Abnormal pulse delivery protection for pulsed field ablation systems

Abstract

One aspect provides a pulsed field ablation system that includes a bridge circuit configured to deliver bipolar and dual-phase voltage pulses to a catheter. An asynchronous current monitoring circuit is electrically coupled to the bridge circuit. An electronic processor is coupled to the bridge circuit and the asynchronous current monitoring circuit. The electronic processor is configured to determine if there is an abnormal pulse delivery in the bridge circuit and to control the bridge circuit to deliver a therapeutic current to the catheter when there is no abnormal pulse delivery. The electronic processor is further configured to inhibit the bridge circuit from delivering a therapeutic current to the catheter when there is the abnormal pulse delivery.

Description

[0001] This application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 387,473, filed on December 14, 2022, the entire content of which is incorporated herein by reference. BACKGROUND OF THE INVENTION

[0002] Pulse field ablation delivers rapid, bipolar, and biphasic high-voltage pulse sequences to perform irreversible electroporation of tissue. Pulse field ablation is used to treat arrhythmias and atrial fibrillation, among other things. Pulse field ablation can also be used as an oncology treatment for cancer. SUMMARY OF THE INVENTION

[0003] Electrophysiological procedures are used to treat many different conditions. A pulse field ablation system can be used to deliver rapid, bipolar, and biphasic high-voltage direct current (DC) pulse sequences to a patient to effect irreversible electroporation. A catheter is used to deliver the high-voltage pulses to the patient. Premature ventricular contractions should be avoided during the procedure to avoid pain due to nerve stimulation and the need for patient sedation due to muscle activation. Delivering biphasic pulses with short durations between pulses helps reduce premature ventricular contractions. However, a pulse field ablation system may sometimes fail and deliver monophasic pulses or biphasic pulses with long intervals, which can cause premature ventricular contractions.

[0004] Accordingly, there is a need for abnormal pulse delivery protection in a pulse field ablation system.

[0005] The techniques disclosed herein generally relate to an abnormal pulse delivery detection circuit and method for a pulse field ablation system. The abnormal pulse delivery detection circuit and method help reduce unwanted or non-therapeutic currents delivered to a patient that cause premature ventricular contractions.

[0006] One aspect provides a pulse field ablation system that includes: a bridge circuit configured to deliver bipolar and biphasic voltage pulses to a catheter; an asynchronous current monitoring circuit electrically coupled to the bridge circuit; and an electronic processor coupled to the bridge circuit and the asynchronous current monitoring circuit. The electronic processor is configured to determine whether there is an abnormal pulse delivery in the bridge circuit and, when there is no abnormal pulse delivery, control the bridge circuit to deliver a therapeutic current to the catheter. The electronic processor is further configured to prohibit the bridge circuit from delivering a therapeutic current to the catheter when there is an abnormal pulse delivery.

[0007] On the other hand, a method for abnormal pulse delivery protection in a pulsed field ablation system is provided. The pulsed field ablation system includes a bridging circuit configured to deliver bipolar and biphasic voltage pulses to a catheter and an asynchronous current monitoring circuit electrically coupled to the bridging circuit. The method includes using the asynchronous current monitoring circuit to determine whether there is abnormal pulse delivery in the bridging circuit, and when there is no abnormal pulse delivery, using an electronic processor to control the bridging circuit to deliver therapeutic current to the catheter. The method further includes using the electronic processor to prohibit the bridging circuit from delivering therapeutic current to the catheter when there is abnormal pulse delivery.

[0008] Various embodiments, examples, aspects, and features are set forth in the following description and the drawings. Other embodiments, examples, aspects, features, objects, and advantages of the techniques described in this disclosure will be apparent from the specification, the drawings, and the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Like reference numerals in the drawings denote identical or functionally similar elements throughout the views. The drawings, together with the following detailed description, are incorporated in and form a part of the specification, and are used to further illustrate various embodiments, examples, aspects, and features of the claimed subject matter and to explain the various principles and advantages of those embodiments, examples, aspects, and features.

[0010] Figure 1 is a simplified block diagram illustrating a pulsed field ablation system according to some examples.

[0011] Figure 2 illustrates a voltage pulse delivered by a pulsed field ablation system according to some examples Figure 1 of.

[0012] Figure 3 is a simplified schematic diagram illustrating the bridging circuit of a pulsed field ablation system according to some examples Figure 1 of.

[0013] Figure 4 is a simplified block diagram illustrating the asynchronous current monitoring circuit of a pulsed field ablation system according to some examples Figure 1 of.

[0014] Figure 5A and Figure 5B are flowcharts of methods for detecting abnormal pulse delivery in a pulsed field ablation system according to some examples Figure 1 of.

[0015] Figure 6 is a flowchart of a method for abnormal pulse delivery protection in a pulsed field ablation system for Figure 1 according to some examples.

[0016] Figure 7 is a flowchart of a method for abnormal pulse delivery protection in a pulsed field ablation system for Figure 1 .

[0017] Those skilled in the art will understand that the elements in the drawings are illustrated for simplicity and clarity and are not necessarily drawn to scale. For example, the dimensions of some of the elements in the drawings may be enlarged relative to other elements to help improve the understanding of the examples.

