Display of indication of mutual distance between electrodes of a flexible ablation catheter

Abstract

To provide methods and systems for displaying indications of mutual distances among electrodes of a flexible ablation catheter.SOLUTION: A system 20 includes a processor 42 and a display 46. The processor is configured to: receive a first position signal of a first electrode coupled to a catheter 22 and a second position signal of a second electrode; calculate, based on each of the position signals, a distance between the first and second electrodes; and produce a first indication if the calculated distance is greater than a first threshold, produce a second indication if the calculated distance is less than the first threshold and greater than a second threshold, and produce a third indication if the calculated distance is less than the second threshold. The display is configured to present a first symbol in response to receiving the first indication, a second symbol in response to receiving the second indication, and a third symbol in response to receiving the third indication.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates generally to medical devices, and more particularly to a method and system for displaying an indication of the mutual distance between electrodes of a flexible ablation catheter. [Background technology]

[0002] A system for performing a minimally invasive medical procedure may include a catheter having a number of electrodes and a device for indicating the location of the electrodes within the body.

[0003] For example, U.S. Patent Application Publication No. 2010 / 0249771 describes a system and method for interactively planning and controlling a patient's treatment for a medical treatment device. The system includes a memory, a processor coupled to the memory, and a treatment control module stored in the memory and executable by the processor. The treatment control module graphically displays in real time a continuously changing treatment area defined by the electrodes as the user moves at least one of the electrodes. This allows the user to more effectively plan and treat it.

[0004] US Patent Application Publication No. 2015 / 0196216 describes a medical device that may include a catheter shaft having a plurality of electrodes coupled thereto and a processor coupled to the catheter shaft. The processor may collect a set of signals from the plurality of electrodes and generate a data set from at least one of the sets of signals, the data set including at least one known data point and one or more unknown data points, determine a non-linear distance between the at least one known data point and the one or more unknown data points, and assign a value to at least one of the unknown data points. Summary of the Invention [Means for solving the problem]

[0005] Embodiments of the invention described herein provide a system including a processor and a display, the processor configured to: (a) receive one or more position signals indicative of (i) a first position of a first electrode coupled to a catheter inserted within an organ of a patient, and (ii) a second position of a second electrode coupled to the catheter, (b) calculate a distance between the first electrode and the second electrode based on the position signals, and (c) generate: (i) a first indication in response to the calculated distance being found to be greater than a first threshold, (ii) a second indication in response to the calculated distance being found to be less than the first threshold and greater than a second threshold, and (iii) a third indication in response to the calculated distance being found to be less than the second threshold. The display is configured to present (i) a first symbol in response to receiving the first indication, (ii) a second symbol in response to receiving the second indication, and (iii) a third symbol in response to receiving the third indication.

[0006] In some embodiments, the display is configured to graphically present a traffic light, where (i) the first symbol comprises a first color displayed at a first location of the traffic light, (ii) the second symbol comprises a second color displayed at a second location of the traffic light, and (iii) the third symbol comprises a third color displayed at a third location of the traffic light. In other embodiments, the organ comprises a heart of a patient, the catheter comprises a lasso-type catheter, and the first electrode and the second electrode comprise ablation electrodes configured to apply one or more ablation pulses to tissue of the heart.

[0007] In one embodiment, if the calculated distance between the first electrode and the second electrode is less than a first threshold, the processor is configured to generate a message indicating whether the user may apply one or more ablation pulses to the tissue. In another embodiment, if the calculated distance between the first electrode and the second electrode is less than a second threshold, the processor is configured to prevent the user from applying one or more ablation pulses to the tissue.

[0008] According to an embodiment of the present invention, a method is further provided, comprising receiving one or more position signals indicative of (i) a first position of a first electrode coupled to a catheter inserted in an organ of a patient, and (ii) a second position of a second electrode coupled to the catheter. Based on the position signals, a distance between the first electrode and the second electrode is calculated. The following indications are generated: (i) a first indication in response to the calculated distance being found to be greater than a first threshold, (ii) a second indication in response to the calculated distance being found to be less than the first threshold and greater than a second threshold, and (iii) a third indication in response to the calculated distance being found to be less than the second threshold. The following symbols are presented: (i) a first symbol in response to receiving the first indication, (ii) a second symbol in response to receiving the second indication, and (iii) a third symbol in response to receiving the third indication.

[0009] According to an embodiment of the present invention, there is further provided a system including a processor and a display, the processor being configured to: (a) receive one or more impedance signals indicative of an impedance measured between at least a first electrode and a second electrode coupled to a catheter inserted within an organ of a patient, (b) estimate a distance between the first electrode and the second electrode based on the one or more impedance signals, and (c) generate: (i) a first indication in response to the estimated distance being found to be greater than a first threshold, (ii) a second indication in response to the estimated distance being found to be less than the first threshold and greater than a second threshold, and (iii) a third indication in response to the estimated distance being found to be less than the second threshold. The display is configured to present (i) a first symbol in response to receiving the first indication, (ii) a second symbol in response to receiving the second indication, and (iii) a third symbol in response to receiving the third indication.

