Visualization of Quality Indicators Indicating Ablation Stability at Ablation Sites

Abstract

The system includes a display and a processor. The processor is configured to: (i) receive a plurality of position measurements indicating respective positions of ablation electrodes at respective times during an ablation procedure at an ablation site within a patient's organ; (ii) estimate a quality metric indicative of the stability of the ablation procedure at the ablation site based on at least the plurality of position measurements; and (iii) visualize the quality metric to a user on the display.

Description

Technical Field

[0001] The present disclosure generally relates to tissue ablation, and more specifically, to methods and systems for visualizing for a user a quality metric indicative of ablation stability at an ablation site.

Background Art

[0002] Various techniques for estimating and visualizing the stability of tissue ablation procedures have been disclosed.

[0003] For example, U.S. Patent No. 6,129,669 describes a system and method for sensing the stability of an ablation instrument within a body region. The system and method position a tracking element at a fixed location spaced from the ablation instrument. The system and method generate an output that varies according to the movement of the ablation instrument over time relative to the tracking element.

[0004] U.S. Patent Application Publication No. 2021 / 0346103 describes that a system for supporting a medical intervention, a method for outputting a feedback signal, and a computer program product are provided. The system includes a feedback device for outputting a feedback signal to a user of an intervention device, and a control device for controlling the feedback device. The control device is configured to receive an actual position of the intervention device and a target position of the intervention device. The control device is further configured to determine a deviation of the actual position from the target position and to control the output of the feedback signal by the feedback device as a function of the deviation.

Brief Description of the Drawings

[0005] The present disclosure will be more fully understood from the following detailed description of embodiments of the present disclosure in conjunction with the drawings.

Figure 1

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[0006] Overview Some medical procedures require the application of ablation signals to the tissue of a patient's organ. For example, radiofrequency (RF) ablation signals can be applied to the heart tissue at the ablation site to treat arrhythmias.

[0007] Tissue ablation is intended to convert the tissue into a damage that is adapted to prevent the unwanted propagation of electrophysiological waves through the tissue to be ablated. In response to ablation, tissue cells die, and at least a portion of the ablated tissue is converted into damage. To prevent the propagation of electrophysiological waves, a physician performing ablation typically defines an ablation line (or ring) that includes a plurality of ablation sites and uses one or more ablation electrodes of a catheter in contact with the tissue to apply an ablation signal to the tissue at each ablation site to obtain an appropriate damage. However, in some cases, the ablation electrode may undesirably move relative to the tissue while applying an ablation signal at a given ablation site. Such movement reduces the stability of the ablation electrode relative to the tissue at the ablation site, thus reducing the quality of the damage and potentially leaving gaps in the ablation line that may not completely prevent the propagation of electrophysiological waves.

[0008] Furthermore, while applying the ablation signal, the physician needs an indication of the stability of the ablated tissue. In this context, the term stability refers to the allowable movement speed and the allowable distance between (i) a first position, e.g., the position of the ablation electrode when the physician starts applying the ablation signal, and (ii) one or more second positions visited by the ablation electrode while the ablation signal is being applied.

[0009] The embodiments of the present disclosure described below provide methods and systems for improving the estimation and visualization of quality metrics indicative of ablation stability at an ablation site.

[0010] In some embodiments, a system for applying ablation pulses to a patient's heart comprises: (i) a power source, such as a radio frequency (RF) generator configured to generate an ablation signal; (ii) a catheter electrically connected to the RF generator, the catheter comprising at least: (a) an ablation electrode configured to apply the ablation signal to tissue in contact with the ablation electrode; and (b) a position sensor configured to generate a position signal indicative of the measured position of the ablation electrode within the heart; (iii) a display; and (iv) a processor configured to display the position of the ablation electrode on a map of the patient's heart. The components of the system are described in detail in FIG. 1 below.

[0011] In some embodiments, the processor is configured to receive a plurality of position measurements indicating the respective positions of the ablation electrodes at each point in time during an ablation procedure at an ablation site within a patient's heart. The processor is configured to receive a reference position that is the position of the ablation electrode when starting to apply an ablation signal to tissue at the ablation site. The processor is further configured to hold a threshold value indicating (i) an allowable distance between the reference position and the plurality of measured positions of the ablation electrode while the ablation signal is being applied, and (ii) an allowable speed of the ablation catheter with respect to the reference position. The above operations are described in detail in FIGS. 2 and 4 below.

[0012] In some embodiments, based on the plurality of position measurements, the reference position, and the threshold value, the processor is configured to estimate a quality metric (also referred to herein as an ablation stability quality metric) indicating the stability of the ablation procedure at the ablation site. In this context, the term "stability" refers to the measured distances and speeds with respect to the threshold values indicating the allowable distances and speeds. In other words, the processor is configured to estimate the quality metric according to at least some of the respective distances of the measured positions from the reference position and / or according to the estimated speed of the ablation electrode while applying the ablation signal at the ablation site, and the estimation is described in detail in FIG. 2 below.