[0018] Device and method components have been represented by conventional symbols in the drawings where appropriate, so as to show only those specific details relevant to the understanding of the embodiments, examples, aspects, and features, and as not to obscure the disclosure with details that are readily apparent to those of ordinary skill in the art and that have the benefits of the description herein. Detailed Description

[0019] Before explaining any embodiments, examples, aspects, and features in detail, it should be understood that those embodiments, examples, aspects, and features are not limited in their application to the construction details and component arrangements set forth in the following description or illustrated in the following drawings. Other embodiments, examples, aspects, and features are possible and can be practiced or carried out in various ways.

[0020] In addition, it should be understood that the terminology and terms used herein are for the purpose of description and should not be regarded as restrictive. The terms "mounted," "connected," and "coupled" are used broadly and encompass direct and indirect mounting, connection, and coupling. The terms "connected" and "coupled" are not limited to physical or mechanical connection or coupling and can include direct or indirect electrical connection or coupling. The electronic communications and notifications described herein can be performed using any known or future-developed means, including wired connections, wireless connections, and the like.

[0021] For ease of description, some or all of the example systems presented herein are illustrated with a single example of each of their components. Some examples may not describe or illustrate all components of the system. Other embodiments, examples, aspects, and features may include more or fewer of each of the illustrated components, may combine some components, or may include additional or alternative components.

[0022] Figure 1 A simplified block diagram of an example of a pulsed field ablation system 100 is illustrated. The pulsed field ablation system 100 is used to deliver a sequence of rapid, bipolar, and biphasic voltage pulses (e.g., as Figure 2 shown) to a catheter 110 to perform irreversible electroporation of tissue. The pulsed field ablation system 100 includes a bridge circuit 120, an asynchronous current monitoring circuit 130, an electronic processor 140, and a memory 150.

[0023] The catheter 110 is a multi-electrode catheter that includes a plurality of electrodes arranged successively around a closed or semi-closed region. The catheter 110 delivers voltage pulses to tissue within the closed or semi-closed region. In some examples, the catheter 110 can be a disposable catheter 110 that is set up after each use, and a new disposable catheter 110 is connected to the pulsed field ablation system 100 for each different procedure. The bridging circuit 120 is electrically coupled to the catheter 110. The bridging circuit 120 generates voltage pulses and delivers the voltage pulses to the catheter 110. The asynchronous current monitoring circuit 130 is electrically coupled to the bridging circuit 120. The asynchronous current monitoring circuit 130 detects abnormal pulses generated by the bridging circuit 120.

[0024] The electronic processor 140 is electrically coupled to the bridging circuit 120 and the asynchronous current monitoring circuit 130 and is configured to control and monitor the bridging circuit 120 and the asynchronous current monitoring circuit 130. In some examples, the electronic processor 140 is implemented as a microprocessor with a separate memory (such as the memory 150). In other examples, the electronic processor 140 can be implemented as a microcontroller (with the memory 150 on the same chip). In other examples, the electronic processor 140 can be implemented using multiple processors (in some cases, located far from each other). Additionally, the electronic processor 140 can be partially or fully implemented as, for example, a field programmable gate array (FPGA), an application specific integrated circuit (ASIC), an x86 processor, etc., and the memory 150 may not be required or can be modified accordingly. In the illustrated example, the memory 150 includes non-transitory computer-readable memory that stores instructions received and executed by the electronic processor 140 to perform the functionality of the pulsed field ablation system 100 described herein. The memory 150 can include, for example, a program storage area and a data storage area. The program storage area and the data storage area can include a combination of different types of memory, such as read-only memory and random access memory. In some examples, the pulsed field ablation system 100 includes one electronic processor 140 and / or multiple electronic processors 140 in a computer cluster arrangement, and one or more of the multiple electronic processors may not be executing the application of the pulsed field ablation system 100, may not be executing all of the applications of the pulsed field ablation system application, or may not be executing a portion of the applications of the pulsed field ablation system application.

[0025] Figure 3A simplified schematic diagram of the bridge circuit 120 is illustrated. In the illustrated example, the bridge circuit 120 is a full H-bridge circuit. In other examples, the bridge circuit 120 may be an inverter bridge circuit or the like. The full H-bridge circuit is composed of a first transistor switch 210, a second transistor switch 220, a third transistor switch 230, and a fourth transistor switch 240. The transistor switches 210 to 240 include, for example, insulated gate bipolar transistors (IGBTs), field effect transistors (FETs), etc.

[0026] The power supply 250 supplies high-voltage power to the H-bridge circuit. For the pulsed field ablation system 100, the high-voltage power may be in the range between 300 volts and 2000 volts. The power supply 250 generates a high-voltage potential between a positive power supply node 250A and a negative power supply node 250B (e.g., electrical ground). The power supply 250 may include a high-voltage battery system or an alternating current (AC) power system that is converted to direct current (DC) power.

[0027] The first transistor switch 210 is electrically coupled between the positive power supply node 250A and the first bridge output node 260. The second transistor switch 220 is electrically coupled between the first bridge output node 260 and the negative power supply node 250B. In one example, the source of the first transistor switch 210 is electrically coupled to the drain of the second transistor switch 220 at the first bridge output node 260. The third transistor switch 230 is electrically coupled between the positive power supply node 250A and the second bridge output node 270. The fourth transistor switch 240 is electrically coupled between the second bridge output node 270 and the negative power supply node 250B. In one example, the source of the third transistor switch 230 is electrically coupled to the drain of the fourth transistor switch 240 at the second bridge output node 270.

