High-voltage pulsed field ablation system

Abstract

A medical system is configured to deliver high-voltage pulsed-field ablation (PFA) signals to a treatment site in a first operating mode and collect electrogram (EGM) or mapping / navigation signals from the treatment site in a second operating mode. In some examples, the medical system includes a switching circuit capable of reducing cross-modal interference between the medical system components used in different operating modes. In some additional examples, the medical system includes a fault protection circuit that inhibits delivery of PFA waveforms to the treatment site when a shoot-through current in the PFA-waveform generator exceeds a safe level.

Description

Atty Ref. No. A0011026WO01 HIGH-VOLTAGE PULSED FIELD ABLATION SYSTEM

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No.63 / 617,683, filed January 4, 2024, the entire content of which is incorporated herein by reference. FIELD

[0002] This application relates generally to pulsed field ablation and more specifically, but not exclusively, to high-voltage pulsed field ablation generators and associated circuits. BACKGROUND

[0003] Pulsed field ablation (PFA) involves application of pulsed electric fields, which reversibly or irreversibly destabilize cell membranes through electro-permeabilization, but generally do not affect the structural integrity of tissue components. The nature of PFA allows for very brief periods of therapeutic energy delivery, e.g., milliseconds to microseconds in duration. In many cases, PFA does not cause collateral damage to non- targeted tissue as frequently or severely as thermal ablation. SUMMARY

[0004] Disclosed herein are, among other things, various examples, aspects, features, and embodiments of a medical system capable of delivering high-voltage PFA signals to a treatment site in a first operating mode and collecting electrogram (EGM) or mapping / navigation signals from the treatment site in a second operating mode. In some examples, the medical system includes a switching circuit capable of reducing cross- modal interference between the medical system components used in different operating modes, such as the interference to EGM signals from the high voltage PFA delivery system. In some additional examples, the medical system includes a fault protection circuit that inhibits delivery of PFA waveforms to the treatment site when a potentially damaging shoot-through or vertical current in the PFA-waveform generator exceeds a safe level. A shoot-through or vertical current occurs when two switching devices in the same side of an H-bridge circuit are on at the same time.Atty Ref. No. A0011026WO01

[0005] One example provides a medical system including an H-bridge circuit configured to generate a pulsed voltage waveform between first and second load terminals thereof. The medical system also includes a switching circuit connected to the first and second load terminals, the switching circuit being configurable to route the pulsed voltage waveform from the H-bridge circuit to a first selected set of a plurality of electrodes of an ablation device and being further configurable to route collected signals from a second selected set of the plurality of electrodes to a receiving circuit. The medical system also includes an electronic controller configured to cause the switching circuit to switch between a first routing configuration corresponding to a first operating mode and a second routing configuration corresponding to a second operating mode. In the first routing configuration, the first selected set of the plurality of electrodes is electrically connected to receive the pulsed voltage waveform from the H-bridge circuit via the switching circuit. In the second routing configuration, the plurality of electrodes and the receiving circuit are electrically disconnected by the switching circuit from the H-bridge circuit.

[0006] Another example provides a signal-routing method including, with an electronic controller, controlling routing configurations of a switching circuit connected to first and second load terminals of an H-bridge circuit, the switching circuit being configurable to route a pulsed voltage waveform from the H-bridge circuit to a first selected set of a plurality of electrodes of an ablation device and being further configurable to route collected signals from a second selected set of the plurality of electrodes to a receiving circuit. The controlling includes producing a first routing configuration by configuring the switching circuit to electrically connect the first set of electrodes to receive the pulsed voltage waveform from the H-bridge circuit via the switching circuit. The controlling also includes producing a second routing configuration by configuring the switching circuit to electrically disconnect the plurality of electrodes and the receiving circuit from the H-bridge circuit.

[0007] Yet another example provides a medical system including an H-bridge circuit configured to apply a pulsed voltage waveform to an ablation device, the H-bridge circuit including a first branch connected between a first power supply rail and a second power supply rail and a second branch connected between the first power supply rail and the second power supply rail. The medical system also includes a fault protection circuitAtty Ref. No. A0011026WO01 electrically coupled to the H-bridge circuit and configured to detect a fault condition when a shoot-through current flowing through the first branch or the second branch exceeds a threshold value. The medical system also includes an electronic controller configured to inhibit the medical system from delivering the pulsed voltage waveform to the ablation device in response to the fault condition being detected.

[0008] Yet another example provides a fault protection method for a medical system, the method including, with an H-bridge circuit, applying a pulsed voltage waveform to an ablation device, the H-bridge circuit including a first branch connected between a first power supply rail and a second power supply rail and a second branch connected between the first power supply rail and the second power supply rail. The method also includes, with a fault protection circuit electrically coupled to the H-bridge circuit, detecting a fault condition when a shoot-through current flowing through the first branch or the second branch exceeds a threshold value. The method also includes, with an electronic controller, inhibiting the medical system from delivering the pulsed voltage waveform to the ablation device in response to the fault condition being detected. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG.1 is a block diagram illustrating a medical system according to some examples.

[0010] FIG.2 graphically illustrates an electrical waveform that can be used in the medical system of FIG.1 according to some examples.

[0011] FIG.3 is a circuit diagram illustrating an H-bridge circuit that can be used in the medical system of FIG.1 to generate the electrical waveform of FIG.2 according to some examples.

[0012] FIG.4 is a circuit diagram illustrating an electrical circuit configured to connect the H-bridge circuit of FIG.3 to various components of the medical system of FIG.1 according to some examples.

[0013] FIG.5 is a circuit diagram illustrating a fault protection circuit used in conjunction with the electrical circuit of FIG.4 according to some examples.Atty Ref. No. A0011026WO01

[0014] FIG.6 is a circuit diagram illustrating a signal-routing circuit used in the medical system of FIG.1 according to some examples.

[0015] FIG.7 is a flowchart illustrating a power-on self-test (POST) performed in the medical system of FIG.1 according to some examples.

[0016] FIG.8 is a flowchart illustrating a fault protection method implemented in the medical system of FIG.1 according to some examples.

[0017] FIG.9 is a flowchart illustrating a signal-routing method implemented in the medical system of FIG.1 according to some examples. DETAILED DESCRIPTION

[0018] In various examples, PFA can be performed in an open chest procedure or with the use of minimally invasive techniques. Vectoring of the electrode polarity has certain advantages in terms of obtaining greater lesion depths and widening or narrowing the area for electrical field transfer. In addition to delivering PFA energy during cardiac surgery or treatment, PFA electrodes can also be used, e.g., for applying pacing signals, detecting mapping and navigation signals, and / or sensing live EGM signals on a beating heart.

[0019] In some examples, PFA is delivered via a sequence of short-duration, high-voltage pulses to perform irreversible electroporation of tissue. Such pulses have significant voltage and energy to form lesions in cardiac tissue, for example, to treat atrial fibrillation, among other arrhythmias. A corresponding PFA-waveform generator can be configured to deliver multiphasic pulses, including but not limited to biphasic pulses suitable for multi-electrode array catheters designed for targeting the pulmonary veins with a single catheter placement excited with brief episodes of pulsed energy. Such “single-shot” PFA systems may deliver waveforms optimized for maximizing the lesion volume while maintaining the temperature excursion and bubble production at benign levels. Some single-shot systems use circular (or spherical) catheters and 1.5 kV generators capable of delivering 30 kW peak power and energies up to 30 Joules. As PFA technology and platforms evolve and expand, catheter and generator systems continue to be refined for current target regions and / or more-challenging anatomy. For example, generators and catheters that are configured to provide higher voltages (for example, 4 kV or 8 kV peak-Atty Ref. No. A0011026WO01 to-peak) may cause deeper lesions, which potential greater efficacy of treatment as a result. Further, if the PFA system is able to create larger lesions via this higher voltage, procedures may generally become more efficient (e.g., taking less time). Beyond this, higher voltages may enable different energy vectoring between electrodes, therein enabling for larger spacing between electrodes on an electrode structure of a catheter. As a result of this potential larger spacing enabled via these higher voltages, new form factors may be possible which can expand the possibilities of where PFA is available as a treatment. As an example, one cardio anatomy of interest is ventricles, for which it can be difficult to create electrode structure form factions from which sufficiently deep lesions can be formed; however, high-voltage applications, such as those described herein, may enable form factions with more space between electrodes that still result in sufficiently large lesions.

