Patent Application
20220015826
The present invention relates to catheters and methods for the ablation of cardiac tissue. More specifically, the invention relates to catheters and methods for focal ablation of cardiac tissue by irreversible electroporation.
Aberrant conductive pathways can disrupt the normal path of the heart's electrical impulses. The aberrant conductive pathways can create abnormal, irregular, and sometimes life-threatening heart rhythms called arrhythmias. Ablation of cardiac tissue is one way of treating arrhythmias and restoring normal conduction. The specific cardiac tissue can be located or mapped using mapping electrodes of a mapping catheter. After mapping, the physician may ablate the aberrant tissue.
Precision, point-by-point, or focal, cardiac ablation is generally accomplished using radio frequency (RF) energy. In radio frequency (RF) ablation, RF energy is directed from an ablation electrode through tissue to an electrode to ablate the tissue and form a lesion. RF energy destroys tissue indiscriminately through cell necrosis, which can result to damage to untargeted tissue, such as nerve and arterial tissues, for example. RF ablation can create other undesired effects, such as tissue charring and steam pops due to the heat generated by the RF energy.
Example 1 is a catheter for focal cardiac ablation by irreversible electroporation. The catheter includes a flexible catheter body extending from a proximal end to a distal end, a plurality of tines disposed at the distal end of the catheter body, a flexible shaft, a return electrode, and an electrical conductor. The catheter body forms a lumen extending from the proximal end to the distal end. The catheter body defining a longitudinal axis. The plurality of tines are formed of an electrically conductive material and configured to deploy from the lumen at the distal end of the catheter body. Each tine of the plurality of tines is configured to self-bias from a linear configuration within the lumen to a curved configuration when deployed from the lumen. The flexible shaft is formed of an electrically conductive material. The shaft is mechanically and electrically coupled to the plurality of tines and extends through the lumen from the proximal end of the catheter body. The shaft is configured to deploy the tines from the lumen when the shaft is moved toward the distal end of the catheter body. The return electrode is disposed on an outer surface of the catheter body. The electrical conductor is electrically coupled to the return electrode. The electrical conductor extends through the catheter body from the proximal end of the catheter body.
Example 2 is the catheter of Example 1, wherein the return electrode includes a ring extending around a circumference of the catheter body.
Example 3 is the catheter of Example 1, wherein the return electrode includes a first ring and a second ring, each of the first ring and the second ring extending around a circumference of the catheter body, the second ring disposed proximally from the first ring.
Example 4 is the catheter of Example 1, wherein the return electrode includes at least one of: a wire coil, a wire mesh and a hypo tube cut in a flexible pattern, the return electrode extending around a circumference of the catheter body.
Example 5 is the catheter of Example 1, wherein catheter body includes a deployable array at the distal end of the catheter body and the return electrode includes a plurality of return electrodes disposed on the deployable array, the deployable array including a plurality of splines, each spline of the plurality of splines including at least one return electrode of the plurality of return electrodes.
Example 6 is the catheter of Example 5, wherein the plurality of splines are configured to transition between a retracted configuration in which each spline of the plurality of splines is substantially parallel to the longitudinal axis and a deployed configuration in which each spline of the plurality of splines is bowed radially outward from the longitudinal axis.
Example 7 is the catheter of any of Examples 1-6, wherein the flexible shaft is formed of a wire coil.
Example 8 it the catheter of any of Example 1-7, wherein the return electrode is disposed between 1 mm and 10 mm from the distal end of the catheter body.
Example 9 is the catheter of any of Example 1-8, wherein each tine of the plurality of tines forms a curve extending from the distal end of the catheter body and away from the longitudinal axis in the curved configuration.
