Systems, apparatuses, and methods for filtering high voltage noise induced by pulsed electric field ablation

Abstract

To provide apparatuses for protecting electronic circuitry, devices and / or other components from induced currents and voltages generated during a cardiac ablation procedure.SOLUTION: An apparatus comprises a protection device couplable between a first electronic device and a second electronic device. The first electronic device is disposable near tissue of a subject such that currents can be induced in the first electronic device by voltage pulse waveforms delivered to a set of electrodes near the tissue. The protection device includes a set of balun circuits connected in series and collectively configured to reduce the currents induced in the first electronic device over a set of predetermined frequency ranges.SELECTED DRAWING: Figure 22

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. Provisional Application No. 62 / 667,887, filed May 7, 2018, the entire disclosure of which is incorporated herein by reference in its entirety. [Background technology]

[0002]

[0002] While the generation of pulsed electric fields for tissue treatment has progressed from the laboratory to clinical applications in the past 20 years, the effects of short pulses of high voltage and high electric fields on tissues have been investigated for over 40 years. The application of short, high direct current (DC) voltages to tissues can generate localized high electric fields, typically in the range of several hundred volts per centimeter, that disrupt cell membranes by generating pores in the membrane. Although the exact mechanism of this electrically driven pore generation, or electroporation, is still under investigation, it is believed that the application of relatively short high electric fields generates instability in the lipid bilayer of the cell membrane, generating a distribution of localized gaps or pores in the cell membrane. This electroporation may be irreversible if the electric field applied to the membrane is greater than a threshold at which the pores do not close but remain open, thereby allowing the exchange of biomolecular material across the membrane, resulting in necrosis and / or apoptosis (cell death). The surrounding tissue may then heal naturally. However, high DC voltage pulses can cause complications (eg, ventricular fibrillation) if delivered during periods of cardiac activity.

[0003]

[0003] For example, to avoid the risk of inducing arrhythmia, high voltage pulses may be applied in synchrony with the subject's cardiac cycle. For example, high voltage pulses can be applied during a specific period of the cardiac cycle. In some applications, a cardiac stimulation device can be used to stimulate a subject's cardiac chamber(s) to establish the periodicity of the heart's electrocardiogram (ECG) activity. Other devices, such as sensing and / or mapping systems, can also be used to monitor the subject's cardiac cycle. However, these devices may be exposed to high voltages when used during a pulsed electric field ablation procedure. Such exposure may result in induced currents that may interfere with the operation of the device. It is therefore desirable to have systems, apparatus, and methods to address this issue. Summary of the Invention

[0004]

[0004] Described herein are systems, devices, and methods for protecting electronic circuits, devices, and / or other components from induced currents during pulsed electric field ablation procedures. In some embodiments, the ablation devices used in these systems may be deployed epicardially or endocardially in cardiac applications. The pulse waveform may include predetermined parameters or may be automatically generated by a signal generator.

[0005]

[0005] In some embodiments, the system may include a set of electrodes positionable near tissue of a subject. A signal generator may be configured to generate a voltage pulse waveform, the signal generator couplable to the set of electrodes and configured to deliver the voltage pulse waveform to the set of electrodes to ablate tissue. The set of electrodes may be configured to induce a current in a first electronic device positioned near the cardiac tissue in response to receiving the voltage pulse waveform. A protection device may be couplable between the first electronic device and the second electronic device. The protection device may be configured to reduce the current induced in the first electronic device.

[0006] In some embodiments, the first electronic device is a pacing device including a set of leads, and the second electronic device is a cardiac stimulation device configured to deliver a pacing signal to the pacing device. In some embodiments, the current induced in the first electronic device includes one or more of a common mode current or a differential mode current. The protection device may include one or more transformers configured to reduce the common mode current or the differential mode current.

[0007]

[0007] In some embodiments, each transformer of the one or more transformers includes a toroid core, a first winding around a first portion of the toroid core, and a second winding around a second portion of the toroid core. In some embodiments, the protection device includes one or more capacitors configured to shunt current above a predetermined frequency to reduce current induced in the first electronic device. In some embodiments, the protection device includes one or more diodes configured to shunt high voltage away from the second electronic device. In some embodiments, the protection device includes one or more inductors configured to reduce alternating current induced in the first electronic device. In some of these embodiments, the one or more inductors include a first inductor coupled to a first lead of the first electronic device and a second inductor coupled to a second lead of the first electronic device. The first and second inductors may be configured to reduce alternating current induced in the first and second leads.

[0008]

[0008] In some embodiments, the protection device includes a first and a second capacitor, each configured to short a voltage above a predetermined frequency, a first transformer coupled between the first electronic device and the first capacitor, and a second transformer coupled between the first capacitor and the second capacitor. The first and the second transformers may be configured to reduce a common mode current or a differential mode current induced in the first electronic device. A set of diodes may be arranged in parallel with the second capacitor and coupled to the second electronic device. The set of diodes may be configured to shunt the high voltage away from the second electronic device. In some of these embodiments, the first and the second transformers are each a common mode transformer configured to reduce a common mode current induced in the first electronic device. In some of these embodiments, one of the first and the second transformers is a differential mode transformer configured to reduce a differential mode current induced in the first electronic device. The other of the first and second transformers is a common mode transformer configured to reduce common mode currents induced in the first electronic device.

[0009]

[0009] In some embodiments, the protection device includes one or more balun circuits configured to reduce a common mode current induced in the first electronic device over a predetermined frequency range. In some of these embodiments, the one or more balun circuits include a plurality of balun circuits each configured to reduce a common mode current induced in the first electronic device over a predetermined frequency range of the set of predetermined frequency ranges. Each predetermined frequency range of the set of predetermined frequency ranges at least partially overlaps at least one other predetermined frequency range of the set of predetermined frequency ranges. In some of these embodiments, the protection device includes one or more inductors configured to reduce an alternating current induced in the first electronic device. The one or more balun circuits may be coupled between the one or more inductors and the second electronic device.

[0010]

[0010] In some embodiments, at least one balun circuit of the one or more balun circuits may include an inductor in parallel with a capacitor and a resistor. In some embodiments, at least one balun circuit of the one or more balun circuits includes a coaxial cable winding including a first and a second conductor. The first conductor may be coupled to a first lead of the first electronic device, and the second conductor may be coupled to a second lead of the first electronic device. In some embodiments, the one or more balun circuits include a plurality of balun circuits connected in series. In some embodiments, a protection device is further coupled between the first electronic device and the signal generator. In some embodiments, the protection device is integrated into at least one of the signal generator and the second electronic device.

[0011]

[0011] In some embodiments, the apparatus may include a protection device coupleable between the first electronic device and the second electronic device, the first electronic device positionable near the subject's cardiac tissue such that a voltage pulse waveform delivered to a set of electrodes near the tissue can induce a current in the first electronic device. The protection device may include a set of capacitors each configured to shunt current above a predetermined frequency to reduce the current induced in the first electronic device. The set of transformers may each be configured to reduce common mode or differential mode currents of the current induced in the first electronic device. The set of diodes may be configured to shunt high voltage away from the second electronic device.

[0012]

[0012] In some embodiments, the signal generator may be configured to generate a voltage pulse waveform. The signal generator may be coupled to the set of electrodes and configured to deliver the voltage pulse waveform to the set of electrodes. The cardiac stimulator may be configured to deliver a pacing signal to the first electronic device, and the cardiac stimulator may be the second electronic device. In some embodiments, the first electronic device may be a pacing device including a set of leads, and the second electronic device may be a cardiac stimulator configured to deliver a pacing signal to the pacing device.

[0013]

[0013] In some embodiments, each of the one or more transformers includes a toroid core, a first winding around a first portion of the toroid core, and a second winding around a second portion of the toroid core. In some of these embodiments, the toroid core of each of the one or more transformers includes a set of laminations having an aspect ratio of 5 or less. In some embodiments, the toroid core of each of the one or more transformers defines a central axis with the first winding of that transformer wrapping around the central axis of the toroid core in a first direction and the second winding of that transformer wrapping around the central axis in a second direction opposite the first direction. In some embodiments, the outer radius of the toroid core of each of the one or more transformers is between about 4 cm and about 10 cm, and the inner radius of the toroid core of each of the one or more transformers is between about 2 cm and about 9 cm. In some embodiments, the thickness of the toroid core of each of the one or more transformers may be between about 1 cm and about 6 cm.

[0014]

[0014] In some embodiments, each of the one or more transformers may include an inductance of at least about 1 millihenry and a resistance of at least about 500 ohms. In some embodiments, each diode of the set of diodes may be a Zener diode. In some embodiments, the set of diodes includes first and second diodes arranged in series and facing in opposite directions. In some embodiments, the set of diodes may be arranged in parallel with at least one capacitor of the set of capacitors.

[0015]

[0015] In some embodiments, the set of capacitors includes a first and a second capacitor. The set of transformers includes a first transformer coupled between the first electronic device and the first capacitor. The second transformer may be coupled between the first capacitor and the second capacitor. The set of diodes includes a first and a second diode coupled to the second electronic device. In some of these embodiments, the first and second transformers may each be a common mode transformer configured to reduce a common mode current of the current induced in the first electronic device. In some embodiments, one of the first and second transformers may be a differential mode transformer configured to reduce a differential mode current of the current induced in the first electronic device, and the other of the first and second transformers is a common mode transformer configured to reduce a common mode current of the current induced in the first electronic device. In some embodiments, the protection device may include one or more inductors configured to reduce an alternating current induced in the first electronic device.

[0016] In some embodiments, the apparatus may include a protection device coupleable between a first electronic device and a second electronic device, the first electronic device positionable near tissue of a subject such that a voltage pulse waveform delivered to a set of electrodes near the cardiac tissue can induce a current in the first electronic device. The protection device may include a set of balun circuits connected in series and collectively configured to reduce the current induced in the first electronic device over a set of predetermined frequency ranges.

[0017]

[0017] In some embodiments, the signal generator may be configured to generate a voltage pulse waveform, and the signal generator may be coupled to the set of electrodes and configured to deliver the voltage pulse waveform to the set of electrodes. In some embodiments, the cardiac stimulator may be configured to deliver a pacing signal to the first electronic device, and the cardiac stimulator may be the second electronic device. In some embodiments, the first electronic device may be a pacing device including a set of leads, and the second electronic device is a cardiac stimulator configured to deliver a pacing signal to the pacing device. In some embodiments, each predetermined frequency range of the set of predetermined frequency ranges may at least partially overlap at least one other predetermined frequency range of the set of predetermined frequency ranges. In some embodiments, each predetermined frequency range of the set of predetermined frequency ranges may have a resonant peak associated with a balun circuit of the set of balun circuits.

[0018]

[0018] In some embodiments, the protection device may further include one or more inductors configured to reduce the alternating current of the current induced in the first electronic device. In some of these embodiments, a set of balun circuits may be coupled between the one or more inductors and the first electronic device. In some of these embodiments, the one or more inductors may include a first and a second set of inductors. The first set of inductors may be coupled between the set of balun circuits and the first electronic device. The second set of inductors may be coupled between the set of balun circuits and the second electronic device.

[0019] In some embodiments, at least one balun circuit of the set of balun circuits may include an inductor in parallel with a capacitor and a resistor. In some embodiments, at least one balun circuit of the set of balun circuits includes a coaxial cable winding including a first and a second conductor. The first conductor may be coupled to a first lead of the first electronic device, and the second conductor may be coupled to a second lead of the first electronic device.

[0020]

[0020] In some embodiments, a method may include delivering a pacing signal to the heart using a pacing device positioned near cardiac tissue of the heart; delivering a voltage pulse waveform using a signal generator to an ablation device positioned near the cardiac tissue to ablate the cardiac tissue; and in response to the delivery of the voltage pulse waveform, inducing a current in a first set of electronic devices positioned near the cardiac tissue, the first set of electronic devices including the pacing device; and reducing the current induced in the first set of electronic devices using a protection device coupled between the first set of electronic devices and a second electronic device.

[0021] In some embodiments, the second electronic device may be a cardiac stimulation device configured to generate a pacing signal. In some embodiments, the second electronic device may be an electrocardiogram (ECG) recording system. In some embodiments, the method may further include: using the protection device to reduce the current induced in the set of first electronic devices includes using one or more transformers or capacitors of the protection device to reduce a common mode current or a differential mode current of the current induced in the set of first electronic devices. In some embodiments, using the protection device to reduce the current induced in the set of first electronic devices includes using a set of diodes of the protection device to shunt high voltage away from the second electronic device. In some embodiments, using the protection device to reduce the current induced in the set of first electronic devices includes using one or more inductors of a balun circuit of the protection device to reduce an alternating current having a frequency within a predetermined range of the frequency of the current induced in the set of first electronic devices. In some embodiments, reducing the current induced in the first set of electronic devices using the protection device includes using one or more inductors of a balun circuit of the protection device to reduce alternating current having a frequency within a predetermined range of the frequency of the current induced in the first set of electronic devices.

[0022]

[0022] The pulse waveforms of the present invention may be hierarchical and nested in organization, with successive groups with various associated time scales. Furthermore, the associated time scales and pulse widths, as well as the number of pulses and hierarchical groups, may be selected to satisfy one or more of a set of Diophantine inequalities with the frequency of cardiac pacing. [Brief description of the drawings]

[0023] [Figure 1] FIG. 1 is a block diagram of an electroporation system, according to an embodiment. [Diagram 2]FIG. 2 is a circuit diagram of a signal generator according to an embodiment. [Diagram 3] FIG. 3 is a circuit diagram of a signal generator according to an embodiment. [Figure 4A] FIG. 4A is a side view of an ablation catheter, according to an embodiment. [Figure 4B] FIG. 4B is a side view of an ablation catheter, according to an embodiment. [Diagram 5] FIG. 5 is a partial enlarged view of a central portion of an ablation catheter, according to an embodiment. [Figure 6] FIG. 6 illustrates a method for tissue ablation, according to an embodiment. [Figure 7] FIG. 7 is an exemplary waveform showing a series of voltage pulses with a defined pulse width for each pulse, according to an embodiment. [Figure 8] FIG. 8 illustrates a schematic of a hierarchy of pulses, showing pulse widths, spacing between pulses, and grouping of pulses, according to an embodiment. [Figure 9] FIG. 9 provides a schematic diagram of a nested hierarchy of monophasic pulses displaying different levels of the nested hierarchy, according to an embodiment. [Figure 10] FIG. 10 is a schematic diagram of a nested hierarchy of biphasic pulses displaying different levels of the nested hierarchy, according to an embodiment. [Figure 11] FIG. 11 illustrates, in accordance with an embodiment, a schematic diagram of a time series of electrocardiogram and cardiac pacing signals along with atrial and ventricular refractory periods, illustrating the time window of irreversible electroporation ablation. [Figure 12] FIG. 12 is a schematic diagram of an ablation system coupled to a patient's heart, in accordance with an embodiment. [Figure 13] FIG. 13 is a block diagram illustrating an ablation system including a protection device, according to some embodiments. [Figure 14] FIG. 14 is a block diagram illustrating an ablation system including a protection device, according to another embodiment. [Figure 15]FIG. 15 is a circuit diagram of an unregulated common mode protection device, according to an embodiment. [Figure 16] FIG. 16 is a perspective view of a common mode transformer according to an embodiment. [Figure 17] FIG. 17 is a circuit diagram of a protection device that is unregulated common mode, according to an embodiment. [Figure 18] FIG. 18 is a circuit diagram of an unregulated common-to-differential mode protection device, according to an embodiment. [Figure 19] FIG. 19 is a perspective view of a differential mode transformer, according to an embodiment. [Figure 20A] FIG. 20A is a circuit diagram of an adjustable protection device, according to an embodiment. [Figure 20B] FIG. 20B is a circuit diagram of an adjustable protection device, according to an embodiment. [Figure 21] FIG. 21 is a plot of resonant peaks and frequencies for the adjustable protection device of FIGS. 20A-20B, according to an embodiment. [Figure 22] FIG. 22 is a circuit diagram of a series of adjustable protection devices, according to an embodiment. [Figure 23] FIG. 23 is a plot of a set of resonant peaks and frequencies for the adjustable protection device shown in FIG. 22, in accordance with an embodiment. [Figure 24] FIG. 24 is a plot of a set of resonant peaks and frequencies for the adjustable protection device shown in FIG. 22, in accordance with an embodiment. [Diagram 25] FIG. 25 illustrates a method for protecting electronic components from high voltage signals, according to an embodiment. [Figure 26] FIG. 26 illustrates a method for tissue ablation, according to an embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0024]

[0050] Described herein are systems, devices, and methods for protecting circuits from high power noise induced during pulsed electric field ablation, e.g., pulsed electric fields for ablating tissue by irreversible electroporation. In general, a pulsed electric field system can be used to generate high electric field strength (e.g., electric fields of about 200 V / cm or more) in a desired region of interest to ablate tissue. As an illustrative example, a pulsed electric field system for treating atrial fibrillation by irreversible electroporation occurring simultaneously with the cardiac cycle is described herein. By synchronizing ablation energy delivery with the cardiac cycle, the risk of arrhythmia induction, such as atrial and / or ventricular fibrillation, can be reduced. For example, a cardiac stimulation device may be used to deliver pacing pulses to one or more cardiac chambers such that the patient's cardiac rhythm is synchronized with the pacing pulses. However, the high voltage pulse waveform applied to tissue, e.g., cardiac tissue, can couple to the pacing device and induce currents in the pacing device and one or more of the devices coupled thereto. This noise can result in device malfunction and / or device failure of the stimulation device.