[0020] Following the delivery of high-voltage pulses, one manifestation of a successful treatment may typically be a relatively large decrease in the electrogram amplitude. In some examples, such a decrease is caused by the creation of lesions in cardiomyocytes, which after ablation, lose their ability to conduct and propagate cardiac electrical activity. Prior to ablation, electrogram amplitudes may typically be about 100 mV peak-to-peak (p- p), whereas following the PFA treatment, the electrogram amplitudes may fall by orders of magnitude, e.g., down to about 20 µV p-p or even lower, which constitutes an amplitude drop of about 80 dB or more. Rapid attenuation of the EGM amplitude immediately following the PFA delivery provides an excellent observable indicator of the therapeutic effect. Conversely, a lack of the EGM-amplitude drop typically indicates a lack of the therapeutic effect, thereby prompting the attending physician to reapply therapy and / or adjust the catheter position and dosage parameters. Given the desired end point of relatively low EGM amplitudes, it is important that the PFA system can collect good- quality EGMs while preserving signal integrity and avoiding detrimental levels of added electrical noise. When such noise is present, it can disadvantageously distort or obscure the collected EGM signal, thereby significantly eroding its usefulness as a therapy effectiveness indicator. It is also important for the PFA system not to add noise to peripheral patient electrosurgical equipment passing and collecting low level signals. For example, cardio mapping and navigation (MAP / NAV) systems generate and collect low level signals and may be vulnerable to electronic noise emanating from the PFA system.Atty Ref. No. A0011026WO01

[0021] In some examples, the difference in energy levels (or dynamic range) between delivering therapy and collecting EGMs in a 4 kV PFA system is substantial and is an important consideration in the design of the corresponding switching circuits. Assuming the delivery potential of 8 kV p-p and a minimum discernable EGM level of 10 µV p-p, the corresponding dynamic range is: Dynamic Range = 20×log10(8000 kV / 10 µV) ≈ 178 dB (1) Given the dynamic range of this magnitude, an improperly designed switching circuit may disadvantageously leak currents sufficient to cause a significant electric shock to the patient and / or cross-modal interference.

[0022] At least some of the above-indicated problems in the state of the art can be beneficially addressed using various embodiments disclosed herein. One example embodiment provides a switching circuit capable of reducing cross-modal interference between the medical system components used in different operating modes. Another example embodiment provides a fault protection circuit that inhibits delivery of PFA waveforms to the treatment site when a shoot-through current in the PFA-waveform generator exceeds a safe level.

[0023] FIG.1 is a block diagram illustrating a medical system 100 according to some examples. The medical system 100 is configured to be used with one or more ablation devices 110, such as catheters and surgical instruments having PFA capabilities. In the example shown, the medical system 100 includes one ablation device 110. In other examples, the medical system 100 may include two or more ablation devices 110. The medical system 100 also includes a medical apparatus 120, an optional pacing device 130, and an optional tracking and navigation system 140. Although these components of medical system 100 are shown as discrete devices in FIG.1 for purposes of illustration, it is to be understood that in some embodiments the functionality ascribed to these components may be combined into relatively fewer components, or broken out into additional discrete components. For example, in some embodiments (not depicted), some or all of tracking and navigation system 140 may be combined with ablation device 110, such that a single instrument provides much of the functionality of both of these two components.Atty Ref. No. A0011026WO01

[0024] The medical apparatus 120 includes a signal generator 122, an electronic controller 123, and an optional cardiac stimulator 128. The electronic controller 123 includes a processor 124 and a memory 126. In the example shown, the medical apparatus 120 is coupled to the ablation device 110, the pacing device 130, and the tracking and navigation system 140 as indicated in FIG.1.

[0025] The signal generator 122 is configured to generate electrical waveforms suitable for ablating a target tissue, such as, for example, the left isthmus region of the heart. The signal generator 122 is electrically connected to the ablation device 110 for delivery of energy to the target tissue. The processor 124 is connected to the memory 126 to read data therefrom and to write data thereto. The processor 124 is also configured to receive digital signals originating from the cardiac stimulator 128 and / or the pacing device 130. In various examples, the processor 124 performs algorithmic processing of pertinent data to determine one or more parameters for the waveforms to be generated by the signal generator 122. The memory 126 stores instructions that, when executed by the processor 124, cause the signal generator 122 to execute various modules, processes, and functions, such as PFA waveform generation operations in accordance with the determined parameters, cardiac pacing synchronization, and electrode tracking and visualization.

[0026] In some examples, the ablation device 110 is a catheter or a surgical instrument configured to receive electrical waveforms from the signal generator 122 and deliver the corresponding energy to the target tissue. During a medical procedure, the ablation device 110 is manipulated and positioned such that one or more electrodes 112 thereof are near the target tissue. The electronic controller 123 configures and operates the signal generator 122 to apply selected waveforms to the one or more electrodes 112 which deliver the corresponding energy to the target tissue. In one example, different ones of the electrodes 112 are independently connectable to the signal generator 122, with each electrode 112 including a respective insulated electrical lead designed to sustain a voltage of greater than about 500 V without a dielectric breakdown in the insulation. In some examples, the electrical insulation on each of the electrical leads is selected such that an electrical potential difference of about 4 kV across its thickness does not cause a dielectric breakdown therein. In some examples, the electronic controller 123 runs a suitableAtty Ref. No. A0011026WO01 algorithm to automatically make decisions on vectoring and waveforms given a specific tissue thickness and then operates the signal generator 122 accordingly.

[0027] When present, the pacing device 130 is suitably coupled to a patient (not explicitly shown in FIG.1) and configured to receive a heart pacing signal from the cardiac stimulator 128 for the patient’s cardiac stimulation. In some examples, an indication for the pacing signal is transmitted by the cardiac stimulator 128 to the electronic controller 123. Based on the indication, the processor 124 and the memory 126 are operated by the electronic controller 123 to select, compute, or otherwise identify a pacing pulse waveform. The electronic controller 123 then configures the signal generator 122 to generate that pacing pulse waveform and apply it, via the cardiac stimulator 128, to the pacing device 130 in proper synchronization with the cardiac cycle.

[0028] When present, the tracking and navigation system 140 is typically used for guiding a medical procedure. In the example shown, the tracking and navigation system 140 is coupled to the medical apparatus 120. In some other examples, the tracking and navigation system 140 is integrated into the medical apparatus 120. The tracking and navigation system 140 is designed to help visualize the real-time position and orientation of catheters, ablation devices, and / or auxiliary devices within the patient’s body, e.g., to increase the accuracy of targeted ablation and reacquisition of pacing sites for re-ablation. In various implementations, the tracking and navigation system 140 enables one or both of impedance-based tracking and electromagnetic tracking.

[0029] In one example, the tracking and navigation system 140 operates to determine the position of an electromagnetic (EM) sensor referenced to the tracked device using three or more magnetic sources of a magnetic-field generator 142 as references. The magnetic sources of the magnetic field generator 142 are positioned such that a volume of magnetic fields 144 generated thereby envelopes the tracked portion of the ablation device 110 or auxiliary device having the corresponding EM sensor. The magnetic fields in that volume are calibrated and can be controlled with the electronic controller 123. Based on the response of the EM sensor to such magnetic fields, position of the tracked portion is accurately determined and tracked in real time. With the tracked location information, a visual representation of the ablation device 110 or auxiliary device is displayed on anAtty Ref. No. A0011026WO01 anatomical map, e.g., to provide spatial and anatomic context for visualizing the electrode locations. Such visual representations can be generated, e.g., using the processor 124 or another processing device coupled to or integrated into the medical apparatus 120 or the tracking and navigation system 140.

[0030] In some examples, the ablation device 110 includes an actuation mechanism 116, e.g., a knob, a lever, a handle, or other suitable mechanism for moving, deflecting, steering, reconfiguring, and otherwise manipulating the ablation device 110 or relevant portions thereof within the patient’s anatomy. The actuation mechanism 116 can be controlled by an operator based on a location of the distal portion of the ablation device 110 and the overall objective of the medical procedure. In some examples, the operator controls the actuation mechanism 116 with the aid of the above-mentioned visual representations generated with the tracking and navigation system 140, e.g., based in part on the signals received from one or more sensors 114 of the ablation device 110.