[0028] The bridge circuit 120 further includes a first patient cathode electrode connector 110A and a second patient cathode electrode connector 110B. The first patient cathode electrode connector 110A and the second patient cathode electrode connector 110B are configured to be connected to opposite electrodes (e.g., positive and negative electrodes respectively) of the catheter 110 (e.g., patient load) to deliver voltage pulses from the bridge circuit 120. The first patient cathode electrode connector 110A and the second patient cathode electrode connector 110B are electrically coupled between the first bridge output node 260 and the second bridge output node 270. A first relay 280A is disposed between the first bridge output node 260 and the first patient cathode electrode connector 110A, and a second relay 280B is disposed between the second patient cathode electrode connector 10B and the second bridge output node 270. The first relay 280A and the second relay 280B are controlled by the electronic processor 140 to selectively disconnect and close the circuit path between the first bridge output node 260, the catheter 110, and the second bridge output node 270.

[0029] The bridge circuit 120 further includes a first patient-isolated internal load connector 290A and a second patient-isolated internal load connector 290B. The first patient-isolated internal load connector 290A and the second patient-isolated internal load connector 290B connect the patient-isolated internal load 290 between the first bridge output node 260 and the second bridge output node 270. The patient-isolated internal load 290 is used to detect leakage faults in the bridge circuit 120. A third relay 280C is disposed between the first bridge output node 260 and the patient-isolated internal load 290, and a fourth relay 280D is disposed between the patient-isolated internal load 290 and the second bridge output node 270. The third relay 280C and the fourth relay 280D are controlled by the electronic processor 140 to selectively open and close the circuit path between the first bridge output node 260, the patient-isolated internal load 290, and the second bridge output node 270.

[0030] A first resistor 300A is electrically coupled between (i) the first bridge output node 260 and (ii) the first relay 280A and the third relay 280C. A second resistor 300B is electrically coupled between (i) the second bridge output node 270 and (ii) the second relay 280B and the fourth relay 280D. A third resistor 300C is electrically coupled between the positive power supply node 250A and the first transistor switch 210. A fourth resistor 300D is electrically coupled between the second transistor switch 220 and the negative power supply node 250B. A fifth resistor 300E is electrically coupled between the positive power supply node 250A and the third transistor switch 230. A sixth resistor 300F is electrically coupled between the fourth transistor switch 240 and the negative power supply node 250B. The resistors 300A to 300F can be used as current detection elements for the asynchronous current monitoring circuit 130, as described in more detail below.

[0031] The electronic processor 140 is used to control the transistor switches 210 to 240 and the relay 280 to selectively open and close the circuit paths respectively. A gate driver may be included in the bridge circuit 120 to provide drive signals to the transistor switches 210 to 240. The gate driver provides drive signals to the transistor switches 210 to 240 based on control signals received from the electronic processor 140. When the transistor switches 210 to 240 are closed, the transistor switches 210 to 240 allow current to flow through the transistor switches 210 to 240 to components connected downstream of the transistor switches 210 to 240. When the transistor switches 210 to 240 are open, the transistor switches 210 to 240 prohibit current from flowing through the transistor switches 210 to 240 to components connected downstream of the transistor switches 210 to 240. Similarly, when the relay 280 is closed, the relay 280 allows current to flow through the relay 280 to components connected downstream of the relay 280. When the relay 280 is open, the relay 280 prohibits current from flowing through the relay 280 to components connected downstream of the relay 280.

[0032] The first relay 280A and the second relay 280B are closed to form a circuit path between the first bridge output node 260, the conduit 110, and the second bridge output node 270 for delivering therapeutic current to the conduit 110. When delivering therapeutic current to the conduit 110, the third relay 280C and the fourth relay 280D are open. The electronic processor 140 controls the transistor switches 210 to 240 to provide sequential bipolar, biphasic high voltage pulses to the conduit 110. The transistor switches 210 to 240 may be configured such that the transistor switches 210 to 240 are normally open. That is, the default state of the transistor switches 210 to 240 is the open state. The electronic processor 140 closes the first transistor switch 210 and the fourth transistor switch 240, and keeps the second transistor switch 220 and the third transistor switch 230 open to provide therapeutic current to the conduit 110 in a first direction (e.g., the positive direction). The electronic processor 140 closes the second transistor switch 220 and the third transistor switch 230, and keeps the first transistor switch 210 and the fourth transistor switch 240 open to provide therapeutic current to the conduit 110 in a second direction (e.g., the negative direction). The switching between the first direction and the second direction is performed at a high frequency. For example, therapeutic current is provided in each direction for a time of 4 microseconds, with a 5 microsecond gap between each direction. During the 5 microsecond gap, all the transistor switches 210 to 240 are turned off.

[0033] The bridging circuit 120 is designed to provide a biphasic voltage pulse having a very short duration (e.g., 4 microseconds for pulsed field ablation). However, components of the bridging circuit 120 may sometimes fail, resulting in an abnormal voltage pulse being delivered to the catheter 110. Abnormal pulse delivery may include single-phase pulse delivery or long-duration biphasic pulse delivery. These abnormal voltage pulses may cause unwanted premature ventricular contractions. The asynchronous current monitoring circuit 130 can be used to detect abnormal pulses generated or delivered by the bridging circuit 120.

