Application of non-therapeutic waveform with gradient sensing in predicting pulsed field ablation (PFA) field

Abstract

A method and a pulsed electric field (PEF) ablation instrument are provided. According to one aspect, a method performed in a PFA generator includes receiving an electrical response for each of at least one non-therapeutic waveform. The process also includes determining an electric field profile based at least in part on the received electrical response. The process also includes selecting a non-therapeutic waveform that produces an electric field profile that meets a criterion. The process also includes mapping the selected non-therapeutic waveform to an ablative waveform.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 354,856, filed on June 23, 2022, entitled "APPLICATION OF NON-THERAPEUTIC WAVEFORMS WITH GRADIENT SENSING TO PREDICT PULSED FIELD ABLATION (PFA) FIELDS" Technical Field

[0003] The present disclosure relates to methods, systems, and devices for increasing the efficiency and effectiveness of ablative energy delivery and improving patient safety. Background Art

[0004] Tissue ablation is used in many medical procedures to treat patients. In some examples, ablation procedures involve modifying target tissue, for example to block electrical propagation through tissue in a patient with a cardiac arrhythmia. Such ablation procedures are typically performed by delivering energy (such as electrical energy) through one or more electrodes of an inserted catheter. The energy results in modification of the target tissue. Summary of the invention

[0005] Pulsed field ablation ("PFA"), which can cause reversible or irreversible electroporation, is a non-thermal ablation technique that creates lesions in desired areas of patient tissue to treat medical conditions (such as cardiac arrhythmias) and ablates areas of tissue and / or organs in the body. To treat cardiac arrhythmias, for example, PFA can be performed to modify tissue in order to stop abnormal electrical propagation and / or interrupt abnormal electrical conduction through cardiac tissue.

[0006] PFA involves the application of short pulsed electric fields (PEFs) that can reversibly or irreversibly destabilize cell membranes through electropermeabilization but generally do not affect the structural integrity of tissue components, including the acellular cardiac extracellular matrix.

[0007] In some PFA systems, the user programs or otherwise manually inputs the desired parameters of the pulsed electric field to be delivered to the tissue into an electrosurgical generator, which is configured to deliver electrical energy to the target tissue through an electrosurgical handpiece. For a given delivery tool, target tissue, or environment, the user can select from waveform parameters such as the type, amplitude, shape, frequency, and repetition of the waveform. These parameters affect the size, shape, and / or location of the lesion caused by the application of PEF.

[0008] The properties of PFA allow for very short duration therapeutic energy delivery, on the order of tens of milliseconds. In addition, PFA may not cause collateral damage to non-targeted tissues as frequently or as severely as thermal ablation techniques. Additionally, pharmacological agents may be preferentially introduced into cells of targeted tissues exposed to PEF with reversible membrane permeabilization.

[0009] Catheters inserted and passed through blood vessels are used to detect and treat various medical conditions. For example, arrhythmias can be treated by inserting a catheter into a blood vessel and guiding it to the heart. Electrodes are usually used to apply electrical energy at the end of the catheter. The electrodes can be used to detect electrical activity in the surrounding tissue and / or can deliver pulsed electric fields to the tissue to destroy the electrical pathways in the tissue, thereby treating arrhythmias. The electrodes can also be used to map the electrical activity in the tissue, and then deliver PEF signals to allow the pulsed electric field to penetrate into the tissue, thereby superpermeating the surrounding myocardial cells and destroying the electrical activity in the target tissue.

[0010] According to one aspect of the present disclosure, a pulsed electric field (PEF) ablation device includes a processing circuit configured to deliver a non-therapeutic PEF waveform to a first set of electrodes. The processing circuit is further configured to determine an electrical response to the delivered non-therapeutic PEF waveform based at least in part on a signal received on at least one test electrode. The processing circuit is also configured to determine an ablative PEF waveform to be applied to a second set of electrodes based at least in part on the electrical response.

[0011] According to some aspects, the first electrode set and the second electrode set have at least one common electrode. The at least one test electrode on which the signal is received is an electrode in at least one of the first electrode set and the second electrode set. In some embodiments, the electrical response includes a voltage across a pair of electrodes. In some embodiments, the electrical response includes an electric field gradient that is scaled by a factor in a response analyzer or an ablative waveform generator to predict the electric field gradient generated by the ablative PEF waveform. In some embodiments, the electrical response includes an impedance between a pair of electrodes. In some embodiments, the non-therapeutic PEF waveform includes at least one pulse, and the electrical response is determined for each pulse in the at least one pulse. In some embodiments, the ablative PEF waveform includes a second pulse sequence having the same periodicity as the first pulse sequence. In some embodiments, the processing circuit is also configured to display a graphical rendering of the electrical response and a graphical rendering of at least two electrodes selected from at least one of the first electrode set, the second electrode set, and the at least one test electrode. In some embodiments, the graphical rendering includes a graphical rendering of electric field gradients between pairs of electrodes superimposed on a graphical rendering of the anatomical region to be treated, the electric field gradients determined based on the electrical response to the non-therapeutic PEF waveform.

[0012] According to another aspect, a method implemented with a PFA system includes delivering a non-therapeutic PEF waveform to a first electrode set. The method also includes determining an electrical response to the delivered non-therapeutic PEF waveform based at least in part on a signal received on at least one test electrode. The method also includes selecting a second electrode set and determining an ablative PEF waveform to be applied to the second electrode set based at least in part on the electrical response.

[0013] According to some aspects, the first electrode set and the second electrode set have at least one common electrode. In some embodiments, the at least one test electrode on which the signal is received is an electrode in at least one of the first electrode set and the second electrode set. In some embodiments, the electrical response includes a voltage across a pair of electrodes. In some embodiments, the electrical response includes an electric field gradient that is scaled by a factor in a response analyzer or an ablative waveform generator to predict the electric field gradient generated by the ablative PEF waveform. In some embodiments, the electrical response includes an impedance between a pair of electrodes. In some embodiments, the non-therapeutic PEF waveform includes a first pulse sequence, and the electrical response is determined for each pulse in the first pulse sequence. In some embodiments, the ablative PEF waveform includes a second pulse sequence having the same periodicity as the first pulse sequence. In some embodiments, the method also includes displaying a graphical rendering of the electrical response and a graphical rendering of at least two electrodes selected from at least one of the first electrode set, the second electrode set, and the at least one test electrode. In some embodiments, the graphical rendering includes a graphical rendering of electric field gradients between pairs of electrodes superimposed on a graphical rendering of the anatomical region to be treated, the electric field gradients determined based on the electrical response to the non-therapeutic PEF waveform.