[0031] FIG.2 graphically illustrates an electrical waveform 202 that can be generated with the signal generator 122 according to some examples. The electrical waveform 202 includes a sequence of biphasic pulses 210, each including a respective positive pulse 222 and a respective negative pulse 224. In the example shown, each pulse 222, 224 has an absolute amplitude value αV0and a pulse width Tp, where V0is a constant. Although, as discussed and depicted herein, a negative pulse 224 follows a positive pulse 222 within each respective biphasic pulse 210, it is to be understood that it is contemplated that in other examples these may be understood to be reversed (e.g., the positive pulse following the negative pulse within a given biphasic pulse) as the “positive” and “negative” aspect of these pulses are primarily discussed in this way to illustrate the opposing nature of a biphasic pulse from the perspective of the tissue (e.g., opposing pulses from electrodes resulting in net neutral charge). Both the scaling factor α and the pulse width Tpare selectable and controllable via the electronic controller 123. For example, a relatively large value of α may be used to obtain a therapeutic waveform 202 whereas a relatively small value of α may be used to obtain a non-therapeutic waveform 202.

[0032] The time delay between the positive pulse 222 and the negative pulse 224 of the same biphasic pulse 210 is d1. The parameter d1is often referred to as the interphaseAtty Ref. No. A0011026WO01 delay. The time delay between two consecutive biphasic pulses 210 in the waveform 202 is d2. The parameter d2is often referred to as the inter-pulse delay. The waveform 202 has a period Tw= d1+ d2+ 2Tp. In some examples, the period Twis on the order of milliseconds. In general, the waveform 202 has N biphasic pulses 210, where N is a positive integer. The parameters N, d1, d2, and Twof the waveform 202 are also selectable and controllable via the electronic controller 123.

[0033] In some examples, one or more of the following considerations are applied when configuring the signal generator 122 for delivery of therapeutic waveforms: i. Biphasic waveforms, such as the waveform 202, are characterized by an approximately zero net charge applied to the targeted tissue, which is beneficial for many treatment scenarios. ii. The value of αV0is selected to produce an electric field strength greater than approximately 350V / cm in the vicinity of the corresponding electrodes 112. This electric field strength corresponds to the irreversible electroporation threshold of a specific targeted tissue, in this example, cardiac myocytes. The value of αV0may differ for different ablation applications targeting different tissues. These electric field strengths can typically be produced with an applied voltage in the range from approximately 1 kV to approximately 4 kV. iii. The pulse width Tpis typically selected to be on the order of microseconds to avoid leakage currents associated with the change of polarity, significant heat generation, and / or unwanted stimulation of muscle or nerve cells. iv. Substantially rectangular pulses 222, 224 with a short rise time and a short fall time are preferred for therapeutic pulses to achieve an approximately maximum field strength for substantially entire pulse duration. v. Biphasic pulses 210 may be delivered in trains. vi. Pulse trains are typically delivered within a relatively short time interval, e.g., shorter than 200ms, to fit into the refractory period of the surrounding myocardium. The inter-pulse delay can be adjusted to achieve a desired train duration.Atty Ref. No. A0011026WO01 vii. Therapeutic pulses are vectored between the electrodes that are selected to produce a therapeutic electric field strength into the targeted volume of tissue. In different examples, such electrodes can be on a same catheter, on multiple catheters, or among catheter and surface / patch electrodes.

[0034] FIG.3 is a circuit diagram illustrating an H-bridge circuit 300 used in the signal generator 122 according to some examples. The H-bridge circuit 300 includes four power switches (labeled Q1, Q2, Q3, and Q4, respectively) connected between a positive power supply rail +HV and a negative power supply rail−HV as indicated in FIG.3. An electrical load, e.g., including the ablation device 110, is connected between load terminals L1, L2 located at the center of the H-like structure of the circuit 300. When the power switches Q1 and Q4 are closed and the power switches Q2 and Q3 are open, a positive voltage is applied across the load. When the power switches Q2 and Q3 are closed and the power switches Q1 and Q4 are open, a negative voltage is applied across the load. When the power switches Q1, Q2, Q3, and Q4 are toggled, the electrical waveform 202 is generated between the load terminals L1, L2 as indicated in FIG.3. In various examples of the H-bridge circuit 300, the power switches Q1, Q2, Q3, and Q4 are implemented using bipolar transistors, FET transistors, insulated-gate bipolar transistors (IGBTs), vacuum relays, and other suitable power-switching elements.

[0035] To avoid shoot-through currents in “vertical” branches 302, 304 of the H-bridge circuit 300, only one of the two power switches of the branch is allowed to be in a conducting (on) state. However, with rapid switching of the power switches Q1, Q2, Q3, and Q4, there is a finite time before the pertinent switch can settle from the on state to a non-conducting (off) state. Thus, when interphase delay d1is shorter than the on-off settling time, shoot-through currents may disadvantageously occur. Other causes of shoot- through currents in the vertical branches 302, 304 of the H-bridge circuit 300 are also possible. Some embodiments disclosed herein beneficially address the problem of shoot- through currents by using a suitable fault protection circuit that substantially prevents occurrences of unsafe (e.g., larger than a selected threshold value) shoot-through currents. Example embodiments of the fault protection circuit are described in more detail below in reference to FIG.5.Atty Ref. No. A0011026WO01

[0036] FIG.4 is a circuit diagram illustrating an electrical circuit 400 configured to connect the H-bridge circuit 300 to various electrical loads in the medical system 100 according to some examples. In the example shown, the electrical loads include a patient load 410 and an EGM load 490 connectable to the H-bridge circuit 300 via relays 480A, 480B, 480C, and 480D as indicated in FIG.4. The states of the relays 480A, 480B, 480C, and 480D and the states of the power switches Q1, Q2, Q3, and Q4 of the H-bridge circuit 300 are controlled with the corresponding control signals (shown in FIG.4 with dashed lines) generated by a control circuit 440. In some examples, the control circuit 440 is a part of the electronic controller 123. The power supply rails +HV and −HV of the H- bridge circuit 300 are powered by a power supply 450.

[0037] In some examples, the patient load 410 includes the ablation device 110 and is electrically coupled between the load terminals L1, L2 of the H-bridge circuit 300 via the first and second relays 480A, 480B. The control circuit 440 can selectively open and close the electrical paths between the load terminal L1, the patient load 410, and the load terminal L2 via the corresponding control signals applied to the first and second relays 480A, 480B. The EGM load 490 is electrically coupled to the patient load 410 via the third and fourth relays 480C, 480D. The control circuit 440 can selectively open and close the electrical paths between the patient load 410 and the EGM load 490 via the corresponding control signals applied to the third and fourth relays 480C, 480D.

[0038] A first resistor R1 is electrically coupled between (i) the load terminal L1 and (ii) the line including the first relay 480A and the third relay 480C. A second resistor R2 is electrically coupled between (i) the load terminal L2 and (ii) the line including the second relay 480B and the fourth relay 480D. A third resistor R3 is electrically coupled between the power supply rail +HV and the first transistor switch Q1. A fourth sensing resistor R4 is electrically coupled between the second transistor switch Q2 and the power supply rail−HV. A fifth resistor R5 is electrically coupled between the power supply rail +HV and the third transistor switch Q3. A sixth resistor R6 is electrically coupled between the fourth transistor switch Q4 and the power supply rail−HV. The resistors R3, R4, R5, and R5 are the current-sensing resistors electrically coupled to the fault protection circuit 500 as described in more detail below.Atty Ref. No. A0011026WO01

[0039] In a first mode of operation, the electrical circuit 400 is configured to deliver high- voltage pulses to the patient load 410. In a second mode of operation, the electrical circuit 400 is configured to collect EGM signals from the EGM load 490. In different examples, the patient load 410 and the EGM load 490 may be connected to the electrical circuit 400 via the same catheter or via different respective catheters. To enable both the PFA delivery and the EGM collection, various solutions can be implemented in the medical system 100. According to one of such solutions, the control circuit 440 is configured to switch the electrical circuit 400 to one signal pathway to deliver high-voltage (e.g., 4 kV) PFA energy and is further configured to switch the electrical circuit 400 to a different signal pathway to route collected EGM signals to an electrophysiological (EP) recorder (not explicitly shown in FIG.4, e.g., see FIG.6). In some examples, the switching between the two signal pathways is fast (e.g., within the pulse width of the therapy waveform 202) and automatic (e.g., done without human intervention in response to one or more stimuli). The EGM signal pathway is well-isolated from the PFA signal delivery pathway and from the high voltage circuitry of the signal generator 122. Example embodiments of a switching circuit that can be used for these purposes in the medical apparatus 120 are described in more detail below in reference to FIG.6.