[0034] Figure 4 A simplified schematic diagram of the asynchronous current monitoring circuit 130 is illustrated. The asynchronous current monitoring circuit 130 may be connected across any one or more of the resistors 300 (e.g., current sensing elements). In the example illustrated, the asynchronous current monitoring circuit 130 includes measurement resistors 300_1 and 300_2 connected in series. The measurement resistors 300_1 and 300_2 represent any one of the resistors 300. A differential amplifier 310 is connected across the measurement resistors 300_1 and 300_2 such that the first ends of the measurement resistors 300_1 and 300_2 are connected to the non-inverting input terminal 310A of the differential amplifier 310, and the second ends of the measurement resistors 300_1 and 300_2 are connected to the inverting input terminal 310B of the differential amplifier 310. Resistors 320A to 320D are connected between the measurement resistors 300_1 and 300_2, the input terminals 310A to 310B of the differential amplifier 310, and the output terminal 310C of the differential amplifier 310 to provide voltage gain. The resistors 320A to 320D may be selected to sufficiently amplify the current flowing through the current sensing element of the pulsed field ablation system 100.

[0035] The output terminal 310C of the differential amplifier 310 is electrically coupled to the non-inverting input terminal of the threshold comparator 330. The asynchronous current monitoring circuit 130 further includes a digital potentiometer 340 that provides a variable voltage output to the inverting input terminal of the threshold comparator 330. A programmable oscillator 350 provides a clock signal to the digital potentiometer 340. The threshold output of the threshold comparator 330 is provided to the enable input of the digital potentiometer 340. The digital potentiometer 340 is configured for a voltage range between a minimum voltage and a maximum voltage. When the digital potentiometer 340 is enabled, for example, using the enable input, the voltage output of the digital potentiometer 340 changes between the minimum voltage and the maximum voltage based on the input clock signal and a control signal received from the electronic processor 140. In Figure 4 the example, the enable input includes a chip select input Chip_Select_n, where n indicates inverted logic.

[0036] The voltage output of the digital potentiometer 340 is also provided to the analog-to-digital converter 360. The analog-to-digital converter 360 converts the analog voltage value detected at the voltage output into a digital value corresponding to the voltage value, and provides the digital value to the electronic processor 140. The electronic processor 140 controls the programmable oscillator 350 to provide a clock signal to the digital potentiometer 340. The reset circuit 370 is coupled between the electronic processor 140 and the enable input of the digital potentiometer 340. The up / down control circuit 380 is coupled between the electronic processor 140 and the control input of the digital potentiometer 340. In Figure 4 the example of

[0037] the up / down control circuit provides an UP / DOWN_n signal to the digital potentiometer 340, where n indicates inverted logic. For example, when the control signal is low, the voltage output of the digital potentiometer 340 increases from its current value to a higher value between the minimum voltage and the maximum voltage. When the control signal is high, the voltage output of the digital potentiometer 340 decreases from its current value to a lower value between the minimum voltage and the maximum voltage.

[0038] The threshold comparator 330 and the digital potentiometer 340 are configured to detect the peak current flowing through the resistor 300. When current flows across the sense resistors 300_1 and 300_2, the voltage drops across the sense resistors 300_1 and 300_2 are amplified by the differential amplifier 310, and a detection parameter proportional to the voltage drop is provided to the non-inverting input of the threshold comparator 330. When the detection parameter at the non-inverting input exceeds the output of the digital potentiometer 340 at the inverting input, the threshold output of the threshold comparator 330 switches state (e.g., from high to low or from low to high). The threshold comparator 330 and the digital potentiometer 340 are also configured such that the digital potentiometer 340 is enabled by the threshold output when the voltage output of the digital potentiometer 340 is less than the detection parameter, and the digital potentiometer is disabled by the threshold output when the voltage output is greater than the detection parameter. When the voltage output of the digital potentiometer 340 corresponds to (i.e., is equal to or just greater than) the detection parameter, the digital potentiometer 340 is disabled by the threshold comparator 330. The voltage output is latched at the voltage value that is converted by the analog-to-digital converter 360 and provided to the electronic processor 140. Once the electronic processor 140 determines the peak, the electronic processor 140 resets the digital potentiometer 340 using the reset circuit 370.

[0038] In some examples, oscillations at the enable input of the digital potentiometer 340 can trigger a write operation to the internal memory, which renders the digital potentiometer 340 unavailable for a significant amount of time. To mitigate this unexpected behavior, a timer circuit 390 is electrically coupled between the threshold output of the comparator 330 and the enable input of the digital potentiometer 340. The time constant of the timer circuit 390 is configured to avoid the threshold output of the threshold comparator 330 inadvertently triggering the write operation. In one example, the time constant of the timer circuit 390 is 0.82 microseconds.