[0025]

[0051] The ablation systems described herein may include a signal generator and a processor configured to apply one or more voltage pulse waveforms to a set of selected electrodes of an ablation device to deliver energy to a region of interest (e.g., ablation energy to tissue at the ostium of a pulmonary vein). The pulse waveforms disclosed herein may assist in the therapeutic treatment of various arrhythmias (e.g., atrial fibrillation). The system may further include a cardiac stimulation device and a pacing device used to electrically pace the heart and / or measure cardiac activity to establish periodicity and predictability of the cardiac cycle and to ensure pacing capture.

[0026]

[0052] The cardiac stimulation device may synchronize the generation of the pulse waveform to the paced heartbeat to reduce unintended tissue damage. For example, a time window within the refractory period of the regular cardiac cycle may be selected for the voltage pulse waveform delivery. Thus, the voltage pulse waveform may be delivered during the refractory period of the cardiac cycle to avoid disrupting the sinus rhythm of the heart. In some embodiments, the ablation device may include one or more catheters, guidewires, balloons, and electrodes. The ablation device may transform into different configurations (e.g., compact and expanded) to position the device within the endocardial cavity. In some embodiments, the system may optionally include one or more return electrodes.

[0027]

[0053] In general, one or more catheters may be advanced minimally invasively through the vasculature to a target location to ablate tissue. In cardiac applications, electrodes that deliver an ablation pulse waveform may be positioned on an endocardial or epicardial device. The methods described herein may include introducing an ablation device into an endocardial cavity of an atrium (e.g., the left atrium) of the heart and positioning the device in contact with a pulmonary vein ostium. The ablation pulse waveform may be generated synchronously with a cardiac pacing signal to avoid disturbance of the cardiac sinus rhythm. The pulse waveform may be delivered to one or more electrodes of the device to ablate tissue. The pulse waveform may include hierarchical waveforms to aid in tissue ablation and reduce damage to healthy tissue.

[0028]

[0054] Generally, the forward and return currents in the pacing device leads are balanced (e.g., equal in magnitude and opposite in direction) during delivery of a pacing pulse. However, electrical coupling of high-voltage ablation energy to the pacing device may induce large unbalanced currents at certain frequencies in the pacing device leads. These induced currents may disrupt operation of the pacing device and / or the cardiac stimulation device coupled thereto. For example, exposure of the pacing device to large voltages may exceed the common-mode rejection of the cardiac stimulation device, disrupting pacing and / or energy delivery of the system. In some embodiments, electrical connectors (e.g., wires, cables) coupling between components of the system may receive noise induced by the high-voltage pulse waveform applied to tissue.

[0029]

[0055] The protection device may be coupled to the pacing device to suppress voltages and currents induced in the pacing device from other electronic components of the ablation system (e.g., cardiac stimulator, signal generator). For example, common mode and differential mode currents induced in the pacing device may be reduced and / or suppressed by the protection device (e.g., filter device). As a result, components of the system, such as the cardiac stimulator, can be protected from currents that may be induced in the pacing device by the high voltage pulse waveform applied by the ablation device. Additionally or alternatively, the protection device may further provide active circuit protection.

[0030]

[0056] The term "electroporation" as used herein refers to the application of an electric field to a cell membrane, which changes the permeability of the cell membrane to the extracellular environment. The term "reversible electroporation" as used herein refers to the application of an electric field to a cell membrane, which temporarily changes the permeability of the cell membrane to the extracellular environment. For example, a cell undergoing reversible electroporation may temporarily and / or intermittently form one or more pores in the cell membrane that close when the electric field is removed. The term "irreversible electroporation" as used herein refers to the application of an electric field to a cell membrane, which permanently changes the permeability of the cell membrane to the extracellular environment. For example, a cell undergoing irreversible electroporation may temporarily and / or intermittently form one or more pores in the cell membrane that persist when the electric field is removed.

[0031]

[0057] Pulse waveforms for electroporation energy delivery as disclosed herein may increase the safety, efficiency, and effectiveness of energy delivery to tissue by lowering the electric field threshold associated with irreversible electroporation, thus resulting in more effective ablative lesions with reduced total energy delivered. In some embodiments, the voltage pulse waveforms disclosed herein may be hierarchical and nested. For example, the pulse waveform may include hierarchical groups of pulses with related time scales. In some embodiments, the methods, systems, and devices disclosed herein may include one or more of the methods, systems, and apparatus described in International Application No. PCT / US2016 / 057664, filed October 19, 2016, entitled "SYSTEMS, APPARATUSES AND METHODS FOR DELIVERY OF ABLATIVE ENERGY TO TISSUE," the contents of which are incorporated herein by reference in their entirety.

[0032] system

[0058] Disclosed herein are systems and devices configured to suppress induced currents in connection with tissue ablation by selective and rapid application of voltage pulse waveforms resulting in irreversible electroporation. In general, the systems for ablation of tissue described herein may include a cardiac stimulation device for generating a cardiac pacing signal delivered to the heart by a pacing device. The cardiac pacing signal is used to synchronize delivery of a pulse waveform generated by a signal generator, and an ablation device having one or more electrodes is used to deliver the pulse waveform. As described herein for cardiac applications, the systems and devices may be deployed epicardially and / or endocardially. Voltage may be applied to a selected subset of electrodes with independent subset selection for anode and cathode electrode selection.

[0033] overview

[0059] FIG. 12 is a schematic diagram of an embodiment of an electroporation system including a pacing device (1207) positioned in a heart (1201) and an ablation device (1212). The pacing device (1207) may be configured to measure cardiac activity and / or deliver pacing signals to the heart (1201), and the ablation device (1212) may be configured to receive and / or deliver pulse waveforms to cardiac tissue. For example, FIG. 12 shows a schematic anterior cross-section of the heart (1201), with lines (1202) diagrammatically approximating the boundaries of the four cardiac chambers, including the right ventricle RV (1215) and the left atrium LA (1214). The pacing device (1207) may be introduced into the right ventricle (1215) and positioned to stimulate the right ventricle (1215) and obtain pacing capture. The pacing device (1207) may include a pacing and / or signal electrode (1209). The pacing electrode (1209) may be configured to pace the right ventricle (1215) as a bipolar pair and may be coupled to a cardiac stimulator (1260). The signal electrode (1209) may be configured as a sensor configured to measure internal activity of the heart (1201) (e.g., an ECG signal). The ablation device (1212) may be configured to couple to a signal generator (1250). The signal generator (1250) may be configured to generate a pulse waveform for irreversible electroporation of tissue, such as, for example, cardiac tissue (1201).

[0034]

[0060] In some embodiments, a distal portion of the ablation device (1212) may be introduced through the atrial septum by transseptal puncture into the endocardial space of the left atrium (1214). In some embodiments, the methods, systems, and devices disclosed herein may include one or more of the methods, systems, and devices described in International Application No. PCT / US2013 / 031252, filed March 14, 2013, entitled "CATHETERS, CATHETER SYSTEMS, AND METHODS FOR PUNCTURING THROUGH A TISSUE STRUCTURE AND ABLATING A TISSUE REGION," the contents of which are incorporated herein by reference in their entirety.

[0035]

[0061] A distal portion of the ablation device (1212) may include a set of electrodes (1213) configured to deliver ablation energy (e.g., pulsed electric field energy) to tissue. For example, the ablation device (1212) may be positioned to align one or more electrodes (1213) to contact an inner diameter surface of a lumen (e.g., the ostium of one or more pulmonary veins) (not shown) to deliver a pulsed waveform to ablate tissue. In some embodiments, the electrodes (1213) of the ablation device (1212) may be a set of independently addressable electrodes. Each electrode may include an insulated conductor configured to maintain a potential of at least about 700V without inductive breakdown of its corresponding insulation. In some embodiments, the insulation of each of the conductors may maintain a potential difference of between about 200V and about 3,000V across its thickness without inductive breakdown. In some embodiments, the set of electrodes may include multiple electrodes. The multiple electrodes may be grouped into one or more anode-cathode subsets, such as, for example, a subset including one anode and one cathode, a subset including two anodes and two cathodes, a subset including two anodes and one cathode, a subset including one anode and two cathodes, a subset including three anodes and one cathode, a subset including three anodes and two cathodes, and / or the like.

[0036]

[0062] During delivery of a pacing signal by the cardiac stimulation device (1260), the forward and return currents through the leads of the pacing device (1212) may be balanced, or stated differently, the magnitude of the forward current may be substantially equal to the magnitude of the return current, while the direction of the forward current is opposite to that of the return current. When the signal generator (1250) delivers a voltage pulse waveform to the heart by the ablation device (1212), currents may be induced in the pacing catheter leads, for example, due to the close proximity of the ablation device (1212) and the pacing device (1207). These may be unbalanced currents with high power, typically in the kW range, that span the frequency range of the cardiac stimulation device (1260) (and other electronic components), affecting their operation, as well as the delivery of the voltage pulse waveform by the signal generator (1250). Therefore, there is a need for methods and devices for suppressing induced currents in an ablation system.

[0037]

[0063] FIG. 1 shows an ablation system (100) configured to deliver a voltage pulse waveform for tissue ablation. The system (100) may include a signal generator (110), an ablation device (140), and optionally a cardiac stimulator (150), a pacing device (160), and a return electrode (170). The signal generator (110) may be coupled to at least one ablation device (140) and optionally to the cardiac stimulator (150). The ablation device (140) may include one or more sets of electrodes (142). The signal or waveform generator (1250), cardiac stimulator (1260), and ablation catheter (1212) may be structurally and functionally similar to the signal generator (110), cardiac stimulator (150), and ablation device (140), respectively, described with respect to FIG. 1.

[0038] Signal Generator

[0064] The signal generator (110) may be configured to generate a pulse waveform for irreversible electroporation of tissue, such as cardiac tissue. The signal generator (110) may be a voltage pulse waveform generator and deliver the pulse waveform to a set of electrodes (142a, 142b, ..., 142n) of the ablation device (140). The signal generator (110) may generate and deliver several types of signals, including, but not limited to, radio frequency (RF), direct current (DC) impulses (such as high voltage, ultrashort pulses used for electroporation), stimulation range impulses, and / or hybrid electrical impulses. For example, the signal generator (110) may generate monophasic (DC) pulses and biphasic (DC and AC) pulses. The signal generator (110) may include a processor (120), a memory (122), a set of electrode channels (124a, 124b, ..., 124n), an energy source (126), a sensing circuit (128), a routing console (130), and a user interface (132). One or more of the signal generator components may be coupled using a communication bus. The processor (120) may incorporate data received from one or more of the memory (122), the electrode channels (124), the energy source (126), the sensing circuit (128), the routing console (130), the user interface (132), the ablation device (140), and the cardiac stimulation device (150) to determine parameters (e.g., amplitude, width, duty cycle, timing, etc.) of a voltage pulse waveform generated by the signal generator (110). The memory (122) may further store instructions that cause the processor (120) to execute modules, processes, and / or functions associated with the system (100), such as pulse waveform generation and delivery, electrode channel configuration, fault checking, energy delivery, and / or cardiac pacing synchronization. For example, the memory (122) may be configured to store anode / cathode configuration data, electrode channel configuration data, pulse waveform data, fault data, energy delivery data, cardiac pacing data, patient data, clinical data, procedural data, and / or the like.

[0039]

[0065] In some embodiments, the ablation device (140) may include a catheter configured to receive and / or deliver the pulsed waveforms described herein. For example, the ablation device (140) may be introduced into the endocardial space of the left atrium and positioned to align one or more electrodes (142a, 142b, ... 142n) with cardiac tissue (e.g., the ostium of one or more pulmonary veins in the left atrium), and then deliver a pulsed waveform to ablate the tissue. In another example, an epicardial approach may be used to ablate tissue with the ablation device (140). The ablation device (140) may include one or more electrodes (142a, 142b, ... 142n), which in some embodiments may be a set of independently addressable electrodes. For example, the electrodes (142a, 142b, ..., 142n) may be grouped into one or more anode-cathode subsets, such as, for example, a subset including one anode and one cathode, a subset including two anodes and two cathodes, a subset including two anodes and one cathode, a subset including one anode and two cathodes, a subset including three anodes and one cathode, a subset including three anodes and two cathodes, and / or the like. The set of electrodes (142) may include any number of electrodes, such as, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, or more electrodes.In some embodiments, the methods, systems, and devices disclosed herein are described in International Patent Application No. PCT / US2017 / 012099, filed January 4, 2017, entitled "SYSTEMS, DEVICES, AND METHODS FOR DELIVERY OF PULSED ELECTRIC FIELD ABLATIVE ENERGY TO ENDOCARDIAL TISSUE," International Patent Application No. PCT / US2018 / 029552, filed April 26, 2018, entitled "SYSTEMS, DEVICES, AND METHODS FOR SIGNAL GENERATION," International Patent Application No. PCT / US2019 / 014226, filed January 18, 2019, entitled "SYSTEMS, DEVICES, AND METHODS FOR FOCAL ABLATION," and International Patent Application No. PCT / US2019 / 014226, filed January 18, 2019, entitled "CATHETERS, CATHETER SYSTEMS, AND METHODS FOR PUNCTURING THROUGH A TISSUE," No. PCT / US2013 / 031252, filed March 14, 2013, entitled "METHOD FOR CARRYING OUT THE INTERNATIONAL ARTHRITIS STRUCTURE AND ABLATING A TISSUE REGION," the contents of each of which are incorporated herein by reference in their entirety.

[0040]

[0066] In some embodiments, the processor (120) may be any suitable processing device configured to operate and / or execute a set of instructions or code, and may include one or more data processors, image processors, graphics processing units, physics units, digital signal processors, and / or central processing units. The processor (120) may be, for example, a general-purpose processor, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), and / or the like. The processor (120) may be configured to operate and / or execute application processes and / or other modules, processes, and / or functions associated with the system and / or a network (not shown) associated with the system. In some embodiments, the processor may include both a microcontroller unit and an FPGA unit, and the microcontroller may send instructions regarding electrode sequences to the FPGA. The underlying device technology may be provided in a variety of component types, such as, for example, metal oxide semiconductor field effect transistor (MOSFET) technologies such as complementary metal oxide semiconductor (CMOS), bipolar technologies such as emitter coupled logic (ECL), polymer technologies (e.g., silicon-conjugated polymer and metal-conjugated polymer-metal structures), mixed analog and digital, and / or the like.

[0041]

[0067] In some embodiments, memory (122) may include a database (not shown) and may be, for example, a random access memory (RAM), a memory buffer, a hard drive, an erasable programmable read only memory (EPROM), an electrically erasable read only memory (EEPROM), a read only memory (ROM), a flash memory, etc. Memory (122) may store instructions that cause processor (120) to execute modules, processes, and / or functions associated with system (100), such as pulse waveform generation, electrode channel configuration, fault detection, energy delivery, and / or cardiac pacing.

[0042]

[0068] In some embodiments, the set of electrode channels (124) may include a set of active solid-state switches. The set of electrode channels (124) may be configured in several ways, including independent anode / cathode configurations for each electrode channel. For example, the electrode channels (124a, 124b, ..., 124n) may be grouped into one or more anode-cathode subsets, such as, for example, a subset including one anode and one cathode, a subset including two anodes and two cathodes, a subset including two anodes and one cathode, a subset including one anode and two cathodes, a subset including three anodes and one cathode, a subset including three anodes and two cathodes, and / or the like. The set of electrode channels (124) may include any number of channels, such as, for example, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, or more electrode channels. Energy delivery may use any combination of electrode channels (124) and any order of energy delivery sequences. The delivered energy may be RF and / or any tissue ablation energy.

[0043]

[0069] The set of electrode channels (124) may be coupled to the routing console (130) to deliver energy to the set of electrodes (142) coupled to the routing console (130). The set of electrode channels (124) may be coupled to an energy source (126) to receive energy (e.g., a pulse waveform). The processor (120) may be coupled to each electrode channel (124) to configure an anode / cathode configuration for each electrode channel (124), which may be configured on a pulse-by-pulse, operator-input basis, and / or the like. The processor (120) and the energy source (126) may be collectively configured to deliver a pulse waveform through the set of electrode channels (124) to the set of electrodes (142). In some embodiments, each electrode channel (124) may include an electronic switch (e.g., a bipolar transistor) and a driver circuit, as described in detail herein. In some embodiments, each electrode channel (124) may have a bootstrap configuration for low-frequency and high-frequency operation. For example, the pulse duration of the voltage pulses delivered through the electrode channels may range between about 1 microsecond and about 1000 microseconds, which in biphasic mode corresponds to an approximate frequency range of between about 500 Hz and about 500 KHz for the frequencies associated with the voltage pulses.

[0044]

[0070] In some embodiments, the energy source (126) may be configured to convert and supply energy to the set of electrodes (142) coupled to the signal generator (110). The energy source (126) of the signal generator (110) may include a DC power source and be configured as an AC / DC switch. In some embodiments, the energy source (126) of the signal generator (110) may deliver square wave pulses with a peak maximum voltage of about 7 kV for a maximum duration of about 1000 μs into a device with an impedance ranging from about 30 Ω to about 3000 Ω. In some of these embodiments, the energy source (126) may be configured to store energy. For example, the energy source (126) may include one or more capacitors to store energy from a power source. Note that while these examples are included purely for non-limiting illustrative purposes, a variety of pulse waveforms with ranges of pulse durations, pulse spacing, pulse grouping, etc. may be generated depending on the clinical application.