[0040] FIG.5 is a circuit diagram illustrating a fault protection circuit 500 used in conjunction with the electrical circuit 400 according to some examples. The fault protection circuit 500 is connected to the control circuit 440 and is configured to sense voltages across resistors R51, R52, each of which represents (e.g., via a current or voltage follower) a respective one of the resistors R3, R4, R5, and R6 (also see FIG.4). Based on the sensed voltages, a shoot-through fault can be detected by the control circuit 440 as described below. When a shoot-through fault is detected, the control circuit 440 operates to generate one or more control signals 562 configured to inhibit or stop the H-bridge circuit 300 of the electrical circuit 400 from delivering the waveform 202 to the patient load 410, e.g., by changing the states of the power switches Q1, Q2, Q3, and Q4 and / or the relays 480A, 480B.

[0041] The fault protection circuit 500 includes a differential amplifier 510 connected across the serially connected resistors R51, R52 such that a first end of the resistor series is connected to a non-inverting (+) input of the differential amplifier 510, and a second endAtty Ref. No. A0011026WO01 of the resistor series is connected to an inverting (−) input of the differential amplifier 510. Resistors R53-R56 are connected between the resistors R51, R52 and the differential amplifier 510 to provide a suitable voltage gain such that the fault protection circuit 500 has a desired sensitivity to shoot-through currents. An output signal 512 of the differential amplifier 510 is electrically coupled to the non-inverting (+) input of a first comparator 530 and to the inverting (−) input of a second comparator 540.

[0042] The fault protection circuit 500 also includes a digital-to-analog converter (DAC) 550 configured to provide reference voltages Vout, −Vout to the inverting (−) input of the comparator 530 and the non-inverting (+) input of comparator 540. The DAC 550 generates reference voltages Vout, −Vout in response to digital values thereof received, via a control signal 564, from the control circuit 440. The first comparator 530 is used to detect a positive shoot-through current, for example, when the corresponding current is flowing from the first end to the second end of the resistor series. The second comparator 540 is similarly used to detect a negative shoot-through current, for example, when the corresponding current is flowing from the second end to the first end of the resistor series.

[0043] When a current flows across the resistors R51, R52, the voltage drop across the resistors is amplified by the differential amplifier 510, and the corresponding amplified signal 512 proportional to the voltage drop is provided to the inputs of the comparators 530 and 540. Assuming a positive current flow through resistors R51 and R52, an output signal 532 of the first comparator 530 switches states (for example, from low to high) when the signal 512 exceeds the reference voltage Vout. Similarly, assuming a negative current flow through resistors R51 and R52, an output signal 542 of the second comparator 540 switches states when the signal 512 exceeds the reference voltage −Vout. The control circuit 440 can determine the presence of a shoot-through fault upon detecting the change in the state of the output signal 532 or in the state of the output signal 542. For example, when a sufficiently large current flows simultaneously through both current sensing resistors of either of the vertical branches 302 and 304 of the H-bridge circuit 300, the corresponding comparator output signals 532, 542 will assert (e.g., change states to “high”). A logic AND gate (not explicitly shown) of the control circuit 440 will also assert, (e.g., switch to “high” = TRUE=fault), and the control circuit 440 will quickly (e.g.,Atty Ref. No. A0011026WO01 within the pulse width of the therapy waveform 202) shut down, via the control signals 562, the high-voltage delivery to the patient load 410.

[0044] FIG.6 is a circuit diagram illustrating a signal-routing circuit 600 that can be used in the medical system 100 according to some examples. The signal-routing circuit 600 includes a switching circuit 620 that can be selectively configured and reconfigured to: (i) route PFA waveforms (such as the waveform 202) from the H-bridge circuit 300 to the ablation device 110 or (ii) route collected or detected signals from the ablation device 110 to a corresponding signal-receiving circuit 610. In FIG.6, the H-bridge circuit 300 is represented by its load terminals L1, L2. In the example shown, the signal-receiving circuit 610 is the mapping and navigation (MAP / NAV) subsystem of the medical system 100 or an EP recorder.

[0045] In the example shown, the ablation device 110 includes a catheter. A distal portion 636 of the catheter 110 has nine electrodes 112, which are labeled 1121-1129. In the above-mentioned first operating mode of the medical system 100, the electrodes 1121-1129are used to deliver PFA waveforms to the treatment site. In the above-mentioned second operating mode of the medical system 100, the electrodes 1121-1129are used to collect MAP / NAV or EGM signals from the treatment site. The catheter 110 also includes an elongated body 634 to enable placement of the electrodes 112 in proximity to the treatment site of the patient. The elongated body 634 typically includes one or more lumens that provide mechanical, electrical, and / or fluid communication between a proximal portion 628 and the distal portion 636 of the catheter 110. In some examples, the elongated body 634 has a central or guidewire lumen for hosting a shaft 638 and a carrier arm 640 in a retracted position. The shaft 638 is movable along the central lumen. In operation, longitudinal movement of the shaft 638 is used to cause the carrier arm 640 to transition between at least a first (e.g., substantially linear) configuration and a second (e.g., looped) configuration. As an illustration, FIG.6 shows the carrier arm 640 in a looped configuration.

[0046] The electrodes 1121-1129are located on the carrier arm 640. Each one of the electrodes 1121-1129is electrically connected, via a dedicated electrical wire of an electrical bus 632 disposed within the corresponding lumen of the elongated body 634, toAtty Ref. No. A0011026WO01 a multi-pin connector 630 located at the proximal portion 628 of the catheter 110. The multi-pin connector 630 is further electrically connected to the switching circuit 620 as indicated in FIG.6.

[0047] In the example shown, the switching circuit 620 includes twenty-seven switches, which are labeled K1-K27. The number of switches in the switching circuit 620 corresponds to the number or electrodes 112 in the matching ablation device 110, with three switches per electrode. Based on the provided description, a person of ordinary skill in the pertinent art will be able to make and use additional embodiments of the switching circuit 620 compatible with other ablation devices 110 having other (than nine) numbers of electrodes 112, without any undue experimentation.

[0048] For an n-th electrode 112nof the catheter 110 shown in FIG.6, the switching circuit 620 has three corresponding dedicated switches Kn, K(n+9), and K(n+18), where n=1, 2, …, 9. For example, for the electrode 1121(n=1), the switching circuit 620 has the corresponding dedicated switches K1, K10, and K19. For the electrode 1122(n=2), the switching circuit 620 has the corresponding dedicated switches K2, K11, and K20, and so on. For the electrode 1129(n=9), the switching circuit 620 has the corresponding dedicated switches K9, K18, and K27.

[0049] The states (OPEN or CLOSED) of individual switches K1-K27 are independently controllable via control signals 618 generated by the control circuit 440 or other suitable circuit of the electronic controller 123. When in the CLOSED state, the switch Kn electrically connects the electrode 112nto the load terminal L1 of the H-bridge circuit 300. When in the CLOSED state, the switch K(n+18) electrically connects the electrode 112nto the load terminal L2 of the H-bridge circuit 300. When in the CLOSED state, the switch K(n+9) electrically connects the electrode 112nto the signal-receiving circuit 610.

[0050] During the first operating mode of the medical system 100, all switches K(n+9) are switched to the OPEN state. The electrodes 1121-1129are sorted into three non- overlapping sets based on the intended PFA delivery configuration. For an electrode 112nbelonging to the first set, the switch Kn is switched to the CLOSED state, and the switch K(n+18) is switched to the OPEN state. For an electrode 112nbelonging to the second set, the switch Kn is switched to the OPEN state, and the switch K(n+18) is switched to theAtty Ref. No. A0011026WO01 CLOSED state. For an electrode 112nbelonging to the third set, both of the switches Kn and K(n+18) are switched to the OPEN state. At least one of the first and second sets is a nonempty set. In some examples, the third set can be empty. At least some of the first, second, and third sets can be dynamically changed during the first operating mode, e.g., to enable PFA delivery via different respective sets of the electrodes 1121-1129.

[0051] During the second operating mode of the medical system 100, all switches Kn and K(n+18) are switched to the OPEN state. This switch configuration beneficially electrically isolates the electrodes 1121-1129and the signal-receiving circuit 610 from the high voltages of and the noise induced by the H-bridge circuit 300. One or more switches K(n+9) are switched to the CLOSED state to enable transmission of the signals picked up at the treatment site by the corresponding one or more electrodes 112nto the signal- receiving circuit 610. The remaining switches K(n+9) are switched to the OPEN state. The sets of the switches K(n+9) that are in the OPEN state and the CLOSED state can be dynamically changed to enable the signal-receiving circuit 610 to receive signals from different sets of the electrodes 1121-1129at different times during the second operating mode.