Example 10 is a catheter for focal cardiac ablation by irreversible electroporation. The catheter includes a flexible catheter body extending from a proximal end to a distal end, a plurality of tines disposed at the distal end of the catheter body, a flexible shaft, a return electrode and an electrical conductor. The catheter body forms a lumen extending from the proximal end to the distal end. The catheter body defines a longitudinal axis. The plurality of tines are formed of an electrically conductive material and are configured to deploy from the lumen at the distal end of the catheter body. Each tine of the plurality of tines is configured to self-bias from a linear configuration within the lumen to a curved configuration when deployed from the lumen. The flexible shaft is formed of an electrically conductive material. The shaft is mechanically and electrically coupled to the plurality of tines and extends through the lumen from the proximal end of the catheter body. The shaft is configured to deploy the tines from the lumen when the shaft is moved toward the distal end of the catheter body. The return electrode is configured to deploy from the catheter body at the distal end of the catheter body and to form a loop extending from the catheter body. The electrical conductor is electrically coupled to the return electrode. The electrical conductor extends through the catheter body from the proximal end of the catheter body.
Example 11 is the catheter of Example 10, wherein the return electrode includes a first wire coil.
Example 12 is the catheter of Example 11, wherein the electrical conductor and the return electrode each include the first wire coil.
Example 13 is the catheter of any of Examples 10-12, wherein the flexible shaft is formed of a second wire coil.
Example 14 is the catheter of any of Examples 10-13, wherein each tine of the plurality of tines forms a curve extending from the distal end of the catheter body and away from the longitudinal axis in the curved configuration.
Example 15 is the catheter of any of Examples 10-14, wherein the loop formed by the return electrode is configured to selectively rotate around the longitudinal axis.
Example 16 is a catheter for focal cardiac ablation by irreversible electroporation. The catheter includes a flexible catheter body extending from a proximal end to a distal end, a plurality of tines disposed at the distal end of the catheter body, a flexible shaft, a return electrode, and an electrical conductor. The catheter body forms a lumen extending from the proximal end to the distal end. The catheter body defining a longitudinal axis. The plurality of tines are formed of an electrically conductive material and configured to deploy from the lumen at the distal end of the catheter body Each tine of the plurality of tines is configured to self-bias from a linear configuration within the lumen to a curved configuration when deployed from the lumen. Each tine of the plurality of tines forms a curve extending from the distal end of the catheter body and away from the longitudinal axis in the curved configuration. The flexible shaft is formed of an electrically conductive material. The shaft is mechanically and electrically coupled to the plurality of tines and extends through the lumen from the proximal end of the catheter body. The shaft is configured to deploy the tines from the lumen when the shaft is moved toward the distal end of the catheter body. The return electrode is disposed on an outer surface of the catheter body. The electrical conductor is electrically coupled to the return electrode. The electrical conductor extends through the catheter body from the proximal end of the catheter body.
Example 17 is the catheter of Example 16, wherein the return electrode includes a ring extending around a circumference of the catheter body.
Example 18 is the catheter of Example 16, wherein the return electrode includes a first ring and a second ring, each of the first ring and the second ring extending around a circumference of the catheter body, the second ring disposed proximally from the first ring.
Example 19 is the catheter of Example 16, wherein the return electrode includes at least one of: a wire coil, a wire mesh and a hypo tube cut in a flexible pattern, the return electrode extending around a circumference of the catheter body.
Example 20 is the catheter of Example 16, wherein catheter body includes a deployable array at the distal end of the catheter body and the return electrode includes a plurality of return electrodes disposed on the deployable array, the deployable array including a plurality of splines, each spline of the plurality of splines including at least one return electrode of the plurality of return electrodes.
Example 21 is the catheter of Example 20, wherein the plurality of splines are configured to transition between a retracted configuration in which each spline of the plurality of splines is substantially parallel to the longitudinal axis and a deployed configuration in which each spline of the plurality of splines is bowed radially outward from the longitudinal axis.
Example 22 is the catheter of any of Examples 16-21, wherein the flexible shaft is formed of a wire coil.
Example 23 is the catheter of any of Examples 16-22, wherein the return electrode is disposed between 1 mm and 10 mm from the distal end of the catheter body.
Example 24 is the catheter of any of Examples 16-23, further comprising an atraumatic tip disposed at the at the distal end of the catheter body.