[0013] In some embodiments, the processor is configured to visualize quality metrics for the physician (and any other user) on the system display. For example, while ablating tissue at a given ablation site, the processor is configured to display an icon in the shape of a sphere or a prolate ellipsoid, also referred to herein as a visitag icon, at the given ablation site. The processor is further configured to assign a color indicating the value of each ablation stability quality metric relative to a threshold of the ablation stability quality metric to the visitag icon, as shown in and described in detail in FIG. 2 below.

[0014] In some embodiments, in response to identifying that the values of the ablation stability quality metrics each exceed their respective thresholds, the processor 33 is configured to display a halo around each visitag icon. In this embodiment, the halo may be displayed for approximately 3 seconds, indicating the end of ablation at the location marked by the visitg icon, and immediately after the halo disappears, the processor generates a new visitag icon at which the calculated center of mass is at the measured current position of the ablation electrode. The halo and the new visitag icon provide the physician with an indication of the stability and status of the ablation procedure at each ablation site, as described in more detail by FIG. 2 below.

[0015] In some embodiments, if the estimated distance of a given position of the ablation electrode (during ablation) from a reference position exceeds a distance threshold, the processor calculates and displays one or more contours indicating each contour by which the ablation electrode has moved while applying an ablation signal to the tissue of a given ablation site, based on the positions visited by the ablation electrode.

[0016] In some embodiments, the processor is configured to display to the physician a table including each value of the calculated ablation stability quality metric. In an alternative embodiment, the processor is configured to display on the heart map any suitable information selected by the physician. For example, the processor may display on map 27 at a given ablation site any other suitable information related to the ablation, such as, but not limited to, (i) the distal end assembly of the catheter (including the ablation electrode), (ii) a visitag icon indicating the result of the ablation at the given ablation site, (iii) the ablation stability quality metric at the given ablation site, and (iv) an ablation metric calculated based on the primary parameters of the ablation.

[0017] The disclosed technique provides real-time indication of the stability of an ablation procedure to a user of the system (e.g., a physician), such that if the ablation stability quality metrics exceed their respective thresholds, the physician may initiate corrective measures to improve the quality of the damage formed in the heart.

[0018] Description of the System FIG. 1 is a schematic depiction of a catheter-based tracking and ablation system 20 according to an embodiment of the present disclosure.

[0019] In some embodiments, system 20 includes a catheter 22 configured to perform a cardiac operation and a control console 24. In the embodiments described herein, catheter 22 includes a focused catheter that can be used for any suitable therapeutic and / or diagnostic purpose, such as sensing electroanatomical signals and / or ablation of tissue within heart 26 (insert figure 23), as described in detail below. In the context of the present disclosure and the claims, the term "ablation" refers to a radiofrequency (RF) ablation procedure or an irreversible electroporation (IRE) procedure. These procedures are intended to create lesions at target locations within heart 26 (also referred to herein as ablation sites), thereby applying one or more high-voltage monopolar or bipolar electrical pulses to one or more electrodes in contact with the tissue to be ablated to treat cardiac arrhythmias.

[0020] In some embodiments, console 24 includes a processor 33 having suitable front-end and interface circuits that receive signals via catheter 22 and control the other components of system 20 described herein, typically a general-purpose computer. Console 24 further includes a user display 35 configured to receive graphic and / or text display items, such as a map 27 of heart 26, from processor 33 and display map 27.

[0021] In some embodiments, map 27 can include any suitable type of three-dimensional (3D) anatomical map generated using any suitable technique. For example, the anatomical map can be generated using anatomical images generated by using a suitable medical imaging system, or using the fast anatomical mapping (FAM) technique available in the CARTO™ system manufactured by Biosense Webster Inc. (Irvine, California), or using any other suitable technique, or using any suitable combination of the above.

[0022] In some embodiments, console 24 includes a recording unit 38 configured to record in the case of a CARTO™ malfunction and / or a pacing malfunction of a particular electrode. Console 24 includes a patient interface unit (PIU) 44, which generates signals indicative of the location and electrocardiogram (ECG) signals to be acquired and processed, and is configured to exchange signals between console 24 and a plurality of entities of system 20 (e.g., catheter 22).

[0023] Next, reference is made to insertion figure 23. In some embodiments, prior to performing an ablation procedure, physician 30 inserts one or more catheters through the vasculature of patient 28 lying on table 29 so as to perform electro-anatomical (EA) mapping of the target tissue within heart 26. Based on the EA mapping, physician 30 plans an ablation or IRE procedure to be performed using focus catheter 22.

[0024] Next, refer to the inserted FIG. 42. In some embodiments, the catheter 22 includes a distal-end assembly (DEA) 40 having one or more ablation electrodes 55 configured to apply an ablation signal to the tissue of the heart 26. The catheter 22 further includes a position sensor 39, which is typically coupled to the distal end of the catheter 22 and is configured to generate a position signal indicative of the measured position of the ablation electrode 55 in the DEA 40, more specifically, in the XYZ coordinate system, as described in detail below.