[0014] According to yet another aspect, a method implemented using a PFA generator includes receiving an electrical response for each of at least one non-therapeutic waveform. The method also includes determining an electric field distribution based at least in part on the received electrical response. The method also includes selecting a non-therapeutic waveform that produces an electric field distribution that meets a criterion. The method also includes mapping the selected non-therapeutic waveform to an ablative waveform.

[0015] According to some aspects, determining the electric field distribution comprises dividing the voltage across a pair of electrodes by the distance between the pair of electrodes. In some embodiments, selecting the non-therapeutic waveform comprises selecting the non-therapeutic waveform that produces the highest ratio of electric field energy within a target region of tissue to electric field energy not within the target region of tissue.

[0016] An example provides a medical treatment device. The device includes a plurality of electrodes that can be placed in electrical communication with a target site of a patient's body. The device also includes a waveform generator configured to selectively apply a pulsed electrical waveform to the plurality of electrodes. The device also includes an electronic controller configured to estimate the impedance of an electrical path between the anchor electrode and the corresponding counter electrode set in the patient's body by causing the waveform generator to apply a first waveform to the anchor electrode and the corresponding counter electrode set and sense the corresponding current. The anchor electrode and the corresponding counter electrode set are selected from the plurality of electrodes in different ways. The first waveform is a non-therapeutic waveform. The electronic controller is further configured to select an electrode group for applying a second waveform to the target site based on the impedance. The electrode group includes one or more anchor electrodes in the differently selected anchor electrodes. The second waveform is a therapeutic waveform.

[0017] Another example provides a medical treatment method. The method includes using a waveform generator to selectively apply a pulsed electrical waveform to a plurality of electrodes placed in electrical communication with a target site of a patient's body. The method also includes using an electronic controller to estimate the impedance of an electrical path between the anchor electrode and the corresponding counter electrode set in the patient's body by applying a first waveform to the anchor electrode and the corresponding counter electrode set and sensing the corresponding current, the anchor electrode and the corresponding counter electrode set are selected in different ways from the plurality of electrodes, and the first waveform is a non-therapeutic waveform. The method also includes using the electronic controller and selecting an electrode group for applying a second waveform to the target site based on the impedance, the electrode group including one or more anchor electrodes in the differently selected anchor electrodes, and the second waveform is a therapeutic waveform.

[0018] Yet another example provides a non-transitory computer readable medium storing instructions that, when executed by an electronic controller of a medical treatment device, cause the medical treatment device to perform operations including the above-described medical treatment method.

[0019] The details of one or more aspects of the present disclosure are set forth in the following drawings and description. Other features, objectives, and advantages of the techniques described in the present disclosure will be apparent from the description and drawings, and from the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] A more complete understanding of the various embodiments together with attendant advantages and features will be more readily appreciated from the following detailed description when considered in conjunction with the accompanying drawings, in which:

[0021] Figure 1 is a block diagram illustrating a PFA system according to some examples.

[0022] Figure 2 is an example of Figure 1 Flowchart of the method implemented in the PFA system.

[0023] Figure 3 is an example of an example according to the attached example Figure 1 Flowchart of the method implemented in the PFA system.

[0024] Figure 4 is an example according to which further examples are Figure 1 Flowchart of a method implemented in a system.

[0025] FIG. 5A to FIG. 5B is an illustration of electrical gradients between electrodes relative to tissue regions according to some examples.

[0026] Figure 6 is an example based on an example Figure 4 Block diagram of the impedance vectoring operation of the method.

[0027] Figure 7 is an example according to another example Figure 4 Block diagram of the impedance vectoring operation of the method.

[0028] FIG. 8A to FIG. 8D is exemplified according to some additional examples Figure 4 A block diagram of certain operations of a method.

[0029] Fig. 9 The following diagrams illustrate the possible Figure 4 The electrical waveform used in the method. DETAILED DESCRIPTION

[0030] Embodiments relate to the application of non-therapeutic waveforms with gradient sensing for predicting PFA electric fields. According to one aspect, a pulsed electric field (PEF) ablation device is configured to deliver a non-therapeutic PEF waveform to a first electrode set to predict the ablative effect of an ablative PEF waveform to be applied to a second electrode set. An electrical response to the delivered non-therapeutic PEF waveform is determined. The electrical response is based at least in part on a signal received on at least one test electrode. An ablative PEF waveform to be applied to the second electrode set is determined based at least in part on the electrical response. This enables a user to predict whether a particular PEF waveform will ablate target tissue in a desired manner.

[0031] Before describing the exemplary embodiments in detail, it should be noted that the embodiments reside primarily in a combination of device components and process steps related to the application of non-therapeutic waveforms with gradient sensing for predicting PFA electric fields. Therefore, components are represented by conventional symbols in the drawings where appropriate, and only those specific details relevant to understanding the embodiments are shown so as not to obscure the present disclosure with details that would be readily apparent to one of ordinary skill in the art having the benefit of the description herein. Like numbers refer to like elements throughout the specification.

[0032] As used herein, the terms "pulse", "pulse signal" or "pulsed electric field" may include a single pulse, or a pulse train, or multiple pulse trains. The single pulse, pulse train, or multiple pulse trains may vary in amplitude, pulse width, and / or other waveform characteristics during the time interval during which the single pulse, pulse train, or multiple pulse trains exist. The term "non-therapeutic waveform" refers to a waveform that is non-ablative and is applied to determine how a tissue area will respond to an ablative waveform. Non-therapeutic waveforms may include pacing pulses, low-amplitude PEF waveforms, or any other electrical pulses that can be measured with other electrodes to map fields and gradients.

[0033] Figure 1 1 is a block diagram illustrating one example of a PFA system 10 configured to deliver electrical energy to irreversibly electroporate tissue. In the illustrated example, the PFA system 10 includes a medical device 12 coupled to an electronic controller 14 that is configured to provide energy control, delivery, monitoring, and other functions described in more detail below. In various examples, the electrical coupling of the medical device 12 to the electronic controller 14 may be direct (not explicitly shown) or indirect via an electrode connection system (ECS) 13. In the illustrated example, the electronic controller 14 includes waveform generators 141, 142 that are configured to generate non-therapeutic PEF waveforms and ablative PEF waveforms.

[0034] In various embodiments, the electronic controller 14 is additionally connected via the ECS 13 to one or more of the following components: (i) a medical device 52; (ii) a body surface mapping vest 82; (iii) three or more surface ECG electrodes 26; and (iv) a patient return electrode (PRE) or large area electrode patch 90. In additional embodiments, the ECS 13 may also provide access to additional electrode sets ( Figure 1 Not explicitly shown; see for example Figure 78), the additional electrode set, for example, includes skin surface electrode patches. Some of these electrode patches are used for potential navigation of catheters in the patient's body 102. In some examples, the skin surface electrode patches include six electrode patches arranged in three pairs, wherein each pair of electrode patches in such pairs of electrode patches is aligned along a corresponding one of three orientation axes, such as aligned along the front / back, left / right and neck / leg directions, respectively.