Example 25 is a catheter for focal cardiac ablation by irreversible electroporation. The catheter includes a flexible catheter body extending from a proximal end to a distal end, a plurality of tines disposed at the distal end of the catheter body, a flexible shaft, a return electrode and an electrical conductor. The catheter body forms a lumen extending from the proximal end to the distal end. The catheter body defines a longitudinal axis. The plurality of tines are formed of an electrically conductive material and are configured to deploy from the lumen at the distal end of the catheter body. Each tine of the plurality of tines is configured to self-bias from a linear configuration within the lumen to a curved configuration when deployed from the lumen. The flexible shaft is formed of an electrically conductive material. The shaft is mechanically and electrically coupled to the plurality of tines and extends through the lumen from the proximal end of the catheter body. The shaft is configured to deploy the tines from the lumen when the shaft is moved toward the distal end of the catheter body. The return electrode is configured to deploy from the catheter body at the distal end of the catheter body and to form a loop extending from the catheter body. The electrical conductor is electrically coupled to the return electrode. The electrical conductor extends through the catheter body from the proximal end of the catheter body.
Example 26 is the catheter of Example 25, wherein the return electrode includes a first wire coil.
Example 27 is the catheter of Example 26, wherein the electrical conductor and the return electrode each include the first wire coil.
Example 28 is the catheter of any of Examples 25-27, wherein the flexible shaft is formed of a second wire coil.
Example 29 is the catheter of any of Examples 25-28, wherein each tine of the plurality of tines forms a curve extending from the distal end of the catheter body and away from the longitudinal axis in the curved configuration.
Example 30 is the catheter of any of Examples 25-29, wherein the loop formed by the return electrode is configured to selectively rotate around the longitudinal axis.
Example 31 is the catheter of any of Examples 25-30, further comprising an atraumatic tip disposed at the at the distal end of the catheter body.
Example 32. A method for focal cardiac ablation by irreversible electroporation. The method includes inserting a distal end of a catheter into a heart and adjacent to tissue containing cells to be ablated, the catheter including a flexible catheter body and a plurality of electrically conductive tines configured to deploy from a lumen at the distal end of the catheter body; moving a shaft extending through the lumen toward the distal end to deploy the plurality of electrically conductive tines from the lumen and into the tissue containing the cells to be ablated, each tine of the plurality of electrically conductive tines self-biasing from a linear configuration within the lumen to a curved configuration when deployed into the tissue; applying a series of voltage pulses between the plurality of electrically conductive tines and a return electrode disposed on an outer surface of the catheter body and spaced apart from the distal end of the catheter body, the voltage pulses forming an electric field causing irreversible electroporation of the cells to be ablated; moving the shaft extending through the lumen toward a proximal end of the catheter body to retract the tines into the lumen; and withdrawing the distal end of the catheter from the heart.
Example 33 is the method of Example 32, wherein the return electrode is disposed between 1 mm and 10 mm from the distal end of the catheter body.
Example 34 is the method of Example 32 or Example 33, wherein each tine of the plurality of tines forms a curve extending from the distal end of the catheter body and away from a longitudinal axis of the catheter body in the curved configuration.
Example 35 is the method of any of Examples 32-34, wherein the return electrode includes a plurality of electrodes, the method further including deploying an array including a plurality of splines at the distal end of the catheter body by transitioning from a retracted configuration in which each spline of the plurality of splines is substantially parallel to a longitudinal axis of the catheter body and a deployed configuration in which each spline of the plurality of splines is bowed radially outward from the longitudinal axis of the catheter body, each spline of the plurality of splines including at least one return electrode of the plurality of return electrodes, wherein deploying the array is after inserting the distal end of a catheter into the heart and \and before applying the series of voltage pulses; and retracting the array by transitioning from the deployed configuration to the retracted configuration after applying the series of voltage pulses and before withdrawing the distal end of the catheter from the heart.
While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.
While the disclosure is amenable to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and are described in detail below. The intention, however, is not to limit the invention to the particular embodiments described. On the contrary, the disclosure is intended to cover all modifications, equivalents, and alternatives falling within the scope of the invention as defined by the appended claims.
Irreversible electroporation uses trains of short, high voltage pulses to kill cells by forming lethal nanopores in the cell membranes. The damaged cells then die through apoptosis. The voltage pulses of irreversible electroporation can be targeted to kill myocardium, and leave other tissues relatively unscathed, thus avoiding the undesired side effects of RF ablation. However, forming transmural lesions in thick myocardium can be difficult with irreversible electroporation. In addition, ablation of heart tissue poses a challenge in that the heart is constantly moving during an ablation procedure. As a result, it can be difficult to maintain stable contact between an ablating electrode and the target tissue. Embodiments of the present disclosure provide catheters and methods for focal cardiac ablation by irreversible electroporation that reduce these problems.