[0025] In some embodiments, the DEA 40 includes a contact force sensor, herein referred to as the force sensor 54, configured to measure the force applied by the DEA 40 of the catheter 22 to the endocardial tissue of the heart 26. The force sensor 54 is configured to generate a force signal indicative of the force applied by the DEA 40 to the endocardial tissue of the heart 26. In some embodiments, the force sensor may include a magnetic field transceiver connected to the DEA 40 by a spring and may generate an indication of the force based on the measurement of the deflection of the spring. Further details of this type of catheter and force sensor are described in the aforementioned U.S. Patent Application Publication Nos. 2009 / 0093806 and 2009 / 0138007. In other embodiments, the force sensor 54 may include any other suitable type of force sensor.

[0026] In this embodiment, the ablation electrode 55 is positioned at the tip of the DEA 40 and is brought into contact with the endocardial tissue of the heart 26 such that the force signal indicates the force applied between the ablation electrode 55 and the endocardial tissue of the heart 26.

[0027] Next, refer again to the overall view of FIG. 1. In some embodiments, the PIU 44 is connected to a power source such as a radio frequency (RF) generator 49 packaged within the housing of the PIU 44. In an alternative embodiment, the RF generator may be external to the housing of the PIU 44 and may be electrically connected to the PIU 44 using a suitable cable. The RF generator 49 is configured to apply a suitable RF ablation signal.

[0028] In some embodiments, the proximal end of catheter 22 is connected to an interface circuit (not shown) of the PIU 44 for, among other things, transferring ablation signals from the PIU 44 to electrodes 55 and applying the ablation signals to tissue of heart 26. The interface circuit is further configured to transfer position signals between position sensor 39 and processor 33.

[0029] In some embodiments, system 20 includes an indifferent electrode 48, also referred to herein as a patch electrode, attached to the skin of patient 28 (e.g., on the back of the patient's torso) and electrically connected to the PIU 44 via cable 21. In other embodiments, system 20 may include any suitable number of skin patches configured to attach respective electrodes, for example, about four or five electrodes, to the skin of patient 28.

[0030] In the context of this disclosure and in the claims, the term "about" or "approximately" used in reference to any numerical value or range indicates an appropriate dimensional tolerance that enables a portion of a component or a collection of components to function for its intended purpose as described herein.

[0031] In some embodiments, the system 20 includes a handle 32 that is used by the physician 30 to navigate the DEA 40 through the vascular system of the patient 28 and into a target location, also referred to herein as an ablation site, within the heart 26 for performing ablation.

[0032] In some embodiments, the position of the distal assembly 40 within the vasculature and heart 26 of patient 28 is measured using the position sensor 39 of the magnetic position tracking system. In this embodiment, the console 24 includes a drive circuit 41 configured to drive a magnetic field generator 36 positioned external to the patient 28 lying on the table 29, for example, under the patient's torso. The position sensor is coupled to the distal end and is configured to generate a position signal in response to the sensed external magnetic field from the magnetic field generator 36. The position signal, also referred to herein as a position measurement, indicates the position of the DEA 40 in the XYZ coordinate system of the position tracking system.

[0033] This position sensing method is implemented in various medical applications, for example, in the CARTO™ system manufactured by Biosense Webster Inc., Irvine, California, and is described in detail in U.S. Patent Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612, and 6,332,089, International Publication No. 96 / 05768, and U.S. Patent Application Publication Nos. 2002 / 0065455 (A1), 2003 / 0120150 (A1), and 2004 / 0068178 (A1).

[0034] In some embodiments, the coordinate system of the position tracking system is aligned with the coordinate systems of the system 20 and the map 27, such that the processor 33 is configured to display the position of the distal assembly 40 on the anatomical map or EA map (e.g., map 27).

[0035] In some embodiments, the processor 33 typically includes a general purpose computer programmed in software to perform the functions described herein. The software can be downloaded to the computer in electronic form, for example, via a network, or alternatively or additionally, provided and / or stored on a non-transitory tangible medium such as magnetic memory, optical memory, or electronic memory.

[0036] This particular configuration of system 20 is shown as an example to illustrate the particular problems addressed by embodiments of the present disclosure and to demonstrate the application of these embodiments in improving the performance of such a system. However, embodiments of the present disclosure are in no way limited to this particular type of exemplary system, and the principles described herein may equally apply to other types of medical systems configured to be used in other types of tissue ablation procedures.

[0037] Calculation and Visualization of Ablation Stability Quality Indicator FIG. 2 is a diagram showing annotations of ablation sites 52 and 53 on map 27 of heart 26 according to an embodiment of the present disclosure. Note that ablation sites 52 and 53 include enlarged views of the respective ablation sites displayed on map 27 by processor 33. An exemplary method for generating the annotations is described in FIG. 4 below.

[0038] In some embodiments, each annotation includes (i) icons such as icons 50 and 51 at ablation sites 52 and 53 respectively, and (ii) tables such as tables 56 and 57 at ablation sites 52 and 53 respectively. Tables 56 and 57 each include calculated quality indicators 58 and 59 respectively, which indicate the stability of the ablation procedures performed at ablation sites 52 and 53. In the context of the present disclosure and the claims, the terms "quality indicator" and "stability quality indicator" are used interchangeably and refer to any suitable type of quantitative size or numerical value or metric that indicates the stability of tissue ablation, as described in detail in the following inserted FIGS. 60 and 61.