[0010] In some embodiments, the organ includes a patient's heart, the catheter includes a lasso-type catheter, and the first electrode and the second electrode include an ablation electrode configured to apply one or more ablation pulses to tissue of the heart. In other embodiments, if the estimated distance between the first electrode and the second electrode is less than a first threshold, the processor is configured to generate a message indicating whether a user can apply one or more ablation pulses to the tissue. In yet other embodiments, if the estimated distance between the first electrode and the second electrode is less than a second threshold, the processor is configured to prevent a user from applying one or more ablation pulses to the tissue.

[0011] The invention will be more fully understood from consideration of the following detailed description taken in conjunction with the drawings, in which: [Brief description of the drawings]

[0012] [Figure 1] 1 is a schematic, pictorial illustration of a catheter-based position tracking and ablation system, in accordance with one embodiment of the present invention; [Diagram 2] 1A-1C are schematic, pictorial illustrations of a lasso-type catheter in expanded and retracted positions and a display showing inter-electrode distance, in accordance with an embodiment of the present invention. [Diagram 3] 1A-1C are schematic, pictorial illustrations of a lasso-type catheter in expanded and retracted positions and a display showing inter-electrode distance, in accordance with an embodiment of the present invention. [Figure 4] 1 is a flow chart that generally illustrates a method for performing an ablation procedure, in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Overview A flexible ablation catheter, such as a lasso catheter, may include multiple ablation electrodes. During an ablation procedure, it may be possible, although undesirable, for the flexible catheter to fold, resulting in two or more electrodes not being able to maintain a sufficient distance between them. In such cases, the results of the ablation procedure may be undesirable.

[0014] The embodiments of the invention described below provide improved techniques for providing symbols indicating the distance between electrodes of a flexible catheter and for issuing a warning if the distance between two or more electrodes is insufficient.

[0015] In some embodiments, the ablation system comprises a flexible catheter, such as a lasso-type catheter, having multiple ablation electrodes and configured to be inserted into a patient's organ to ablate tissue.

[0016] In some embodiments, the ablation system includes a processor configured to receive one or more position signals indicative of a first position of a corresponding first electrode and a second position of a corresponding second electrode of the catheter, the processor configured to calculate a distance between the first electrode and the second electrode based on the position signals.

[0017] In some embodiments, the processor is configured to generate: (i) a first indication in response to the calculated distance being found to be greater than a first threshold, (ii) a second indication in response to the calculated distance being found to be less than the first threshold and greater than a second threshold, and (iii) a third indication in response to the calculated distance being found to be less than the second threshold.

[0018] In some embodiments, the ablation system includes a display configured to present (i) a first symbol in response to receiving the first indication, (ii) a second symbol in response to receiving the second indication, and (iii) a third symbol in response to receiving the third indication. For example, the first and second thresholds may indicate distances between the electrodes of 3 mm and 1 mm. In some embodiments, the display is configured to graphically present a traffic light, where (i) the first symbol includes a green color displayed at a first location on the traffic light, (ii) the second symbol includes an amber color displayed at a second location on the traffic light, and (iii) the third symbol includes a red color displayed at a third location on the traffic light.

[0019] In some embodiments, if the display presents a red or amber light, the physician performing the ablation can, for example, adjust the position of the electrodes before applying the ablation pulse so that the display presents a green light instead of the red or amber light.

[0020] The disclosed technology can improve safety for patients undergoing ablation procedures, improve the quality of ablation procedures, and reduce cycle times for ablation procedures.

[0021] System Description 1 is a schematic, pictorial illustration of a catheter-based position tracking and ablation system 20, in accordance with an embodiment of the present invention. In some embodiments, system 20 includes a catheter 22, in this example an expandable lasso-type cardiac catheter, and a control console 24. In the embodiments described herein, catheter 22 may be used for any suitable therapeutic and / or diagnostic purposes, such as ablation of tissue within a heart 26.

[0022] In some embodiments, the console 24 includes a processor 42, typically a general-purpose computer, with front-end and interface circuitry suitable for receiving signals from the catheter 22 and controlling other components of the system 20 described herein. The processor 42 may be programmed in software to perform functions used by the system, and the processor 42 is configured to store data for the software in memory 50. The software may be downloaded to the console 24 in electronic form, for example, over a network, or may be provided on a non-transitory tangible medium, such as an optical, magnetic, or electronic storage medium. Alternatively, some or all of the functions of the processor 42 may be performed using an application specific integrated circuit (ASIC) or any suitable type of programmable digital hardware component.

[0023] Reference is now made to inset 25. In some embodiments, catheter 22 includes a distal end assembly or end effector 40 having a lasso shape (shown in detail in FIGS. 2 and 3 below) and a shaft 23 for inserting distal end assembly 40 to a target location for ablating tissue within heart 26. During an ablation procedure, a physician 30 inserts catheter 22 through the vascular system of a patient 28 lying on a table 29. Physician 30 moves distal end assembly 40 to a target location within heart 26 using a manipulator 32 near the proximal end of catheter 22 connected to interface circuitry of a processor 42. It should be noted that the present invention is not limited to a lasso shape configuration in that other shapes, such as planar array or ray type end effectors, are within the scope of the present invention.