The flexible shaft 16 includes an electrically conductive biocompatible material, such as a platinum iridium alloy, gold, stainless-steel, a titanium alloy, or a nickel-cobalt alloy, such as MP35N, for example. The flexible shaft 16 may further include an insulating polymer coating. In some embodiments, the flexible shaft 16 is in the form of a wire coil. The electrical conductor 20 is also formed of any of the previously mentioned electrically conductive materials and may also further include an insulating polymer coating.
The optional atraumatic tip 22 may formed of a biocompatible material, such as polyether ether ketone (PEEK), polyisobutylene polyurethane, silicone, polyether block amide or titanium, for example. The atraumatic tip 22 is disposed at the distal end 24 and forms the tip of the catheter 10 when the catheter 10 is in the undeployed configuration, as shown in
The plurality of tines 14 is disposed at the distal end 24 of the catheter body 12. The flexible shaft 16 is mechanically and electrically coupled to the plurality of tines 14 and extends through the lumen 28 from the proximal end 26 of the catheter body 12.
The return electrode 18 is disposed on an outer surface 30 of the catheter body 12. In the embodiment shown in
The return electrode 18 is spaced apart from the distal end 24 of the catheter body 12 by a distance S, which may be as little as 1 mm, 2 mm, 3 mm, 4 mm or 5 mm, or as much as 6 mm, 7 mm, 8 mm, 9 mm or 10 mm, or within any range defined between any two of the foregoing values, such as 1 mm to 10 mm, 2 mm to 9 mm, 3 mm to 8 mm, 4 mm to 7 mm, 5 mm to 6 mm, 1 mm to 5 mm, 6 mm to 10 mm, 2 mm to 5 mm, 3 mm to 4 mm or 2 mm to 6 mm, for example.
The electrical conductor 20 is electrically coupled to the return electrode 18. The electrical conductor 20 extends through the catheter body 12 from the proximal end 26. In some embodiments, the electrical conductor 20 extends through the lumen 28 from the proximal end 26 of the catheter body 12, as shown in
The flexible shaft 16 may be moved distally to deploy the plurality of tines 14 from the lumen 28, as shown in
As shown in
Each tine of the plurality of tines 14 may penetrate tissue T to a depth of as little as 1 mm, 1.5 mm, 2 mm, 2.5 mm, 3 mm or 3.5 mm or as great as 4 mm, 4.5 mm, 5 mm, 5.5 mm, 6 mm, 6.5 mm or 7 mm, or within any range defined between any two of the foregoing values, such as 1 mm to 7 mm, 1.5 mm to 6.5 mm, 2 mm to 6 mm, 2.5 mm to 5.5 mm, 3 mm to 5 mm, 4 mm to 4.5 mm, 1 mm to 2 mm, 2 mm to 7 mm or 1 mm to 3 mm, for example.
In some embodiments, each tine of the plurality of tines 14 may have a rectangular cross-section having a cross-sectional length and a cross-sectional width. The cross-sectional length may be as small 0.25 mm, 0.30 mm, 0.35 mm, 0.40 mm, 0.45 mm or 0.50 mm, or as large as 0.55 mm, 0.60 mm, 0.65 mm, 0.70 mm, 0.75 mm or 0.80 mm, or within any range defined between any two of the foregoing values, such as 0.25 mm to 0.80 mm, 0.30 mm to 0.75 mm, 0.35 mm to 0.70 mm, 0.40 mm to 0.65 mm, 0.45 mm to 0.60 mm, 0.50 mm to 0.55 mm, 0.30 mm to 0.60 mm, 0.25 mm to 0.50 mm, or 0.55 mm to 0.75 mm, for example. The cross-sectional width may be as small 0.10 mm, 0.13 mm, 0.15 mm, 0.18 mm, 0.20 mm or 0.23 mm, or as large as 0.25 mm, 0.28 mm, 0.30 mm, 0.33 mm, 0.36 mm or 0.38 mm, or within any range defined between any two of the foregoing values, such as 0.10 mm to 0.38 mm, 0.13 mm to 0.36 mm, 0.15 mm to 0.33 mm, 0.18 mm to 0.30 mm, 0.20 mm to 0.28 mm, 0.23 mm to 0.25 mm, 0.20 mm to 0.30 mm, 0.10 mm to 0.20 mm, or 0.25 mm to 0.38 mm, for example.