[0039] Next, refer to insertion diagrams 60 and 61, which respectively show the calculation of quality indicators 58 and 59, and the generation of icons 50 and 51. Note that icons 50 and 51, also referred to herein as visitags or visitag icons, are generated using software, herein referred to as the VisiTag™ module, manufactured by Biosense Webster Inc. (Irvine, California). A visitag is typically displayed on map 27 of heart 26 and provides a visual representation of each ablation lesion formed during an ablation procedure to physician 30. Examples related to the calculation, display, and utilization of visitags are described in more detail, for example, in U.S. Patent Nos. 9,498,147 and 9,757,182.

[0040] In some embodiments, when physician 30 initiates a tissue ablation, physician 30 contacts the tissue of heart 26 with ablation electrode 55 at a first position 64 (e.g., position 64a or position 64b) of each ablation site (e.g., ablation site 52 or ablation site 53). In this embodiment, based on the position signal received from position sensor 39, processor 33 is configured to generate an icon 66 having a spherical or ellipsoidal shape of revolution with a calculated center-of-mass (COM) at position 64a. In this embodiment, icon 66 has a radius of approximately 2 mm, although in other embodiments, icon 66 may have any other suitable size and / or shape.

[0041] In some cases, while the physician 30 applies the ablation signal to the tissue at the ablation site 52, the ablation electrode 55 may move relative to the position 64a. This relative movement can include the respiratory movement of the patient 28 and / or other movement of the DEA 40 relative to the position 64a at each ablation site. In some embodiments, while planning the ablation, the physician 30 defines a set of thresholds stored in the processor 33 for each ablation site intended to receive the ablation signal, such as (i) a minimum contact force between the DEA 40 and the tissue while applying the ablation signal (e.g., greater than a force of about 5 grams), (ii) a minimum duration of ablation signal application (e.g., about 3 to 5 seconds), (iii) a reference position, e.g., the position 64a (also referred to herein as the first position), and a maximum distance (e.g., about 2 mm or any other suitable size) between the second (different) position where the ablation electrode 55 is located while applying the ablation signal, (iv) a maximum speed of movement of the ablation electrode 55 between the first position and the second position (e.g., about 2.5 mm per second), and (v) a maximum value of a stability quality metric, among others but not limited to these.

[0042] During ablation treatment, it should be noted that physician 30 typically intends to define a plurality of ablation sites that are intended to generate an ablation line, which is the spatial trajectory of the ablation site, to prevent unwanted propagation of the electrophysiological wave through the tissue intended to be ablated. Subsequently, physician 30 uses ablation electrode 55 to individually apply ablation signals to the heart tissue site by site. In some cases, due to ablation instability, one or more sites (such as ablation sites 52 and / or 53) may not receive the desired ablation signal in the heart tissue during ablation along the planned ablation line (for example, due to unwanted movement of DEA 40 and / or insufficient ablation power, duration, or contact force). Ablation instability can result in one or more gaps, also referred to herein as voids, within the ablation line. If a gap exists, cardiac dysfunction may not be alleviated by the treatment. Therefore, any unwanted movement of ablation electrode 55 while applying the ablation signal degrades the stability and the quality of the lesion formed at each ablation site.

[0043] Next, refer to inserted figure 60. In the case shown in inserted figure 60, while applying the ablation signal to the tissue at ablation site 52, ablation electrode 55 moved from position 64a (i.e., the first position or reference position) to position 67 (for example, the second position). In some embodiments, based on the position signal from position sensor 39, processor 33 is configured to calculate a vector 65 indicating the direction and average distance between position 64a and position 67. It should be noted that during tissue ablation at ablation site 52, ablation electrode 55 is assumed to be in the same place (for example, position 64a) (and, for example, not moving along the ablation line) throughout the application of the ablation signal.

[0044] In other embodiments, instead of vector 65, processor 33 is configured to calculate the average distance between position 64a and position 67, which represents the quality metric described above. For example, quality metric 58 in Table 56 is based on the average distance calculated between position 64a and position 67.

[0045] In some embodiments, based on the position signal and an appropriate algorithm, processor 33 is configured to exclude the respiratory movement of patient 28 and calculate the average size of vector 65. One implementation of such an algorithm is described, for example, in U.S. Patent Application No. 17 / 188,844, in which the processor receives respiratory data and probe location data, identifies the period during which the probe is stable relative to the boundary of the heart cavity, and uses the algorithm to notify the surgeon of the time interval during which the probe is stable relative to the cavity boundary. Such an algorithm can be used to exclude respiratory movement and leave the movement of the probe relative to the cavity boundary not related to respiration.

[0046] Additionally or alternatively, quality metric 58 can be based on any quantitative measure, including any suitable type of calculated (e.g., average, median, maximum) distance, speed, and combinations of calculated distance and speed, of the movement of DEA 40 (and ablation electrode 55) relative to position 64a.