[0024] In some embodiments, the catheter 22 includes at least one position sensor 39 of a position tracking system coupled to the distal end of the catheter 22, e.g., coupled proximate to the distal tip assembly 40. In this example, the position sensor 39 includes a magnetic position sensor, but in other embodiments, any other suitable type of position sensor (e.g., other than magnetic-based) may be used. For example, current-based position sensing may be determined by measuring the impedance between an electrode inside the body to an electrode in a patch outside the body via a current applied to the electrode, as described in the inventor's U.S. Patent Application No. 7,869,865 (a copy of which is provided in the appendix), which is incorporated herein by reference. Variations of impedance and magnetic position sensing techniques, as well as techniques combining both magnetic and impedance position sensing techniques, are described in U.S. Patent Nos. 7,536,218, 7,756,576, 7,848,787, and 8,456,182. The catheter 22 may include a number of position sensors 39 disposed, for example, between the electrodes of the distal tip assembly 40.

[0025] Referring again to the schematic diagram of Figure 1, in some embodiments, while guiding the distal tip assembly 40 within the heart 26, the processor 42 receives signals from a magnetic position sensor 39 in response to a magnetic field from an external magnetic field generator 36, for example, to measure the position of the distal tip assembly 40 within the heart 26. In some embodiments, the console 24 includes a driver circuit 34 configured to drive the magnetic field generator 36. The magnetic field generator 36 is positioned at a known position external to the patient 28, such as, for example, under a table 29.

[0026] In some embodiments, the processor 42 is configured to display, for example on a display 46 of the console 24 , the tracked position of the distal tip assembly 40 superimposed on an image 44 of the heart 26 .

[0027] This method of position sensing using an external magnetic field has been implemented in a variety of medical applications, for example in the CARTO™ system manufactured by Biosense Webster Inc. (Irvine, Calif.), and is described in detail in U.S. Pat. Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612, and 6,332,089, PCT International Publication No. WO 96 / 05768, and U.S. Patent Application Publication Nos. 2002 / 0065455(A1), 2003 / 0120150(A1), and 2004 / 0068178(A1), the disclosures of which are all incorporated herein by reference.

[0028] In some embodiments, the processor 42 is configured to calculate the distance between any electrode pair of the distal end assembly 40 (shown in Figures 2 and 3 below) based on one or more position signals received from the one or more position sensors 39.

[0029] In some embodiments, the display 46 is configured to present one or more traffic light icons (TLIs), such as TLI 66, that have a symbol indicating a calculated distance between two selected electrodes of the distal tip assembly 40. The TLIs and symbols are described in more detail in Figures 2 and 3 below.

[0030] In an alternative embodiment, the processor 42 is configured to receive one or more signals indicative of an impedance measured between at least one pair of selected electrodes of the distal tip assembly 40. In the context of this disclosure and claims, the term "impedance" typically refers to an electrical impedance measured between two selected electrodes, as is well known in the art. The processor 42 is configured to estimate a distance between the pair of electrodes based on the measured impedance. The processor 42 is further configured to maintain one or more impedance thresholds indicative of a distance threshold between the selected electrodes. The processor 42 is then configured to present to the user one or more symbols indicative of whether the estimated distance exceeds at least one of the thresholds, as described in more detail in Figures 2-4 below.

[0031] In other embodiments, the system 20 may have, for example, one or more traffic light poles (not shown) connected to the console 24, or a combination of TLI and poles, or any other suitable technology, to present one or more of the aforementioned symbols to the physician 30.

[0032] Symbols indicating the distance between each electrode FIG. 2 is a schematic, pictorial illustration of distal tip assembly 40 in an extended position and TLI 65 and TLI 66 of display 46 presenting symbols indicative of inter-electrode distance, according to one embodiment of the present invention.

[0033] In some embodiments, the distal end assembly 40 comprises a flexible arm 54 made of any suitable material, such as a nickel-titanium alloy (e.g., Nitinol) or any other suitable material. The distal end assembly 40 comprises a plurality of electrodes 55, electrode 55A, electrode 55B, and electrode 55C, coupled to the arm 54, which are configured to apply ablation pulses received from a pulse generator (not shown) of the console 24 to target tissue of the heart 26. The pulse generator can be either or both of an alternating current radio frequency (RF) generator or a biphasic pulse field generator for irreversible electroporation.

[0034] In some embodiments, electrodes 55, electrode 55A, electrode 55B, and electrode 55C are coupled to one another at a predetermined distance, which in this example is greater than about 3 mm.

[0035] The terms "about" or "approximately" used in the context of this disclosure and in the claims with respect to any numerical value or range of values ​​are intended to indicate a reasonable tolerance of dimensions that enables a portion of a component or a collection of components to function in accordance with its intended purpose as described herein.