[0052] FIG.7 is a flowchart illustrating a power-on self-test (POST) 700 performed in the medical system 100 according to some examples. The POST 700 can be performed, e.g., using the fault protection circuit 500.

[0053] The POST 700 includes the electronic controller 123 setting one or more POST thresholds (in a block 702). In some examples, the POST thresholds are represented by the digital values of Vout and −Vout communicated by the control circuit 440 to the DAC 550. In response to the received digital values, the DAC 550 applies the corresponding voltages to the first comparator 530 and the second comparator 540, respectively.

[0054] The POST 700 also includes the electronic controller 123 operating the power supply 450 to apply suitable voltages to the power rails +HV and −HV of the H-bridge circuit 300 (in a block 704). Operations of the block 704 further include the control circuit 440 switching the power switches Q1, Q2, Q3, and Q4 of the H-bridge circuit 300 to generate a test waveform between the load terminals L1, L2. In some examples, the testAtty Ref. No. A0011026WO01 waveform includes or is the waveform 202. In some other examples, a different suitable test waveform can also be used in the block 704.

[0055] The POST 700 also includes the electronic controller 123 determining (in a decision block 706) whether a fault condition is present. In one example, the electronic controller 123 detects the presence of a fault condition when the control circuit 440 determines that the magnitude of shoot-through currents through at least one of the vertical branches 302, 304 of the H-bridge circuit 300 is too high. This determination can be made based on the output signals 532, 542 of the comparators 530 and 540 generated in the fault protection circuit 500 in response to the test waveform of the block 704 and based on the POST thresholds set in the block 702. When the electronic controller 123 determines that a fault condition is present (“Yes” at the decision block 706), the processing of the POST 700 is directed to operations of a block 708. When the electronic controller 123 determines that a fault condition is not present (“No” at the decision block 706), the processing of the POST 700 is directed to operations of a block 710.

[0056] Operations of the block 708 include the electronic controller 123 generating an error message for the user, stating that the POST 700 has failed. The POST 700 is thereafter terminated. In various examples, based on the error message, the user can typically make adjustments in the configuration of the medical system 700 and then repeat the POST 700.

[0057] Operations of the block 710 include the electronic controller 123 generating an information message for the user stating that the POST 700 is successful. Operations of the block 710 further include the electronic controller 123 transitioning the medical system 100 into a therapy delivery mode. The POST 700 is thereafter terminated.

[0058] FIG.8 is a flowchart illustrating a fault protection method 800 carried out in the medical system 100 according to some examples. The method 800 can be implemented, e.g., using the fault protection circuit 500.

[0059] The method 800 includes the electronic controller 123 receiving a user input requesting PFA delivery (in a block 802). The method 800 also includes the electronic controller 123 operating the H-bridge circuit 300 to deliver a portion of the correspondingAtty Ref. No. A0011026WO01 PFA waveform to the ablation device 110 (in a block 804). The method 800 further includes the electronic controller 123 determining (in a decision block 806) whether a fault condition is present. In one example, the electronic controller 123 detects the presence of a fault condition when the control circuit 440 determines that the magnitude of shoot- through currents through at least one of the vertical branches 302, 304 of the H-bridge circuit 300 is too large. This determination is made based on the output signals 532, 542 of the comparators 530 and 540 generated in the fault protection circuit 500 in response to the portion of the waveform delivered the block 804 and based on applicable threshold voltage(s) applied to the comparators 530 and 540 as described above in reference to FIG. 5. When the electronic controller 123 determines that a fault condition is present (“Yes” at the decision block 806), the processing of the method 800 is directed to operations of a block 808. When the electronic controller 123 determines that a fault condition is not present (“No” at the decision block 806), the processing of the method 800 is directed to operations of a decision block 810.

[0060] Operations of the block 808 include the control circuit 440 generating one or more control signals 562 configured to inhibit or stop the H-bridge circuit 300 from delivering the PFA waveform 202 to the ablation device 110, e.g., by changing the states of the power switches Q1, Q2, Q3, and Q4 and / or of the relays 480A, 480B. The method 800 is thereafter terminated.

[0061] Operations of the block 810 include the electronic controller 123 determining whether the PFA delivery is completed. When the PFA delivery is not yet completed (“No” at the decision block 810), the processing of the method 800 is directed back to operations of the block 804. When the electronic controller 123 determines that the PFA delivery is completed (“Yes” at the decision block 810), the method 800 is terminated.

[0062] FIG.9 is a flowchart illustrating a signal-routing method 900 implemented in the medical system 100 according to some examples. The method 900 can be implemented, e.g., using the switching circuit 620.

[0063] The method 900 includes the electronic controller 123 determining whether the medical system 100 is to be operated in a first operating mode or in a second operating mode (in a decision block 902). In the first operating mode, the medical system 100 isAtty Ref. No. A0011026WO01 configured to deliver high-voltage pulses to the ablation device 110. In the second operating mode, the medical system 100 is configured to collect EGM or MAP / NAV signals from the ablation device 110. In various examples, the completion determination in the decision block 902 is made based on the user input or based on the applicable programmatic script that specifies different operating modes for different periods of time. When the electronic controller 123 determines that the medical system 100 is to be operated in the first operating mode (“First” at the decision block 902), the processing of the method 900 is directed to operations of a block 904. When the electronic controller 123 determines that the medical system 100 is to be operated in the second operating mode (“Second” at the decision block 902), the processing of the method 900 is directed to operations of a block 906.

[0064] Operations of the block 904 include the electronic controller 123 generating an set of control signals 618 for the switches K1-K27 of the switching circuit 620 to connect the first and second sets of the electrodes 112nof the ablation device 110 to the load terminals L1 and L2, respectively, of the H-bridge circuit 300. The control signals 618 generated by the electronic controller 123 in the block 904 also cause all switches K(n+9) to be in the OPEN state to electrically isolate the signal-receiving circuit 610 from the ablation device 110. Operations of the block 904 also include the electronic controller 123 switching the power switches Q1-Q4 of the H-bridge circuit 300 to deliver a PFA waveform to the connected electrodes 112nof the ablation device 110.

[0065] Operations of the block 906 include the electronic controller 123 generating another set of control signals 618 for the switching circuit 620 to isolate the ablation device 110 from the H-bridge circuit 300 by placing the switches Kn and K(n+18) in the OPEN state. The control signals 618 generated by the electronic controller 123 in the block 906 also cause some of the switches K(n+9) to be in the CLOSED state to enable the signal-receiving circuit 610 to collect EGM or MAP / NAV signals from the corresponding electrodes 112nof the ablation device 110.

[0066] The method 900 also includes the electronic controller 123 determining whether the medical system 100 is to continue with operations of one of the first and second operating modes (in a decision block 908). When the electronic controller 123 determinesAtty Ref. No. A0011026WO01 that the operations will continue (“Yes” at the decision block 908), the processing of the method 900 is looped back to the block 902. When the electronic controller 123 determines that the operations will not continue (“No” at the decision block 908), the method 900 is terminated.

[0067] According to an example embodiment disclosed above, e.g., in the summary section and / or in reference to any one or any combination of some or all of FIGS.1-9, provided is a medical system comprising: an H-bridge circuit configured to generate a pulsed voltage waveform between first and second load terminals thereof; a switching circuit connected to the first and second load terminals, the switching circuit being configurable to route the pulsed voltage waveform from the H-bridge circuit to a first selected set of a plurality of electrodes of an ablation device and being further configurable to route collected signals from a second selected set of the plurality of electrodes to a receiving circuit; and an electronic controller configured to control routing configurations of the switching circuit, wherein, in a routing configuration corresponding to a first operating mode, the first set of electrodes is electrically connected to receive the pulsed voltage waveform from the H-bridge circuit via the switching circuit; and wherein, in a routing configuration corresponding to a second operating mode, the plurality of electrodes and the receiving circuit are electrically disconnected by the switching circuit from the H-bridge circuit.

[0068] In some embodiments of the above system, the switching circuit includes three respective switches per electrode of the plurality of electrodes.