[0047] In some embodiments, based on (i) the position of ablation electrode 55 received from position sensor 39 while an ablation signal is being applied, and (ii) the stored threshold values described above, processor 33 is configured to estimate a quality metric indicating the stability of ablation at each ablation site.

[0048] In the example of ablation site 52, the quality metric is equal to approximately 0.68 mm, which is less than the threshold of the stability quality metric, and thus indicates a sufficiently stable ablation at ablation site 52.

[0049] Next, refer again to insertion figure 61. In some embodiments, processor 33 is configured to calculate (i) position 68 and distance 69 (between position 64b and position 68), and (ii) position 70 and distance 71 (between position 64b and position 70) based on the position signal received from position sensor 39 and after excluding the respiratory movement of patient 28. In some embodiments, processor 33 is configured to estimate a quality metric 59 indicative of ablation stability within ablation site 53 based on the calculated distances (and optionally, the calculated velocity of movement of DEA 40 within ablation site 53). As described for ablation site 52, during tissue ablation at ablation site 53, ablation electrode 55 is assumed to be in the same location for the entire time the ablation signal is applied to the tissue. Thus, a smaller distance between position 64b and the other measured positions of ablation electrode 55 typically indicates a stable ablation treatment at each ablation site.

[0050] Next, refer again to the overall view of FIG. 2. As shown in table 57, quality metric 59 has a value of approximately 2.25 mm, which exceeds the threshold of the stability quality metric, and thus indicates insufficient stability of the ablation treatment at ablation site 53.

[0051] In some embodiments, processor 33 is configured to display a halo 72 surrounding icon 51, which is displayed as soon as it is identified that quality metric 59 exceeds the threshold of the stability quality metric. In this embodiment, both icons 50 and 51 have the same shape and size (e.g., a pseudo-3D ball having a radius of about 2 mm or any other suitable radius) and provide a visual representation of the ablation lesion to physician 30 to assist physician 30 in planning and performing an ablation strategy by displaying one or more parameters of lesion formation as described above.

[0052] In some embodiments, in response to the display of the halo 72, the physician 30 typically terminates the application of the ablation signal immediately. In this embodiment, the halo 72 is typically displayed for about 3 seconds (or any other appropriate time interval) to indicate to the physician 30 that the ablation stability has been disrupted at the ablation site 53. In some embodiments, simultaneously, the processor 33 is configured to start calculating and estimating the stability of newly occurring ablation sites (e.g., adjacent to the ablation site 53) and display a new icon (not shown) indicating the stability of the ablation treatment at the new ablation site.

[0053] Additionally, or alternatively, the processor 33 is configured to visualize the quality metric by assigning an appropriate color indicating the estimated quality metric to the icons 50 and 51. In the embodiment of FIG. 2, the processor 33 is configured to apply a dark gray indicating a stable ablation and a lighter color at the edge 73 for indicating small movements (fractions of a millimeter) such as the movement from the position 64a to the position 67 to the icon 50.

[0054] In some embodiments, the processor 33 is configured to calculate and display one or more contours, such as the contours 62 and 63, based on the position signal received from the position sensor 39 and after excluding the respiratory movement of the patient 28, based on the positions accessed by the ablation electrodes 55. The processor 33 is further configured to display, for example, the selected numbers associated with the ablation treatments performed at the ablation sites 52 and 53, respectively, in Tables 56 and 57.

[0055] This specific order of the graphical user interface (GUI) displayed on the display 35 is shown as an example to illustrate the specific problems addressed by embodiments of the present invention and to demonstrate the application of these embodiments in enhancing the execution of the system 20 for tissue ablation procedures. However, embodiments of the present invention are in no way limited to this particular type of exemplary GUI and / or system, and the principles described herein can be similarly applied to other types of GUIs in any suitable type of medical system and procedure. For example, the processor 33 is configured to display other suitable types of graphic elements instead of, or in addition to, the halo 72, visitag icons (icons 50 and 51), the colors of the visitag icons, and the contours 62 and 63.

[0056] FIG. 3 is a diagram showing annotations of ablation parameters on a map 27 of the heart 26 according to another embodiment of the present disclosure.

[0057] While applying an ablation signal to the tissue of the heart 26, for example, at the ablation site 53, the physician 30's line of sight typically has to focus on the ablation site shown on the map 27 and cannot view other elements shown on the display 35. In some embodiments, the processor 33 is configured to display on the map 27 an ablation stability quality indicator and / or any other parameter related to the ablation procedure. In the embodiment of FIG. 3, the processor 33 displays an ablation index 74 that is a combined calculation of (i) the distal end assembly 40, (ii) the icon 51 (visitag), (iii) the ablation stability quality indicator 59, and (iv) the main parameters of the ablation signal (e.g., contact force, power, and duration of the ablation signal) applied to the tissue of the heart 26 at the ablation site 53 (and / or any other ablation site).