[0036] Reference is now made to inset 60, which is a section of display 46 depicted in FIG. 1 above. In some embodiments, inset 60 includes TLI 65 and TLI 66, each of which includes symbol 67, symbol 68, and symbol 69. Note that symbol 67 may have a red or white color, symbol 68 may have an amber or white color, and symbol 69 may have a green or white color. It should be noted that the color schemes discussed above are provided by way of example only, and that in other embodiments, at least one of TLI 65 and TLI 66 may include one or more color schemes of any other suitable type.

[0037] In some embodiments, processor 42 is configured to receive one or more position signals, e.g., from one or more position sensors 39, each indicative of the position of a respective electrode of the catheter. In this example, processor 42 receives position signals indicative of the positions of electrode 55A, electrode 55B, and electrode 55C.

[0038] In some embodiments, processor 42 is configured to calculate a distance 72 between electrodes 55A and 55B and a distance 74 between electrodes 55A and 55C based on the position signal. Although distance 72 or distance 74 is shown as the distance between the centerlines of the electrodes, it is within the scope of the present invention to measure the distance from other data such as the side of the electrodes or the edge of the electrodes. Processor 42 is configured to generate: (i) a first indication in response to the calculated distance being found to be greater than the aforementioned first threshold (3 mm); (ii) a second indication in response to the calculated distance being found to be less than 3 mm and greater than the aforementioned second threshold (1 mm); and (iii) a third indication in response to the calculated distance being found to be less than 1 mm.

[0039] In the context of the present disclosure, the terms "distance" and "inter-electrode distance" are used interchangeably and refer to the mutual distance between any one or more selected pairs of electrodes of the distal tip assembly 40, which may be calculated by the processor 42 as described in detail in Figures 2 and 3 of the present disclosure. In other words, the terms "distance" and "inter-electrode distance" refer to the distance measured between corresponding reference points on any two selected electrodes 55 of the distal tip assembly 40.

[0040] In some embodiments, if the measured distance is greater than a first threshold, the inter-electrode distance is within a desired distance range. In other embodiments, if the measured distance is less than a second threshold, which may indicate a minimum allowable distance between adjacent electrodes 55, processor 42 may generate a warning to physician 30 to withhold or discontinue application of one or more ablation pulses to target tissue of heart 26.

[0041] In some embodiments, TLI 65 is configured to present a symbol indicative of distance 72 between electrodes 55A and 55B, and TLI 66 is configured to present a symbol indicative of distance 74 between electrodes 55A and 55C. In such embodiments, TLI 65 and TLI 66 are configured to present (i) symbol 69 in response to receiving the first indication, (ii) symbol 68 in response to receiving the second indication, and (iii) symbol 67 in response to receiving the third indication. That is, (i) if the inter-electrode distance is less than 1 mm, each TLI presents symbol 67 in red and symbols 68 and 69 in white; (ii) if the inter-electrode distance is between 1 mm and 3 mm, each TLI presents symbol 68 in amber and symbols 67 and 69 in white; and (iii) if the inter-electrode distance is greater than 3 mm, each TLI presents symbol 69 in green and symbols 67 and 68 in white.

[0042] 2, because distance 72 and distance 74 are both greater than 3 mm, processor 42 generates and transmits a first indication to TLI 65 and TLI 66, respectively. In response to receiving the first indication, TLI 65 and TLI 66 both present symbol 69 in green and symbol 67 and symbol 68 in white.

[0043] 2, the inter-electrode distance is large enough to prevent the ablation pulse from being undesirably transferred or shared between electrodes 55A and 55B, or between electrodes 55A and 55C. In some embodiments, prior to applying an ablation pulse to one or more of electrodes 55A, 55B, and 55C, physician 30 can glance at display 46 and verify that the inter-electrode distance is large enough to apply an ablation pulse to each electrode.

[0044] Additionally or alternatively, processor 42 is configured to receive one or more signals (also referred to herein as impedance signals) from one or more selected pairs of electrodes (e.g., electrodes 55A and 55B, and electrodes 55A and 55C) indicative of the impedance measured between each electrode pair of the catheter. In this example, processor 42 receives signals indicative of (i) a first impedance measured between electrodes 55A and 55B, and (ii) a second impedance measured between electrodes 55A and 55C.

[0045] In some embodiments, the processor 42 is configured to calculate a distance 72 between the electrodes 55A and 55B and a distance 74 between the electrodes 55A and 55C based on the first impedance signal and the second impedance signal. The processor 42 is further configured to maintain a first impedance threshold and a second impedance threshold indicating first and second thresholds for the distances mentioned above. In this example, the first impedance threshold indicates an inter-electrode distance of about 3 mm and the second impedance threshold indicates an inter-electrode distance of about 1 mm. In such an embodiment, the processor 42 is configured to generate: (i) a first indication in response to the measured threshold being found to be greater than the first impedance threshold (i.e., an inter-electrode distance greater than about 3 mm); (ii) a second indication in response to the measured threshold being found to be less than the first impedance threshold and greater than the second impedance threshold (i.e., indicating a distance less than about 3 mm and greater than about 1 mm); and (iii) a third indication in response to the measured threshold being found to be less than the second impedance threshold (i.e., indicating an inter-electrode distance less than about 1 mm).