[0045]

[0071] In some embodiments, the sensing circuit (128) may be configured to determine the amount of current being delivered to a device coupled to the signal generator (110) (e.g., an electrode (142) coupled to the electrode channel (124)). As described in more detail herein, the sensing circuit (128) may also be used to classify faults in an electrode channel, monitor capacitor discharge, and / or sense arcing. In some embodiments, the sensing circuit (128) may be a DC sensing circuit and / or a low-side sensing circuit. The sensing circuit may include one or more operational amplifiers, differential amplifiers (DA), instrumentation amplifiers (IA), and / or current shunt monitors (CSM).

[0046]

[0072] In some embodiments, the routing console (130) may be configured to electrically couple the set of electrodes (142) of the ablation device (140) to the set of electrode channels (124). The routing console (130) may be configured to selectively deliver energy to the set of electrodes (142) using the set of electrode channels (124). One or more ablation devices (140), each having a set of electrodes (142), may be coupled to the routing console (130). The set of electrodes (142) may include any number of electrodes, such as, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, or more electrodes.

[0047]

[0073] In some embodiments, the electrode channels (124) configured for energy delivery (e.g., configured as an anode / cathode pair of electrode channels) may not be adjacent to one another. For example, the set of electrode channels (124) may include a set of N electrode channels (124n) in a linear array. In one embodiment, a first electrode channel may correspond to the first electrode channel (124a) in the linear array of N electrode channels (124n). One or more of the second and third electrode channels (124b, 124c) may not be adjacent to the first electrode channel (124a) in the linear array of N electrode channels (124n).

[0048]

[0074] A multi-electrode ablation device may allow for precise energy delivery to target tissue. In some embodiments, the electrodes (142) of the ablation device (140) may be configured for energy delivery (e.g., as an anode / cathode pair of electrodes (142)) and may be adjacent to one another in a linear array of electrodes (142) in the ablation device (140). For example, the ablation device (140) may include a set of electrodes (142) as a linear array of N electrodes (142n). As discussed in more detail herein, FIG. 5 illustrates another embodiment of an ablation device (500) including a linear array of electrodes (530). A signal generator (110) coupled to the ablation device (140) may include a set of electrode channels (124) having N electrode channels (124n) corresponding to the N electrodes (142n) of the ablation device (140). In one embodiment, a first electrode channel (124a) of the N electrode channels (124n) may correspond to a first electrode (142a) in the linear array of N electrodes (142n). One or more of the second and third electrode channels (124b, 124c) of the N electrode channels (124n) may not correspond to any of the electrodes adjacent to the first electrode (142a) in the linear array of N electrodes (142n).

[0049]

[0075] Configurable electrode channel and electrode selection may provide flexibility in electrode positioning to ablate a desired region of interest. In one embodiment, a routing console (130) may couple to a set of 16 electrodes (142) of an ablation device (140). The routing console (130) may receive input from the processor (120) and / or the user interface (132) for electrode channel selection and energy delivery to one or more electrodes (142). Additionally or alternatively, the routing console (130) may couple to a cardiac stimulation device (150) and be configured to receive data from the device (e.g., cardiac pacing data from a pacing device) used to synchronize pulse waveforms with the patient's cardiac cycle. In an embodiment, pacing and / or cardiac stimulation device functionality may be integrated and / or included by a waveform or signal generator.

[0050]

[0076] In some embodiments, the user interface (132) may be configured as a communication interface between an operator and the system (100). The user interface (132) may include input and output devices (e.g., a touch surface and a touch display). For example, patient data from the memory (122) may be received by the user interface (132) and output visually and / or audibly. Current data from the sensing circuitry (128) may be received and output on a display of the user interface (132). As another example, an operator may control an input device having one or more buttons, knobs, dials, switches, trackballs, touch surfaces, and / or the like to generate control signals to the signal generator (110) and / or the ablation device (140).

[0051]

[0077] In some embodiments, the input devices of the user interface (132) may include a touch surface for operator input and may be configured to detect contact and movement on the touch surface using any of a number of touch sensitivity technologies, including capacitive, resistive, infrared, optical imaging, dispersive signal, acoustic pulse recognition, and surface acoustic wave technologies. Additionally or alternatively, the user interface (132) may include step switches or foot pedals.

[0052]

[0078] In some embodiments, the output devices of the user interface (132) may include one or more of a display device and an audio device. The display device may include at least one of a light emitting diode (LED), a liquid crystal display (LCD), an electroluminescent display (ELD), a plasma display panel (PDP), a thin film transistor (TFT), and an organic light emitting diode (OLED). The audio device may audibly output patient data, sensor data, system data, other data, alarms, alerts, and / or the like. The audio device may include at least one of a speaker, a piezoelectric audio device, a magnetostrictive speaker, and / or a digital speaker. In one embodiment, the audio device may output an audible alert when a malfunction is detected in the signal generator (110).

[0053]

[0079] In some embodiments, the signal generator (110) may be mounted on a dolly or cart. In some embodiments, the user interface (132) may be formed in the same or a different housing as the signal generator (110). The user interface (132) may be attached to any suitable object, such as a fixture (e.g., a bed rail), a wall, a ceiling, or may be freestanding. In some embodiments, the input device may include a wired and / or wireless transmitter configured to transmit control signals to a wired and / or wireless receiver of the signal generator (110).

[0054]

[0080] In some embodiments, the cardiac stimulator (150) including the pacing device (160) may be configured to generate a cardiac pacing signal delivered to the patient via the pacing device (160) to pace one or more ventricles for cardiac stimulation. The pacing device (160) may be configured to pace the heart and measure cardiac activity. The pacing device (160) may include a pacing electrode and a signal electrode. In some embodiments, the pacing device (160) may deliver pacing pulses generated by the cardiac stimulator (150) using the pacing electrode. The pacing device (160) may further measure cardiac activity corresponding to activity within the heart (e.g., an ECG signal) using the signal electrode. An indication of the pacing signal may be transmitted by the cardiac stimulator (150) to the signal generator (110). Based on the pacing signal, an indication of a voltage pulse waveform may be selected, calculated, and / or otherwise identified by the processor (120) and generated by the signal generator (110). In some embodiments, the signal generator (110) may further include circuitry for cardiac stimulation and / or generation of the pacing signal, thereby providing stimulator functionality. In some embodiments, the signal generator (110) may be configured to generate the voltage pulse waveform in synchronization with an indication of the pacing signal (e.g., within a common refractory window). For example, in some embodiments, the common refractory window may begin substantially immediately (or after a very small delay) after the ventricular pacing signal and last for a period of approximately 250 milliseconds (ms) or less thereafter (e.g., between about 150 ms and about 250 ms). In such embodiments, the entire pulse waveform may be delivered within this period. Cardiac pacing is further described herein with respect to FIG. 11.

[0055]

[0081] A return electrode (170) may be coupled to the patient (e.g., placed on the patient's back) to allow current to pass from the pacing device (160) through the patient and then to the return electrode (170) to provide a safe current return path from the patient (not shown). In some embodiments, the systems described herein may include one or more sterile covers configured to create a sterile barrier around portions of the system (100). In some embodiments, the system (100) may include one or more sterile covers to form a sterile field. For example, a sterile cover may be placed between the ablation device(s) and the patient to form a barrier between an internal non-sterile side including the patient, signal generator, and ablation device, and an external sterile side including the operator. Additionally or alternatively, components of the system (100) may be sterilizable. A sterile cover may include, for example, a sterile drape configured to cover at least a portion of the system components. In one embodiment, a sterile cover (e.g., a sterile drape) may be configured to create a sterile barrier over the user interface (132) of the system (100). The sterile drape may be transparent, allowing an operator to view and manually manipulate the user interface (132). The sterile cover may fit snugly around one or more system components or may hang loosely to allow adjustment of the components within the sterile field.

[0056]

[0082] FIG. 2 shows a circuit diagram of an embodiment of a signal generator (200), which may be structurally and / or functionally similar to the signal generator (110). The signal generator (200) may include one or more electrode channels (201, 202, 203). FIG. 2 shows each of the electrode channels having a similar circuit configuration, which may be structurally and / or functionally similar to the electrode channels (124a, 124b, ..., 124n). In some embodiments, each of the electrode channels (201, 202, 203) may be individually configured as a half-bridge amplifier, while a pair of electrode channels may be jointly configured as a full-bridge amplifier. The signal generators described herein may include flexibly programmable electrode configurations, where various subsets of electrodes may be dynamically and rapidly configured as anodes and cathodes. Thus, in an ablation energy delivery process, energy may be rapidly delivered across consecutive paired electrode subsets. In some cases, a given electrode may be configured as an anode and then immediately as a cathode in the process of sequencing through a series of paired electrode subsets. Similarly, biphasic waveforms may also be delivered with the aid of this topology, where an initially applied anode-cathode pair may be reversed in polarity after a very short switching time interval, and repeated alternating sequencing of anode / cathode selection may result in a biphasic voltage pulse train. The signal generator (200) may include N electrode channels, e.g., 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, or more electrode channels. Although described for convenience with respect to a first electrode channel (201), each electrode channel may include a first electronic switch (220) configured to switch between an on state and an off state. The first drive circuit (222) may be coupled to a gate terminal of the first electronic switch (220) to control the state of the first electronic switch (220). The first electrode channel (201) further includes a second electronic switch (230) configured to switch between an on and an off state. The second drive circuit (232) may be coupled to a gate terminal of the second electronic switch (230) to control the state of the second electronic switch (230).Each of the drive circuits (222, 232) may be coupled to and controlled by a processor (e.g., processor (120)). The output channel (211) may be coupled to an emitter terminal of the first electronic switch (220) and to a collector terminal of the second electronic switch (230) and may form part of a current path for current to pass through an electrode (not shown) on the medical device, through an electrical load (such as a patient's anatomy), and to one or more output channels coupled to a second electrode channel, described below. The output channel (211) may be coupled to a first electrode, such as first electrode 142(a) of the ablation device (140).

[0057]

[0083] Similarly, the second and third electrode channels (202, 203) may include respective first electronic switches (220', 220''), each configured to switch between an on state and an off state. A first drive circuit (222', 222'') may be coupled to the respective first electronic switches (220', 220'') to control the state of the first electronic switches (220', 220''). The output channels (212, 213) may be coupled between an emitter terminal of the first electronic switch (220', 220'') and a collector terminal of the second electronic switch (230', 230''). The output channels (212, 213) may be coupled to respective second and third electrodes, such as the second electrode (142b) and the third electrode (142c) of the ablation device (140). The second and third electrode channels (202, 203) further include respective second electronic switches (230', 230'') configured to switch between on and off states. A second drive circuit (232', 232'') may be coupled to a gate terminal of the second electronic switch (230', 230'') to control the state of the second electronic switch (230', 230''). Each of the drive circuits (222', 222'', 232', 232'') may be coupled to and controlled by a processor (e.g., processor (120)). The drive circuits controlled by the processor effectively comprise the routing console 130. As described above, the routing console may be configured to couple to a set of device electrodes connected to the output channels. Each electrode channel (201, 202, ...) corresponds to a respective electrode (142a, 142b, ...) of the set of device electrodes.As an exemplary illustration of waveform delivery, when switches (220, 230) are in their on and off states, respectively, switches (220', 230') are in their on and off states, respectively, switches (220'' and 230'' are in their off and on states, respectively, and all other switches of all other electrode channels are in their off states, a positive voltage pulse is delivered at output channel N (211) as the anode or positive terminal, and output channels N+3 (212 in FIG. 2) and N+4 (213 in FIG. 2) as the cathode or negative / ground terminal. During the on states of the switches, The time width of the pulse is determined by the interval between the electrodes. Thus, successive pulses may be delivered by any successive anode-cathode pairs, including repetition of pulsing of a given or certain anode-cathode combination. Waveform delivery may be interspersed across successive electrodes using the generator architecture disclosed herein. Although the examples of electrode channel selection disclosed above describe the selection of one anode channel and two cathode channels, it should be apparent that a variety of such anode-cathode combinations may be selected without limitation.

[0058]

[0084] The electronic switches (220-220'', 230-230'', 320-320'', 330-330'') described herein may include one or more bipolar transistors, such as bipolar junction transistors or bipolar field effect transistors. In some embodiments, one or more of the electronic switches include an insulated gate bipolar transistor (IGBT). Such an IGBT switch may be capable of handling high instantaneous power associated with high voltages, in the approximate range of about 50,000 W to about 300,000 W. An energy source (not shown) may be coupled to a collector terminal of the first electronic switch (220, 220', 220'') of the electrode channel (201, 202, 203) through a respective resistive element (240, 240', 240''). As described in more detail herein, the resistive elements (240, 240', 240'') may each be configured to discharge the capacitive element of the energy source when the energy source is not in use. In some embodiments, the resistive elements may have a resistance ranging between about 5 ohms and about 25 ohms. Each of the electrode channels (201, 202, 203) may be coupled to a sensing circuit (250) and a current sensing resistor (252). In some embodiments, the sensing circuit (250) may be configured to detect arcing during use. In FIG. 2, the sensing circuit (250) may be coupled between the emitter terminal of the second electronic switch (230, 230', 230'') and ground (254). Additionally or alternatively, each electrode channel (201, 202, 203) may be coupled to a respective sensing circuit (250) and current sensing resistor (252).

[0059]

[0085] In some embodiments, the first electrode channel (201) may be configured as an anode by a processor, such as the processor (120) coupled to a set of drive circuits (222, 232), as described with respect to FIGS. 1 and 2. One or more of the second and third electrode channels (202, 203) may be configured as cathodes as well by the processor (120). In one embodiment, the first electrode channel (201) may be configured as an anode by setting the first electronic switch (220) of the first electrode channel (201) to an on state and by setting the second electronic switch (230) of the first electrode channel (201) to an off state. Each of the second and third electrode channels (202, 203) may be configured as a cathode by setting the respective first electronic switch (220′, 220″) to an off state and the respective second electronic switch (230′, 230″) to an on state. In this manner, the electrode channels (201, 202) may, for example, form a current path to a tissue site (e.g., coupled to each of the output channels (211, 212) using a first electronic switch (220) of the first electrode channel (201) and a second electronic switch (230') of the second electrode channel (202).

[0060]

[0086] The processor (120) and the energy source (126) may be collectively configured to deliver a pulse waveform to the set of electrodes during use via one or more of the electrode channels (201, 202, 203). The signal generator (200) may deliver a biphasic (AC) pulse, and in some embodiments, deliver a voltage pulse to the set of output channels (211, 212, 213) with output channel (211) as the anode and output channels (212, 213) as the cathode, then immediately reverse polarity and then deliver a voltage pulse of the opposite polarity with output channel (211) as the cathode and output channels (212, 213) as the anode, and so on until a desired number of biphasic pulses have been delivered to the set of output channels (211, 212, 213) in the form of a suitable waveform. Subsequently (possibly at programmable time intervals), a different set of device electrodes (or output channels) may be configured as anodes, and the waveform may again be delivered across this new set of device electrodes. In this manner, a voltage waveform may be sequenced across any desired collection of electrodes. In general, the processor (120) and energy source (126) may be jointly configured to deliver a pulse waveform across an ordered set of electrodes (142a, 142b, ..., 142n).

[0061]

[0087] In some embodiments, as described in more detail herein, the pulse waveform delivered using the signal generator (200) may include a set of hierarchical levels and / or may be synchronized with an index of the pacing signal generated from the cardiac stimulation device (150).

[0062]

[0088] 3 shows a circuit diagram of an embodiment of a signal generator (300), which may be structurally and / or functionally similar to the signal generator (110). For example, the signal generator (300) may include one or more electrode channels (301, 302, 316), which may be structurally and / or functionally similar to the electrode channels (124a, 124b, ..., 124n). For ease of explanation, unless otherwise stated, the elements of FIG. 3 may have the same components, functionality, and / or values ​​as discussed with respect to the similar elements of FIG. 2. For example, the electrode channels (201, 202, 203) used to deliver a pulse waveform to a set of electrodes in FIG. 2 may be the same set of electrode channels (301, 302, 316) used for capacitive energy release in FIG. 3. The signal generator (300) may include one or more electrode channels (301, 302, ..., 316), and FIG. 3 shows each of the electrode channels having the same circuit configuration. Although FIG. 3 shows 16 electrode channels, it should be understood that the signal generator (300) may include N electrode channels, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, or more electrode channels. The first electrode channel (301) may include a first electronic switch (320) configured to switch between an on state and an off state. The first drive circuit (322) may be coupled to a gate terminal of the first electronic switch (320) to control the state of the first electronic switch (320). The first electrode channel (301) may further include a second electronic switch (330) configured to switch between an on state and an off state. The second drive circuit (332) may be coupled to the gate terminal of the second electronic switch (330) to control the state of the second electronic switch (330). The output channel (361) may be coupled between the emitter terminal of the first electronic switch (320) and the collector terminal of the second electronic switch (330).