[0035] The medical device 12 includes an elongated body 16 that can be passed through the vasculature of a patient's body 102 and / or can be positioned near a tissue region to be diagnosed or treated. In various examples, the elongated body 16 includes a catheter, a sheath, or an intravascular introducer. The elongated body 16 has a proximal portion 18 and a distal portion 20, and can include one or more lumens disposed within the elongated body 16, thereby providing mechanical, electrical, and / or fluid communication between the proximal portion 18 of the elongated body 16 and the distal portion 20 of the elongated body 16. The distal portion 20 can generally define one or more treatment regions of the medical device 12 that are operable to monitor, diagnose, and / or treat a portion of the patient's body 102.

[0036] The treatment area can have a variety of configurations to facilitate such operations. In the case of bipolar pulsed field delivery, the electrodes 24 in the distal portion 20 are grouped in a bipolar configuration for energy delivery, where energy is transferred between one or more electrodes on the same electrode array and one or more different electrodes. In another configuration, one or more of the electrodes 24 are used as one pole, and one or more electrodes 64 of the second medical device 52 are used as the opposite pole of the bipolar configuration. For example, as Figure 1 As shown, the distal portion 20 includes an electrode carrier arm 22 that can be transformed between a linear configuration and an expanded configuration, wherein the carrier arm 22 has an arcuate or substantially circular shape. The electrode carrier arm 22 includes a plurality of electrodes 24 (e.g., nine electrodes 24, such as Figure 1 ), the plurality of electrodes are configured to deliver pulsed field energy. In addition, when in the expanded configuration, the electrode carrier arm 22 can be located in a plane that is locally substantially orthogonal to the longitudinal axis of the elongated body 16. The planar orientation of the expanded electrode carrier arm 22 can facilitate easy placement of the plurality of electrodes 24 in contact with the target tissue. The electrodes 64 of the second medical device 52 have a linear configuration, such as Figure 1 For example, the distal portion 60 of the medical device 52 has electrodes 64 arranged linearly along the common longitudinal axis. In various additional embodiments, other suitable geometric configurations of the electrodes 24, 64 in the medical devices 12, 52 may also be used.

[0037] When placed on the patient's body 102, the ECG electrodes 26 are used to monitor the patient's cardiac activity. ECG records acquired using the ECG electrodes 26 can be used, for example, to determine the timing of pulse train delivery to coincide with a desired portion of the cardiac cycle, such as during the ventricular refractory period. ECG records can also be monitored to determine when non-therapeutic stimulation pulses delivered to the myocardium result in activation (capture) of the ventricles.

[0038] An input device 15 is included that communicates with the electronic controller 14 for operating and controlling various functions of the system 10. The system 10 also includes a display device 17 to display information to the user / operator. The system 10 is further configured to deliver a non-therapeutic PEF waveform using a waveform generator 142 and determine a response to the waveform. Based on the response to the non-therapeutic PEF waveform, the system 10 operates to determine and then deliver an ablative PEF waveform using a waveform generator 141. These functions enable the user to select an ablative waveform that will more likely produce effective ablation of a target area of ​​tissue without ablating other areas of tissue.

[0039] The electronic controller 14 also includes a processor 145 in communication with one or more memories 146 containing software modules that provide instructions or algorithms for automatically operating and executing the various sequences, calculations, and / or procedures described herein. Interface circuits 147 enable signal transmission and / or communication between the various circuits of the electronic controller 14 and other components of the system 10, such as described in more detail below.

[0040] The non-therapeutic waveform generator 142 is configured to generate a non-therapeutic waveform for delivery to the electrodes 24, 64 and / or other associated electrodes located in and / or around the area of ​​tissue to be ablated (target tissue). For example, the non-therapeutic waveform can be a pulse train that delivers an electric field with an amplitude less than a certain threshold. In various examples, the threshold represents an electric field amplitude that does not ablate the target tissue. For cardiac tissue, the threshold can be less than about 400 volts / cm, for example, where a field strength of 400 volts / cm may be ablative.

[0041] Thus, the electronic controller 14 may deliver current or pulses to one or more separate electrodes, which may include electrodes 24, 64 and / or one or more of the other electrodes mentioned above. Some of the other electrodes may be inserted when performing the method disclosed herein for determining an ablative PEF waveform that will achieve ablation of target tissue, or may be inserted at a previous time, such as when an electrical lead or device is inserted into the heart to provide a pacing signal to control the heart rhythm. For example, a catheter with electrodes 24, 64 may be inserted to apply one or both of an ablative PEF waveform and a non-therapeutic PEF waveform. In addition, some of the electrodes 24, 64 and / or other electrodes may be configured to detect electrical signals in response to the non-therapeutic PEF waveform applied. In addition, electrodes outside the patient's body may be configured to detect electrical signals in response to a non-therapeutic PEF waveform applied to one or more of the electrodes 24, 64 inside the patient's body.

[0042] In some examples, the electrical signals detected with the various electrodes are analyzed using the associated circuitry of the electronic controller 14 (e.g., including a complex impedance analysis circuit or module) 143 to determine the ablative PEF waveform to be applied to the set of electrodes 24 of the medical device 12. For example, in some cases, the electronic controller 14 operates to determine the electric field between a pair of electrodes based on the voltage of the signal detected between the electrodes in the pair of electrodes. By determining the electric field between multiple pairs of electrodes having different orientations relative to the target tissue, the electronic controller 14 further operates to determine the voltage gradient field near the target tissue. The voltage gradient field can be displayed on the display 17. The magnitude of the voltage at each point in the area of ​​the target tissue can be displayed by a color selected by a mapping of the voltage to the color. These magnitudes as a function of position can be overlaid on a map of the area including the target tissue. For example, a graphical image of a human heart and the positions of the various electrodes can be overlaid on the display 17, where the voltage magnitude (as indicated by color and / or intensity) is a function of the position within the heart. Alternatively or in addition, the electric field gradient can be displayed by arrows between the electrodes. This feature enables a user to try different settings of non-therapeutic waveforms applied to different electrode sets to determine an electrode set to which an ablative waveform may be applied to best achieve desired ablation of the target tissue. For example, a user may select an electrode set that best focuses the electric field in the region of the target tissue while providing reduced electric field strength in the region surrounding the target tissue. It is also noted that impedance may be measured between each pair of electrodes or each electrode set selected from electrodes 24, 64, electrodes of vest 82, and other electrodes.