[0069] In some embodiments of any of the above systems, the switching circuit includes a plurality of first switches and a plurality of second switches; wherein each of the first switches is switchable by the electronic controller to selectively connect and disconnect a respective electrode of the plurality of electrodes to and from the first load terminal; and wherein each of the second switches is switchable by the electronic controller to selectively connect and disconnect a corresponding electrode of the plurality of electrodes to and from the second load terminal.

[0070] In some embodiments of any of the above systems, the switching circuit further includes a plurality of third switches, wherein each of the third switches is switchable byAtty Ref. No. A0011026WO01 the electronic controller to selectively connect and disconnect an associated electrode of the plurality of electrodes to and from the receiving circuit.

[0071] In some embodiments of any of the above systems, the receiving circuit is a part of a mapping and navigation system or a part of an electrophysiological recorder.

[0072] In some embodiments of any of the above systems, the ablation device is a catheter including an electrical bus disposed in an elongated body thereof and configured to separately connect each electrode of the plurality of electrodes to the switching circuit.

[0073] In some embodiments of any of the above systems, the H-bridge circuit comprises: a first branch connected between a first power supply rail and a second power supply rail, the first branch including a first power switch, a first resistor configured to sense a first electrical current flowing through the first power switch, a second power switch serially connected with the first power switch, and a second resistor configured to sense a second electrical current flowing through the second power switch; and a second branch connected between the first power supply rail and the second power supply rail, the second branch including a third power switch, a third resistor configured to sense a third electrical current flowing through the third power switch, a fourth power switch serially connected with the third power switch, and a fourth resistor configured to sense a fourth electrical current flowing through the fourth power switch.

[0074] In some embodiments of any of the above systems, further comprising a fault protection circuit electrically coupled to the first, second, third, and fourth resistors and configured to detect a fault condition based on the sensed first, second, third, and fourth electrical currents.

[0075] In some embodiments of any of the above systems, the electronic controller is further configured to inhibit the medical system from delivering the pulsed voltage waveform to the ablation device in response to the fault condition being detected.

[0076] In some embodiments of any of the above systems, the fault condition is detected when a shoot-through current flowing through the first branch or the second branch exceeds a threshold value.Atty Ref. No. A0011026WO01

[0077] In some embodiments of any of the above systems, the fault protection circuit comprises: a differential amplifier configured to generate an output signal proportional to a difference between a selected pair of the sensed first, second, third, and fourth electrical currents; a comparator configured to compare a voltage of the output signal with a threshold voltage; and a control circuit configured to detect the fault condition based on the comparison.

[0078] According to another example embodiment disclosed above, e.g., in the summary section and / or in reference to any one or any combination of some or all of FIGS.1-9, provided is a signal-routing method comprising: with an electronic controller, controlling routing configurations of a switching circuit connected to first and second load terminals of an the H-bridge circuit, the switching circuit being configurable to route a pulsed voltage waveform from the H-bridge circuit to a first selected set of a plurality of electrodes of an ablation device and being further configurable to route collected signals from a second selected set of the plurality of electrodes to a receiving circuit, the controlling including: producing a first routing configuration by configuring the switching circuit to electrically connect the first set of electrodes to receive the pulsed voltage waveform from the H-bridge circuit via the switching circuit; and producing a second routing configuration by configuring the switching circuit to electrically disconnect the plurality of electrodes and the receiving circuit from the H-bridge circuit.

[0079] In some embodiments of the above method, the switching circuit includes three respective switches per electrode of the plurality of electrodes.

[0080] In some embodiments of any of the above methods, the switching circuit includes a plurality of first switches and a plurality of second switches; wherein each of the first switches is switchable by the electronic controller to selectively connect and disconnect a respective electrode of the plurality of electrodes to and from the first load terminal; and wherein each of the second switches is switchable by the electronic controller to selectively connect and disconnect a corresponding electrode of the plurality of electrodes to and from the second load terminal.

[0081] In some embodiments of any of the above methods, the switching circuit further includes a plurality of third switches, wherein each of the third switches isAtty Ref. No. A0011026WO01 switchable by the electronic controller to selectively connect and disconnect an associated electrode of the plurality of electrodes to and from the receiving circuit.

[0082] In some embodiments of any of the above methods, the receiving circuit is a part of a mapping and navigation system or a part of an electrophysiological recorder.

[0083] In some embodiments of any of the above methods, the ablation device is a catheter including an electrical bus disposed in an elongated body thereof and configured to separately connect each electrode of the plurality of electrodes to the switching circuit.

[0084] According to yet another example embodiment disclosed above, e.g., in the summary section and / or in reference to any one or any combination of some or all of FIGS.1-9, provided is a medical system comprising: an H-bridge circuit configured to apply a pulsed voltage waveform to an ablation device, the H-bridge circuit including a first branch connected between a first power supply rail and a second power supply rail and a second branch connected between the first power supply rail and the second power supply rail; a fault protection circuit electrically coupled to the H-bridge circuit and configured to detect a fault condition when a shoot-through current flowing through the first branch or the second branch exceeds a threshold value; and an electronic controller configured to inhibit the medical system from delivering the pulsed voltage waveform to the ablation device in response to the fault condition being detected.

[0085] In some embodiments of the above system, the first branch includes a first power switch, a first resistor configured to sense a first electrical current flowing through the first power switch, a second power switch serially connected with the first power switch, and a second resistor configured to sense a second electrical current flowing through the second power switch; and wherein the second branch includes a third power switch, a third resistor configured to sense a third electrical current flowing through the third power switch, a fourth power switch serially connected with the third power switch, and a fourth resistor configured to sense a fourth electrical current flowing through the fourth power switch.

[0086] In some embodiments of any of the above systems, the fault protection circuit is electrically coupled to the first, second, third, and fourth resistors and is configured toAtty Ref. No. A0011026WO01 detect the fault condition based on the sensed first, second, third, and fourth electrical currents.

[0087] In some embodiments of any of the above systems, the fault protection circuit comprises: a differential amplifier configured to generate an output signal proportional to a difference between a selected pair of the sensed first, second, third, and fourth electrical currents; a comparator configured to compare a voltage of the output signal with a threshold voltage; and a control circuit configured to detect the fault condition based on the comparison.

[0088] According to yet another example embodiment disclosed above, e.g., in the summary section and / or in reference to any one or any combination of some or all of FIGS.1-9, provided is a fault protection method for a medical system, the method comprising: with an H-bridge circuit, applying a pulsed voltage waveform to an ablation device, the H-bridge circuit including a first branch connected between a first power supply rail and a second power supply rail and a second branch connected between the first power supply rail and the second power supply rail; with a fault protection circuit electrically coupled to the H-bridge circuit, detecting a fault condition when a shoot- through current flowing through the first branch or the second branch exceeds a threshold value; and with an electronic controller, inhibiting the medical system from delivering the pulsed voltage waveform to the ablation device in response to the fault condition being detected.

[0089] With regard to the processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating certain implementations and should in no way be construed to limit the claims.Atty Ref. No. A0011026WO01

[0090] Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the application is capable of modification and variation.

[0091] All terms used in the claims are intended to be given their broadest reasonable constructions and their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary in made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary.

[0092] Unless explicitly stated otherwise, each numerical value and range should be interpreted as being approximate as if the word “about” or “approximately” preceded the value or range.

[0093] The use of figure numbers and / or figure reference labels (if any) in the claims is intended to identify one or more possible embodiments of the claimed subject matter in order to facilitate the interpretation of the claims. Such use is not to be construed as necessarily limiting the scope of those claims to the embodiments shown in the corresponding figures.

[0094] Although the elements in the following method claims, if any, are recited in a particular sequence with corresponding labeling, unless the claim recitations otherwise imply a particular sequence for implementing some or all of those elements, those elements are not necessarily intended to be limited to being implemented in that particular sequence.Atty Ref. No. A0011026WO01

[0095] Reference herein to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the disclosure. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments necessarily mutually exclusive of other embodiments. The same applies to the term “implementation.”

[0096] Unless otherwise specified herein, the use of the ordinal adjectives “first,” “second,” “third,” etc., to refer to an object of a plurality of like objects merely indicates that different instances of such like objects are being referred to, and is not intended to imply that the like objects so referred-to have to be in a corresponding order or sequence, either temporally, spatially, in ranking, or in any other manner.

[0097] Unless otherwise specified herein, in addition to its plain meaning, the conjunction “if” may also or alternatively be construed to mean “when” or “upon” or “in response to determining” or “in response to detecting,” which construal may depend on the corresponding specific context. For example, the phrase “if it is determined” or “if [a stated condition] is detected” may be construed to mean “upon determining” or “in response to determining” or “upon detecting [the stated condition or event]” or “in response to detecting [the stated condition or event].”

