Systems and methods for treating tissue with pulsed field ablation
Pulsed field ablation systems are disclosed, some of which may include an output pulse generation circuit and a high voltage pulse generation circuit electrically connected to the output pulse generation circuit. The high voltage pulse generation circuit may be configured to deliver a high voltage pulse set to the output pulse generation circuit. The output pulse generation circuit may be configured to generate an output pulse set at least in response to the high voltage pulse set. The output pulse set may be deliverable to a set of selectable electrodes and may be configured to cause pulsed field ablation of tissue. Each pulse in the output pulse set may have a rise time that is shorter than a rise time of at least one high voltage pulse in the high voltage pulse set.
1 . A pulsed field ablation system comprising:
a high voltage supply;
a controller system; and
a circuit communicatively connected to the controller system, the circuit electrically connected to the high voltage supply to receive input voltage therefrom, the circuit comprising:
a first plurality of capacitors electrically connected to the high voltage supply via a plurality of switches, and
at least a first output switch set electrically connecting the first plurality of the capacitors to a plurality of selectable pulsed field ablation electrodes,
wherein the controller system is configured to cause:
(i) switching of at least some of the plurality of switches to produce a first switch configuration in which the first plurality of capacitors is in a first series circuit configured to charge the first plurality of capacitors,
(ii) switching, subsequent (i), of at least some of the plurality of switches to produce a second switch configuration in which the first plurality of capacitors is in a second series circuit configured to apply an output voltage across at least the first output switch set, the output voltage greater than the input voltage, the second series circuit different than the first series circuit, and
(iii) switching of at least one output switch of the output switches of at least the first output switch set to generate a plurality of output pulse sets at least from energy stored at least in the first plurality of capacitors, each output pulse set in the plurality of output pulse sets configured to cause pulsed field ablation.
2 . The pulsed field ablation system of claim 1 , wherein electric current through the first plurality of capacitors in the second series circuit is in an opposite direction to electric current through the first plurality of capacitors in the first series circuit.
3 . The pulsed field ablation system of claim 1 , wherein, in the first switch configuration, each switch in a first switch set of the plurality of switches is in a respective NON-OPEN state configured to allow a respective level of electric current to be deliverable through the switch in the first switch set, and wherein, in the second switch configuration, each switch in the first switch set is in a respective OPEN state configured to prevent flow of electric current through the switch in the first switch set, the respective level of electric current deliverable through the switch in the first switch set in the respective NON-OPEN state greater than any electric current deliverable through the switch in the first switch set in the respective OPEN state.
4 . The pulsed field ablation system of claim 3 , wherein at least a first switch in the first switch set is a semiconductor switch, and wherein the pulsed field ablation system comprises an electric current control circuit electrically connected to the first switch and configured to control electric current through the first switch.
5 . The pulsed field ablation system of claim 3 , wherein, in the first switch configuration, each switch in a second switch set of the plurality of switches is in a respective OPEN state configured to prevent flow of electric current through the switch in the second switch set, and wherein, in the second switch configuration, each switch in the second switch set is in a respective NON-OPEN state configured to allow a respective level of electric current to be deliverable through the switch in the second switch set, the respective level of electric current deliverable through the switch in the second switch set in the respective NON-OPEN state greater than any electric current deliverable through the switch in the second switch set in the respective OPEN state.
6 . The pulsed field ablation system of claim 5 , wherein at least a first switch in the first switch set is a semiconductor switch comprising a transistor.
7 . The pulsed field ablation system of claim 6 , wherein the transistor is a bipolar junction transistor.
8 . The pulsed field ablation system of claim 6 , wherein the transistor is an insulated-gate bipolar transistor.
9 . The pulsed field ablation system of claim 6 , wherein the transistor is a field effect transistor.
10 . The pulsed field ablation system of claim 6 , wherein the transistor is a MOSFET.
11 . The pulsed field ablation system of claim 1 , wherein the plurality of switches is arranged in a full bridge configuration.
12 . The pulsed field ablation system of claim 1 , wherein the controller system is configured to repeat (i) and (ii) with each successive output pulse set of the plurality of output pulse sets that is generated.
13 . The pulsed field ablation system of claim 12 , wherein voltage across each capacitor of the first plurality of capacitors increases, and concurrently, voltage across each capacitor of the one or more second capacitors decreases in response to each occurrence of the controller system causing (i).
14 . The pulsed field ablation system of claim 1 , wherein the circuit comprises one or more second capacitors, the plurality of switches electrically connecting the one or more second capacitors to the first plurality of capacitors to charge the first plurality of capacitors with charge stored in the one or more second capacitors.
15 . The pulsed field ablation system of claim 14 , wherein voltage across each capacitor of the first plurality of capacitors increases, and concurrently, voltage across each capacitor of the one or more second capacitors decreases in response to the controller system causing (i).
16 . The pulsed field ablation system of claim 14 , wherein voltage across the first plurality of capacitors incrementally increases, and concurrently, voltage across the one or more second capacitors incrementally decreases with each successive output pulse set of the plurality of output pulse sets that is generated.
17 . The pulsed field ablation system of claim 14 , wherein a sum of (iv) the voltage across each capacitor of the first plurality of capacitors and (v) the voltage across each capacitor of the one or more second capacitors remains constant with each successive output pulse set of the plurality of output pulse sets that is generated.
18 . The pulsed field ablation system of claim 1 , wherein the circuit comprises a plurality of sensing circuits, each sensing circuit of the plurality of sensing circuits electrically connected to a respective capacitor of the first plurality of capacitors, and wherein the controller system is configured to determine, based at least on a signal set provided by a particular sensing circuit of the plurality of sensing circuits, a capacitance of the respective capacitor of the first plurality of capacitors.
19 . The pulsed field ablation system of claim 18 , wherein the signal set provided by the particular sensing circuit of the plurality of sensing circuits includes a signal provided by a voltage sensing portion of the particular sensing circuit.
20 . The pulsed field ablation system of claim 19 , wherein the circuit comprises an electric current sensing circuit configured to sense electric current through each capacitor of the first plurality of capacitors, and wherein the controller system is configured to determine, based at least on a signal set provided by the electric current sensing circuit, the capacitance of each respective capacitor of the first plurality of capacitors.
21 . The pulsed field ablation system of claim 18 , wherein the particular sensing circuit comprises a plurality of redundant sensing circuits, and wherein the controller system is configured to determine multiple capacitance values for each respective capacitor of the first plurality of capacitors, each capacitance value of the multiple capacitance values determined based at least on a signal set provided by a respective one of the redundant sensing circuits of the particular sensing circuit.
22 . The pulsed field ablation system of claim 18 , wherein the controller system is configured to individually determine the capacitance of each respective capacitor of the first plurality of capacitors, each capacitance determined based at least on a signal set provided by the respective sensing circuit of the plurality of sensing circuits.