[0043] In some embodiments, the electronic controller 14 may execute one or more algorithms to determine one or more ablative waveforms and a set of electrodes to which the one or more ablative waveforms are to be applied based on the analyzed responses, for example to achieve an electric field distribution that focuses the energy of the electric field generated by the ablative waveform to the area of ​​the target tissue. For example, the electronic controller 14 may operate the non-therapeutic waveform generator 142 to generate and deliver multiple non-therapeutic waveform sets, and the response analyzer 143 then operates to determine the electric field distribution between the electrodes for each non-therapeutic waveform set. Thereafter, the electronic controller 14 may operate to identify a set of non-therapeutic waveforms that produces an electric field distribution that focuses the energy delivered to the target tissue while minimizing the energy delivered to non-targeted tissue. In some embodiments, the electronic controller 14 multiplies the electric field distribution determined based on the electrical response to the non-therapeutic waveform by a constant factor to estimate the electric field distribution generated in response to the ablative pulse, the amplitude of which is amplified by the constant factor relative to the amplitude of the non-therapeutic waveform.

[0044] The ablative waveform generator 141 is configured to generate and deliver an ablative PEF waveform that can be selected based on an electrical response to a non-therapeutic PEF waveform. In some examples, the ablative waveform generator 141 can operate in one or more operating modes, including, for example: (i) bipolar energy delivery between at least two electrodes 24 or other conductive portions of the medical device 12 within the patient's body 102; (ii) monopolar energy delivery to one or more electrodes 24 or conductive portions on the medical device 12 within the patient's body 102, and through any one or more electrodes 64 of the second medical device 52 within the patient's body 102 or a patient return or ground electrode 90 that is spaced apart from the multiple electrodes 24 of the medical device 12 (such as on the patient's skin or on an auxiliary device positioned away from the medical device 12); and (iii) a combination of monopolar and bipolar modes.

[0045] In addition to monitoring, recording, or otherwise transmitting measurements or conditions within the medical device 12 or the surrounding environment at the distal portion of the medical device 12, additional measurements may be made through connection to the multi-electrode catheter, including, for example, temperature, electrode-tissue interface impedance, delivered charge, current, power, voltage, work, etc., in the electronic controller 14 and / or the medical device 12. The surface ECG electrodes 26 may communicate with the electronic controller 14 for initiating or triggering one or more alerts or therapeutic deliveries during operation of the medical device 12. An additional neutral electrode patient ground patch ( Figure 1 Not shown; see Figure 78 ) to assess the expected bipolar electrical path impedance, and to monitor and alert the operator when inappropriate and / or unsafe conditions are detected, including, for example: inappropriate (excessive or insufficient) delivery of charge, current, power, voltage, and work performed by the multiple electrodes 24; inappropriate and / or excessive temperatures of the multiple electrodes 24, inappropriate electrode-tissue interface impedance, and incorrect and / or unintentional electrical connection with the patient's body 102 prior to delivering high voltage energy.

[0046] The electronic controller 14 also includes a mapping and navigation system 144 (which is integrated into the electronic controller or as a physically separate subsystem) that is configured to track and monitor the positions of multiple electrodes 24 and / or 64 as the medical device 12, 52 moves within the patient's body 102. Information communication or transmission from the electrodes 24, 64 and the body surface mapping vest 82 to the mapping and navigation system 144 occurs via the ECS 13. In operation, the electronic controller 14 utilizes the connection with the delivery catheter 16 to obtain additional information, such as for estimating cardiac cycle information for display and / or gating geometry. In some examples, the catheter 52 is also in communication with the mapping and navigation system 144. The mapping and navigation system 144 can cooperate with other circuits of the electronic controller 14 to measure the position of at least one of the electrodes 24, 64 before, during, and / or after the generation and delivery of the waveform. The mapping and navigation system 144 may be used to navigate to various energy delivery points and evaluate the electric field distribution to estimate at least one measure of the therapeutic effect from PEF delivery at various locations.

[0047] Figure 2 is a flow chart illustrating a method 200 implemented in the system 10 according to some examples. The method 200 includes delivering a non-therapeutic PEF waveform to a first set of electrodes (in block S10). The method 200 also includes determining an electrical response to the delivered non-therapeutic PEF waveform based at least in part on a signal received on at least one test electrode (in block S12). The method 200 also includes selecting a second set of electrodes and determining an ablative PEF waveform to be applied to the second set of electrodes based at least in part on the electrical response (in block S14).

[0048] In some examples, the first electrode set and the second electrode set are selected from electrodes 24, 64 and have at least one common electrode. In some examples, at least one test electrode on which a signal is received is an electrode in at least one of the first electrode set 24, 64 and the second electrode set 24, 64. In some embodiments, the electrical response includes a voltage across a pair of electrodes 24 and / or 64. In some examples, the electrode set to which the non-therapeutic pulse is applied, the electrode set through which the response is measured, and the electrode set to which the ablative pulse is applied are selected by the user. In some examples, the electrical response includes an electric field gradient that is scaled by a selected or fixed factor in the electronic controller 14 to estimate the electric field gradient generated by the ablative PEF waveform. In some examples, the electrical response includes an impedance between a pair of electrodes 24 and / or 64. In some examples, the non-therapeutic PEF waveform includes at least one pulse, and the electrical response is determined for each pulse in the at least one pulse. In some examples, the ablative PEF waveform includes a second pulse sequence having the same periodicity as the first pulse sequence including at least one pulse. In some examples, method 200 also includes displaying a graphical rendering of the electrical response and a graphical rendering of at least two electrodes selected from at least one of the first electrode set, the second electrode set, and the at least one test electrode. In some examples, the graphical rendering includes a graphical rendering of electric field gradients between multiple pairs of electrodes superimposed on the graphical rendering of the anatomical region to be treated, the electric field gradients determined based on the electrical response to the non-therapeutic PEF waveform.

[0049] Figure 3is a flow chart illustrating a method 300 implemented in the system 10 according to a further example. In some examples, the method 300 is used to determine an ablative waveform based on an analysis of an electrical response to a non-therapeutic waveform. The method 300 may be performed using various circuits of the electronic controller 14. The method 300 includes receiving an electrical response to one or more non-therapeutic waveforms (in box S18). The method 300 also includes determining an electric field distribution based at least in part on the received electrical response (in box S20). In some examples, the operation of box S20 includes calculating the electric field distribution between each pair of electrodes in the at least one pair of electrodes by dividing the voltage between the at least one pair of electrodes by the distance between the pair of electrodes. The method 300 also includes selecting a non-therapeutic waveform that produces an electric field distribution that meets an applicable standard (in box S22). For example, the processor 145 may select a non-therapeutic waveform from a previously applied set of non-therapeutic waveforms that produces an electric field distribution that approximately maximizes the electric field magnitude in the target tissue while approximately minimizing the electric field magnitude in the non-target tissue. Method 300 also includes mapping the selected non-therapeutic waveform to an ablative waveform (in block S24). In some examples, the mapping operation of block S24 includes applying a corresponding scaling factor to each of the one or more parameters of the selected non-therapeutic waveform to determine a corresponding parameter of the ablative waveform.