[0098] Throughout the detailed description, the drawings, which are not to scale, are illustrative only and are used in order to explain, rather than limit the disclosure. The use of terms such as height, length, width, top, bottom, is strictly to facilitate the description of the embodiments and is not intended to limit the embodiments to a specific orientation. For example, height does not imply only a vertical rise limitation, but is used to identify one of the three dimensions of a three-dimensional structure as shown in the figures. Such "height" would be vertical where the electrodes are horizontal but would be horizontal where the electrodes are vertical, and so on. Similarly, while all figures show the different layers as horizontal layers such orientation is for descriptive purpose only and not to be construed as a limitation.Atty Ref. No. A0011026WO01

[0099] Also, for purposes of this description, the terms “couple,” “coupling,” “coupled,” “connect,” “connecting,” or “connected” refer to any manner known in the art or later developed in which energy is allowed to be transferred between two or more elements, and the interposition of one or more additional elements is contemplated, although not required. Conversely, the terms “directly coupled,” “directly connected,” etc., imply the absence of such additional elements. The same type of distinction applies to the use of terms “attached” and “directly attached,” as applied to a description of a physical structure. For example, a relatively thin layer of adhesive or other suitable binder can be used to implement such “direct attachment” of the two corresponding components in such physical structure.

[0100] The described embodiments are to be considered in all respects as only illustrative and not restrictive. In particular, the scope of the disclosure is indicated by the appended claims rather than by the description and figures herein. All changes that come within the meaning and range of equivalency of the claims are to be embraced within their scope.

[0101] The functions of the various elements shown in the figures, including any functional blocks labeled as “processors” and / or “controllers,” may be provided through the use of dedicated hardware as well as hardware capable of executing software in association with appropriate software. When provided by a processor, the functions may be provided by a single dedicated processor, by a single shared processor, or by a plurality of individual processors, some of which may be shared. Moreover, explicit use of the term “processor” or “controller” should not be construed to refer exclusively to hardware capable of executing software, and may implicitly include, without limitation, digital signal processor (DSP) hardware, network processor, application specific integrated circuit (ASIC), field programmable gate array (FPGA), read only memory (ROM) for storing software, random access memory (RAM), and nonvolatile storage. Other hardware, conventional and / or custom, may also be included. Similarly, any switches shown in the figures are conceptual only. Their function may be carried out through the operation of program logic, through dedicated logic, through the interaction of program control and dedicated logic, or even manually, the particular technique being selectable by the implementer as more specifically understood from the context.Atty Ref. No. A0011026WO01

[0102] As used in this application, the term “circuitry” may refer to one or more or all of the following:(a) hardware-only circuit implementations (such as implementations in only analog and / or digital circuitry); (b) combinations of hardware circuits and software, such as (as applicable): (i) a combination of analog and / or digital hardware circuit(s) with software / firmware and (ii) any portions of hardware processor(s) with software (including digital signal processor(s)), software, and memory(ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions); and(c) hardware circuit(s) and or processor(s), such as a microprocessor(s) or a portion of a microprocessor(s), that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.” This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and / or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

[0103] It should be appreciated by those of ordinary skill in the art that any block diagrams herein represent conceptual views of illustrative circuitry embodying the principles of the disclosure. Similarly, it will be appreciated that any flow charts, flow diagrams, state transition diagrams, pseudo code, and the like represent various processes which may be substantially represented in computer readable medium and so executed by a computer or processor, whether or not such computer or processor is explicitly shown.

[0104] The following examples are a non-limiting list of clauses in accordance with one or more techniques of this disclosure

[0105] Example 1. A medical system, comprising: an H-bridge circuit configured to generate a pulsed voltage waveform between first and second load terminals thereof; a switching circuit connected to the first and second load terminals, the switching circuit being configurable to route the pulsed voltage waveform from the H-bridge circuitAtty Ref. No. A0011026WO01 to a first selected set of a plurality of electrodes of an ablation device and being further configurable to route collected signals from a second selected set of the plurality of electrodes to a receiving circuit; and an electronic controller configured to cause the switching circuit to switch between a first routing configuration corresponding to a first operating mode and a second routing configuration corresponding to a second operating mode, wherein, in the first routing configuration, the first selected set of the plurality of electrodes is electrically connected to receive the pulsed voltage waveform from the H- bridge circuit via the switching circuit; and wherein, in the second routing configuration, the plurality of electrodes and the receiving circuit are electrically disconnected by the switching circuit from the H-bridge circuit.

[0106] Example 2. The medical system of Example 1, wherein the switching circuit includes three respective switches per electrode of the plurality of electrodes.

[0107] Example 3. The medical system of Example 1, wherein the switching circuit includes a plurality of first switches and a plurality of second switches; wherein each of the first switches is switchable by the electronic controller to selectively connect and disconnect a respective electrode of the plurality of electrodes to and from the first load terminal; and wherein each of the second switches is switchable by the electronic controller to selectively connect and disconnect a corresponding electrode of the plurality of electrodes to and from the second load terminal.

[0108] Example 4. The medical system of Example 3, wherein the switching circuit further includes a plurality of third switches; and wherein each of the third switches is switchable by the electronic controller to selectively connect and disconnect an associated electrode of the plurality of electrodes to and from the receiving circuit.

[0109] Example 5. The medical system of Example 1, wherein the receiving circuit is a part of a mapping and navigation system or a part of an electrophysiological recorder.

[0110] Example 6. The medical system of Example 1, wherein the ablation device is a catheter including an electrical bus disposed in an elongated body thereof andAtty Ref. No. A0011026WO01 configured to separately connect each electrode of the plurality of electrodes to the switching circuit.

[0111] Example 7. The medical system of Example 1, wherein the H-bridge circuit comprises: a first branch connected between a first power supply rail and a second power supply rail, the first branch including a first power switch, a first resistor configured to sense a first electrical current flowing through the first power switch, a second power switch serially connected with the first power switch, and a second resistor configured to sense a second electrical current flowing through the second power switch; and a second branch connected between the first power supply rail and the second power supply rail, the second branch including a third power switch, a third resistor configured to sense a third electrical current flowing through the third power switch, a fourth power switch serially connected with the third power switch, and a fourth resistor configured to sense a fourth electrical current flowing through the fourth power switch.

[0112] Example 8. The medical system of Example 7, further comprising a fault protection circuit electrically coupled to the first, second, third, and fourth resistors and configured to detect a fault condition based on the sensed first, second, third, and fourth electrical currents.

[0113] Example 9. The medical system of Example 8, wherein the electronic controller is further configured to inhibit the medical system from delivering the pulsed voltage waveform to the ablation device in response to the fault condition being detected.

[0114] Example 10. The medical system of Example 8, wherein the fault condition is detected when a shoot-through current flowing through the first branch or the second branch exceeds a threshold value.

[0115] Example 11. The medical system of Example 8, wherein the fault protection circuit comprises: a differential amplifier configured to generate an output signal proportional to a difference between a selected pair of the sensed first, second, third, and fourth electrical currents; a comparator configured to compare a voltage of the output signal with a threshold voltage; and a control circuit configured to detect the fault condition based on the comparison.Atty Ref. No. A0011026WO01

[0116] Example 12. A signal-routing method, comprising: with an electronic controller, controlling routing configurations of a switching circuit connected to first and second load terminals of an the H-bridge circuit, the switching circuit being configurable to route a pulsed voltage waveform from the H-bridge circuit to a first selected set of a plurality of electrodes of an ablation device and being further configurable to route collected signals from a second selected set of the plurality of electrodes to a receiving circuit, the controlling including: producing a first routing configuration by configuring the switching circuit to electrically connect the first selected set of the plurality of electrodes to receive the pulsed voltage waveform from the H-bridge circuit via the switching circuit; and producing a second routing configuration by configuring the switching circuit to electrically disconnect the plurality of electrodes and the receiving circuit from the H-bridge circuit.

[0117] Example 13. The signal-routing method of Example 12, wherein the switching circuit includes three respective switches per electrode of the plurality of electrodes.

[0118] Example 14. The signal-routing method of Example 13, wherein the switching circuit includes a plurality of first switches and a plurality of second switches; wherein each of the first switches is switchable by the electronic controller to selectively connect and disconnect a respective electrode of the plurality of electrodes to and from the first load terminal; and wherein each of the second switches is switchable by the electronic controller to selectively connect and disconnect a corresponding electrode of the plurality of electrodes to and from the second load terminal.