[0063]

[0089] Similarly, the second and sixteenth electrode channels (302, 316) may include respective first electronic switches (320', 320'') configured to switch between on and off states. A first drive circuit (322', 322'') may be coupled to the respective first electronic switches (320', 320'') to control the state of the first electronic switches (320', 320''). The output channel (362, 376) may be coupled between an emitter terminal of the first electronic switch (320', 320'') and a collector terminal of the second electronic switch (330', 330''). The second and sixteenth electrode channels (302, 316) further include respective second electronic switches (330', 330'') configured to switch between on and off states. The second drive circuit (332', 332'') may be coupled to a gate terminal of the second electronic switch (330', 330'') to control a state of the second electronic switch (330', 330''). Each of the output channels (361, 362, 376) may be coupled to a respective electrode on one or more medical devices (not shown). Thus, each electrode channel (301, 302, 316) may correspond to a respective electrode of a set of electrodes on one or more medical devices.

[0064]

[0090] The electronic switches described herein may include one or more bipolar transistors. In some embodiments, one or more of the electronic switches include an insulated gate bipolar transistor. An energy source (not shown) may be coupled to a collector terminal of the first electronic switch (320, 320', 320'') of the electrode channel (301, 302, 316) through a respective resistive element (340, 340', 340''). The resistive elements (340, 340', 340'') may each be configured to discharge a capacitive element of the energy source when the energy source is not in use. Each of the electrode channels (301, 302, 316) may be coupled to a sensing circuit (350) and a current sensing resistor (352). In some embodiments, the sensing circuit (350) may be configured to detect arcing during use. In Figure 3, a sensing circuit (350) may be coupled between the emitter terminal of the second electronic switch (330, 330', 330'') and ground (354). Additionally or alternatively, each electrode channel (301, 302, 316) may be coupled to a respective sensing circuit (350) and current sensing resistor (352).

[0065]

[0091] In some embodiments, active monitoring of the electrode channels may be provided by the signal generator (110), as described with respect to FIGS. 1 and 3. For example, the processor (120) of the signal generator (110) may be configured to perform one or more fault checks to verify the operation of one or more electrode channels (124a, 124b, ..., 124n) (e.g., electronic switches and driver circuits), the energy source (126) (e.g., DC power supply), and the sensing circuitry (128) (e.g., arc detection). Fault checks may be performed on one or more electrode channels (124a, 124b, ..., 124n) at predetermined intervals (e.g., between pulse waveform deliveries when the energy source (126) is not in use, at the beginning prior to delivery of a pulse waveform). In some embodiments, the signal generator (300) may perform a series of fault checks on one or more electrode channels to classify the working condition of the one or more electrode channels. In one embodiment, after initially delivering a pulse waveform to the set of electrodes (142a, 142b, ..., 142n), a first fault check may be performed individually on one or more of the set of electrode channels (301, 302, ..., 316). In some embodiments, the first fault check may include setting the first electronic switch (320) to an ON state and the second electronic switch (330) to an OFF state for the first electrode channel (301). A verification DC voltage may be applied to the first electrode channel (301) for fault check. In one embodiment, the verification DC voltage may be about 50V. If substantially no current is detected by the sensing circuit (350) during the first fault check, the first electrode channel (301) may be classified as passing the first fault check. If a threshold current, e.g., a current of 10 mA or greater, is detected by the sensing circuit (350), the first electrode channel (301) may be classified as failing the first fault check (e.g., faulty). In some embodiments, the second fault check may include setting the first electronic switch (320) to an off state and the second electronic switch (330) to an on state for the first electrode channel (301).If substantially no current is detected by the sensing circuit (350) during the second fault check, the first electrode channel (301) may be classified as passing the second fault check. If a current equal to or greater than a threshold current, e.g., 10 mA, is detected by the sensing circuit (350), the first electrode channel (301) may be classified as failing the second fault check. In some embodiments, the third fault check may include setting the first electronic switch (320) to an on state and the second electronic switch (330) to an on state for the first electrode channel (301). The first electrode channel (301) may be classified as passing the third fault check when a predetermined amount of current is detected by the sensing circuit (350) during the third fault check, and may be classified as failing the third fault check when a current other than the predetermined amount is detected by the sensing circuit (350). For example, a predetermined amount of current (eg, about 5A) may be equal to the DC voltage output by the energy source (eg, about 50V) divided by the resistance of the resistive element (340) (eg, about 10Ω).

[0066]

[0092] A failure of the first fault test may indicate a malfunction of the second electronic switch (330) and / or the drive circuit (332) of the second drive circuit (e.g., the lower IGBT circuit of FIG. 3), while a failure of the second fault test may indicate a malfunction of the first electronic switch (320) and / or the first drive circuit (322) (e.g., the upper IGBT circuit of FIG. 3). A failure of the third fault test may indicate a malfunction of one or more of the energy source, the sensing circuit, the electronic switch, and the drive logic. Thus, the fault test may verify the individual and joint operation of the upper and lower IGBT circuits for the fault tested electrode channel. Each of the fault tests described herein may be performed for each electrode channel (301, 302, ..., 316) at predetermined intervals.

[0067]

[0093] In some embodiments, the fault check may be performed on the electrode channels (124) based on a predetermined criteria (e.g., a predetermined number of pulses delivered, a predetermined amount of energy delivered, and / or the like). Each electrode channel, or a subset of the electrode channels, may be examined. For example, the fault check may be performed on each electrode channel (124) configured as an anode, or on each electrode channel (124) after five pulses have been delivered. In some embodiments, the fault check may be performed in conjunction with voltage pulse waveform delivery and capacitor discharge, as described in more detail herein.

[0068]

[0094] Using a signal generator as described herein to generate and deliver a high voltage pulse waveform may lead to the signal generator's energy source (e.g., one or more capacitors) storing excess energy. This energy may be discharged to ground through a set of discharge pulses using the electrode channels. The discharge may occur before the delivery of a subsequent pulse waveform. In other words, the electrode channels may be used not only to deliver tissue ablation energy to one or more electrodes, but also to separately internally discharge excess energy to ground. This configuration may be used in place of a dump circuit and / or a bleeder resistor circuit to discharge excess stored energy in the signal generator.

[0069]

[0095] In some embodiments, as described with respect to FIGS. 1 and 3, each electrode channel (124) may sequentially partially discharge the energy source (126) to ground over a set of cycles. Each electrode channel (124) may be configured as a half-bridge amplifier to partially discharge the energy source to ground. The energy source (126) may complete the discharge of a predetermined amount of energy within a few seconds. As used herein, a discharge cycle refers to the release of energy to ground of the energy source using each of the electrode channels of the set of electrode channels. For example, energy may be partially discharged to ground through each electrode channel (124) of the signal generator (110) one at a time. In some embodiments, fault detection may be performed on the electrode channels (124) at predetermined intervals (e.g., before each discharge cycle, after a predetermined number of discharge cycles, etc.) to ensure that the energy release occurs as intended. As the stored energy is reduced by discharging, the pulse width of the discharge pulse may be increased without damaging the electrode channels (124). For example, an initial first amount of stored energy in the energy source (126) (e.g., about 3 kJ) may correspond to a discharge pulse having a first predetermined pulse width (e.g., about 0.5 μs). After discharging the energy source to a second amount of stored energy, the pulse width of the discharge pulse may be configured to a second predetermined pulse width (e.g., about 2 μs).

[0070]

[0096] In some embodiments, the set of electrode channels shown in FIG. 3 may correspond to a set of discharge paths to ground that reduce the amount of stored energy of the energy source (126). In some embodiments, a first electrode channel (301) of the set of electrode channels (301, 302, ..., 316) may be configured to partially discharge energy to ground after delivering a pulse waveform to the set of electrodes (142). For example, the first electronic switch (320) may be set to an on state and the second electronic switch (330) may be set to an on state for a predetermined period of time to at least partially discharge the energy source (126). This current through the first electrode channel (301) may be approximately equal to the DC voltage of the energy source (126) divided by the resistance of the resistive element (340). The first electrode channel (301) may discharge the energy to ground using a predetermined pulse width (e.g., about 0.5 μs).

[0071]

[0097] When the first electrode channel (301) partially discharges the energy source (126), each of the remaining electrode channels (302, ..., 316) may be configured to partially discharge the energy source (126), one at a time, in a manner similar to the first electrode channel (301). In some embodiments, a channel inactive time period (e.g., dead time) may follow the electrode channel's partial energy discharge. For example, the channel inactive time period following each electrode channel's energy discharge may be about 100 μs. In some embodiments, a discharge cycle inactive time period may follow each discharge cycle. For example, the discharge cycle inactive time period may be about 5 ms and may correspond to a bootstrap charging time. By staggering the discharge of each electrode channel, the signal generator (300) may discharge the capacitor energy at a faster rate than conventional circuit topologies.

[0072]

[0098] The energy source may be discharged to ground sequentially over a set of discharge cycles until a set of electrode channels (124) reaches a predetermined energy threshold. In some embodiments, the energy discharge may occur such that the pulse width increases over time or over each discharge cycle. The number of pulses may decrease as the pulse width increases. In some embodiments, the energy release may be configured as follows: a first pulse width may be between about 0.1 μs and about 1 μs and may be set between about 90 discharge cycles and about 130 discharge cycles; a second pulse width may be between about 1 μs and about 5 μs and may be set between about 80 discharge cycles and about 90 discharge cycles; a third pulse width may be between about 5 μs and about 10 μs and may be set between about 70 discharge cycles and about 80 discharge cycles; a fourth pulse width may be between about 10 μs and about 15 μs and may be set for about 70 discharge cycles or less; and a fifth pulse width may be between about 15 μs and about 25 μs and may be set for about 70 discharge cycles or less.

[0073]

[0099] In one illustrative and non-limiting example, a set of 16 electrode channels may be used to discharge about 3 kJ of an energy source to ground at an average rate of about 1 kJ / sec such that the signal generator may complete the discharge in about 3 seconds. In one embodiment, the energy discharge may be configured as follows: a first pulse width of about 0.5 μs may be set for about 110 discharge cycles over about 730 ms, a second pulse width of about 2 μs may be set for about 80 discharge cycles over about 530 ms, a third pulse width of about 6 μs may be set for about 73 discharge cycles over about 490 ms, a fourth pulse width of about 12.5 μs may be set for about 70 discharge cycles over about 480 ms, and a fifth pulse width of about 25 μs may be set for any remaining discharge cycles remaining to complete the discharge of the energy source over about 780 ms.

[0074]

[0100] In some embodiments, the fault detection described herein may be performed using an electrode channel prior to some energy discharge for that electrode channel. If an electrode channel is determined to be in a fault state, the electrode channel may be removed from the set of electrode channels used to discharge the energy source to ground and / or a fault status may be output to an operator. Electrode channel verification may be performed for each of the electrode channels, or a subset of the electrode channels, at predetermined intervals, such as after each energy discharge pulse, one or more discharge cycles (e.g., checking electrode channel for faults after every cycle or every two cycles), pulse width transitions (e.g., detecting electrode channel faults between pulse width increases), and at predetermined time intervals (e.g., checking electrode channel for faults every 0.1 seconds, every 0.25 seconds, every 0.5 seconds, every 1 second, etc.). Ablation Devices

[0075]

[0101] The systems described herein may include one or more multi-electrode ablation devices configured to ablate cardiac tissue to treat atrial fibrillation, such as in the left atrial chamber of the heart. FIG. 4A illustrates an embodiment of an ablation device (e.g., structurally and / or functionally similar to ablation device (140)) that may be configured to use a set of electrodes to deliver a voltage pulse waveform to ablate tissue and electrically isolate a pulmonary vein. In some of these embodiments, the ablation device may transform from a first configuration to a second configuration such that the electrodes of the ablation device flare outward to contact a lumen or ostium or opening cavity (e.g., a pulmonary vein ostium or pulmonary vein antrum) in the tissue. The ablation devices described herein are for illustrative or explanatory purposes only, and various other ablation devices may be implemented without departing from the scope of the present invention.

[0076]

[0102] The ablation device (400) includes a catheter shaft (410) at a proximal end of the device (400), a distal cap (412) of the device (400) and a set of splines (414) coupled thereto. The distal cap (412) may include an atraumatic shape. A proximal end of the set of splines (414) may be coupled to a distal end of the catheter shaft (410), and a distal end of the set of splines (414) may be tethered to the distal cap (412) of the device (400). Each spline (414) of the ablation device (400) may include one or more electrodes (416) formed on a surface of the spline (414). Each electrode (416) may include an insulated conductor configured to maintain an electrical potential of at least about 700V without inductively breaking down its corresponding insulation. In other embodiments, the insulation of each of the conductors may maintain a potential difference of between about 200V and about 1500V across its thickness without inductive breakdown. Each spline (414) may include an insulated conductor for each electrode (416) formed within the body of the spline (414) (e.g., within the lumen of the spline (414)). The spline wire sets (418, 419) may be conductive and electrically couple adjacent electrodes (416) disposed on different splines (414). For example, spline wire (418) (connecting electrodes (416)) and spline wire (419) (connecting electrodes (416')) may extend transversely to the longitudinal axis of the ablation device (400).

[0077]

[0103] 4A shows a set of splines (414) where each spline (414) includes a pair of electrodes (416 and 416') having approximately the same size, shape, and gap as the electrodes (416 and 416') of the adjacent spline (414). In other embodiments, the size, shape, and gap of the electrodes (416, 416') may differ. For example, the electrode (416) electrically coupled to the first spline wire (418) may differ in size and / or shape from the electrode (416') electrically coupled to the second spline wire (419).

[0078]

[0104] In some embodiments, the first spline wire (418) may include a first set of spline wires (420, 421, 422, 423), with each spline wire in the set of spline wires (420, 421, 422, 423) coupling an electrode (416) between a different pair of splines in the set of splines (414). In some of these embodiments, the set of spline wires (420, 421, 422, 423) may form a continuous loop between the electrodes (416) coupled thereto. Similarly, the second spline wire (419) may include a second set of spline wires (424, 425, 426), with each spline wire in the set of spline wires (424, 425, 426) coupling an electrode (416') across the set of splines (414). A second set of spline wires (424, 425, 426) may couple a different electrode (416') across the set of splines (414) than the first set of spline wires (420, 421, 422, 423). In some of these embodiments, the first set of spline wires (420, 421, 422, 423) may form a first continuous loop between the electrodes (416) coupled thereto, and the second set of spline wires (424, 425, 426) may form a second continuous loop between the electrodes (416') coupled thereto. The first continuous loop may be electrically isolated from the second continuous loop. In some of these embodiments, the electrode (416) coupled to the first continuous loop may be configured as an anode, and the electrode (416') coupled to the second continuous loop may be configured as a cathode. A pulse waveform generated by the signal generator may be delivered to the first and second continuous loops of electrodes (416 and 416'). In some embodiments, the splined wires, e.g., 421, 422, 423, etc., may be replaced by similar electrical connections at the proximal portion of the device (e.g., in the handle of the device). For example, the electrodes (416) may all be electrically wired together in the handle of the device.

[0079]

[0105] In another embodiment shown in Figure 4B, a first spline wire (461) of the set of spline wires (461, 462) may couple an electrode (459) between a first spline (451) and a second spline (452) of the set of splines, and a second spline wire (462) of the set of spline wires (461, 462) may couple an electrode (460) between a third spline (453) and a fourth spline (454) of the set of splines. The electrode (459) coupled by the first spline wire (461) and the electrode (460) coupled by the second spline wire (462) may be configured as an anode and a cathode, respectively (or vice versa). The pulse waveform may be delivered to an electrode (459) that is coupled by a first spline wire (461) and an electrode (460) that is coupled by a second spline wire (462). In some embodiments, instead of spline wires, the leads of at least two of the electrodes in the set of electrodes may be electrically coupled to or near a proximal portion of the ablation device, for example, in a handle.

[0080]

[0106] In other embodiments, referring to FIG. 4A, one or more of the spline wires (418, 419) may form a continuous loop between the electrodes (416) electrically coupled to them. For example, the first set of spline wires (418) may form a first continuous loop between the electrodes (416) coupled to it, and the second set of spline wires (419) may form a second continuous loop between the electrodes (416') coupled to it. In this case, the first continuous loop may be electrically isolated from the second continuous loop. In one embodiment, each of the electrodes (416) coupled to the first set of spline wires (418) may be configured as an anode, while each of the electrodes (416) coupled to the second set of spline wires (419) may be configured as a cathode. Each group of electrically coupled electrodes (416) may be independently addressable. In some embodiments, instead of splined wires, the leads of at least two of the electrodes of the set of electrodes may be electrically coupled to or near a proximal portion of the ablation device, for example, in the handle.

[0081]

[0107] In other embodiments, the size, shape, and spacing of the electrodes (416) may vary. The ablation device (400) may include any number of splines, such as, for example, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, or more splines. In some embodiments, the ablation device (400) may include between 3 and 20 splines. For example, in one embodiment, the ablation device (400) may include between 4 and 9 splines.

[0082]

[0108] For each of the ablation devices described herein, each of the splines may include a polymer and define a lumen to form a hollow tube. One or more electrodes of the ablation devices described herein may include a diameter of about 0.2 mm to about 2.5 mm and a length of about 0.2 mm to about 5.0 mm. In some embodiments, the electrodes may include a diameter of about 1 mm and a length of about 1 mm. Because the electrodes may be independently addressable, the electrodes may be energized in any sequence using any pulse waveform sufficient to ablate tissue by irreversible electroporation. For example, different sets of electrodes may deliver different sets of pulses (e.g., hierarchical pulse waveforms). It should be understood that the size, shape, and spacing of the electrodes on and between the splines may be configured to deliver sufficient energy to create proximal / transmural lesions to electrically isolate one or more pulmonary veins. In some embodiments, alternate electrodes (e.g., all distal electrodes) may be at the same potential, as well as all other electrodes (e.g., all proximal electrodes). Therefore, ablation can be delivered rapidly with all electrodes working simultaneously. A variety of such electrode pair options exist and may be implemented based on their convenience.