[0050] In some examples, determining the electric field distribution in step S20 includes dividing the voltage between a pair of electrodes by the distance between the pair of electrodes. In some examples, selecting a non-therapeutic waveform in step S22 includes selecting a non-therapeutic waveform that produces an approximately highest ratio of electric field energy within a target region of tissue to electric field energy outside the target region.

[0051] Figure 44 is a flowchart illustrating a method 400 implemented in the system 10 according to an additional example. The method 400 uses a mapping and navigation system 144 to render organs adjacent to relevant electrodes (e.g., a subset of electrodes 24, 64) and tissues to be targeted for treatment. In one example, the mapping and navigation system 144 operates to provide a graphical image of the patient's heart on the display 17 and overlays the position of the relevant electrodes thereon. This feature enables the operator of the system 10 to visualize the location of the electrodes 24, 64 relative to the targeted tissue. When a non-therapeutic waveform is delivered to the targeted tissue via the relevant electrodes, the electronic controller 14 operates to add the estimated electric field distribution within the targeted tissue and adjacent tissue selected for different electrodes to the graphical image. Then, the operator can advantageously use the combined information visualized on the display 17 to more accurately target the selected tissue volume to achieve the desired therapeutic effect. In various embodiments of the method 400, the electrode selection can be fully automated, semi-automated, or performed manually by the operator. In each of such embodiments, an electrode group can be selected to obtain an electric field distribution that is approximately optimal for treating the target tissue to achieve the desired therapeutic effect. In some examples, selected inter-electrode non-therapeutic pulse delivery to sequential electrodes is performed at a relatively high frequency, for example, such that a selection cycle through can be completed in less than about 200 milliseconds.

[0052] Method 400 includes positioning distal catheter portion 20, 40 so that electrodes 24, 64 are placed adjacent or relatively close to tissue targeted for ablation (in block 402). In various examples, the positioning operation of block 402 is assisted by utilizing the aforementioned graphical images generated by mapping and navigation system 144 and displayed on display 17.

[0053] The method 400 also includes measuring the catheter inter-electrode impedance (in block 404). In some examples, the operations of block 404 include delivering one or more non-therapeutic waveforms between a selected one of the electrodes 24, 64 (referred to as the anchor electrode) and the other catheter electrodes and sensing corresponding voltages and currents between corresponding pairs of electrodes. The selection of the anchor electrode 24, 64 is changed to cycle through all possible combinations of electrodes 24, 64. The corresponding values ​​of the voltage and sensed current are then processed, for example in the response analyzer 143, to determine the corresponding (typically complex-valued) inter-electrode impedance.

[0054] The method 400 also includes measuring the catheter-to-surface electrode impedance (in block 406). In some examples, the operations of block 406 include delivering one or more non-therapeutic waveforms between the selected anchor electrode 24 or 64 and the surface electrode positioned on the skin of the patient's body 102 and sensing the corresponding current between multiple pairs of electrodes. The anchor electrode is changed to cycle through all possible combinations of electrodes 24 and surface electrodes. The sensed voltage and current values ​​are then processed, for example, in the response analyzer 143 to determine the corresponding complex electrode impedance.

[0055] The method 400 also includes selecting an electrode between which to deliver the therapeutic waveform (in block 408). In one example, the operations of block 408 include receiving input from an operator regarding the volume of tissue to be treated, for example using a user interface and with the aid of information visualized on the display 17 as indicated above. The operator may also enter or select relevant parameters for the expected therapeutic effect (in block 408). The processor 145 then processes the received operator input using the various impedances measured in blocks 404, 406 to identify a suggested selection of electrodes for delivering the therapeutic waveform.

[0056] Method 400 also includes receiving additional input from an operator (in box 410). The additional input received in box 410 is responsive to the automatic electrode selection made in box 408 and is intended to make adjustments to such electrode selection based on auxiliary information (when relevant and / or available). In some examples, these adjustments are based on predicted or estimated electric field distributions, dynamic stability assessments, and / or additional patient-specific considerations. In some examples, the operator may reposition the catheter and repeat at least some measurements using non-therapeutic waveforms. In some examples, the operation of box 410 is optional and may be omitted.

[0057] Method 400 also includes delivering a therapeutic waveform to treat the targeted tissue in block 412. The therapeutic waveform is delivered using the electrode selection of block 408, which is optionally adjusted in block 410. Upon completion of the delivery and evaluation of treatment results in block 412, the catheter may be optionally repositioned in block 414 in preparation for the next round of PEF energy delivery.

[0058] FIG. 5A to FIG. 5B 4 is an illustration of electrical gradients between different pairs of electrodes 24 relative to a target region 502 of tissue according to some examples. The target region 502 is illustratively shown as having an approximately elliptical shape. The short axis and the long axis of the elliptical shape are labeled 504 and 506, respectively. Through the operations of block 402 of method 400, the distal portion 20 of the catheter 12 is positioned such that its electrodes 24 4Approximately centered relative to the target area 502. Different electrode selections then enable the electric field vector to be oriented in different ways relative to the axes 504 and 506, as explained in more detail below.

[0059] Figure 5A is an example of electrode selection, where electric field vectors 520 and 530 are approximately aligned with short axis 504. The corresponding multiple pairs of electrodes are (24 3 ,twenty four 4 ) and (24 4 ,twenty four 5 ). In some examples, the electrodes shown are selected so that the corresponding electric field is substantially aligned along the axis of least impedance of region 502.

[0060] Figure 5B is an example of electrode selection, where electric field vectors 540, 550 and 560 are approximately aligned with long axis 506. The corresponding multiple pairs of electrodes are (24 4 ,twenty four 7 ),(twenty four 4 ,twenty four 8 ) and (24 4 ,twenty four 9 ).although Figure 5A and Figure 5B A plan view is shown, but one of ordinary skill in the relevant art will readily appreciate that the concepts illustrated apply similarly in three dimensions, such as for spherical volumes, ellipsoids, or more complex geometries and impedance axes (or other measurable electrical quantities), depending on the available vectorized geometry for evaluation using the non-therapeutic pulse at box 406 of method 400.