[0058] In other embodiments, in addition to or instead of the visitag, ablation stability quality metric, and ablation metric, the processor 33 is configured to display on the map 27 any other suitable type of graphic element indicating other parameters related to the ablation procedure. For example, the temperature and impedance measured at the ablation site, and the contact force between the DEA 40 and the ablated tissue can be displayed as annotations on the DEA 40 and the map 27.

[0059] FIG. 4 is a flowchart schematically showing a method for calculating and visualizing an ablation stability quality metric 59 on a map 27 of a heart 26 according to an embodiment of the present disclosure.

[0060] This method begins with a catheter insertion 100 where, as described in FIG. 1 above, the physician 30 inserts into the DEA 40 of the catheter 22 having at least the ablation electrode 55 and the position sensor 39.

[0061] In a position signal receiving step 102, the processor 33 receives from the position sensor 39 a plurality of position measurements indicating the respective positions of the ablation electrodes 55 at each point in time during the ablation procedure at the ablation site 53, as described in detail in FIGS. 1 and 2 above.

[0062] In an ablation stability estimation step 104, based on (i) the position signal received from the position sensor 39 and (ii) at least one stored threshold value of (a) an allowable distance (e.g., an average distance of about 2 mm) and (b) an allowable speed (e.g., a maximum speed of about 2.5 mm per second), the processor 33 estimates (e.g., calculates) the ablation stability quality metric 59, as described in detail in FIG. 2 above.

[0063] In the display step 106 of ending the present method, the processor 33 displays, for example, a visual indication of the ablation stability quality index at each ablation site on the map 27 for the physician 30 as described in detail in FIGS. 2 and 3 above.

[0064] In some embodiments, the processor 33 assigns a color indicating the value of each ablation stability quality index relative to the threshold of the ablation stability quality index to the visitag icons (e.g., icons 50 and 51). For example, as shown in FIG. 2 above, the processor 33 assigns (i) a first color indicating that the value of the ablation stability quality index 58 is less than the threshold of the ablation stability quality index to the icon 50, and (ii) a second (different) color indicating that the value of the ablation stability quality index 59 exceeds the threshold of the ablation stability quality index to the icon 51.

[0065] Additionally or alternatively, in response to identifying that the value of the ablation stability quality index 59 exceeds the threshold of the ablation stability quality index, the processor 33 displays a halo 72 around the icon 51. In this embodiment, the halo 72 is displayed for about 3 seconds, indicating the end of ablation at the location marked by the icon 51. Immediately after the halo 72 disappears, the processor 33 generates a new visitag where the calculated center of mass is at the measured current position of the ablation electrode 55. These annotations (e.g., halo 72 and new visitag) provide an indication of the stability and status of the ablation procedure at the ablation site 53 to the physician 30 as described in detail in FIG. 2 above.

[0066] Furthermore, if the estimated distance of a given position of the ablation electrode 55 (during ablation) from a reference position (e.g., position 64b) exceeds a distance threshold, the processor 33 calculates and displays one or more contours such as contours 62 and 63. The displayed contours are based on the positions visited by the ablation electrode 55 and show the respective contours of the movement of the DEA 40 and the ablation electrode 55 while an ablation signal is being applied to the tissue at the ablation site 53.

[0067] Additionally or alternatively, the processor 33 displays to the physician 30 the respective values of tables 56 and 57 and the calculated ablation stability quality indicators 58 and 59, as described in FIG. 2 above. In an alternative embodiment, the processor 33 displays on the map 27 any suitable information selected by the physician 30. For example, the processor 33 displays on the map 27 at the ablation site 53 (i) the distal end assembly 40, (ii) the icon 51, (iii) the ablation stability quality indicator 59, and (iv) the ablation indicator 74, and / or any other suitable information as described in FIG. 3 above.

[0068] The embodiments described herein primarily address the visualization of stability quality indicators for tissue ablation in a patient's heart 26, but the methods and systems described herein can also be used for other applications such as visualization of tissue ablation and lesion formation in any other organ of the patient 28, and any evaluation of the lesion.

Examples

[0069] A system (20) including a display (35) and a processor (33), configured to: (i) receive a plurality of position measurements indicating respective positions of an ablation electrode (55) at respective times during an ablation treatment at an ablation site (52, 53) within an organ (26) of a patient (28); (ii) estimate a quality metric (58, 59) indicative of the stability of the ablation treatment at the ablation site (52, 53) based on at least the plurality of position measurements; and (iii) visualize the quality metric (58, 59) for a user (30) on the display (35).

Example

[0070] The system according to Example 2, wherein the processor is configured to estimate the quality metric according to at least respective distances of some of the positions from a reference position.

Example

[0071] The system according to Example 2, wherein the reference position includes a first position of the ablation electrode when applying a first ablation signal to the organ at the ablation site, and at least some of the positions include one or more second positions of the ablation electrode when applying one or more respective second ablation signals subsequent to the first ablation signal to the organ at the ablation site.

Example

[0072] The system according to Example 2, wherein the processor is configured to display a contour including some of the positions in response to identifying that the quality metric exceeds a threshold.

Example

[0073] The system according to Examples 1 to 4, wherein the processor is configured to estimate a speed of the ablation electrode during the ablation treatment and estimate the quality metric according to the speed.