[0083]

[0109] For each of the ablation devices discussed herein, the electrodes (e.g., ablation electrodes, return electrodes) may comprise a biocompatible metal, such as titanium, palladium, silver, platinum, or a platinum alloy. For example, it may be preferred that the electrodes comprise platinum or a platinum alloy. Each electrode may comprise a conductor having sufficient electrical insulation to maintain a potential difference of at least 700V across its thickness without inductive breakdown. In other embodiments, the insulation of each of the conductors may maintain a potential difference of between about 200V and about 3,000V across its thickness without inductive breakdown, including all values ​​and subranges in between. The insulated conductors may run to a proximal handle portion of the catheter, from where they may connect to a suitable electrical connector. The catheter shaft may be made of a flexible polymeric material, such as, for example, Teflon, nylon, Pebax, etc.

[0084]

[0110] FIG. 5 illustrates an embodiment of an ablation device (500) (e.g., structurally and / or functionally similar to ablation device (140)) that may be configured to use a set of electrodes to deliver a voltage pulse waveform generated by a signal generator (110) described herein to ablate tissue, which may, in some embodiments, create linear, circumferential ablation lesions. The ablation device (500) may include a catheter (510) having a flexible, elongate shaft (520). The elongate shaft (520) may be advanced and withdrawn from a lumen of the catheter (510). The flexibility of the catheter (510) may facilitate positioning the electrodes (530) around asymmetric and / or complex contours. The elongate shaft (520) may include a set of electrodes (530) spaced apart along the elongate shaft (520). In some embodiments, the electrodes (530) may be integrally formed with the elongate shaft (520). Each of the electrodes (530) may be connected to a respective output channel of the signal generator. The electrodes (530) may be independently configured as an anode or cathode and configured to deliver a pulse waveform to target and ablate tissue. In some embodiments, the set of electrodes (530) may have a gap (532) between the electrodes configured to create adjacent ablation lesions, such as a target in the left atrium and a lesion surrounding a pulmonary vein. In some embodiments, the ratio of the gap (532) between consecutive electrodes (530) to the longitudinal length of each electrode may be less than about 3:1, or less than about 2:1.

[0085] Protection Devices

[0111] Generally, systems and devices configured for suppressing induced currents in connection with tissue ablation may include a protection device coupled between a first electronic device (e.g., a pacing device) and a second electronic device (e.g., a protected apparatus). The protection device configured to suppress voltages and currents induced in the first electronic device, as described in more detail herein. The induced currents may include one or more of a common mode current and a differential mode current. In some embodiments, the protection device may include one or more transformers and capacitors configured to suppress the induced currents and one or more diodes configured to shunt the induced voltages. In some embodiments, the protection device may include one or more inductors configured to suppress alternating currents induced in the first electronic device over a set of predetermined frequency ranges. In some embodiments, the protection device may include one or more balun circuits configured to suppress common mode currents induced in the first electronic device over a set of predetermined frequency ranges. In some embodiments, the protection device may be formed separately from the apparatus and the pacing device. In some embodiments, one or more protection devices may be formed integrally with one or more of the apparatus and the pacing device.

[0086]

[0112] 13 is a block diagram illustrating an ablation system (1300) including a protection device (1314) (e.g., a filter box) according to some embodiments. In some embodiments, the ablation system (1300) may include a signal generator (1309), a cardiac stimulator (1303), an interface device (1305), a protection device (1314), pacing electrode leads (1317, 1318) in a pacing device (1320), and an electrical ablation lead (1311) coupled to an ablation device (e.g., an ablation catheter) (1330). The signal generator (1309) and the cardiac stimulator (1303) may be structurally and functionally similar to the signal generator (1250) and the cardiac stimulator (1260), respectively, described with respect to FIG. 12. The cardiac stimulation device (1303) may be configured to generate and deliver a pacing signal to the pacing device (1320) via the interface device (1305), the protection device (1314), and the leads (1317, 1318). The pacing signal may be further delivered to the signal generator (1309) via the interface device (1305). The interface device (1305) may be configured to enable a connection between two or more of the cardiac stimulation device (1303), the one or more pacing devices (1320), the signal generator (1309), and the ablation device(s) (1330). For example, connectors such as wired connectors (e.g., cables several meters long) may be used to enable convenient and adaptable placement of the system components within a space such as a clinical operating room. In some embodiments, the signal generator (1309) may be configured to generate a voltage pulse waveform in synchronization with an indication of the pacing signal (e.g., within a common refractory window). A signal generator (1309) may deliver a voltage pulse waveform via an ablation lead (1311) (eg, a cable) to an ablation device (1330) to ablate tissue.

[0087]

[0113] As the signal generator (1309) delivers the voltage pulse waveform to the ablation device (1330), the cardiac simulator (1303) may deliver a pacing signal to the pacing device (1320). However, due to the proximity of the pacing device (132) to the voltage pulse waveform applied to the tissue, currents may be induced in the pacing device leads (1317, 1318). These imbalance currents may span a range of frequencies and affect the operation of one or more components of the system, such as the cardiac stimulation device (1303) and the signal generator (1309). The induced voltages and currents from the pacing device (1320) may interfere with the operation of the cardiac stimulation device (1303), such that the signal generator (1309) does not receive a proper pacing signal from the cardiac stimulation device (1303). Thus, operation of the signal generator (1309) may be disrupted, resulting in errors and interruptions in ablation energy delivery. As described in more detail herein, protective devices may be configured to suppress the propagation of induced currents and voltages within the system.

[0088]

[0114] 14 is a block diagram illustrating an ablation system (1400) including an interface device integrated with a protection device (1407) in the same enclosure (e.g., housing) and a cardiac simulator (1408) integrated with a signal generator (1405) in the same enclosure. A pacing signal may be generated by the integrated signal generator (1405) and cardiac simulator (1408) and delivered to a pacing device (1430) via pacing device leads (1417, 1418). The combined interface device and protection device (1407) may be configured to inhibit (or reduce) currents induced in the pacing device leads (1417, 1418).

[0089]

[0115] In some embodiments, one or more electrode channels (1421, 1422) on the intracardiac device (1432) may be used as sensing channels for ECG analysis. An incoming ECG signal received from the patient via the electrode channels (1421, 1422) may be filtered by a combined interface and protection device (1407) before being delivered via the leads (1411, 1412) to the signal generator (1405) for ECG analysis. In some embodiments, the ECG signal may also be delivered through the leads (1401, 1402) to an ECG recording system (1440) and / or other external devices (e.g., sensing and / or mapping systems). The signal generator (1405) may deliver a voltage pulse waveform via a cable (1409) to an ablation device (1450) to ablate tissue.

[0090]

[0116] In some embodiments, one or more of the interface device (e.g., interface (1305)), protection device (e.g., protection device (1314)), or interface and protection device (e.g., interface and protection device (1407)) can be integrated into the cardiac stimulating device and / or the signal generator (e.g., cardiac stimulating device (1303), signal generator (1309), or cardiac stimulating device (1408) and signal generator (1405)). For example, in an alternative arrangement, the protection device can be integrated into the signal generator, which is then connected to and / or integrated into the cardiac stimulating device, such that induced currents from the pacing device leads can be suppressed (e.g., filtered) by the protection device before reaching the cardiac stimulating device.

[0091]

[0117] FIG. 15 is a circuit diagram of a protection circuit (1500) configured to suppress common mode currents in a transformer as described below, according to an embodiment. The protection circuit (1500) may be configured to suppress large voltages and common mode currents induced in the pacing device leads (1509, 1510) by pulse waveforms generated by a signal generator (not shown in FIG. 15). In addition to suppressing common mode currents, the protection circuit may be configured in common-differential mode (as described with respect to FIG. 18) and adjustable mode (as described with respect to FIGS. 20A-24). The protection circuit (1500) may include a first common mode transformer L2 (1507), a second common mode transformer L1 (1505), a first capacitor C1 (1502), a second capacitor C2 (1504), and first and second Zener diodes (1513, 1514). In some embodiments, the first diode D1 (1513) and the second diode D2 (1514) may be configured to shunt induced voltages away from the second electronic device (e.g., the cardiac stimulating device (1501)). The second capacitor C2 (1504) may short relatively high frequencies across the pacing device leads (1509, 1510) to suppress induced currents from flowing in the pacing device leads (1509, 1510). The first common mode transformer (1507) and the second common mode transformer (1505) may be configured to suppress common mode currents in the pacing device leads (1509, 1510) as high impedance elements for common mode currents. A first capacitor C1 (1502) may short out above a predetermined frequency (higher than the lower end of the band-stop range) across the pacing device leads (1509, 1510) to inhibit induced currents from flowing in the pacing device leads (1509, 1510).

[0092]

[0118] The signal generator may be structurally and / or functionally similar to the signal generator (1309) described with respect to Figure 13 or the signal generator (1405) described with respect to Figure 14. The protection circuit (1500) may be configured to be coupled to the cardiac simulator (1501) and the pacing device leads (1509, 1510). The pacing device leads (1509, 1510) may be included in a pacing device that may be introduced into a heart chamber of the patient (1503). The cardiac stimulator (1501) may be configured to generate a cardiac pacing signal that is delivered to the patient (1503).

[0093]

[0119] FIG. 16 shows an embodiment of the first common mode transformer L2 (1507) and the second common mode transformer L1 (1505). As shown in FIG. 16, the common mode transformer (1600) may include a toroid core (1608), a first winding (1601, 1611), and a second winding (1602, 1612). The toroid core (1608) may be annular and may include or be a soft magnetic material (e.g., iron) having high magnetic permeability. The toroid core (1608) may be selected to have a structure with relatively wide laminations (e.g., a set of laminations, each of which has a cross-section with an aspect ratio of 5 or less) to accommodate losses in the core (1608). The first winding (1601 to 1611) and the second winding (1602 to 1612) are wound around the body of the core (1608) in the same direction, while the first winding (1601 to 1611) is wound around the circumference of the core (1608) in a first direction (e.g., counterclockwise as shown in FIG. 16) and the second winding (1602 to 1612) is wound around the circumference of the core (1608) in a second direction opposite to the first direction (e.g., clockwise as shown in FIG. 16).

[0094]

[0120] In some embodiments, the outer radius of the core (1608) may be between about 4 cm and about 10 cm, and the inner radius of the core (1608) may be between about 2 cm and about 9 cm, including all values ​​and subranges therebetween. In some embodiments, the thickness of the core (1608) may be between about 1 cm and about 6 cm. In some examples, the number of turns (e.g., bends) on each winding (1601, 1602) may be between about 3 and about 50, including all values ​​and subranges therebetween.

[0095]

[0121] In some embodiments, a common mode current having a non-zero frequency may flow from the leads 1601 and 1602 at the ends of the toroid in parallel directions through the first winding (1601 to 1611) and the second winding (1602 to 1612) such that a first magnetic field generated by a current through the first winding (1601 to 1611) and a second magnetic field generated by a current through the second winding (1602 to 1612) may have equal strength in the same direction (1615). In other words, when a common mode current flows through the first and second windings, the common mode transformer (1600) may generate a magnetic field in a single circumferential direction (i.e., either parallel or anti-parallel to the arrow 1615). Equal strength and in-phase magnetic fields may add together, resulting in a high impedance to the common mode current, which passes through the common mode transformer (1600) significantly weakened. For example, the suppression of common mode power may be at least about 15 dB over a frequency band between about 100 kHz and about 10 MHz, including all values ​​and subranges therebetween. In some embodiments, the suppression may be 20 dB, 25 dB, or more. The impedance to the common mode current may further include a real component (e.g., due to resistive core losses) in addition to an imaginary component (e.g., due to high inductance of the core windings). The actual attenuation (e.g., common mode rejection) depends on the relative strengths of the transformer impedance and the load impedance. Thus, the common mode transformer (1600) may be configured to have an inductance of at least about 1 millihenry and an effective resistance of at least about 500 ohms. In other words, this impedance may act to suppress, reduce, or minimize the strength of the common mode current.

[0096]

[0122] Returning to Fig. 15, the first common mode transformer (1507) and the second common mode transformer (1505) may be configured as high impedance elements for common mode currents to suppress common mode currents in the leads. As shown in Fig. 15, the first common mode transformer (1507) may be positioned between the pacing device leads (1509, 1510) of the first electronic device (1503) (e.g., a pacing device) and the first capacitor C1 (1502). The first capacitor C1 (1502) may be used as a low impedance capacitor for frequencies greater than the lower end of the desired band-stop range (e.g., 0.5 MHz or greater). Therefore, the first capacitor C1 (1502) may short out relatively high frequencies (higher than the lower end of the band-stop range) across the pacing device leads (1509, 1510) and inhibit induced currents from flowing in the pacing device leads (1509, 1510).

[0097]

[0123] As shown in FIG. 15, a second common mode transformer (1505) may be positioned between the first capacitor C1 (1502) and the second capacitor C2 (1504). Similar to the second common mode transformer (1507), the first common mode transformer (1505) may be configured to generate a high impedance and therefore suppress, reduce, or minimize the magnitude of common mode currents. Similar to the first capacitor C1 (1502), the second capacitor C2 (1504) may shunt relatively high frequencies (e.g., voltages having frequencies above a predetermined threshold) across the pacing device leads (1509, 1510) and suppress induced currents from flowing in the pacing device leads (1509, 1510).

[0098]

[0124] The first and second diodes D1 (1513) and D2 (1514) are diodes (e.g., Zener diodes) configured to allow current to flow not only from its anode to its cathode but also in the reverse direction when a predetermined voltage (e.g., Zener voltage) is reached. The first and second diodes D1 (1513) and D2 (1514) are configured to protect the circuit from overvoltage. For example, the first and second diodes D1 (1513) and D2 (1514) may be configured to shunt high voltages away from the second electronic device (e.g., the cardiac stimulating device (1501)).

[0099]

[0125] FIG. 17 shows a circuit diagram of a protection circuit (1700) in an unconditioned common mode fashion. Similar to the protection circuit (1500) of FIG. 15, the protection circuit (1700) may be configured to suppress common mode currents and induced voltages induced in the pacing device leads (1727, 1728) by pulse waveforms generated by a signal generator (not shown in FIG. 17). Inductors (1724, 1725) (e.g., chokes) may add an additional measure of high current suppression, whether common mode or differential mode. Furthermore, in addition to the unconditioned common mode, the protection circuit may also include circuitry that operates in an unconditioned common-differential mode (as described with respect to FIG. 18) and an adjustable mode (as described with respect to FIGS. 20A-24).

[0100]

[0126] The signal generator may be structurally and / or functionally similar to the signal generator (1309) described with respect to Figure 13 or the signal generator (1405) described with respect to Figure 14. The protection circuit (1700) may be configured to be coupled to a second electronic device (e.g., a cardiac simulator (1701)) and to the pacing device leads (1727, 1728). The pacing device leads (1727, 1728) may be included within a first electronic device (e.g., a pacing device) (1722), which may be introduced into a cardiac chamber of the patient. The second electronic device (e.g., a cardiac stimulator (1701)) may be configured to generate a cardiac pacing signal that is delivered to the patient (1722). The protection circuit (1700) may include a first common mode transformer L2 (1718), a second common mode transformer L1 (1717), a first capacitor C1 (1702), a second capacitor C2 (1704), first and second diodes (1713, 1714), and first and second inductors (e.g., chokes) (1724, 1725).

[0101]

[0127] The first common mode transformer L2 (1718), the second common mode transformer L1 (1717), the first capacitor C1 (1702), the second capacitor C2 (1704), and the first and second diodes (1713, 1714) may be similar in structure and / or function to the first common mode transformer L2 (1507), the second common mode transformer L1 (1505), the first capacitor C1 (1502), the second capacitor C2 (1504), and the first and second diodes (1513, 1514), respectively, described with respect to Figure 15. The first common mode transformer (1718) and the second common mode transformer (1717) may be configured as high impedance elements for common mode currents to suppress common mode currents induced in the leads (1727, 1728). A first capacitor C1 (1702) and a second capacitor C2 (1704) may short relatively high frequencies (higher than the lower end of the band-stop range) across the pacing device leads (1727, 1728) to inhibit induced currents from flowing in the pacing device leads (1727, 1728). First and second diodes D1 (1713) and D2 (1714) may be configured to shunt high voltages away from the second electronic device (e.g., the cardiac stimulating device (1701)).

[0102]

[0128] The first and second inductors (1724, 1725) may be configured to block or suppress induced higher frequency alternating current (AC) while passing lower frequency current and / or direct current (DC). In some examples, the first and second inductors (1724, 1725) may be configured to suppress induced currents for frequencies corresponding to the lower or upper ends of a predetermined band rejection range. In some examples, the first inductor (1724) may be coupled to a first pacing device lead (1727) and the second inductor (1725) may be coupled to a second pacing device lead (1728).

[0103]

[0129] Figure 18 shows a circuit diagram of an unconditioned common-differential mode protection circuit (1800). Similar to the protection circuit (1500) of Figure 15, the protection circuit (1800) may be configured to suppress induced differential mode currents as well as common mode currents and induced voltages induced in the pacing device leads (1841, 1842) by pulse waveforms generated by a signal generator (not shown in Figure 18). In general, the protection circuit may operate in an unconditioned common mode (as described with respect to Figures 15 and 17), an unconditioned common-differential mode (as described herein with respect to Figure 18), and / or an adjustable mode (as described with respect to Figures 20A-24).