[0039] For simplicity of illustration, Figure 1 and Figure 4 a single asynchronous current monitor 130 is illustrated. However, the pulsed field ablation system 100 can include multiple asynchronous current monitors 130 connected across multiple resistors 300 to measure current in two directions. In one example, a first asynchronous current monitor 130 is connected across a first resistor 300A to measure current in a first direction, and a second asynchronous current monitor 130 is also connected across the first resistor 330A to measure current in a second direction. In another example, a third asynchronous current monitor 130 is connected across a second resistor 300B to measure current in a first direction, and a fourth asynchronous current monitor 130 is also connected across the second resistor 330B to measure current in a second direction. In some examples, a single asynchronous current monitor 130 can include multiple components, such as multiple differential amplifiers 310, a threshold comparator 330, and a digital potentiometer 340 connected across a first resistor 300A and a second resistor 300B. For example, first and second differential amplifiers 310, first and second threshold comparators 330, and first and second digital potentiometers 340 can be connected across the first resistor 300A to detect current flowing in the first and second directions, respectively. Similarly, third and fourth differential amplifiers 310, third and fourth threshold comparators 330, and third and fourth digital potentiometers 340 can be connected across the second resistor 300B to detect current flowing in the first and second directions, respectively.

[0040] Figure 5AIt is a flowchart of an example method 400 for detecting abnormal pulse delivery in a pulsed field ablation system 100. In the illustrated example, method 400 includes determining a first peak current value in a first direction (at block 410) and determining a second peak current value in a second direction (at block 420). In one example, the electronic processor 140 uses a first asynchronous current monitor 130 to detect the first peak current value in the first direction and uses a second asynchronous current monitor 130 to detect the second peak current value in the second direction. In another example, the electronic processor 140 uses a first digital potentiometer 340 to detect the first peak current value in the first direction and uses a second digital potentiometer 340 to detect the second peak current value in the second direction. Detect the first peak current value and the second peak current value for the first current detection element (e.g., the first resistor 300A)

[0041] Method 400 includes determining whether there is abnormal pulse delivery based on the first peak current value and the second peak current value (at block 430). In one example, the electronic processor 140 uses the following formula to calculate the monophasic asymmetry index (MAI):

[0042]

[0043] where I1 is the first peak current value and I2 is the second peak current value. An MAI of 1 represents total asymmetry, i.e., an ideal monophasic pulse. An MAI of 0 represents complete symmetry, i.e., an ideal biphasic pulse. Any value above 0 or above a suitable fractional or decimal threshold between 0 and 1 can indicate abnormal pulse delivery.

[0044] In some examples, the pulsed field ablation system 100 can optionally use two current detection elements (e.g., the first resistor 300A and the second resistor 300B) to detect the current flow on either side of the catheter 110 to determine whether there is abnormal pulse delivery. Figure 5B An extension of method 400 is illustrated to determine whether there is abnormal pulse delivery based on two current detection elements. In the illustrated example, method 400 includes determining a third peak current value in a first direction (at block 440) and determining a fourth peak current value in a second direction (at block 450). In one example, the electronic processor 140 uses a third asynchronous current monitor 130 to detect the third peak current value in the first direction and uses a fourth asynchronous current monitor 130 to detect the fourth peak current value in the second direction. In another example, the electronic processor 140 uses a third digital potentiometer 340 to detect the third peak current value in the first direction and uses a fourth digital potentiometer 340 to detect the fourth peak current value in the second direction. Detect the third peak current value and the fourth peak current value for the second current detection element (e.g., the second resistor 300B)

[0045] Method 400 includes further determining whether there is an abnormal pulse delivery (at block 460) based on the third peak current value and the fourth peak current value. In one example, the electronic processor 140 uses the following formula to calculate the monopolar asymmetry index (MAI):

[0046]

[0047] where I3 is the third peak current value and I4 is the fourth peak current value. An MAI of 1 represents total asymmetry, i.e., an ideal monopolar pulse. An MAI of 0 represents full symmetry, i.e., an ideal bipolar pulse. Any value above 0 or above a suitable fractional or decimal threshold between 0 and 1 can indicate an abnormal pulse delivery.

[0048] The period between successive calculations of the MAI by the electronic processor 140 can vary from one bipolar / monopolar pulse to an entire pulse train. The electronic processor 140 can change the period used to calculate the MAI based on user input or based on requirements of the pulsed field ablation system 100 (e.g., to determine abnormal pulse delivery). However, the asynchronous current monitor may need to be reset after the calculation to detect subsequent monopolar pulses that may occur before the end of the pulse train. Based on the duration and number of pulses for which the MAI will be calculated, the threshold for the MAI can be defined based on empirical data. After the threshold has been defined, method 400 uses the calculated MAI to determine whether the treatment delivery has a monopolar pulse. For the evaluation of method 400, the unilateral MAI (e.g., the MAI determined at block 430) can be calculated every 900 microseconds with a threshold of 0.76 and a pulse of 200 microseconds to reset the digital potentiometer.

[0049] Figure 6 is a flowchart of an example method 500 for abnormal pulse delivery protection in the pulsed field ablation system 100. In the illustrated example, method 500 includes using the asynchronous current monitoring circuit 130 to determine whether there is an abnormal pulse delivery in the pulsed field ablation system 100 (at block 510). The electronic processor 140 uses Figure 5A and / or Figure 5B the method 400 of

[0050] Method 500 includes using an electronic processor 140 to control a bridging circuit 120 to deliver a therapeutic current to a catheter 110 (at block 520) when there is no abnormal pulse delivery. In response to determining that there is no abnormal pulse delivery based on the MAI, the electronic processor 140 operates the bridging circuit 120 normally to generate a therapeutic current and provide the therapeutic current to the catheter 110. Method 500 includes using an electronic processor 140 to inhibit the bridging circuit 120 from delivering a therapeutic current to the catheter 110 (at block 530) when there is an abnormal pulse delivery. In response to determining that there is an abnormal pulse delivery based on the MAI, the electronic processor 140 may turn off the bridging circuit 120 and inhibit the bridging circuit 120 from providing a therapeutic current to the catheter 110.