[0061] Figure 6 4 is a block diagram illustrating the impedance vectoring operation of block 404 of method 400 according to one example. In the illustrated example, the electrode 24 in the distal portion 20 of the catheter 12 4 The electrode 24 of the distal portion 20 of the catheter 12 is selected as the anchor electrode for impedance vectorization. 1 -twenty four 3 and 24 5 -29 3 and the electrode 64 of the distal portion 60 of the catheter 52 1 -64 4 are sequentially selected to serve as anchor electrodes 24 4 For each such sequential selection, the non-therapeutic waveform is applied to the anchor electrode 24 4 Transmission between the selected counter electrode, such as Figure 6The values ​​of the applied voltage and the sensed current for each selection are then processed in block 404 of method 400 to determine the corresponding inter-electrode impedance. Block 404 of method 400 generally includes sequentially selecting electrodes 24 1 -twenty four 9 Each electrode in is used as an anchor electrode, and for each anchor electrode, a similar Figure 6 The impedance indicated in is vectorized.

[0062] Figure 7 406 of the method 400 according to one example. In the example shown, the surface electrode (patch) includes a PRE 90 and a surface electrode 702 1 ,702 2 and 702 3 The PRE 90 is positioned at the lower back of the patient's body 102. The surface electrodes 702 1 ,702 2 and 702 3 They are located at the right shoulder, left shoulder, and left hip, respectively, of the patient's body 102. In other examples, other locations for surface electrodes may similarly be used. Figure 7 The catheter configuration illustrated in the circular expansion panel in FIG. Figure 6 Same as shown.

[0063] exist Figure 7 In the illustrated example, the impedance vectoring operation of block 406 of method 400 includes sequentially selecting electrodes 24 1 -twenty four 9 and 64 1 -64 4 Each electrode in is used as an anchor electrode. For each such sequential selection, the surface electrodes 90, 702 1 ,702 2 and 702 3 The non-therapeutic waveform is transmitted between the anchor electrode and the selected counter electrode, such as Figure 7 The values ​​of applied voltage and sensed current for each selection are then processed in block 406 of method 400 to determine the corresponding inter-electrode impedance.

[0064] FIG. 8A to FIG. 8D is a block diagram illustrating certain operations of method 400 according to some examples. Fig. 8A The overall electrode configuration of system 10 is illustrated, in which case method 400 is performed. Fig. 8A The electrode configuration is roughly similar to Figure 7The electrode configuration is shown, except that the distal portion 60 of the catheter 52 has five electrodes 64 instead of four.

[0065] Figure 8B Example signal pathways along which a non-therapeutic waveform propagates through the patient's body 102 during a subset of the impedance vectoring operations of blocks 404 , 406 of method 400 are illustrated. Figure 8B Two sets of such signal paths are shown in FIG. The first set of signal paths represents several impedance vectoring configurations, where the electrode 24 3 is the anchor electrode. The corresponding example paths are labeled 831 to 834. The second set of signal paths represents several impedance vectoring configurations, where electrode 24 4 is the anchor electrode. The corresponding example pathways are labeled 841 and 842. Some of the pathways 831 to 834, 841, and 842 are located between the distal portions 20 and 60. Some other pathways of the pathways 831 to 834, 841, and 842 are located between the distal portion 20 and the surface electrode 702. 1 ,702 2 between.

[0066] Figure 8C An example vectorization configuration selected in blocks 408, 410 of the method 400 for delivering a therapeutic waveform is illustrated. In the example shown, the selected vectorization configuration has five vectors, labeled 851, 853, 854, 861, and 862. The selection is based on the Figure 8B Evaluation of pathways 831 to 834, 841, and 842 shown, as well as other signal pathways (not explicitly shown) that have been cycled through in blocks 404, 406 of method 400. Based on such evaluation, five pairs of electrodes corresponding to signal pathways 831, 833, 834, 841, and 842 have been selected for delivery of therapeutic waveforms. Vectors 851, 853, 854, 861, and 862 represent delivery of such therapeutic waveforms via these five pairs of electrodes.

[0067] Fig.8D Illustrated for Figure 8C 899 of an example graphical image of estimated PEF effects within the target tissue and adjacent tissue of the treatment vectorization configuration illustrated in FIG. For example, in block 408 or 410 of method 400, graphical image 899 may be displayed on display 17. For purposes of illustration and without any implied limitation, graphical image 899 is shown in FIG. Fig.8D 890 is shown as showing three different zones of estimated PEF effect: thermal zone 891, ablation zone 892, and reversible electroporation zone 893. In other examples, a different number of zones (other than three) may be similarly depicted and displayed.

[0068] In some examples, one or more of the following selection criteria and / or considerations are applied to the selection of multiple pairs of electrodes for therapeutic delivery based on impedance vectorization measurements, such as for Figure 8C Example of vectorized configuration with multiple pairs of electrodes selected:

[0069] (1) For single catheter measurements, individual electrode impedance measurements enable selection of multiple pairs of electrodes required to apply a therapeutic electric field across the targeted tissue volume.

[0070] (2) For multi-catheter measurements, impedance can be used to estimate or predict the tissue volume that the treatment field will encompass. Different pairs of electrodes can be selected or deselected on each of the multiple catheters used for therapeutic delivery to obtain the desired PEF exposure in the targeted tissue volume.

[0071] (3) The measurements may indicate when some electrodes are unacceptably close to each other. Electrodes identified in this manner may be deselected to avoid electrical shorts or overcurrent conditions. Unacceptably close proximity of two electrodes may be indicated by a low impedance value measured directly between these electrodes, or may alternatively be inferred from an impedance field calculated from impedance measurements on multiple other electrodes.

[0072] (4) In some cases, the measurement results may provide an indication of previously ablated tissue based on the observation of lower than normal impedance in some areas of tissue. Such an indication may then be used, for example, to adjust catheter positioning and / or deselect electrodes within the ablation zone, for example by turning off the corresponding electrodes, to focus current drive to areas that have not been estimated by the measurement to have impedance values ​​indicative of previously effective ablation.

[0073] Fig. 9 An electrical waveform 902 that may be used in method 400 according to some examples is graphically illustrated. Electrical waveform 902 includes a sequence of biphasic pulses 910, each of which includes a corresponding positive pulse 922 and a corresponding negative pulse 924. In the example shown, each pulse 922, 924 has an absolute amplitude value αV 0 and pulse width T p , where V 0 is a constant. The scaling factor α and pulse width T p Both may be selected and controlled via the electronic controller 14. For example, a relatively large value of α may be used to obtain a therapeutic waveform 902, while a relatively small value of α may be used to obtain a non-therapeutic waveform 902. The time delay between the positive pulse 922 and the negative pulse 924 of the same biphasic pulse 910 is d 1 Parameter d 1 The time delay between two consecutive biphasic pulses 910 in waveform 902 is d 2Parameter d 2 This is often referred to as the inter-pulse delay. Waveform 902 has a period T w =d 1 +d 2 +2T p In some examples, the period T w In general, the waveform 902 has N biphasic pulses 910, where N is a positive integer. The parameters N, d 1 d 2 and T w Selection and control may also be via electronic controller 14 .