[0046] In the example of FIG. 2, both impedance signals are greater than the first impedance threshold, so TLI 65 and TLI 66 both present symbol 69 in green, and both symbols 67 and 68 in white.

[0047] FIG. 3 is a schematic, pictorial illustration of distal tip assembly 40 in a folded position and TLI 65 and TLI 66 of display 46 presenting symbols indicating inter-electrode distance, according to one embodiment of the present invention.

[0048] In the example of FIG. 3, a physician 30 may use distal end assembly 40 in a pulmonary vein (PV) isolation procedure, for example, to ablate an ostium (not shown) of a PV in heart 26 having an inner diameter of approximately 15 mm to 32 mm, or any other inner diameter.

[0049] In some embodiments, during a PV isolation procedure, physician 30 applies manipulator 32 to obtain a suitable outer diameter 53 for the shape of distal end assembly 40. In this example, physician 30 can position distal end assembly 40 to have an outer diameter 53 of approximately 11 mm. In this configuration, physician 30 can fit distal end assembly 40 to the inner diameter of the aforementioned PV and position at least electrodes 55A, 55B, and 55C (as well as typically electrode 55) in contact with the inner circumference of the PV.

[0050] In the example of FIG. 3, electrodes 55A and 55B are positioned at a distance 76 from each other, for example about 2 mm, and electrodes 55A and 55C are positioned at a distance 78 from each other, for example about 0.5 mm.

[0051] 2 above, or any other suitable technique. Based on the calculation of distance 76, processor 42 generates a second indication, and based on the calculation of distance 78, processor 42 generates a third indication.

[0052] Reference is now made to inset 61 of FIGURE 3, which is one of the aforementioned sections of display 46. In some embodiments, TLI 65 is configured to present symbol 68 in amber and symbols 67 and 69 in white in response to receiving a second indication from processor 42. Similarly, TLI 66 is configured to present symbol 67 in red and symbols 68 and 69 in white in response to receiving a third indication from processor 42.

[0053] In some embodiments, based on the colors presented by the TLI 65 and TLI 66 in Fig. 3, the physician 30 may not apply an ablation pulse to any of the electrodes 55A, 55B, and 55C. Furthermore, even if one of the TLI 65 and TLI 66 presents a red or amber color, the physician 30 may use the manipulator 30 to adjust the positioning of the distal tip assembly 40 until a green color is obtained for the symbols 69 of both the TLI 65 and TLI 66. After a green color is obtained for both the TLI 65 and TLI 66, the physician 30 may control the system 20 to apply an ablation pulse to the target tissue of the heart 26.

[0054] In some embodiments, TLI 65 and TLI 66 provide physician 30 with a quick and clear indication as to whether it is safe to apply ablation pulses via one or more of electrodes 55A, 55B, and 55C to target tissue in heart 26. In other embodiments, the techniques described above may be applied mutatis mutandis to any selected pair of electrodes from the distal tip assembly 40.

[0055] In other embodiments, instead of having multiple TLIs, the display 46 is configured to have any other suitable display method for providing an indication of inter-electrode distance. For example, the display 46 may have a matrix in which all electrodes intended to receive an ablation pulse are arranged in columns and rows, and may display the aforementioned red, amber, or green color for each electrode pair.

[0056] In an alternative embodiment, processor 42 is configured to receive the aforementioned first and second impedance signals from one or more pairs of electrodes (e.g., electrodes 55A and 55B, and electrodes 55A and 55C) indicative of the impedance measured between each electrode pair of the catheter. In this example, processor 42 receives (i) an impedance signal indicative of a first impedance measured between electrodes 55A and 55B, and (ii) an impedance signal indicative of a second impedance measured between electrodes 55A and 55C.

[0057] In some embodiments, the processor 42 is configured to calculate a distance 76 between the electrodes 55A and 55B and a distance 78 between the electrodes 55A and 55C based on the first impedance signal and the second impedance signal. As described above, the processor 42 is configured to maintain a first impedance threshold and a second impedance threshold indicative of an inter-electrode distance of about 3 mm and about 1 mm, respectively. As described in FIG. 2 above, the processor 42 is configured to generate a first indication, a second indication, and a third indication, respectively, in response to the measured threshold being found to be (i) greater than the first impedance threshold, (ii) less than the first impedance threshold and greater than the second impedance threshold, and (iii) less than the second impedance threshold.

[0058] 3, (i) the impedance signal measured between electrodes 55A and 55B is less than a first impedance threshold and greater than a second impedance threshold, and (ii) the impedance signal measured between electrodes 55A and 55C is less than the second impedance threshold. Based on the measured impedance and the impedance thresholds, processor 42 is configured to infer that electrodes 55A and 55B are positioned at a distance 76 from one another, e.g., about 2 mm, thereby generating a second indication, and (ii) electrodes 55A and 55C are positioned at a distance 78 from one another, e.g., about 0.5 mm, thereby generating a third indication.

[0059] In such an embodiment, TLI 65 is configured to present symbol 68 in amber and symbols 67 and 69 in white in response to receiving a second indication from processor 42. Similarly, TLI 66 is configured to present symbol 67 in red and symbols 68 and 69 in white in response to receiving a third indication from processor 42.