[0051] Figure 7 Is a flowchart of an example method 600 for abnormal pulse delivery protection in a pulsed field ablation system 100. Method 600 is similar to method 500 and may be executed concurrently with method 500 to provide abnormal pulse delivery protection. In the illustrated example, method 600 includes using an electronic processor 140 to control a bridging circuit 120 to deliver a therapeutic current to a catheter 110 (at block 610). The electronic processor 140 operates the bridging circuit 120 normally to generate a therapeutic current and provide the therapeutic current to the catheter 110. Method 600 also includes using an asynchronous current monitoring circuit 130 to determine whether there is an abnormal pulse delivery in the pulsed field ablation system 100 (at block 620). The electronic processor 140 uses Figure 5A and / or Figure 5B Method 400 of to determine whether there is an abnormal pulse delivery in the pulsed field ablation system 100. In some examples, method 600 may implement an initial delay before starting abnormal pulse delivery detection.

[0052] Method 600 includes using electronic processor 140 to reset asynchronous current monitoring circuit 130 (at block 630) when there is no abnormal pulse delivery. In response to determining that there is no abnormal pulse delivery based on the MAI, electronic processor 140 uses reset circuit 370 to reset asynchronous current monitoring circuit 130. After asynchronous current monitoring circuit 130 is reset, method 600 includes waiting for a predetermined amount of time (at block 640) before continuing to execute the next instance of determining whether there is an abnormal pulse delivery at block 620. A settling time can be used to determine the predetermined time. In one example, the predetermined time is 900 microseconds. As long as no abnormal pulse is detected, method 600 continues to deliver the therapeutic current. However, method 600 resets the asynchronous current monitor after each instance of current monitoring to reset digital potentiometer 340. Method 600 includes using electronic processor 140 to inhibit bridge circuit 120 from delivering the therapeutic current to catheter 110 when there is an abnormal pulse delivery (at block 650). In response to determining that there is an abnormal pulse delivery based on the MAI, electronic processor 140 can open bridge circuit 120 and inhibit bridge circuit 120 from providing the therapeutic current to catheter 110.

[0053] It should be understood that the various aspects disclosed herein can be combined in combinations different from those specifically presented in the specification and drawings. It should also be understood that, depending on the example, certain acts or events of any of the processes or methods described herein can be performed in a different order, can be completely added, combined, or omitted (e.g., not all of the described acts or events may be required to perform the techniques). Additionally, although certain aspects of the present disclosure are described as being performed by a single module or unit for clarity, it should be understood that the techniques of the present disclosure can be performed by a combination of units or modules associated with, for example, a medical device.

[0054] In one or more examples, the described techniques can be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions can be stored as one or more instructions or code on a computer-readable medium and executed by a hardware-based processing unit. The computer-readable medium can include a non-transitory computer-readable medium that corresponds to a tangible medium such as a data storage medium (e.g., RAM, ROM, EEPROM, flash memory, or any other medium that can be used to store the desired program code in the form of instructions or data structures and that can be accessed by a computer).

[0055] The instructions may be executed by one or more processors, such as one or more digital signal processors (DSPs), general-purpose microprocessors, application specific integrated circuits (ASICs), field programmable gate arrays (FPGAs), or other equivalent integrated or discrete logic circuitry. Thus, the term “processor” as used herein may refer to any of the foregoing structures or any other physical structure suitable for implementing the described techniques. Additionally, these techniques may be fully implemented in one or more circuits or logic elements.

[0056] The following examples are a non-limiting list of articles according to one or more techniques of the present disclosure.

[0057] Example 1. A pulsed field ablation system, the pulsed field ablation system comprising: a bridging circuit configured to deliver bipolar and biphasic voltage pulses to a catheter; an asynchronous current monitoring circuit electrically coupled to the bridging circuit; and an electronic processor coupled to the bridging circuit and the asynchronous current monitoring circuit, the electronic processor being configured to: determine whether there is an abnormal pulse delivery in the bridging circuit; when there is no such abnormal pulse delivery, control the bridging circuit to deliver a treatment current to the catheter; and when there is such abnormal pulse delivery, prohibit the bridging circuit from delivering the treatment current to the catheter.

[0058] Example 2. The pulsed field ablation system according to Example 1, wherein the abnormal pulse delivery includes one or more selected from the group consisting of single-phase pulse delivery and long-duration biphasic pulse delivery.

[0059] Example 3. The pulsed field ablation system according to any one of the preceding claims, wherein the electronic processor is configured to: determine a first peak current value in a first direction; determine a second peak current value in a second direction; and determine whether there is such abnormal pulse delivery based on the first peak current value and the second peak current value.

[0060] Example 4. The pulsed field ablation system according to Example 3, wherein the electronic processor is further configured to: determine a third peak current value in the first direction; determine a fourth peak current value in the second direction; and further determine whether there is such abnormal pulse delivery based on the third peak current value and the fourth peak current value.

[0061] Example 5. The pulsed field ablation system according to any one of the preceding claims, wherein the asynchronous current monitoring circuit includes a digital potentiometer configured to: provide an output proportional to the current flowing through the current detection element of the bridging circuit, wherein the electronic processor is electrically coupled to the digital potentiometer and configured to receive the output from the digital potentiometer; and determine a peak current value of the current flowing through the current detection element based on the output.