Example

[0074] The system according to any one of Examples 1 to 4, wherein the processor is configured to exclude the patient's respiratory movement when estimating the quality index.

Example

[0075] The system according to any one of Examples 1 to 4, wherein the processor is configured to visualize the quality index by displaying an icon at the ablation site and assigning a color indicating the estimated quality index to the icon.

Example

[0076] The system according to Example 7, wherein the icon includes an ellipsoid of revolution.

Example

[0077] The system according to Example 7, wherein the processor is configured to change the color of at least a part of the icon in response to identifying that the quality index exceeds a threshold.

Example

[0078] The system according to Example 7, wherein the processor is configured to display a halo surrounding the icon in response to identifying that the quality index exceeds a threshold.

Example

[0079] A method comprising: (i) receiving a plurality of position measurements indicating the respective positions of the ablation electrodes (55) at each point in time during an ablation treatment at the ablation sites (52, 53) within the organ (26) of the patient (28); (ii) estimating a quality index (58, 59) indicating the stability of the ablation treatment at the ablation sites (52, 53) based on at least the plurality of position measurements; and (iii) visualizing the quality index (58, 59) to the user (30).

Example

[0080] The method according to Example 11, wherein estimating the quality index depends on at least some respective distances of the positions from the reference position.

Example

[0081] The method according to Example 12, wherein the reference position includes a first position of the ablation electrode when applying a first ablation signal to the organ at the ablation site, and at least some of the positions include one or more second positions of the ablation electrode when applying one or more respective second ablation signals subsequent to the first ablation signal to the organ at the ablation site.

Example

[0082] The method according to Example 13, wherein visualizing the quality index includes displaying a contour including some of the positions in response to identifying that the quality index exceeds a threshold.

Example

[0083] The method according to Examples 11 to 14, wherein estimating the quality index includes (i) estimating the speed of the ablation electrode during the ablation procedure and (ii) estimating the quality index according to the speed.

Example

[0084] The method according to Examples 11 to 14, wherein estimating the quality index includes eliminating the patient's respiratory movement.

Example

[0085] The method according to Examples 11 to 14, wherein visualizing the quality index includes displaying an icon at the ablation site and assigning a color indicating the estimated quality index to the icon.

Example

[0086] The method according to Example 17, wherein displaying the icon includes displaying a rotational ellipsoid.

Example

[0087] The method according to Example 17, wherein displaying the icon includes changing at least a part of the color of the icon in response to identifying that a quality index exceeds a threshold.

Example

[0088] The method according to Example 17, wherein displaying the icon includes displaying a halo surrounding the icon in response to identifying that a quality index exceeds a threshold.

[0089] It should be understood that the above-described examples are given by way of example, and the present disclosure is not limited to what is particularly illustrated and described above in this specification. Rather, the scope of the present disclosure includes both the various combinations and sub-combinations of the features described above, as well as those variations and modifications that would occur to those skilled in the art upon reading the foregoing description and that are not disclosed in the prior art. Documents incorporated by reference into this patent application should be regarded as an integral part of this application, provided that only the definitions in this specification are to be considered insofar as any terms in these incorporated documents are defined in a manner inconsistent with the definitions made explicitly or implicitly in this specification.

[0090] 〔Embodiment〕 (1) A system, comprising a display, and a processor, wherein the processor receives a plurality of position measurement values indicating respective positions of an ablation electrode at each point in time during an ablation treatment at an ablation site within an organ of a patient, estimates a quality index indicating the stability of the ablation treatment at the ablation site based on at least the plurality of position measurement values, A system configured to visualize the quality metric to a user on the display. (2) The system according to embodiment 2, wherein the processor is configured to estimate the quality metric according to at least some respective distances of the positions from a reference position. (3) The system according to embodiment 2, wherein the reference position includes a first position of the ablation electrode when applying a first ablation signal to the organ at the ablation site, and at least some of the positions include one or more second positions of the ablation electrode when applying one or more respective second ablation signals subsequent to the first ablation signal to the organ at the ablation site. (4) The system according to embodiment 2, wherein in response to identifying that the quality metric exceeds a threshold, the processor is configured to display a contour including some of the positions. (5) The system according to embodiment 1, wherein the processor is configured to estimate a speed of the ablation electrode during the ablation procedure and estimate the quality metric according to the speed.

[0091] (6) The system according to embodiment 1, wherein when estimating the quality metric, the processor is configured to exclude the respiratory movement of the patient. (7) The system according to embodiment 1, wherein the processor is configured to visualize the quality metric by displaying an icon at the ablation site and assigning a color indicating the estimated quality metric to the icon. (8) The system according to embodiment 7, wherein the icon includes an ellipsoid of revolution. (9) The system according to embodiment 7, wherein in response to identifying that the quality metric exceeds a threshold, the processor is configured to change at least a part of the color of the icon. The system of embodiment 7, wherein in response to identifying that the quality indicator exceeds a threshold, the processor is configured to display a halo surrounding the icon.