[0074] In some examples, when configuring ablative waveform generator 141 for delivering therapeutic waveforms, one or more of the following considerations apply:

[0075] (i) Biphasic waveforms, such as waveform 902, are characterized by approximately zero net charge applied to the target tissue, which is beneficial for many treatment scenarios.

[0076] (ii) Select αV 0 The value A of αV is set to produce an electric field strength greater than about 350 V / cm near the corresponding electrode. This electric field strength corresponds to the irreversible electroporation threshold of a specific targeted tissue (cardiomyocytes in this example). For different ablation applications targeting different tissues, αV 0 The value of A may vary. These electric field strengths can typically be produced using applied voltages in the range of about 1 kV to about 3 kV.

[0077] (iii) Pulse width T p It is typically selected to be in the range of between about 1 μs and about 10 μs to avoid significant heat generation and / or undesired stimulation of muscle or nerve cells.

[0078] (iv) For therapeutic pulses, substantially square pulses 922, 924 with short rise and fall times are preferred to achieve near maximum field strength over substantially the entire pulse duration.

[0079] (v) Biphasic pulses 910 are delivered in trains of tens to hundreds of pulses per train, for example 50 to 200 pulses per train.

[0080] (vi) Pulse trains are typically delivered in relatively short time intervals (eg, less than 200 ms) to accommodate the refractory period of the surrounding myocardium. The inter-pulse delay is adjusted to achieve the desired train duration.

[0081] (vii) Therapeutic pulses are vectored between electrodes selected to produce therapeutic electric field strengths in a targeted volume of tissue. In various examples, such electrodes may be on the same catheter, on multiple catheters, or between a catheter and a surface / patch electrode.

[0082] In some examples, when configuring non-therapeutic waveform generator 142 to deliver a non-therapeutic waveform, one or more of the following considerations apply:

[0083] (a) A biphasic waveform (such as waveform 902) may be preferred for the reasons described above.

[0084] (b)αV 0 The value of is selected to produce an electric field strength below the irreversible electroporation threshold. These electric field strengths can typically be generated using an applied voltage in the range of about 50V to about 500V.

[0085] (c) Pulse width T p Typically selected to be in the range between about 1 μs and about 50 μs to avoid stimulation of muscle or nerve cells. At low voltages, heating is not a problem. Variable pulse width T that matches or approximates the intended therapeutic dose p Often provides a more realistic picture of frequency dependent variables such as impedance.

[0086] (d) In various examples, the non-therapeutic waveform includes a square or rectangular wave, a sine wave, a triangular peak wave, a multi-step wave, or a generally monophasic waveform. Fig. 9 The waveform 902 shown in FIG. 1 is provided only as a non-limiting example. Furthermore, the non-therapeutic waveform need not be "biphasic".

[0087] Even the biphasic character confers the above-mentioned charge balancing benefits.

[0088] (e) Delivery between electrodes may be performed at a relatively high frequency, for example in less than 200 ms or in approximately the same duration as the corresponding therapeutic waveform.

[0089] (f) In some examples, a single pulse is applied to each electrode, with all other electrodes acting as return paths, followed by a second electrode, and so on, such that each individual electrode is powered with all other electrodes as return paths. Single pulses are generally considered to be preferred embodiments because they consume less energy and time. In some other examples, pulse routines utilizing multiple pulses may benefit from improvements in the accuracy of local measurements, provided that the totality of such multiple pulses remains non-therapeutic.

[0090] (g) The electrodes for which individual impedances are to be assessed may be pre-selected by the operator based on their positioning within the anatomy as determined by the imaging and navigation systems.

[0091] (h) The impedance between the catheter electrodes and the various surface electrodes can be evaluated to determine whether some electrode sets can be configured to properly steer or direct the therapeutic delivery field.

[0092] (i) For non-therapeutic waveforms, the inter-pulse delay may be chosen to be as short as possible, since heat generation is generally not a problem.

[0093] According to an example disclosed above, for example in the Summary section and / or with reference to Figures 1 to 9 Any one of some or all of the figures in the claims or any combination thereof provides a medical treatment device, the medical treatment device comprising: a plurality of electrodes that can be placed in electrical communication with a target site of a patient's body; a waveform generator that is configured to selectively apply a pulsed electrical waveform to the plurality of electrodes; and an electronic controller that is configured to: estimate the impedance of an electrical path between the anchor electrode and the corresponding set of counter electrodes within the patient's body by causing the waveform generator to apply a first waveform to the anchor electrode and the corresponding set of counter electrodes and sense the corresponding current, the anchor electrode and the corresponding set of counter electrodes being selected in different ways from the plurality of electrodes, the first waveform being a non-therapeutic waveform; and select an electrode group for applying a second waveform to the target site based on the impedance, the electrode group comprising one or more of the anchor electrodes selected in different ways, the second waveform being a therapeutic waveform.

[0094] In some examples of the foregoing medical treatment devices, the electronic controller is configured to cause the waveform generator to selectively apply the second waveform to the electrode set.

[0095] In some examples of any of the above medical treatment devices, the medical treatment device also includes a first catheter, wherein the plurality of electrodes includes a first electrode array located in a distal portion of the first catheter.

[0096] In some examples of any of the above medical treatment devices, the medical treatment device also includes a second catheter, wherein the plurality of electrodes includes a second electrode array located in a distal portion of the second catheter.

[0097] In some examples of the above-described medical treatment devices, the plurality of electrodes includes one or more surface patch electrodes placeable on the skin of the patient's body.

[0098] In some examples of the above-mentioned medical treatment devices, the electrical path includes one or more of the following: an electrical path between an electrode in the first array and another electrode in the first array; an electrical path between an electrode in the first array and an electrode in the second array; an electrical path between an electrode in the first array and one of the surface patch electrodes; and an electrical path between an electrode in the second array and one of the surface patch electrodes.

[0099] In some examples of the above medical treatment devices, the first waveform is selected from the group of waveforms consisting of: a biphasic waveform; a monophasic waveform; a rectangular pulse wave; a sine wave; a triangular peak wave; and a multi-step wave.

[0100] In some examples of the foregoing medical treatment devices, the second waveform is a biphasic rectangular pulse waveform.

[0101] In some examples of any of the above-described medical treatment devices, the medical treatment device also includes a mapping and navigation system configured to track the position of one or more electrodes of the plurality of electrodes to determine one or more distances between the anchor electrode and the corresponding set of counter electrodes.

[0102] In some examples of the foregoing medical treatment devices, the electronic controller is configured to estimate the electric field strength at the target site based on the one or more distances.