[0062] Example 6. The pulsed field ablation system according to Example 5, the pulsed field ablation system further comprising: an analog-to-digital converter electrically coupled between the output of the digital potentiometer and the electronic processor, the analog-to-digital converter being configured to convert an analog voltage value received from the digital potentiometer into a digital value provided to the electronic processor.

[0063] Example 7. The pulsed field ablation system according to any one of Examples 5 to 6, wherein the asynchronous current monitoring circuit further includes a threshold comparator configured to receive, at a non-inverting input, a detection parameter corresponding to the current flowing through the current detection element; receive, at an inverting input, the output of the digital potentiometer; and provide a threshold output to the digital potentiometer, wherein the digital potentiometer is configured to be enabled by the threshold output when the output is less than the detection parameter and to be disabled by the threshold output when the output is greater than the detection parameter.

[0064] Example 8. The pulsed field ablation system according to Example 7, wherein the asynchronous current monitoring circuit further includes a differential amplifier electrically coupled between the current detection element and the threshold comparator, wherein the differential amplifier is configured to detect a voltage drop across the current detection element and provide the detection parameter to the threshold comparator, wherein the detection parameter is proportional to the voltage drop across the current detection element.

[0065] Example 9. The pulsed field ablation system according to any one of Examples 7 to 8, wherein the asynchronous current monitoring circuit further includes a timer circuit electrically coupled between the threshold comparator and the digital potentiometer.

[0066] Example 10. The pulsed field ablation system according to any one of Examples 5 to 9, wherein the asynchronous current monitoring circuit includes a second digital potentiometer configured to provide a second output proportional to the current flowing through a second current detection element of the bridge circuit, wherein the electronic processor is electrically coupled to the second digital potentiometer and configured to receive the second output from the second digital potentiometer; and determine a second peak current value of the current flowing through the second current detection element based on the second output.

[0067] Example 11. The pulsed field ablation system according to any one of Examples 5 to 10, wherein the bridge circuit includes: a first transistor switch electrically coupled between a positive power supply node and a first bridge output node; a second transistor switch electrically coupled between the first bridge output node and a negative power supply node; a third transistor switch electrically coupled between the positive power supply node and a second bridge output node; and a fourth transistor switch electrically coupled between the second bridge output node and the negative power supply node, wherein the electronic processor is electrically coupled to the first transistor switch, the second transistor switch, the third transistor switch, and the fourth transistor switch, and the electronic processor controls to selectively open and close the first transistor switch, the second transistor switch, the third transistor switch, and the fourth transistor switch.

[0068] Example 12. The pulsed field ablation system according to Example 11, wherein the current detection element is electrically coupled between the first bridge output node and the second bridge output node.

[0069] Example 13. The pulsed field ablation system according to Example 12, wherein the first direction is the current flow direction from the first transistor switch to the fourth transistor switch, and the second direction is the current flow direction from the third transistor switch to the second transistor switch.

[0070] Example 14. The pulsed field ablation system according to any one of the preceding claims, wherein the electronic processor is further configured to change the period for determining the abnormal pulse delivery.

[0071] Example 15. A method for protecting against abnormal pulse delivery in a pulsed field ablation system, the pulsed field ablation system including a bridging circuit configured to deliver bipolar and biphasic voltage pulses to a catheter and an asynchronous current monitoring circuit coupled to the bridging circuit, the method comprising: using the asynchronous current monitoring circuit to determine whether there is abnormal pulse delivery in the bridging circuit; when there is no abnormal pulse delivery, using an electronic processor to control the bridging circuit to deliver a treatment current to the catheter; and when there is abnormal pulse delivery, using the electronic processor to prohibit the bridging circuit from delivering the treatment current to the catheter.

[0072] Example 16. The method according to Example 15, wherein the abnormal pulse delivery includes one or more selected from the group consisting of single-phase pulse delivery and long-duration biphasic pulse delivery.

[0073] Example 17. The method according to any one of Examples 15 to 16, the method further comprising: determining a first peak current value in a first direction; determining a second peak current value in a second direction; and determining whether there is the abnormal pulse delivery based on the first peak current value and the second peak current value.

[0074] Example 18. The method according to Example 17, the method further comprising: determining a third peak current value in the first direction; determining a fourth peak current value in the second direction; and further determining whether there is the abnormal pulse delivery based on the third peak current value and the fourth peak current value.

[0075] Example 19. The method according to any one of Examples 15 to 18, the method further comprising: using a digital potentiometer of the asynchronous current monitoring circuit to provide an output proportional to the current flowing through a current sensing element of the bridging circuit; determining a peak current value of the current flowing through the current sensing element based on the output.

[0076] Example 20. The method according to Example 19, the method further comprising: using an analog-to-digital converter to convert an analog voltage value received from the digital potentiometer into a digital value.

[0077] Example 21. The method according to any one of Examples 19 to 20, the method further comprising: using a threshold comparator of the asynchronous current monitoring circuit to receive a detection parameter corresponding to the current flowing through the current sensing element; using the threshold comparator to receive the output of the digital potentiometer; using the threshold comparator to enable the digital potentiometer when the output is less than the detection parameter, and using the threshold comparator to disable the digital potentiometer when the output is greater than the detection parameter.