[0092] (11) A method comprising: receiving a plurality of position measurements indicating respective positions of an ablation electrode at respective times during an ablation procedure at an ablation site within an organ of a patient; estimating a quality indicator indicative of stability of the ablation procedure at the ablation site based at least on the plurality of position measurements; and visualizing the quality indicator to a user. (12) The method of embodiment 11, wherein estimating the quality indicator depends on respective distances of at least some of the positions from a reference position. (13) The method of embodiment 12, wherein the reference position includes a first position of the ablation electrode when a first ablation signal is applied to the organ at the ablation site, and at least some of the positions include one or more second positions of the ablation electrode when one or more respective second ablation signals subsequent to the first ablation signal are applied to the organ at the ablation site. (14) The method of embodiment 13, wherein visualizing the quality indicator includes displaying a contour including some of the positions in response to identifying that the quality indicator exceeds a threshold. (15) The method of embodiment 11, wherein estimating the quality indicator includes (i) estimating a velocity of the ablation electrode during the ablation procedure and (ii) estimating the quality indicator according to the velocity.

[0093] (16) The method of embodiment 11, wherein estimating the quality indicator includes excluding respiratory movement of the patient. (17) The method according to embodiment 11, wherein visualizing the quality indicator includes displaying an icon at the ablation site and assigning a color indicating the estimated quality indicator to the icon. (18) The method according to embodiment 17, wherein displaying the icon includes displaying an ellipsoid of revolution. (19) The method according to embodiment 17, wherein displaying the icon includes changing at least a part of the color of the icon in response to identifying that the quality indicator exceeds a threshold. (20) The method according to embodiment 17, wherein displaying the icon includes displaying a halo surrounding the icon in response to identifying that the quality indicator exceeds a threshold.

Claims

1. A system comprising: a display; and a processor, wherein the processor is configured to: receive a plurality of position measurements indicating respective positions of an ablation electrode at respective times during an ablation procedure at an ablation site within an organ of a patient; estimate a quality metric indicative of stability of the ablation procedure at the ablation site based at least on the plurality of position measurements; and visualize the quality metric to a user on the display.

2. The system of claim 2, wherein the processor is configured to estimate the quality metric according to respective distances of at least some of the positions from a reference position.

3. The system of claim 2, wherein the reference position includes a first position of the ablation electrode when a first ablation signal is applied to the organ at the ablation site, and at least some of the positions include one or more second positions of the ablation electrode when one or more respective second ablation signals subsequent to the first ablation signal are applied to the organ at the ablation site.

4. The system of claim 2, wherein the processor is configured to display a contour including some of the positions in response to identifying that the quality metric exceeds a threshold value.

5. The system of claim 1, wherein the processor is configured to estimate a speed of the ablation electrode during the ablation procedure and estimate the quality metric according to the speed.

6. The system of claim 1, wherein the processor is configured to exclude respiratory movement of the patient when estimating the quality metric.

7. The system of claim 1, wherein the processor is configured to visualize the quality metric by displaying an icon at the ablation site and assigning a color indicative of the estimated quality metric to the icon.

8. The system of claim 7, wherein the icon includes an ellipsoid of revolution.

9. The system according to claim 7, wherein in response to identifying that the quality indicator exceeds a threshold value, the processor is configured to change the color of at least a part of the icon.

10. The system according to claim 7, wherein in response to identifying that the quality indicator exceeds a threshold value, the processor is configured to display a halo surrounding the icon.

11. A method comprising: receiving a plurality of position measurements indicating respective positions of an ablation electrode at respective times during an ablation procedure at an ablation site within an organ of a patient; estimating a quality indicator indicative of stability of the ablation procedure at the ablation site based at least on the plurality of position measurements; visualizing the quality indicator to a user.

12. The method according to claim 11, wherein estimating the quality indicator depends on respective distances of at least some of the positions from a reference position.

13. The method according to claim 12, wherein the reference position includes a first position of the ablation electrode when a first ablation signal is applied to the organ at the ablation site, and at least some of the positions include one or more second positions of the ablation electrode when one or more respective second ablation signals subsequent to the first ablation signal are applied to the organ at the ablation site.

14. The method according to claim 13, wherein visualizing the quality indicator includes displaying a contour including some of the positions in response to identifying that the quality indicator exceeds a threshold value.

15. The method according to claim 11, wherein estimating the quality indicator includes (i) estimating a speed of the ablation electrode during the ablation procedure and (ii) estimating the quality indicator according to the speed.

16. The method according to claim 11, wherein estimating the quality indicator includes eliminating respiratory movement of the patient.

17. The method according to claim 11, wherein visualizing the quality indicator includes displaying an icon at the ablation site and assigning a color indicative of the estimated quality indicator to the icon.

18. The method according to claim 17, wherein displaying the icon includes displaying a rotational ellipsoid. **Claim 19** The method according to claim 17, wherein displaying the icon includes changing the color of at least a part of the icon in response to identifying that the quality indicator exceeds a threshold value. **Claim 20** The method according to claim 17, wherein displaying the icon includes displaying a halo surrounding the icon in response to identifying that the quality indicator exceeds a threshold value.

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