[0060] Performing an ablation procedure using graphically presented symbols indicating interelectrode distance FIG. 4 is a flow chart that generally illustrates a method for performing an ablation procedure using symbols 67, 68, and 69 of TLI 65 and TLI 66, graphically presented, in accordance with an embodiment of the present invention.

[0061] The method begins with a catheter insertion step 100, in which distal tip assembly 40 of lasso-shaped catheter 22 is inserted and placed in contact with cardiac target tissue 26. In a position signal receiving step 102, processor 42 receives position signals indicative of the respective positions of at least electrodes 55A, 55B, and 55C of catheter 22, as described above in FIGS.

[0062] In a distance calculation step 104, the processor 42 calculates a distance, such as distance 72 and distance 76 between the electrodes 55A and 55B, based on the received position signal, as described above in FIG. 2 and FIG. 3. In an indication generation step 106, the processor 42 generates a first indication, a second indication, and a third indication in response to finding that the calculated distance is greater than 3 mm, between 1 mm and 3 mm, and less than 1 mm, respectively. In other words, if the inter-electrode distance is less than a first threshold (e.g., about 3 mm), the physician 30 must carefully consider whether the placement of the electrodes 55 is suitable for applying ablation. When the inter-electrode distance is less than a second threshold (e.g., about 1 mm), the physician 30 must adjust the inter-electrode distance before applying an ablation pulse to the tissue of the heart 26.

[0063] In a symbol presentation step 108, the display 46 presents, for example, in TLI 65 and TLI 66, symbols 67, 68, and 69 corresponding to the first indication, the second indication, and the third indication, as described, for example, in Figures 2 and 3 above.

[0064] In decision step 110, the physician 30 views the TLIs 65 and 66 presented on the display 46 and determines whether to adjust the inter-electrode distance based on the symbols 67, 68, and 69. In some embodiments, as shown in the example of FIG. 2 above, both the TLIs 65 and 66 present the symbols 69 in green and the symbols 67 and 68 in white. In this example, the method then proceeds to a tissue ablation step 112, in which the processor 42 controls the pulse generator to apply one or more ablation pulses to one or more of the electrodes 55A, 55B, and 55C. Note that step 112 completes the method, and that after step 112 is completed, the physician 30 removes the distal end assembly 40 from the patient's heart 26.

[0065] In other embodiments, at least one of TLI 65 and TLI 66 is red or amber, for example, as shown for both TLI 65 and TLI 66 in FIG. 3 above. In such an embodiment, physician 30 adjusts the inter-electrode distance, for example using manipulator 32. The method then returns to step 102, where position signals are received indicative of the adjusted positions of electrodes 55A, 55B, and 55C. Thereafter, the inter-electrode distance is subsequently recalculated and an indication of the distance is displayed, as described in steps 104-108.

[0066] Additionally or alternatively to decision step 110, processor 42 is configured to display a warning or alert, such as a pop-up graphical or text message, on display 46 based on the calculated distance and the generated indication, indicating whether physician 30 can apply one or more ablation pulses as described above in step 112, or whether physician 30 should adjust the inter-electrode distance between the respective counter-electrodes from the electrodes of distal tip assembly 40, as described above in the return process of the method.

[0067] In other embodiments, processor 42 is configured to disable application of one or more ablation pulses to the target tissue and display an alert if the calculated distance between any pair of electrodes from among electrodes 55A, 55B, and 55C is less than a second threshold. In such embodiments, processor 42 prevents physician 30 from unintentionally (e.g., accidentally) applying one or more ablation pulses. However, physician 30 may still choose to ignore the message and control system 20 to apply ablation pulses to the target tissue.

[0068] In an alternative embodiment, steps 102 and 104 may be replaced by receiving a signal of a measured impedance between a pair of electrodes (e.g., an impedance measured between electrodes 55A and 55B), the measured impedance being indicative of a distance between electrodes 55A and 55B. Further, instead of maintaining a first distance threshold and a second distance threshold, processor 42 may maintain a first impedance threshold and a second impedance threshold, in this example indicative of a distance of about 3 mm and about 1 mm between electrodes 55A and 55B. In such an embodiment, in step 106, processor 42 may generate one or more indications by comparing the measured impedance to the impedance thresholds, and the operations performed in steps 108, 110, and 112 remain as described above.

[0069] Although the embodiments described herein primarily address cardiac ablation procedures using lasso-type catheters, the methods and systems described herein may also be used in other applications, such as for any type of ablation applied to any suitable tissue using any type of flexible catheter having multiple electrodes. Additionally, the methods and systems described herein may also be used in any suitable electrosurgical procedure using a flexible instrument having multiple electrodes.

[0070] Therefore, it will be understood that the above-described embodiments are cited by way of example, and that the present invention is not limited to what has been particularly shown and described in the above specification. Rather, the scope of the present invention includes both combinations and subcombinations of the various features described in the above specification, as well as variations and modifications thereof not disclosed in the prior art that would occur to one skilled in the art upon reading the foregoing description. Documents incorporated by reference into this patent application shall be considered as an integral part of this application, except that if any term is defined in these incorporated documents in a manner that is inconsistent with the definition expressly or impliedly made herein, then only the definition in this specification shall be considered.