The electric field E may be as low as 300 V/cm, 350 V/cm, 400 V/cm, 450 V/cm, 500 V/cm, 550 V/cm or 600 V/cm, or as high as 650 V/cm, 700 V/cm, 750 V/cm, 800 V/cm, 850 V/cm, 900 V/cm, 950 V/cm or 1,000 V/cm or within any range defined between any two of the foregoing values, such as 300 V/cm to 1,000 V/cm, 350 V/cm to 950 V/cm, 400 V/cm to 900 V/cm, 450 V/cm to 850 V/cm, 500 V/cm to 800 V/cm, 550 V/cm to 750 V/cm, 600 V/cm to 700 V/cm, 300 V/cm to 650 V/cm, 400 V/cm to 500 V/cm, or 700 V/cm to 900 V/cm, for example.
It is believed that the electric field E can be concentrated further into the depth of the tissue T to form transmural lesions in thick myocardium by deploying the plurality of tines 14 deep within the tissue T and generating the electric field between the plurality of tines 14 and the return electrode 18 disposed on the outer surface 30 of the catheter body 12 and spaced apart from the distal end 24.
In some embodiments, the plurality of splines 48 are formed of the same material making up the rest of the catheter body 12, such polyether block amide, polyisobutylene polyurethane or silicone. In some embodiments, the plurality of splines 48 may further include a material having a shape memory, for example Nitinol or a gold/stainless steel alloy.
The plurality of splines 48 are configured to transition between an undeployed configuration shown in
The return electrode 56 is formed of an electrically conductive biocompatible material, such as stainless steel, platinum, platinum iridium alloy, platinum-clad tantalum, titanium, Nitinol, or a nickel-cobalt alloy, such as MP35N, for example. In some embodiments, the return electrode 56 is in the form of a wire coil. In some other embodiments, the return electrode 56 is in the form of a mesh or a hypo tube cut in a flexible pattern. The electrical conductor 58 is also formed of an electrically conductive material, such as stainless steel, platinum, platinum iridium alloy, platinum-clad tantalum, titanium, Nitinol, or a nickel-cobalt alloy, such as MP35N, for example. In some embodiments, the electrical conductor 58 is in the form of a wire coil. In some other embodiments, the electrical conductor 58 is in the form of a mesh or a hypo tube cut in a flexible pattern. In some embodiments, the return electrode 56 and the electrical conductor 58 may form a single, continuous wire coil. In embodiments in which the return electrode 56 and the flexible shaft 16 are both formed of different wire coils within the catheter body 12, the wire coil of the return electrode 56 may be a first coil and the wire coil of the flexible shaft 16 may be a second coil.
For clarity of illustration, all embodiments described above are shown with the plurality of tines 14 including four tines. However, it is understood that the disclosure encompasses embodiments with as few as two tines and as many as six tines.
Various modifications and additions can be made to the exemplary embodiments discussed without departing from the scope of the present invention. For example, while the embodiments described above refer to particular features, the scope of this invention also includes embodiments having different combinations of features and embodiments that do not include all of the described features. Accordingly, the scope of the present invention is intended to embrace all such alternatives, modifications, and variations as fall within the scope of the claims, together with all equivalents thereof.
As used herein, the phrase “within any range defined between any two of the foregoing values” literally means that any range may be selected from any two of the values listed prior to such phrase regardless of whether the values are in the lower part of the listing or in the higher part of the listing. For example, a pair of values may be selected from two lower values, two higher values, or a lower value and a higher value.
This application claims priority to Provisional Application No. 63/052,823, filed Jul. 16, 2020, which is herein incorporated by reference in its entirety.
| Number | Date | Country | |
|---|---|---|---|
| 63052823 | Jul 2020 | US |