[0104]

[0130] The signal generator may be structurally and / or functionally similar to the signal generator (1309) described with respect to Fig. 13 or the signal generator (1405) described with respect to Fig. 14. The protection circuit (1800) may be configured to be coupled to a second electronic device (e.g., a cardiac simulator (1830)) and the first and second pacing device leads (1841, 1842). The first and second pacing device leads (1841, 1842) may be included within a first electronic device (1831) (e.g., a pacing device) that may be introduced into a heart chamber of a patient. The second electronic device (1830) (e.g., a cardiac stimulator) may be configured to generate a cardiac pacing signal that is delivered to the patient. The protection circuit (1800) may include a first differential mode transformer L3 (1834), a second common mode transformer L4 (1833), a first capacitor C4 (1802), a second capacitor C3 (1804), and first and second Zener diodes (1837, 1838).

[0105]

[0131] The first differential mode transformer L3 (1834) is described with respect to FIG. 19. As shown in FIG. 19, the differential mode transformer (1900) includes a toroid core (1908), a first winding (1901, 1911), and a second winding (1902, 1912). The toroid core (1908) may include and / or be constructed of a soft magnetic material (e.g., iron) that is annular and has high magnetic permeability. The toroid core (1908) may be selected to have a structure with relatively wide laminations to accommodate losses in the core (1908). The first winding (1901, 1911) may be wound around the body of the core (1908) in a first direction, and the second winding (1902, 1912) may be wound around the body of the core (1908) in a second direction opposite the first direction. A first winding (1901, 1911) may be wound around the circumference of the core (1908) in a first direction (e.g., counterclockwise as shown in FIG. 19), and a second winding (1902, 1912) may be wound around the circumference of the core (1908) also in a first direction (e.g., counterclockwise). Similar to the toroid core (1608) in the common mode transformer (1600) of FIG. 16, in some examples, the outer radius of the core (1908) may be between about 4 cm and about 10 cm, and the inner radius of the core (1908) may be between about 2 cm and about 9 cm. In some examples, the thickness of the core (1908) may be between about 1 cm and about 6 cm. In some examples, the number of turns / turns on each winding (1901, 1902) may be between about 3 and about 50.

[0106]

[0132] A differential mode current with a non-zero frequency flowing through the first windings (1901, 1911) in a first direction (e.g., from left to right in FIG. 19) may generate a first magnetic field in the core (1908) in a first direction indicated by the arrow (1915). In this differential mode, a current flowing through the second windings (1902, 1912) in a second direction opposite the first direction (e.g., from right to left in FIG. 19) generates a second magnetic field in the same direction (1914). The strengths of the first and second magnetic fields may be similar or equal. In other words, the winding configuration of the differential mode transformer (1900) allows currents flowing in opposite directions through the first winding (1901, 1911) and the second winding (1902, 1912) (e.g., differential mode currents) to induce magnetic fields in the toroid core (1908) that point in the same direction (1914, 1915). These in-phase magnetic fields may add up to provide a high impedance to the differential mode currents flowing through the coupled pacing device leads (e.g., 1841, 1842 in FIG. 18). The impedance to the differential mode currents may further include a real component (e.g., due to resistive core losses) in addition to an imaginary component (e.g., due to high inductance of the core windings). This high impedance of the differential mode transformer (1900) may act to suppress, reduce, or minimize the magnitude of the differential mode currents through the set of pacing device leads. In some embodiments, the combination of differential mode transformer L3 (1834) and common mode transformer L4 (1833) may be configured to suppress induced common mode currents and induced differential mode currents at a predetermined band-stop frequency range.

[0107]

[0133] Returning to Figure 18, the common mode transformer L4 (1833), the first capacitor C4 (1802), the second capacitor C3 (1804), and the first and second diodes (1837, 1838) are similar in structure and / or function to the second common mode transformer L1 (1505), the first capacitor C1 (1502), the second capacitor C2 (1504), and the first and second diodes (1513, 1514), respectively, described with respect to Figure 15. The common mode transformer L4 (1833) may be configured as a high impedance element for common mode currents to suppress common mode currents in the leads. A first capacitor C4 (1802) and a second capacitor C3 (1804) may short relatively high frequencies (higher than the lower end of the band-stop range) across the pacing device leads (1841, 1842) to inhibit induced currents from flowing in the pacing device leads (1841, 1842). First and second diodes D3 (1837) and D4 (1838) may be configured to shunt high voltages away from the second electronic device (e.g., the cardiac stimulating device (1830)).

[0108]

[0134] 20A-20B show circuit diagrams of a protection device including an adjustable circuit (2020) (e.g., a balun circuit). The balun circuit (2020) may be configured to join a balanced line (e.g., two conductors with equal currents in opposite directions) to an unbalanced line (e.g., one conductor and a ground coaxial cable). The balun circuit (2020) may be configured to convert an unbalanced signal to a balanced signal by suppressing common mode currents. In some embodiments, the balun circuit (2020) may be configured to provide impedance transformation in addition to converting between balanced and unbalanced signal modes. The balun circuit (2020) may be implemented in any of the protection devices described herein (e.g., described with respect to FIGS. 15, 17, and 18).

[0109]

[0135] As shown in FIG. 20A, in some embodiments, a balun circuit (2020) may be coupled to first and second inductors (e.g., chokes) (2003, 2004). The first and second inductors (2003, 2004) may be configured to suppress large currents for frequencies corresponding to the lower or upper ends of a predetermined band-rejection range. In some embodiments, the first inductor (2003) may be coupled to a first pacing device lead (2001) and the second inductor (2004) may be coupled to a second pacing device lead (2002). The pacing device leads (2001, 2002) may be coupled to a first electronic device (not shown) that is introduced into a patient's heart chamber. The balun circuit (2020) may be coupled to a second electronic device (e.g., a cardiac stimulator) (not shown) via third and fourth leads (2011, 2012).

[0110]

[0136] In some embodiments, the balun circuit (2020) may include a coaxial cable (2009) formed into a coaxial winding (2016) having a center conductor (configured to carry a signal) connected to a first lead (2001) at a first contact (2006) and a shield conductor (configured to connect to electrical ground) connected to a second lead (2002) at a second contact (2007). A capacitor (2014) connected in series with a resistor (2015) may be coupled in parallel across the length of the coaxial cable (2009) at the second contact (2007) and the third contact (2018) (i.e., the capacitor (2014) and resistor (2015) may be connected to the shield conductor of the coaxial cable (2009) at the second contact (2007) and the third contact (2018). The coaxial cable (2009) may be coupled to the third and fourth leads (2011, 2012).

[0111]

[0137] FIG. 20B shows a circuit diagram (2050) equivalent to the adjustable balun circuit (2020) of FIG. 20A. As shown in FIG. 20B, the coaxial shield conductor of the coaxial winding (2016) is represented by an equivalent inductor (2051). The inductor (2051) may be coupled in parallel with a series connected capacitor (2053) and resistor (2052). The capacitor (2053) may be configured to resonate with the inductor (2051). For example, a vector network analyzer may be configured to select a capacitance value for the capacitor (2053). The resistance value of the resistor (2052) may be selected to configure the width and height of the resonant peak as described in more detail with respect to FIGS. 21, 23, and 24.

[0112]

[0138] FIG. 21 is a schematic diagram of a resonant peak obtained using an adjustable circuit (e.g., a balun circuit). The balun circuit can be similar in structure and / or function to the balun circuit (2020) described with respect to FIG. 20A. When power is transmitted through the shield of a coaxial winding, the ratio of power transmitted through the shield of the winding (P r ) may be measured, for example, with a network analyzer. The plot in FIG. 21 shows the transmit power (P r ) (2102). Resonance occurs at a frequency f 0 (2171) has a peak (2170), and the peak has a height A m (2175) is f 0 The resonant frequency f 0 (2171) may be adjusted by selecting a capacitance value of a capacitor (e.g., capacitor (2014) in FIG. 20A) of an adjustable circuit. In some examples, the circuit may be configured for high power attenuation. The broadening of the resonant peak (2173), may be measured, for example, by the full width of the resonant peak at half height (2173), and may be adjusted by the resistance value of a resistor (e.g., resistor (2015) in FIG. 20A). In some examples, increasing the resistance value increases the broadening (2173) and decreases the height (2175) of the resonant peak.

[0113]

[0139] 22 is a schematic diagram of a set of adjustable circuits (e.g., a set of balun circuits). Each adjustable balun circuit in the set of adjustable circuits (2205, 2206, 2207) may be structurally and / or functionally similar to the adjustable circuit (2020) as described with respect to FIG. 20A. The set of adjustable circuits (2205, 2206, 2207) may be collectively configured as a wideband common mode suppression circuit in a protection device.

[0114]

[0140] In some embodiments, a set of adjustable circuits (2205, 2206, 2207) may be coupled to first and second inductors (e.g., chokes) (2221, 2223). The first and second inductors (2221, 2223) may be configured to suppress induced currents for frequencies corresponding to the lower or upper ends of a predetermined band-rejection range. For example, the first inductor (2221) may be coupled to a first pacing device lead (2201) and the second inductor (2223) may be coupled to a second pacing device lead (2203). The first and second pacing device leads (2201, 2203) may be coupled to a first electronic device (e.g., a pacing device) that is introduced into a heart chamber of a patient. The set of adjustable circuits (2205, 2206, 2207) may be interconnected by respective coaxial lines (2209, 2210) and configured to attenuate common mode currents over a set of predetermined frequency ranges. Each adjustable circuit in the set of adjustable circuits (2205, 2206, 2207) may be configured for a different frequency range such that the frequency response curves overlap (as described with respect to FIG. 23). Thus, the set of adjustable circuits (2205, 2206, 2207) may provide attenuation over the overlapping frequency ranges to suppress common mode currents over a predetermined range of frequencies. The other end of the set of adjustable circuits (2205, 2206, 2207) may be coupled to a second electronic device (e.g., a cardiac stimulating device) via third and fourth inductors (2227, 2229). The third and fourth inductors (2227, 2229) may be configured to suppress currents corresponding to frequencies at the lower or upper ends of a predetermined band-stop range.

[0115]

[0141] 23 is a schematic diagram of a set of resonant peaks for each tunable circuit of a set of tunable circuits (e.g., the set of tunable circuits (2205, 2206, 2207) of FIG. 22) according to an embodiment. r) is transmitted through the coaxial winding and may be measured, for example, with a network analyzer. The plot in FIG. 23 shows the transmit power (P r ) as a logarithmic function (2302). Figure 23 illustrates the resonant peaks (2305, 2306, 2307) of each tunable circuit in a set of tunable circuits (e.g., the set of tunable circuits (2205, 2206, 2207) of Figure 22). For example, each tunable circuit in the set of tunable circuits (2205, 2206, 2207) may be configured to have overlapping frequency response curves.

[0116]

[0142] FIG. 24 is a schematic diagram of common mode current suppression by a set of adjustable circuits (e.g., the set of adjustable circuits (2205, 2206, 2207) of FIG. 22). The set of adjustable circuits (e.g., the set of adjustable balun circuits (2205, 2206, 2207) of FIG. 22) may have overlapping resonant frequencies as described with respect to FIG. 23. FIG. 24 shows the net resonant peak (2403) from the set of adjustable circuits. Similar to FIG. 23, the plot in FIG. 24 shows a logarithmic function (2402) of transmit power (Pr) as a function of frequency f (2401). The net effect of the set of adjustable circuits may be broadband suppression over a range of frequencies (2409) from overlapping frequency ranges. method

[0117]

[0143] Also described in this section are methods for protecting electronic circuitry from induced currents during tissue ablation processes performed in a heart chamber using the systems and devices described herein. The heart chamber may be a left atrial chamber and may include associated pulmonary veins. Generally, the methods described herein include introducing and placing a pacing device (e.g., pacing device (160), pacing device (1207)) in contact with one or more heart chambers. The pacing device may transmit pacing signals to the heart using a cardiac stimulator (e.g., cardiac stimulator (150)) and / or measure cardiac activity. An ablation device (140, 1212) may be introduced and placed in contact with an ostium or sinus region of one or more pulmonary veins. A pulse waveform may be delivered by one or more electrodes (e.g., electrode (1213)) of the ablation device to ablate tissue. The pacing device may be electrically coupled to the system and configured to deliver pacing signals to the heart and / or measure cardiac activity. In some embodiments, the protection device may suppress induced currents and voltages from the first electronic device.

[0118]

[0144] Additionally or alternatively, the pulse waveform may include multiple levels of hierarchy to reduce total energy delivery, for example, as described in International Application No. PCT / US2016 / 057664, filed October 19, 2016, entitled "Systems, apparatuses and methods for delivery of ablative energy to tissue," incorporated herein by reference. Such tissue ablation may be delivered synchronously with the paced heartbeat to reduce the risk of atrial and / or ventricular fibrillation, as well as damage to healthy tissue. It should be understood that any of the ablation devices described herein (e.g., ablation device (140), ablation device (1212)) may be used to ablate tissue, optionally using the methods discussed below.

[0119]

[0145] In some embodiments, the ablation devices described herein (e.g., ablation device (140), ablation device (1212)) may be used for local ablation of cardiac features / structures identified as causing arrhythmias (e.g., fibrillation). For example, a cardiac electrophysiology diagnostic catheter (e.g., a mapping catheter) may be used to map areas causing arrhythmias that may then be ablated by local ablation using any of the ablation devices described herein. Local ablation may create, for example, point-like lesions that neutralize rotors while sparing surrounding tissue. In some embodiments, one or more local ablation lesions may be created in combination with one or more box-shaped or linear lesions to treat arrhythmias. As a non-limiting example, in some embodiments, a system may include one or more mapping catheters and one or more ablation devices (e.g., ablation device (140), ablation device (1212)) useful for creating lesions by local ablation. Examples of suitable local ablation catheters are described in International Application No. PCT / US2019 / 014226, which is incorporated herein by reference.

[0120]

[0146] FIG. 25 is an example method (2500) of tissue ablation. In some embodiments, the voltage pulse waveforms described herein may be applied during a refractory period of the cardiac cycle to avoid disrupting the sinus rhythm of the heart. The method (2500) includes introducing (2502) a pacing device (e.g., pacing device (160, 1207)) into the endocardial space of the right ventricle. At (2504), the pacing device may be advanced to be placed in contact with the right ventricle. For example, a sensor electrode may be configured for measuring cardiac activity (e.g., ECG signals) and a pacing electrode may be configured for transmitting pacing signals and may be placed in contact with an inner surface of the right ventricle. At (2506), an ablation device (e.g., ablation device (140, 1212)) may be introduced into the endocardial space of the left atrium. At (2508), the ablation device may be advanced to be placed in contact with a pulmonary vein ostium. In one non-limiting example, electrodes of the ablation device may form an approximately circular array of electrodes positioned in contact with the inner diameter surface at the ostium of the pulmonary vein. In some embodiments, a pacing signal may be generated (2510) by a cardiac stimulator (e.g., cardiac stimulator (150, 1260)) for cardiac stimulation of the heart. The pacing signal may then be applied (2512) to the heart using pacing electrodes of a pacing device. For example, the heart may be electrically paced with the pacing signal to ensure pacing capture, such as to establish periodicity and predictability of the cardiac cycle. One or more of atrial and ventricular pacing may be applied. Examples of pacing signals applied to the patient's cardiac activity are described in more detail herein.

[0121]

[0147] In some embodiments, pacing capture may be confirmed automatically by one or more of the signal generator, the processor (e.g., the signal generators (110, 1250)) and by a user. For example, a user may confirm pacing capture using a user interface (e.g., an input / output device, such as a touch panel monitor or other type of monitor) based on a measured cardiac activity signal. If the signal generator, the processor, and / or a user viewing a displayed cardiac output determine that there is no pacing capture, generation of the pulse waveform may be withheld and the user may be prompted to adjust system parameters, for example, by repositioning the pacing device to improve tissue engagement and / or modifying parameters of the pacing signal (e.g., pulse width, pulse amplitude, pulse frequency, etc.).

[0122]

[0148] In some embodiments, at 2514, the pacing device may further measure cardiac activity corresponding to the cardiac electrical activity (e.g., an ECG signal). For example, the measured cardiac activity may include measured cardiac pacing pulses, R-waves, and high-voltage signals. One or more of the measured cardiac activity parameters may be used to generate a protection signal.

[0123]

[0149] At (2516), the generated pulse waveform may be delivered to tissue for ablation. In some embodiments, a refractory period may follow the pacing signal. For example, a common refractory period may be between both the atrium and the ventricle's refractory time windows. The voltage pulse waveform may be applied during the common refractory period. In some embodiments, the pulse waveform may be generated with a time offset relative to an index of the pacing signal. For example, the onset of the refractory period may be offset from the pacing signal by the time offset. The voltage pulse waveform(s) may be applied to a series of heartbeats over the corresponding common refractory period.

[0124]

[0150] At (2518), the currents and voltages induced in the pacing device are inhibited from the electronic device by a protective device, e.g., the protective device inhibits the induced currents and voltages from coupling to the cardiac stimulating device and / or other components coupled to the protective device.