[0071] [Embodiment] (1) A system comprising: a catheter having a distal tip assembly, the catheter having at least a first electrode and a second electrode disposed on the distal tip assembly; 1. A processor comprising: receiving one or more position signals indicative of (i) a first position of the first electrode coupled to a catheter inserted within an organ of a patient; and (ii) a second position of the second electrode coupled to the catheter; calculating a distance between the first electrode and the second electrode based on the position signal; (i) generating a first indication in response to the calculated distance being found to be greater than a first threshold, (ii) generating a second indication in response to the calculated distance being found to be less than the first threshold and greater than a second threshold, and (iii) generating a third indication in response to the calculated distance being found to be less than the second threshold. a processor configured to: and a display configured to present (i) a first symbol in response to receiving the first indication, (ii) a second symbol in response to receiving the second indication, and (iii) a third symbol in response to receiving the third indication; A system comprising: (2) the display is configured to graphically present a traffic light; (i) the first symbol includes a first color displayed at a first location of the traffic light, (ii) the second symbol includes a second color displayed at a second location of the traffic light, and (iii) the third symbol includes a third color displayed at a third location of the traffic light. A system as described in embodiment 1. (3) the organ comprises a heart of the patient; the catheter comprises a lasso-type catheter; the first electrode and the second electrode include an ablation electrode configured to apply one or more ablation pulses to tissue of the heart. A system as described in embodiment 1. (4) The system of embodiment 3, wherein the processor is configured to generate a message indicating whether a user can apply the one or more ablation pulses to the tissue when the calculated distance between the first electrode and the second electrode is less than the first threshold. (5) The system of embodiment 3, wherein the processor is configured to prevent a user from applying the one or more ablation pulses to the tissue if the calculated distance between the first electrode and the second electrode is less than the second threshold.

[0072] (6) A method comprising the steps of: receiving one or more position signals indicative of (i) a first position of a first electrode coupled to a catheter inserted within an organ of a patient, and (ii) a second position of a second electrode coupled to the catheter; calculating a distance between the first electrode and the second electrode based on the position signal; (i) generating a first indication in response to the calculated distance being found to be greater than a first threshold, (ii) generating a second indication in response to the calculated distance being found to be less than the first threshold and greater than a second threshold, and (iii) generating a third indication in response to the calculated distance being found to be less than the second threshold; (i) presenting a first symbol in response to receiving the first indication, (ii) presenting a second symbol in response to receiving the second indication, and (iii) presenting a third symbol in response to receiving the third indication; A method comprising: (7) Presenting the first symbol, the second symbol, and the third symbol includes graphically presenting a traffic light; and (i) the first symbol includes a first color displayed at a first location of the traffic light, (ii) the second symbol includes a second color displayed at a second location of the traffic light, and (iii) the third symbol includes a third color displayed at a third location of the traffic light. The method according to embodiment 6. (8) the organ comprises a heart of the patient; the catheter comprises a lasso-type catheter; the first electrode and the second electrode include an ablation electrode for applying one or more ablation pulses to tissue of the heart. The method according to embodiment 6. (9) The method of embodiment 8, comprising generating a message indicating whether a user can apply the one or more ablation pulses to the tissue if the calculated distance between the first electrode and the second electrode is less than the first threshold. (10) The method of embodiment 8, comprising preventing a user from applying the one or more ablation pulses to the tissue if the calculated distance between the first electrode and the second electrode is less than the second threshold.

[0073] (11) A system comprising: 1. A processor comprising: receiving one or more impedance signals indicative of an impedance measured between at least a first electrode and a second electrode coupled to a catheter inserted within the organ of the patient; estimating a distance between the first electrode and the second electrode based on the one or more impedance signals; (i) generating a first indication in response to the estimated distance being found to be greater than a first threshold, (ii) generating a second indication in response to the estimated distance being found to be less than the first threshold and greater than a second threshold, and (iii) generating a third indication in response to the estimated distance being found to be less than the second threshold. a processor configured to a display configured to present (i) a first symbol in response to receiving the first indication, (ii) a second symbol in response to receiving the second indication, and (iii) a third symbol in response to receiving the third indication; A system comprising: (12) The display is configured to graphically present a traffic light; (i) the first symbol includes a first color displayed at a first location of the traffic light, (ii) the second symbol includes a second color displayed at a second location of the traffic light, and (iii) the third symbol includes a third color displayed at a third location of the traffic light. A system as described in embodiment 11. (13) The organ comprises a heart of the patient, the catheter comprises a lasso-type catheter; the first electrode and the second electrode include an ablation electrode configured to apply one or more ablation pulses to tissue of the heart. A system as described in embodiment 11. (14) The system of embodiment 13, wherein the processor is configured to generate a message indicating whether a user can apply the one or more ablation pulses to the tissue when the estimated distance between the first electrode and the second electrode is less than the first threshold. (15) The system of embodiment 13, wherein the processor is configured to prevent a user from applying the one or more ablation pulses to the tissue when the estimated distance between the first electrode and the second electrode is less than the second threshold.