[0119] Example 15. The signal-routing method of Example 14, wherein the switching circuit further includes a plurality of third switches; and wherein each of the third switches is switchable by the electronic controller to selectively connect and disconnect an associated electrode of the plurality of electrodes to and from the receiving circuit.

[0120] Example 16. The signal-routing method of Example 12, wherein the receiving circuit is a part of a mapping and navigation system or a part of an electrophysiological recorder.Atty Ref. No. A0011026WO01

[0121] Example 17. The signal-routing method of claim 12, wherein the ablation device is a catheter including an electrical bus disposed in an elongated body thereof and configured to separately connect each electrode of the plurality of electrodes to the switching circuit.

[0122] Example 18. A medical system, comprising: an H-bridge circuit configured to apply a pulsed voltage waveform to an ablation device, the H-bridge circuit including a first branch connected between a first power supply rail and a second power supply rail and a second branch connected between the first power supply rail and the second power supply rail; a fault protection circuit electrically coupled to the H-bridge circuit and configured to detect a fault condition when a shoot-through current flowing through the first branch or the second branch exceeds a threshold value; and an electronic controller configured to inhibit the medical system from delivering the pulsed voltage waveform to the ablation device in response to the fault condition being detected.

[0123] Example 19. The medical system of Example 18, wherein the first branch includes a first power switch, a first resistor configured to sense a first electrical current flowing through the first power switch, a second power switch serially connected with the first power switch, and a second resistor configured to sense a second electrical current flowing through the second power switch; and wherein the second branch includes a third power switch, a third resistor configured to sense a third electrical current flowing through the third power switch, a fourth power switch serially connected with the third power switch, and a fourth resistor configured to sense a fourth electrical current flowing through the fourth power switch.

[0124] Example 20. The medical system of Example 19, wherein the fault protection circuit is electrically coupled to the first, second, third, and fourth resistors and is configured to detect the fault condition based on the sensed first, second, third, and fourth electrical currents.

[0125] Example 21. The medical system of Example 19, wherein the fault protection circuit comprises: a differential amplifier configured to generate an output signal proportional to a difference between a selected pair of the sensed first, second, third, and fourth electrical currents; a comparator configured to compare a voltage of the outputAtty Ref. No. A0011026WO01 signal with a threshold voltage; and a control circuit configured to detect the fault condition based on the comparison.

[0126] Example 22. A fault protection method for a medical system, the method comprising: with an H-bridge circuit, applying a pulsed voltage waveform to an ablation device, the H-bridge circuit including a first branch connected between a first power supply rail and a second power supply rail and a second branch connected between the first power supply rail and the second power supply rail; with a fault protection circuit electrically coupled to the H-bridge circuit, detecting a fault condition when a shoot- through current flowing through the first branch or the second branch exceeds a threshold value; and with an electronic controller, inhibiting the medical system from delivering the pulsed voltage waveform to the ablation device in response to the fault condition being detected.

Claims

Atty Ref. No. A0011026WO01 WHAT IS CLAIMED:

1. A medical system, comprising: an H-bridge circuit (300) configured to generate a pulsed voltage waveform between first and second load terminals (L1, L2) thereof; a switching circuit (620) connected to the first and second load terminals, the switching circuit being configurable to route the pulsed voltage waveform from the H- bridge circuit to a first selected set of a plurality of electrodes (112) of an ablation device (110) and being further configurable to route collected signals from a second selected set of the plurality of electrodes to a receiving circuit (610); and an electronic controller (123) configured to cause the switching circuit to switch between a first routing configuration corresponding to a first operating mode and a second routing configuration corresponding to a second operating mode, wherein, in the first routing configuration, the first selected set of the plurality of electrodes is electrically connected to receive the pulsed voltage waveform from the H- bridge circuit via the switching circuit; and wherein, in the second routing configuration, the plurality of electrodes and the receiving circuit are electrically disconnected by the switching circuit from the H-bridge circuit.

2. The medical system of claim 1, wherein the switching circuit includes three respective switches (Kn, K(n+9), K(n+18)) per electrode of the plurality of electrodes.

3. The medical system of claim 1, wherein the switching circuit includes a plurality of first switches (K1-K9) and a plurality of second switches (K19-K27); wherein each of the first switches is switchable by the electronic controller to selectively connect and disconnect a respective electrode of the plurality of electrodes to and from the first load terminal; and wherein each of the second switches is switchable by the electronic controller to selectively connect and disconnect a corresponding electrode of the plurality of electrodes to and from the second load terminal.Atty Ref. No. A0011026WO01 4. The medical system of claim 3, wherein the switching circuit further includes a plurality of third switches (K10- K18); and wherein each of the third switches is switchable by the electronic controller to selectively connect and disconnect an associated electrode of the plurality of electrodes to and from the receiving circuit.

5. The medical system of claim 1, wherein the receiving circuit is a part of a mapping and navigation system or a part of an electrophysiological recorder.

6. The medical system of claim 1, wherein the ablation device includes a catheter including an electrical bus (632) disposed in an elongated body thereof and configured to separately connect each electrode of the plurality of electrodes to the switching circuit.

7. The medical system of claim 1, wherein the H-bridge circuit comprises: a first branch (302) connected between a first power supply rail and a second power supply rail, the first branch including a first power switch, a first resistor configured to sense a first electrical current flowing through the first power switch, a second power switch serially connected with the first power switch, and a second resistor configured to sense a second electrical current flowing through the second power switch; and a second branch (304) connected between the first power supply rail and the second power supply rail, the second branch including a third power switch, a third resistor configured to sense a third electrical current flowing through the third power switch, a fourth power switch serially connected with the third power switch, and a fourth resistor configured to sense a fourth electrical current flowing through the fourth power switch.

8. The medical system of claim 7, further comprising a fault protection circuit (500) electrically coupled to the first, second, third, and fourth resistors and configured to detect a fault condition based on the sensed first, second, third, and fourth electrical currents.Atty Ref. No. A0011026WO01 9. The medical system of claim 8, wherein the electronic controller is further configured to inhibit the medical system from delivering the pulsed voltage waveform to the ablation device in response to the fault condition being detected.

10. The medical system of claim 8, wherein the fault condition is detected when a shoot-through current flowing through the first branch or the second branch exceeds a threshold value.

11. The medical system of claim 8, wherein the fault protection circuit comprises: a differential amplifier (510) configured to generate an output signal proportional to a difference between a selected pair of the sensed first, second, third, and fourth electrical currents; a comparator (530, 540) configured to compare a voltage of the output signal with a threshold voltage; and a control circuit (440) configured to detect the fault condition based on the comparison.

12. A signal-routing method, comprising: with an electronic controller (123), controlling (900) routing configurations of a switching circuit (620) connected to first and second load terminals (L1, L2) of an H- bridge circuit (300), the switching circuit being configurable to route a pulsed voltage waveform from the H-bridge circuit to a first selected set of a plurality of electrodes (112) of an ablation device (110) and being further configurable to route collected signals from a second selected set of the plurality of electrodes to a receiving circuit (610), the controlling including: producing a first routing configuration by configuring (904) the switching circuit to electrically connect the first selected set of the plurality of electrodes to receive the pulsed voltage waveform from the H-bridge circuit via the switching circuit; and producing a second routing configuration by configuring (906) the switching circuit to electrically disconnect the plurality of electrodes and the receiving circuit from the H-bridge circuit.Atty Ref. No. A0011026WO01 13. The signal-routing method of claim 12, wherein the switching circuit includes three respective switches (Kn, K(n+9), K(n+18)) per electrode of the plurality of electrodes.

14. The signal-routing method of claim 13, wherein the switching circuit includes a plurality of first switches (K1-K9) and a plurality of second switches (K19-K27); wherein each of the first switches is switchable by the electronic controller to selectively connect and disconnect a respective electrode of the plurality of electrodes to and from the first load terminal; and wherein each of the second switches is switchable by the electronic controller to selectively connect and disconnect a corresponding electrode of the plurality of electrodes to and from the second load terminal.

15. The signal-routing method of claim 14, wherein the switching circuit further includes a plurality of third switches (K10- K18); and wherein each of the third switches is switchable by the electronic controller to selectively connect and disconnect an associated electrode of the plurality of electrodes to and from the receiving circuit.

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