[0125]

[0151] In some embodiments, hierarchical voltage pulse waveforms with nested structures and time interval hierarchies as described herein may be useful for irreversible electroporation and provide control and selectivity in different tissue types. FIG. 26 is a flow chart (2600) of another example method of a tissue ablation process. The method (2600) includes the introduction of a device (e.g., ablation device (140, 1212)) into the endocardial space of the left atrium at (2602). At (264), the device may be advanced to be positioned at the ostium of a pulmonary vein. In embodiments where the device may include first and second configurations (e.g., compact and expanded), at (2606), the device may be introduced in a first configuration and transformed to a second configuration to contact tissue at or near the pulmonary vein antrum or ostium. At (2608), the device may include electrodes and may be configured in an anode-cathode subset, as discussed in detail above. For example, a subset of the electrodes of the device may be selected as anodes, while another subset of the electrodes of the device may be selected as cathodes, and a voltage pulse waveform is applied between the anodes and cathodes.

[0126]

[0152] At (2660), the pulse waveform may be generated by a signal generator (e.g., signal generator (110)) and may include multiple levels in a hierarchy. Various hierarchical waveforms may be generated by a signal generator as disclosed herein. For example, a pulse waveform may include a first level of a hierarchy of pulse waveforms including a first set of pulses, each pulse having a pulse duration and a first time interval separating successive pulses. A second level of the hierarchy of pulse waveforms may include a plurality of the first set of pulses as the second set of pulses. The successive first set of pulses may be separated by a second time interval. The second time interval may be at least three times as long as the first time interval. A third level of the hierarchy of pulse waveforms may include a plurality of a second set of pulses as the third set of pulses. The successive second set of pulses may be separated by a third time interval. The third time interval may be at least 30 times as long as the time interval of the second level. At (2612), a pulse waveform generated by a signal generator (eg, signal generator (110)) may be delivered to tissue using an ablation device.

[0127]

[0153] Although the examples herein identify separate monophasic and biphasic waveforms, it is understood that combination waveforms may of course also be generated, in which some portions of the waveform hierarchy are monophasic while other portions are biphasic. Voltage pulse waveforms having a hierarchical structure may be applied (optionally with time delays) across different anode-cathode subsets. As described above, one or more of the waveforms applied across the anode-cathode subsets may be applied during the refractory period of the cardiac cycle. The pulse waveforms may be delivered to tissue. It should be understood that the steps described in Figures 25 and 26 may be combined and modified as necessary.

[0128]

[0154] In some embodiments, a pulse waveform may be delivered to the ostium of a patient's pulmonary veins via a set of splines of the ablation device. In some embodiments, a voltage pulse waveform as described herein may be selectively delivered to a subset of electrodes, such as an anode-cathode subset, for ablation and isolation of pulmonary veins. For example, a first electrode of a group of electrodes may be configured as an anode and a second electrode of a group of electrodes may be configured as a cathode. These steps may be repeated for a desired number of ostium or sinus regions of the pulmonary veins being ablated (e.g., 1, 2, 3, or 4 ostia). Suitable examples of ablation devices and methods are described in International Application No. PCT / US2019 / 014226.

[0129]

[0155] FIG. 6 is a method (600) for one embodiment of a signal generation process using the systems and devices described herein. The method (600) includes controlling (602) the state of a first and second electronic switch of a first electrode channel. For example, (602) may control the state of the first electronic switch (220) and the second electronic switch (230) of the first electrode channel (201) shown in FIG. 2. In some embodiments, a drive circuit (e.g., drive circuit (222, 232)) coupled to the electronic switch may be configured to control the state of the electronic switch. In some embodiments, the electronic switch may be configured to switch between an on state and an off state using the drive circuit. At (604), the first electrode channel may be configured as an anode. The state of the first and second electronic switches of the second electrode channel may be controlled (606), for example, by the drive circuit controlling the on / off state of the respective electronic switch. At (608), the second electrode channel may be configured as a cathode.

[0130]

[0156] In some embodiments, hierarchical voltage pulse waveforms with nesting and time interval hierarchies as described herein may be useful for irreversible electroporation as well as provide control and selectivity in different tissue types. In some embodiments, at (610), a first pulse waveform may be generated having a set of hierarchical levels. In some embodiments, a first level of the hierarchy of the first pulse waveform may include a first set of pulses, each pulse having a pulse duration. A first time interval may separate successive pulses. A second level of the hierarchy of the first pulse waveform may include a set of the first set of pulses as a second set of pulses, with a second time interval separating successive first set of pulses. The second time interval may be at least three times as long as the first time interval. A third level of the hierarchy of pulse waveforms may include a set of the second set of pulses as a third set of pulses, with a third time interval separating successive second set of pulses. The third time interval may be at least 30 times as long as the time interval of the second level. At (612), the energy source may deliver a first pulse waveform via the first electrode channel and the second electrode channel to the set of electrodes in use. The first pulse waveform may be delivered at a first time.

[0131]

[0157] At a second time after the first time, a state of the first and second electronic switches of the first electrode channel may be controlled at (614). The first electrode channel may be configured as a cathode at (616). A state of the first and second electronic switches of the second electrode channel may be controlled at (618). The second electrode channel may be configured as an anode at (620). In some embodiments, a second pulse waveform may be generated at (622) having a set of levels of a hierarchy, such as including the first, second, and third hierarchical levels described herein. An energy source may deliver the second pulse waveform at (624) via the first and second electrode channels to the set of electrodes in use at a second time. Pulse Waveform

[0132]

[0158] Disclosed herein are methods, systems, and devices for selectively and rapidly applying pulsed electric fields / waveforms to effect tissue ablation by irreversible electroporation. The pulsed waveform(s) disclosed herein are useful with any of the systems (100, 200, 300), ablation devices (e.g., 140, 400, 500), and methods (e.g., 600) described herein. Some embodiments are directed to pulsed high voltage waveforms with sequenced delivery schemes for delivering energy to tissue via a set of electrodes. In some embodiments, peak electric field values ​​may be reduced and / or minimized while at the same time maintaining a sufficiently high electric field strength in the area where tissue ablation is desired. This also reduces the likelihood of excessive tissue damage or electrical arcing and localized elevated temperatures. In some embodiments, a system useful for irreversible electroporation may include a signal generator that can be configured to deliver a pulsed voltage waveform to a set of electrodes of an ablation device. In some embodiments, the signal generator processor is configured to control a set of electrode channels whereby selected pairs of the anode-cathode subset of electrodes may be triggered sequentially based on a predefined sequence, in one embodiment, sequenced delivery may be triggered from the cardiac stimulator and / or pacing device. In some embodiments, the ablation pulse waveform may be applied during a refractory period of the cardiac cycle to avoid disrupting the sinus rhythm of the heart. One exemplary way to implement this is to electrically pace the heart with a cardiac stimulator (e.g., cardiac stimulator (150)), ensure pacing capture so as to establish periodicity and predictability of the cardiac cycle, and then clearly define a time window within the refractory period of this cardiac cycle during which the ablation waveform is delivered.

[0133]

[0159] In some embodiments, the pulse voltage waveforms disclosed herein are hierarchical and nested in structure. In some embodiments, the pulse waveforms include hierarchical groups of pulses with various associated time scales. Pulse waveforms for electroporation energy delivery as disclosed herein may increase the safety, efficiency, and effectiveness of energy delivery by lowering the electric field threshold associated with irreversible electroporation, resulting in more effective ablation lesions while delivering reduced total energy. This may broaden the field of clinical applications of electroporation, including therapeutic treatment of various arrhythmias.

[0134]

[0160] FIG. 7 shows a pulse voltage waveform in the form of a series of rectangular double pulses, each pulse associated with a pulse width or duration, such as pulse (700). The pulse width / duration may be about 0.5 microseconds, about 1 microsecond, about 5 microseconds, about 10 microseconds, about 25 microseconds, about 50 microseconds, about 100 microseconds, about 125 microseconds, about 140 microseconds, about 150 microseconds, including all values ​​and subranges in between. The pulse waveform in FIG. 7 shows a set of monophasic pulses, with all pulses having the same polarity (all positive in FIG. 7, measured from a zero baseline). In some embodiments, such as irreversible electroporation applications, the height of each pulse (700) or the voltage amplitude of the pulse (700) may range from about 400V to about 1,000V, about 5,000V, about 10,000V, about 15,000V, including all values ​​and subranges in between. 7, pulses (700) are separated from adjacent pulses by a time interval (702), sometimes referred to as a first time interval. The first time interval may be about 10 microseconds, about 50 microseconds, about 100 microseconds, about 200 microseconds, about 500 microseconds, about 800 microseconds, about 1 millisecond, including all values ​​and subranges therebetween, to produce irreversible electroporation.

[0135]

[0161] In Figure 8, pulse waveforms are introduced with a hierarchical structure of nested pulses. Figure 8 shows a series of monophasic pulses, such as pulse (800), where the pulse width / pulse duration w is the period between successive pulses t 1 (802) (sometimes called the first time interval), and 1 The successive pulses are arranged to form a group of pulses (810) (sometimes referred to as a first set of pulses). Further, the waveform has a period t 2 The number m of such groups of pulses (sometimes called the second set of pulses), separated by a time interval (812) (sometimes called the second time interval) 2 8, marked (820), m 2 A collection of such pulse groups constitutes the next level of the hierarchy and may be called a packet and / or a third set of pulses. 1 Both may range from microseconds to hundreds of microseconds, including all values ​​and subranges in between. In some embodiments, the time interval t 2 But in time interval t 1 In some embodiments, the ratio t 2 / t 1 may range between about 3 and about 300, including all values ​​and subranges therebetween.

[0136]

[0162] Figure 9 further details the structure of the nested pulse hierarchical waveform. In this figure, a series of m 1 pulses (individual pulses not shown) form a group of pulses (902) (e.g., a first set of pulses). The period t 2 A series of m time intervals (910) separated by a time interval between groups (e.g., a second time interval). 2 Such groups form a packet (910) (e.g., a second set of pulses). The period between one packet and the next packet is t 3(e.g., a third time interval) 3 Such packets form the next level in the hierarchy, i.e., a superpacket (e.g., a third set of pulses) labeled in the figure as (920). In some embodiments, the time interval t 3 But in time interval t 2 In some embodiments, the time interval t 3 But in time interval t 2 In some embodiments, the ratio t 3 / t 2 may range between about 30 and about 800, including all values ​​and subranges therebetween. The amplitude of an individual voltage pulse in a pulse hierarchy may range anywhere from 500V to over 7,000V, including all values ​​and subranges therebetween.

[0137]

[0163] FIG. 10 provides an example of a biphasic waveform sequence with a hierarchical structure. In the example shown, a biphasic pulse (1000) has a positive voltage portion as well as a negative voltage portion to complete one cycle of the pulse. 1 There is a time delay (1002) (e.g., a first time interval) between adjacent cycles of n 1 Such cycles form a group of pulses (1010) (e.g., a first set of pulses). The period between one group and the next is t 2 A series of n groups separated by a time interval (1012) (e.g., a second time interval) between groups of 2 Such groups form a packet (1020) (e.g., a second set of pulses). The figure also illustrates a time delay (1030) between the packets (e.g., a third time interval) of period t 3As with the monophasic pulses, higher levels of the hierarchy may also be formed. The amplitude of each pulse or the voltage amplitude of the biphasic pulse may range anywhere from 500V to 7,000V or more, including all values ​​and subranges in between. The pulse width / pulse duration may range from nanoseconds or subnanoseconds to tens of microseconds, while the delay t 1 The time interval between groups, t, may range from zero to a few microseconds. 2 may be at least 10 times greater than the pulse width. In some embodiments, the time interval t 3 But in time interval t 2 In some embodiments, the time interval t 3 But in time interval t 2 It may be at least 50 times greater.

[0138]

[0164] The embodiments disclosed herein may include waveforms that are constructed as hierarchical waveforms that include waveform elements / pulses at various levels of the hierarchy. An individual pulse, such as pulse (800) of FIG. 8, may comprise a first level of the hierarchy and have an associated pulse duration and a first time interval between successive pulses. A set of pulses, i.e., elements of the first level structure, form a second level of the hierarchy, such as group of pulses / second set of pulses (810) of FIG. 8. Other parameters associated with the waveform include parameters such as total duration of the second set of pulses (not shown), total number of first level elements / first set of pulses, and second time interval between successive first level elements that describe the second level structure / second set of pulses. In some embodiments, the total duration of the second set of pulses may be between about 20 microseconds and about 10 milliseconds, including all values ​​and subranges in between. A set of groups, second set of pulses, or elements of the second level structure form a third level of the hierarchy, such as third set of packets / pulses of group (820) of FIG. 8. Other parameters include the total duration of the third set of pulses (not shown), the total number of second level elements / second sets of pulses, and the third time interval between successive second level elements that describe the third level structure / third set of pulses. In some embodiments, the total duration of the third set of pulses may be between about 60 microseconds and about 200 milliseconds, including all values ​​and subranges therebetween. The generally repetitive or nested structure of the waveform may continue up to multiple higher levels, such as 10 levels of structure, or more.

[0139]

[0165] In some embodiments, hierarchical waveforms with nesting and time interval hierarchy as described herein may be useful for ablation energy delivery for irreversible electroporation and provide good control and selectivity for application in different tissue types. Various hierarchical waveforms may be generated with a suitable pulse generator of the type described in this disclosure. Although the examples herein identify separate monophasic and biphasic waveforms for clarity, it should be noted that combination waveforms may also be generated / implemented, where some parts of the waveform hierarchy are monophasic while other parts are biphasic.

[0140]

[0166] In some embodiments, the ablation pulse waveforms described herein may be applied during the refractory period of the cardiac cycle to avoid disrupting the sinus rhythm of the heart. In some embodiments, a method of treatment may include electrically pacing the heart with a cardiac stimulating device (e.g., cardiac stimulating device (150)) to ensure pacing capture to establish periodicity and predictability of the cardiac cycle, and then defining a time window within the refractory period of the cardiac cycle during which one or more pulse ablation waveforms may be delivered. FIG. 11 illustrates an example in which both atrial and ventricular pacing is applied (e.g., with a pacing lead or catheter in the right atrium and right ventricle, respectively). With time represented on the horizontal axis, FIG. 11 illustrates a series of ventricular pacing signals (1100, 1110) and a series of atrial pacing signals (1120, 1130), along with a series of ECG waveforms (1140, 1142) driven by the pacing signals. As shown in FIGURE 11 by the thick arrows, there is an atrial refractory time window (1122) and a ventricular refractory time window (1102) following the atrial pacing signal (1120) and the ventricular pacing signal (1100), respectively. As shown in FIGURE 11, there is a period T rA common refractory window (1150) may be defined for each pulse waveform. In some embodiments, the electroporation ablation waveform(s) may be applied during this common refractory window (1150). The start of this refractory window (1150) is offset from the pacing signal (1100) by a time offset (1104), as shown in FIG. 11. The time offset (1104) may be less than about 25 milliseconds in some embodiments. At the next heartbeat, a similarly defined refractory window (1152) is the next window available for application of the ablation waveform(s). In this manner, with each heartbeat remaining within the common refractory window, the ablation waveform(s) may be applied over a series of heartbeats. In one embodiment, each packet of pulses as defined above in the pulse waveform hierarchy may be applied to a given electrode set in one heartbeat, such that a series of packets are applied over a series of heartbeats. Similarly, a first waveform packet may be delivered sequentially over a first electrode order, followed by a second waveform packet over a second electrode order, and so on, although in some cases it may be advantageous for the second electrode order to be different from the first electrode order. The signal generator and routing console architecture disclosed herein allows for a variety of such hierarchical waveform delivery, where the delivery of a waveform packet to a given electrode set may be intermixed with the delivery of waveform packets to different electrode sets, in the sense disclosed herein. This intermixed waveform delivery modality described herein may include monophasic pulses, biphasic pulses, and mixed pulses that include both monophasic and biphasic components.

[0141]

[0167] Although the examples herein identify separate monophasic and biphasic waveforms, it is understood that combination waveforms may of course also be generated, in which some portions of the waveform hierarchy are monophasic while others are biphasic. Voltage pulse waveforms having a hierarchical structure may be applied (optionally with time delays) across different anode-cathode subsets. As mentioned above, one or more of the waveforms applied across the anode-cathode subsets may be applied during the refractory period of the cardiac cycle. It should be understood that the steps of the methods described herein may be combined and modified as necessary. Similarly, while the examples of electrode channel selection disclosed herein describe the selection of one anode and two cathode channels, it should be apparent that a wide variety of channels may be selected to act as anodes or cathodes without limitation.

[0142]

[0168] Although cardiac ablation devices are described herein for ablation, it should be understood that the protection devices and embodiments disclosed herein are applicable to other clinical procedures and that other ablation devices may be used without departing from the scope of the present invention.

[0143]

[0169] As used herein, the terms "about" and / or "approximately" when used in conjunction with numerical values ​​and / or ranges generally refer to a numerical value and / or range that is close to the recited numerical value and / or range. In some instances, the terms "about" and "approximately" may mean within ±10% of the recited value. For example, in some instances, "about 100 [units]" may mean ±10% of 100 (e.g., from 90 to 110). The terms "about" and "approximately" may be used interchangeably.