[0103] In some examples of the foregoing medical treatment devices, the electronic controller is configured to estimate a pulsed electric field effect of the second waveform within the target site based on the one or more distances.

[0104] In some examples of the foregoing medical treatment apparatus, the electronic controller is configured to generate a graphical image showing an anatomical map of the target site with the estimated pulsed electric field effect overlaid thereon.

[0105] It should be understood that the various aspects disclosed herein may be combined in combinations different from those specifically presented in the specification and drawings. It should also be understood that, depending on the example, certain actions or events of any of the processes or methods described herein may be performed in a different order, may be added, merged, or omitted entirely (e.g., not all described actions or events may be required to perform these techniques). In addition, although for clarity, certain aspects of the present disclosure are described as being performed by a single module or unit, it should be understood that the techniques of the present disclosure may be performed by a combination of units or modules associated with, for example, a medical device.

[0106] In one or more examples, the described techniques can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions can be stored as one or more instructions or codes on a computer-readable medium and executed by a hardware-based processing unit. The computer-readable medium may include a non-transitory computer-readable medium that corresponds to a tangible medium, such as a data storage medium (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store desired program code in the form of instructions or data structures and can be accessed by a computer).

[0107] Instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general purpose microprocessors, application specific integrated circuits (ASICs), field programmable logic arrays (FPGAs), or other equivalent integrated or discrete logic circuits. Thus, the term "processor" as used herein may refer to any of the aforementioned structures or any other physical structure suitable for implementing the described techniques. Additionally, these techniques may be fully implemented in one or more circuits or logic elements.

[0108] It will be appreciated by those skilled in the art that the present invention is not limited to the contents specifically shown and described above. In addition, unless otherwise indicated above, it should be noted that all drawings are not drawn to scale. In the case of not departing from the scope of the present invention which is limited only by the following claims, various modifications and variations are possible according to the above teachings.

Claims

1. A medical treatment device, comprising: a plurality of electrodes placeable in electrical communication with a targeted site of a patient's body; a waveform generator configured to selectively apply a pulsed electrical waveform to the plurality of electrodes; and An electronic controller, the electronic controller being configured to: estimating an impedance of an electrical path between the anchor electrode and the corresponding set of counter electrodes within the patient's body by causing the waveform generator to apply a first waveform to the anchor electrode and the corresponding set of counter electrodes, the anchor electrode and the corresponding set of counter electrodes being selected differently from the plurality of electrodes, and sensing a corresponding current, the first waveform being a non-therapeutic waveform; as well as An electrode set is selected based on the impedance for applying a second waveform to the target site, the electrode set including one or more of the differently selected anchor electrodes, the second waveform being a therapeutic waveform.

2. The medical treatment device of claim 1, wherein the electronic controller is configured to cause the waveform generator to selectively apply the second waveform to the electrode group.

3. The medical treatment device according to claim 1, further comprising a first catheter, Wherein the plurality of electrodes comprises a first electrode array located in a distal portion of the first catheter.

4. The medical treatment device according to claim 3, further comprising a second catheter, Wherein the plurality of electrodes comprises a second electrode array located in a distal portion of the second catheter.

5. The medical treatment device of claim 4, wherein the plurality of electrodes comprises one or more surface patch electrodes placeable on the skin of the patient's body.

6. The medical treatment device of claim 5, wherein the electrical path comprises one or more of: an electrical path between one electrode in the first array and another electrode in the first array; an electrical path between electrodes in the first array and electrodes in the second array; an electrical path between an electrode in the first array and one of the surface patch electrodes; and An electrical path between an electrode in the second array and one of the surface patch electrodes.

7. The medical treatment device of claim 1, wherein the first waveform is selected from the group consisting of: Biphasic waveform; Single-phase waveform; Rectangular pulse wave; Sine wave; Triangular peak wave; and Multi-step waves.

8. The medical treatment device of claim 7, wherein the second waveform is a biphasic rectangular pulse waveform.

9. The medical treatment device according to claim 1 further comprising a mapping and navigation system configured to track the position of one or more electrodes of the plurality of electrodes to determine one or more distances between the anchor electrode and the corresponding set of counter electrodes.

10. The medical treatment device of claim 9, wherein the electronic controller is configured to estimate the electric field strength at the target site based on the one or more distances.

11. The medical treatment device of claim 9, wherein the electronic controller is configured to estimate a pulsed electric field effect of the second waveform within the target site based on the one or more distances.

12. The medical treatment device of claim 11, wherein the electronic controller is configured to generate a graphical image showing an anatomical map of the target site with the estimated pulsed electric field effects overlaid thereon.

13. A medical treatment method, comprising: selectively applying a pulsed electrical waveform to a plurality of electrodes placed in electrical communication with a targeted site of a patient's body using a waveform generator; estimating, with an electronic controller, an impedance of an electrical path between an anchor electrode and a corresponding set of counter electrodes within the patient's body by applying a first waveform to the anchor electrode and the corresponding set of counter electrodes, the anchor electrode and the corresponding set of counter electrodes being variously selected from the plurality of electrodes, the first waveform being a non-therapeutic waveform; as well as An electrode set including one or more of the differently selected anchor electrodes is selected, using the electronic controller and based on the impedance, for applying a second waveform to the target site, the second waveform being a therapeutic waveform.

14. The medical treatment method according to claim 13, further comprising: The electronic controller is used to cause the waveform generator to selectively apply the second waveform to the electrode set.

15. The medical treatment method of claim 13, wherein the plurality of electrodes comprises: a first electrode array located in a distal portion of a first catheter; a second electrode array located in a distal portion of a second catheter; and One or more surface patch electrodes, the one or more surface patch electrodes are located on the skin of the patient's body.

16. The medical treatment method of claim 15, wherein the electrical pathway comprises one or more of: an electrical path between one electrode in the first array and another electrode in the first array; an electrical path between electrodes in the first array and electrodes in the second array; an electrical path between an electrode in the first array and one of the surface patch electrodes; and An electrical path between an electrode in the second array and one of the surface patch electrodes.

17. The medical treatment method according to claim 13, further comprising: Using a mapping and navigation system, the position of one or more electrodes of the plurality of electrodes is tracked to determine one or more distances between the anchor electrode and the corresponding set of counter electrodes.

18. The medical treatment method according to claim 17, further comprising: An effect of the pulsed electric field of the second waveform within the target site is estimated, using the electronic controller, based on the one or more distances.

19. The medical treatment method according to claim 18, further comprising: A graphical image is generated using the electronic controller, the graphical image displaying an anatomical map of the targeted site with the estimated pulsed electric field effects overlaid thereon.

20. A non-transitory computer readable medium storing instructions that, when executed by an electronic controller of a medical treatment device, cause the medical treatment device to perform operations including the method of claim 13.

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