797A1.
[0170] Example methods of ablating tissue and/or creating a lesion may include operations involving use of various examples described herein. Example methods of manufacturing ablation apparatus and components thereof may include operations associated with acquiring, producing, and assembling various parts, elements, components, and systems described herein.
[0171] Unless specifically indicated, it will be understood that the description of the structure, function, and/or methodology with respect to any illustrative example herein may apply to any other illustrative example. More generally, it is within the scope of the present disclosure to utilize any one or more features of any one or more examples described herein in connection with any other one or more features of any other one or more other examples described herein. Accordingly, any combination of any of the features or examples described herein is within the scope of this disclosure.
[0172] The terminology used herein is for the purpose of describing particular examples only and is not intended to be limiting of the invention. As used herein, the singular forms a, an and the are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms comprise and/or comprising, when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
[0173] The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present innovation has been presented for purposes of illustration and description but is not intended to be exhaustive or limited to the innovation in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the innovation. The examples were described in order to explain the principles of the innovation and the practical application, and to enable others of ordinary skill in the art to understand the innovation, including various alternate examples incorporating various modifications as are suited to the particular use contemplated.
[0174] Following from the above description and invention summaries, it should be apparent to those of ordinary skill in the art that, while the methods and apparatuses herein described constitute examples according to the present disclosure, it is to be understood that the scope of the disclosure contained herein is not limited to the above precise examples and that changes may be made without departing from the scope of the disclosure. Likewise, it is to be understood that it is not necessary to meet any or all of the identified advantages or objects disclosed herein in order to fall within the scope of the disclosure, since inherent and/or unforeseen advantages may exist even though they may not have been explicitly discussed herein.