[0144]

[0170] Some embodiments described herein relate to computer storage products with non-transitory computer-readable media (which may also be referred to as non-transitory processor-readable media) having instructions or computer code for performing various computer-implemented operations. The computer-readable media (or processor-readable media) is non-transitory in the sense that it does not include a transitory propagating signal (e.g., a propagating electromagnetic wave that carries information over a transmission medium such as space or a cable) itself. The media and computer code (which may also be referred to as code or algorithms) may be designed and constructed for one or more specific purposes. Examples of non-transitory computer readable media include, but are not limited to, magnetic storage media such as hard disks, floppy disks, and magnetic tapes, optical storage media such as compact disks / digital video disks (CD / DVDs), compact disk read only memories (CD-ROMs) and holographic devices, magneto-optical storage media such as optical disks, solid-state storage devices such as solid-state drives (SSDs) and solid-state hybrid drives (SSHDs), carrier signal processing modules, and hardware devices specially configured to store and execute program code, such as application specific integrated circuits (ASICs), programmable logic devices (PLDs), read only memories (ROMs), and random access memory (RAM) devices. Other embodiments described herein relate to computer program products, which may include, for example, instructions and / or computer code disclosed herein.

[0145]

[0171] The systems, devices, and / or methods described herein may be performed by software (executed on hardware), hardware, or a combination thereof. Hardware modules may include, for example, general-purpose processors (or microprocessors or microcontrollers), field programmable gate arrays (FPGAs), and / or application-specific integrated circuits (ASICs). Software modules (executed on hardware) may be expressed in a variety of software languages ​​(e.g., computer code), including C, C++, Java, Python, Ruby, Visual Basic, and / or other object-oriented, procedural, or other programming languages ​​and development tools. Examples of computer code include, but are not limited to, microcode or microinstructions, machine instructions such as those produced by a compiler, code used to produce web services, and files containing higher-level instructions executed by a computer using an interpreter. Further examples of computer code include, but are not limited to, control signals, encryption code, and compression code.

[0146]

[0172] In some embodiments, the systems, devices, and methods may be in communication with other computing devices (not shown), for example, via one or more networks, each of which may be any type of network (e.g., wired network, wireless network). A wireless network may refer to any type of digital network that is not connected by any type of cable. Examples of wireless communication in a wireless network include, but are not limited to, cellular, radio, satellite, and microwave communication. However, a wireless network may connect to a wired network to communicate information with the Internet, other carriers' voice and data networks, business networks, and personal networks. Wired networks are carried over copper twisted pair, coaxial cable, and / or fiber optic cable. There are many different types of wired networks, including wide area networks (WANs), metropolitan area networks (MANs), local area networks (LANs), Internet area networks (IANs), campus area networks (CANs), global area networks (GANs) such as the Internet, and virtual private networks (VPNs). Hereinafter, network refers to any combination of wireless, wired, public, and private data networks interconnected, typically through the Internet, to provide an integrated networking and information access system.

[0147]

[0173] Cellular communications may encompass technologies such as GSM, PCS, CDMA or GPRS, W-CDMA, EDGE or CDMA2000, LTE, WiMAX, and 5G networking standards. Some wireless network deployments combine networks from multiple cellular networks or use a mix of cellular, Wi-Fi, and satellite communications. In some embodiments, the systems, devices, and methods described herein may include radio frequency receivers, transmitters, and / or optical (e.g., infrared) receivers and transmitters to communicate with one or more devices and / or networks.

[0148]

[0174] The specific examples and descriptions herein are exemplary in nature and embodiments may be developed by one of ordinary skill in the art based on the teachings herein without departing from the scope of the invention, which is limited only by the appended claims. The technical ideas contained in this disclosure are described below as appendices. [Appendix 1] a set of electrodes positionable near tissue of a subject; a signal generator configured to generate a voltage pulse waveform, the signal generator couplable to the set of electrodes and configured to deliver the voltage pulse waveform to the set of electrodes to ablate the tissue, the set of electrodes configured to induce a current in a first electronic device positioned near the tissue in response to receiving the voltage pulse waveform; a protection device coupleable between the first electronic device and a second electronic device, the protection device configured to reduce the current induced in the first electronic device. [Appendix 2] 2. The system of claim 1, wherein the first electronic device is a pacing device including a set of leads, and the second electronic device is a cardiac stimulation device configured to deliver pacing signals to the pacing device. [Appendix 3] the current induced in the first electronic device comprises one or more of a common mode current or a differential mode current; 3. The system of claim 1, wherein the protection device includes one or more transformers configured to reduce the common mode current or the differential mode current. [Appendix 4] 4. The system of claim 3, wherein each transformer of the one or more transformers includes a toroid core, a first winding around a first portion of the toroid core, and a second winding around a second portion of the toroid core. [Appendix 5] 5. The system of claim 1, wherein the protection device includes one or more capacitors configured to shunt current above a predetermined frequency to reduce the current induced in the first electronic device. [Appendix 6] 6. The system of any one of claims 1-5, wherein the protection device includes one or more diodes configured to shunt high voltage away from the second electronic device. [Appendix 7] 7. The system of any one of claims 1 to 6, wherein the protection device includes one or more inductors configured to reduce alternating current induced in the first electronic device. [Appendix 8] 8. The system of claim 7, wherein the one or more inductors include a first inductor coupled to a first lead of the first electronic device and a second inductor coupled to a second lead of the first electronic device, the first and second inductors configured to reduce alternating current induced in the first and second leads. [Appendix 9] The protection device comprises: first and second capacitors, each configured to short out voltages above a predetermined frequency; a first transformer coupled between the first electronic device and the first capacitor; a second transformer coupled between the first capacitor and the second capacitor, the first and second transformers configured to reduce common mode or differential mode currents induced in the first electronic device; and and a set of diodes arranged in parallel with the second capacitor and coupled to the second electronic device, the set of diodes configured to shunt high voltage away from the second electronic device. [Appendix 10] 10. The system of claim 9, wherein the first and second transformers are each a common mode transformer configured to reduce common mode currents induced in the first electronic device. [Appendix 11] 10. The system of claim 9, wherein one of the first and second transformers is a differential mode transformer configured to reduce differential mode current induced in the first electronic device, and the other of the first and second transformers is a common mode transformer configured to reduce common mode current induced in the first electronic device. [Appendix 12] 3. The system of claim 1 or 2, wherein the protection device includes one or more balun circuits configured to reduce common mode currents induced in the first electronic device over a predetermined frequency range. [Appendix 13] 13. The system of claim 12, wherein the one or more balun circuits include a plurality of balun circuits, each configured to reduce common mode currents induced in the first electronic device over a predetermined frequency range of a set of predetermined frequency ranges, each predetermined frequency range of the set of predetermined frequency ranges at least partially overlapping at least one other predetermined frequency range of the set of predetermined frequency ranges. [Appendix 14] 14. The system of claim 12 or 13, wherein the protection device includes one or more inductors configured to reduce alternating current induced in the first electronic device, and the one or more balun circuits are coupled between the one or more inductors and the second electronic device. [Appendix 15] 15. The system of any one of appendixes 12-14, wherein at least one balun circuit of the one or more balun circuits includes an inductor in parallel with a capacitor and a resistor. [Appendix 16] 16. The system of any one of appendixes 12-15, wherein at least one balun circuit of the one or more balun circuits includes a coaxial cable winding including a first and a second conductor, the first conductor coupled to a first lead of the first electronic device, and the second conductor coupled to a second lead of the first electronic device. [Appendix 17] 17. The system of any one of appendixes 12 to 16, wherein the one or more balun circuits include a plurality of balun circuits connected in series. [Appendix 18] 18. The system of any one of claims 1-17, wherein the protection device is further coupled between the first electronic device and the signal generator. [Appendix 19] 19. The system of any one of claims 1 to 18, wherein the protection device is integrated into at least one of the signal generator and the second electronic device. [Appendix 20] a protection device coupleable between a first electronic device and a second electronic device, the first electronic device positionable near tissue of a subject such that a current can be induced in the first electronic device by a voltage pulse waveform delivered to a set of electrodes near the tissue, the protection device comprising: a set of capacitors, each configured to shunt current above a predetermined frequency to reduce the current induced in the first electronic device; a set of transformers each configured to reduce a common mode current or a differential mode current of the currents induced in the first electronic device; a set of diodes configured to shunt high voltage away from the second electronic device. [Appendix 21] 21. The apparatus of claim 20, further comprising a signal generator coupled to the set of electrodes and configured to deliver the voltage pulse waveform to the set of electrodes, the signal generator being configured to generate the voltage pulse waveform. [Appendix 22] 22. The apparatus of claim 20 or 21, further comprising a cardiac stimulation device configured to deliver a pacing signal to the first electronic device, the cardiac stimulation device being the second electronic device. [Appendix 23] 22. The apparatus of claim 20 or 21, wherein the first electronic device is a pacing device including a set of leads, and the second electronic device is a cardiac stimulation device configured to deliver pacing signals to the pacing device. [Appendix 24] 24. The apparatus of any one of claims 20-23, wherein each transformer of the one or more transformers includes a toroid core, a first winding around a first portion of the toroid core, and a second winding around a second portion of the toroid core. [Appendix 25] 25. The apparatus of claim 24, wherein the toroid core of each transformer of the one or more transformers includes a set of laminations having an aspect ratio of 5 or less. [Appendix 26] 26. The apparatus of claim 24 or 25, wherein the toroid core of each transformer of the one or more transformers defines the central axis with the first winding of each transformer of the one or more transformers wrapped about the central axis of the toroid core in a first direction and the second winding of each transformer of the one or more transformers wrapped about the central axis in a second direction opposite the first direction. [Appendix 27] 27. The apparatus of any one of claims 24-26, wherein an outer radius of the toroid core of each of the one or more transformers is between about 4 cm and about 10 cm, and an inner radius of the toroid core of each of the one or more transformers is between about 2 cm and about 9 cm. [Appendix 28] 28. The apparatus of any one of claims 24 to 27, wherein a thickness of the toroid core of each of the one or more transformers is between about 1 cm and about 6 cm. [Appendix 29] 29. The apparatus of any one of claims 20-28, wherein each transformer of the one or more transformers comprises an inductance of at least about 1 millihenry and a resistance of at least about 500 ohms. [Appendix 30] 30. The apparatus of any one of appendixes 20 to 29, wherein each diode of the set of diodes is a Zener diode. [Appendix 31] 31. The apparatus of any one of appendixes 20-30, wherein the set of diodes includes first and second diodes arranged in series and facing in opposite directions. [Appendix 32] 32. The apparatus of any one of claims 20 to 31, wherein the set of diodes is arranged in parallel with at least one capacitor of the set of capacitors. [Appendix 33] the set of capacitors includes a first and a second capacitor; The set of transformers a first transformer coupled between the first electronic device and the first capacitor; a second transformer coupled between the first capacitor and the second capacitor; Including, 21. The apparatus of any one of claims 20, wherein the set of diodes includes a first and a second diode coupled to the second electronic device. [Appendix 34] 34. The apparatus of claim 33, wherein the first and second transformers are each a common mode transformer configured to reduce common mode currents of the currents induced in the first electronic device. [Appendix 35] 34. The apparatus of claim 33, wherein one of the first and second transformers is a differential mode transformer configured to reduce a differential mode current of the current induced in the first electronic device, and the other of the first and second transformers is a common mode transformer configured to reduce a common mode current of the current induced in the first electronic device. [Appendix 36] 36. The apparatus of any one of appendixes 20-35, wherein the protection device includes one or more inductors configured to reduce alternating current induced in the first electronic device. [Appendix 37] a protection device coupleable between a first electronic device and a second electronic device, the first electronic device positionable near tissue of a subject such that a current can be induced in the first electronic device by a voltage pulse waveform delivered to a set of electrodes near the tissue, the protection device comprising: An apparatus comprising: a set of balun circuits connected in series and collectively configured to reduce the current induced in the first electronic device over a set of predetermined frequency ranges. [Appendix 38] 38. The apparatus of claim 37, further comprising a signal generator coupled to the set of electrodes and configured to deliver the voltage pulse waveform to the set of electrodes, the signal generator being configured to generate the voltage pulse waveform. [Appendix 39] 40. The apparatus of claim 37 or 38, further comprising a cardiac stimulator configured to deliver a pacing signal to the first electronic device, the cardiac stimulator being the second electronic device. [Appendix 40] 40. The apparatus of claim 37 or 38, wherein the first electronic device is a pacing device including a set of leads, and the second electronic device is a cardiac stimulation device configured to deliver pacing signals to the pacing device. [Appendix 41] 41. The apparatus of any one of claims 37 to 40, wherein each predetermined frequency range of the set of predetermined frequency ranges at least partially overlaps with at least one other predetermined frequency range of the set of predetermined frequency ranges. [Appendix 42] 42. The apparatus of any one of appendixes 37 to 41, wherein each predetermined frequency range of the set of predetermined frequency ranges has a resonant peak associated with a balun circuit of the set of balun circuits. [Appendix 43] 42. The apparatus of any one of claims 37 to 41, wherein the protection device further comprises one or more inductors configured to reduce alternating current in the current induced in the first electronic device. [Appendix 44] 43. The apparatus of claim 42, wherein the set of balun circuits is coupled between the one or more inductors and the first electronic device. [Appendix 45] the one or more inductors include first and second sets of inductors; the first set of inductors is coupled between the set of balun circuits and the first electronic device; 43. The apparatus of claim 42, wherein the second set of inductors are coupled between the set of balun circuits and the second electronic device. [Appendix 46] 45. The apparatus of any one of appendixes 37-44, wherein at least one balun circuit of the set of balun circuits includes an inductor in parallel with a capacitor and a resistor. [Appendix 47] 46. ​​The apparatus of any one of claims 37-45, wherein at least one balun circuit of the set of balun circuits includes a coaxial cable winding including a first and a second conductor, the first conductor coupled to a first lead of the first electronic device and the second conductor coupled to a second lead of the first electronic device. [Appendix 48] delivering a pacing signal to the heart using a pacing device positioned proximate cardiac tissue of the heart; delivering a voltage pulse waveform using a signal generator to an ablation device positioned near tissue to ablate said tissue; inducing a current in a first set of electronic devices positioned proximate the cardiac tissue in response to delivery of the voltage pulse waveform, the first set of electronic devices including the pacing device; and reducing the current induced in the first set of electronic devices using a protection device coupled between the first set of electronic devices and a second electronic device. [Appendix 49] 50. The method of claim 49, wherein the second electronic device is a cardiac stimulation device configured to generate the pacing signal. [Appendix 50] 50. The method of claim 49, wherein the second electronic device is an electrocardiogram (ECG) recording system. [Appendix 51] 51. The method of any one of claims 48 to 50, wherein using the protection device to reduce the currents induced in the first set of electronic devices includes using one or more transformers or capacitors of the protection device to reduce common mode or differential mode currents of the currents induced in the first set of electronic devices. [Appendix 52] 52. The method of any one of claims 48-51, wherein using the protection devices to reduce the current induced in the first set of electronic devices includes shunting high voltage away from the second set of electronic devices using a diode set of the protection devices. [Note 53] 53. The method of any one of claims 48 to 52, wherein using the protection device to reduce the current induced in the first set of electronic devices includes using one or more inductors in a balun circuit of the protection device to reduce alternating current having a frequency within a predetermined range of a frequency of the current induced in the first set of electronic devices.

Claims

1. a protection device coupleable between a first electronic device and a second electronic device, the first electronic device positionable near tissue of a subject such that a current can be induced in the first electronic device by a voltage pulse waveform delivered to a set of a plurality of electrodes near the tissue, the protection device comprising: An apparatus comprising: a set of a plurality of balun circuits connected in series and collectively configured to reduce the current induced in the first electronic device over a set of a plurality of predetermined frequency ranges.

2. 10. The apparatus of claim 1, further comprising a signal generator configured to generate the voltage pulse waveform, the signal generator coupled to the set of multiple electrodes and configured to deliver the voltage pulse waveform to the set of multiple electrodes.

3. The apparatus of claim 1 , further comprising a cardiac stimulator configured to deliver a pacing signal to the first electronic device, the cardiac stimulator being the second electronic device.

4. 10. The apparatus of claim 1, wherein the first electronic device is a pacing device including a set of multiple leads, and the second electronic device is a cardiac stimulation device configured to deliver pacing signals to the pacing device.

5. The apparatus of claim 1 , wherein each predetermined frequency range of the set of multiple predetermined frequency ranges at least partially overlaps at least one other predetermined frequency range of the set of multiple predetermined frequency ranges.

6. The apparatus of claim 1 , wherein each predetermined frequency range of the set of multiple predetermined frequency ranges has a resonant peak associated with one balun circuit of the set of multiple balun circuits.

7. The apparatus of claim 1 , wherein the protection device further comprises one or more inductors configured to reduce alternating current in the current induced in the first electronic device.

8. The apparatus of claim 7 , wherein the set of multiple balun circuits is coupled between the one or more inductors and the first electronic device.

9. the one or more inductors include first and second sets of a plurality of inductors; the first set of inductors is coupled between the set of balun circuits and the first electronic device; The apparatus of claim 7 , wherein the second set of inductors is coupled between the set of balun circuits and the second electronic device.

10. The apparatus of claim 1 , wherein at least one balun circuit of the set of multiple balun circuits includes an inductor in parallel with a capacitor and a resistor.

11. 10. The apparatus of claim 1, wherein at least one balun circuit of the set of the plurality of balun circuits includes a coaxial cable winding including a first and a second conductor, the first conductor coupled to a first lead of the first electronic device and the second conductor coupled to a second lead of the first electronic device.

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