[0078] Example 22. The method according to Example 21, the method further comprising: using a differential amplifier to detect a voltage drop across the current sensing element; and using the differential amplifier to provide the detection parameter to the threshold comparator, wherein the detection parameter is proportional to the voltage drop across the current sensing element.

[0079] Example 23. The method according to any one of Examples 18 to 22, the method comprising: using a second digital potentiometer to provide a second output proportional to the current flowing through the second current sensing element of the bridge circuit; and determining a second peak current value of the current flowing through the second current sensing element based on the second output.

[0080] Example 24. The method according to any one of Examples 15 to 23, the method further comprising: changing a period for determining the abnormal pulse delivery.

Claims

1. A pulsed field ablation system, the pulsed field ablation system comprising: A bridging circuit configured to deliver bipolar and biphasic voltage pulses to a catheter; An asynchronous current monitoring circuit electrically coupled to the bridging circuit; And An electronic processor coupled to the bridging circuit and the asynchronous current monitoring circuit, the electronic processor being configured to: Determine that there is no abnormal pulse delivery in the bridging circuit; In response to determining that there is no such abnormal pulse delivery, control the bridging circuit to deliver a treatment current to the catheter; Determine that the abnormal pulse delivery exists in the bridging circuit; And In response to determining that there is such abnormal pulse delivery, prohibit the bridging circuit from delivering a treatment current to the catheter.

2. The pulsed field ablation system according to claim 1, wherein the abnormal pulse delivery comprises one or more selected from the group consisting of single-phase pulse delivery and long-duration biphasic pulse delivery.

3. The pulsed field ablation system according to claim 1, wherein the electronic processor is configured to: Determine a first peak current value in a first direction; Determine a second peak current value in a second direction; and Based on the first peak current value and the second peak current value, determine whether there is such abnormal pulse delivery.

4. The pulsed field ablation system according to claim 3, wherein the electronic processor is further configured to: Determine a third peak current value in the first direction; Determine a fourth peak current value in the second direction; and Further based on the third peak current value and the fourth peak current value, determine whether there is such abnormal pulse delivery.

5. The pulsed field ablation system according to claim 1, wherein the asynchronous current monitoring circuit includes a digital potentiometer configured to: provide an output proportional to the current flowing through a current sensing element of the bridging circuit, wherein the electronic processor is electrically coupled to the digital potentiometer and is configured to: Receive the output from the digital potentiometer; and Based on the output, determine the peak current value flowing through the current sensing element.

6. The pulsed field ablation system according to claim 5, the pulsed field ablation system further comprising: An analog-to-digital converter electrically coupled between the output of the digital potentiometer and the electronic processor, the analog-to-digital converter being configured to convert an analog voltage value received from the digital potentiometer into a digital value provided to the electronic processor.

7. The pulsed field ablation system according to claim 5, wherein the asynchronous current monitoring circuit further includes: A threshold comparator configured to receive at a non-inverting input a detection parameter corresponding to the current flowing through the current sensing element; Receive at an inverting input the output of the digital potentiometer; And Provide a threshold output to the digital potentiometer, The digital potentiometer is configured to be enabled by the threshold output when the output is less than the detection parameter, and is configured to be disabled by the threshold output when the output is greater than the detection parameter.

8. The pulsed field ablation system according to claim 7, wherein the asynchronous current monitoring circuit further comprises a differential amplifier electrically coupled between the current detection element and the threshold comparator, wherein the differential amplifier is configured to detect a voltage drop across the current detection element and provide the detection parameter to the threshold comparator, and the detection parameter is proportional to the voltage drop across the current detection element.

9. The pulsed field ablation system according to claim 7, wherein the asynchronous current monitoring circuit further comprises a timer circuit electrically coupled between the threshold comparator and the digital potentiometer.

10. The pulsed field ablation system according to claim 5, wherein the asynchronous current monitoring circuit includes a second digital potentiometer configured to provide a second output proportional to the current flowing through a second current detection element of the bridge circuit, and the electronic processor is electrically coupled to the second digital potentiometer and configured to receive the second output from the second digital potentiometer; and determine a second peak current value of the current flowing through the second current detection element based on the second output.

11. The pulsed field ablation system according to claim 5, wherein the bridge circuit comprises: a first transistor switch electrically coupled between a positive power supply node and a first bridge output node; a second transistor switch electrically coupled between the first bridge output node and a negative power supply node; a third transistor switch electrically coupled between the positive power supply node and a second bridge output node; and and a fourth transistor switch electrically coupled between the second bridge output node and the negative power supply node, wherein the electronic processor is electrically coupled to the first transistor switch, the second transistor switch, the third transistor switch, and the fourth transistor switch, and the electronic processor controls to selectively open and close the first transistor switch, the second transistor switch, the third transistor switch, and the fourth transistor switch.

12. The pulsed field ablation system according to claim 11, wherein the current detection element is electrically coupled between the first bridge output node and the second bridge output node.

13. The pulsed field ablation system according to claim 12, wherein the first direction is the current flow direction from the first transistor switch to the fourth transistor switch, and the second direction is the current flow direction from the third transistor switch to the second transistor switch.

14. The pulsed field ablation system according to claim 1, wherein the electronic processor is further configured to: change the period for determining the abnormal pulse delivery.

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