Claims

1. 1. A system comprising: a catheter having a distal tip assembly, the catheter having at least a first electrode and a second electrode disposed on the distal tip assembly; 1. A processor comprising: receiving one or more position signals indicative of (i) a first position of the first electrode coupled to a catheter inserted within an organ of a patient; and (ii) a second position of the second electrode coupled to the catheter; calculating a distance between the first electrode and the second electrode based on the position signal; (i) generating a first indication in response to the calculated distance being found to be greater than a first threshold, (ii) generating a second indication in response to the calculated distance being found to be less than the first threshold and greater than a second threshold, and (iii) generating a third indication in response to the calculated distance being found to be less than the second threshold. a processor configured to: and a display configured to present (i) a first symbol in response to receiving the first indication, (ii) a second symbol in response to receiving the second indication, and (iii) a third symbol in response to receiving the third indication; A system comprising:

2. the display is configured to graphically present a traffic light; (i) the first symbol includes a first color displayed at a first location of the traffic light, (ii) the second symbol includes a second color displayed at a second location of the traffic light, and (iii) the third symbol includes a third color displayed at a third location of the traffic light. The system of claim 1 .

3. the organ comprises a heart of the patient; the catheter comprises a lasso-type catheter; the first electrode and the second electrode include an ablation electrode configured to apply one or more ablation pulses to tissue of the heart. The system of claim 1 .

4. 4. The system of claim 3, wherein the processor is configured to generate a message indicating whether a user can apply the one or more ablation pulses to the tissue if the calculated distance between the first electrode and the second electrode is less than the first threshold.

5. 4. The system of claim 3, wherein the processor is configured to prevent a user from applying the one or more ablation pulses to the tissue if the calculated distance between the first electrode and the second electrode is less than the second threshold.

6. 1. A method comprising: receiving one or more position signals indicative of (i) a first position of a first electrode coupled to a catheter inserted within an organ of a patient, and (ii) a second position of a second electrode coupled to the catheter; calculating a distance between the first electrode and the second electrode based on the position signal; (i) generating a first indication in response to the calculated distance being found to be greater than a first threshold, (ii) generating a second indication in response to the calculated distance being found to be less than the first threshold and greater than a second threshold, and (iii) generating a third indication in response to the calculated distance being found to be less than the second threshold; (i) presenting a first symbol in response to receiving the first indication, (ii) presenting a second symbol in response to receiving the second indication, and (iii) presenting a third symbol in response to receiving the third indication; A method comprising:

7. presenting the first symbol, the second symbol, and the third symbol includes graphically presenting a traffic light; and (i) the first symbol includes a first color displayed at a first location of the traffic light, (ii) the second symbol includes a second color displayed at a second location of the traffic light, and (iii) the third symbol includes a third color displayed at a third location of the traffic light. The method according to claim 6.

8. the organ comprises a heart of the patient; the catheter comprises a lasso-type catheter; the first electrode and the second electrode include an ablation electrode for applying one or more ablation pulses to tissue of the heart. The method according to claim 6.

9. 10. The method of claim 8, comprising generating a message indicating whether a user can apply the one or more ablation pulses to the tissue if the calculated distance between the first electrode and the second electrode is less than the first threshold.

10. 10. The method of claim 8, comprising preventing a user from applying the one or more ablation pulses to the tissue if the calculated distance between the first electrode and the second electrode is less than the second threshold.

11. 1. A system comprising:

1. A processor comprising: receiving one or more impedance signals indicative of an impedance measured between at least a first electrode and a second electrode coupled to a catheter inserted within the organ of the patient; estimating a distance between the first electrode and the second electrode based on the one or more impedance signals; (i) generating a first indication in response to the estimated distance being found to be greater than a first threshold, (ii) generating a second indication in response to the estimated distance being found to be less than the first threshold and greater than a second threshold, and (iii) generating a third indication in response to the estimated distance being found to be less than the second threshold. a processor configured to a display configured to present (i) a first symbol in response to receiving the first indication, (ii) a second symbol in response to receiving the second indication, and (iii) a third symbol in response to receiving the third indication; A system comprising:

12. the display is configured to graphically present a traffic light; (i) the first symbol includes a first color displayed at a first location of the traffic light, (ii) the second symbol includes a second color displayed at a second location of the traffic light, and (iii) the third symbol includes a third color displayed at a third location of the traffic light. The system of claim 11.

13. the organ comprises a heart of the patient; the catheter comprises a lasso-type catheter; the first electrode and the second electrode include an ablation electrode configured to apply one or more ablation pulses to tissue of the heart. The system of claim 11.

14. 14. The system of claim 13, wherein the processor is configured to generate a message indicating whether a user can apply the one or more ablation pulses to the tissue if the estimated distance between the first electrode and the second electrode is less than the first threshold.

15. 14. The system of claim 13, wherein the processor is configured to prevent a user from applying the one or more ablation pulses to the tissue when the estimated distance between the first electrode and the second electrode is less than the second threshold.

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