Electrical ablation devices and methods

1. A computer-implemented system for delivering energy to tissue having a necrotic threshold, the computer-implemented system comprising:

an electrode array comprising a plurality of electrodes;

a central electrode positioned intermediate the plurality of electrodes;

a ground pad adjacent the tissue;

a processor; and

a memory coupled to the processor and storing instructions to be executed by the processor to:

apply a first sequence of electrical pulses to the electrode array less than the necrotic threshold to induce thermal heating in the tissue;

apply a second sequence of electrical pulses to the central electrode equal to or greater than the necrotic threshold to induce cell necrosis in the tissue by irreversible electroporation; and

apply a ground potential to the ground pad.

2. The computer-implemented system of claim 1 , further comprising an energy source coupled to the electrode array and the central electrode, wherein the energy source is operative to generate and deliver the first sequence of electrical pulses and the second sequence of electrical pulses to the tissue.

3. The computer-implemented system of claim 2 , further comprising at least one of a temperature sensor and a pressure sensor adjacent at least one of the electrode array and the central electrode, wherein the energy source is operative to generate and deliver the second sequence of electrical pulses when at least one of a predetermined temperature and a predetermined pressure is achieved.

4. The computer-implemented system of claim 2 , further comprising a controller comprising the processor and the memory, wherein the controller is coupled to the energy source, and wherein the controller is configured to control at least one parameter associated with the delivery of the first sequence of electrical pulses and the second sequence of electrical pulses.

5. The computer-implemented system of claim 4 , wherein the at least one parameter comprises frequency, amplitude, pulse width, polarity, voltage, total number of pulses, and delay between pulses bursts.

6. The computer-implemented system of claim 1 , wherein the first sequence of electrical pulses is sufficient to create a thermal zone in a first portion of the tissue induced by thermal heating in an area near an electrode-tissue-interface of each of the plurality of electrodes, and wherein the second sequence of electrical pulses is sufficient to create a necrotic zone in a second portion of tissue induced by irreversible electroporation in an area surrounding each of the plurality of electrodes and the central electrode.

7. The computer-implemented system of claim 1 , further comprising instructions to be executed by the processor to:

deliver a first energy dose that is less than the necrotic threshold to induce thermal heating by the first sequence of electrical pulses; and

deliver a second energy dose equal to or greater than the necrotic threshold to induce cell necrosis in the tissue by irreversible electroporation by the second sequence of electrical pulses.

8. The computer-implemented system of claim 1 , further comprising instructions to be executed by the processor to:

form a pre-heated zone by applying an electric field that is less than about 800 V/cm by the first sequence of electrical pulses; and

form a necrotic zone by applying an electric filed that is greater than about 800 V/cm by the second sequence of electrical pulses.

9. The computer-implemented system of claim 1 , further comprising instructions to be executed by the processor to:

heat the mass of tissue by applying an electric field that is less than about 800V/cm by the first sequence of electrical pulses to lower the necrotic threshold; and

induce cell necrosis by irreversible electroporation by applying an electric filed that is greater than about 800 V/cm by the second sequence of electrical pulses.

10. The computer-implemented system of claim 1 , further comprising instructions to be executed by the processor to:

apply the first sequence of electrical pulses to the electrode array less than the necrotic threshold to lower the necrotic threshold.

11. The computer-implemented system of claim 1 , further comprising instructions to be executed by the processor to:

apply a sequence of electrical pulses to the electrode array, the sequence of electrical pulses having amplitudes in a range of about ±100 VDC to about ±10,000 VDC, pulse widths in a range of about 1 μs to about 100 ms, and frequencies in a range of about 1 Hz to about 10,000 Hz; and

re-apply the sequence of electrical pulses to the central electrode.

12. A computer-implemented system for delivering energy to tissue having a necrotic threshold, the system comprising:

an electrode arrangement comprising a plurality of outer electrodes;

an inner electrode surrounded by the plurality of outer electrodes;

a processor; and

a memory coupled to the processor and storing instructions to be executed by the processor to:

apply a first sequence of electrical pulses to the plurality of outer electrodes to induce thermal heating in the tissue without inducing irreversible electroporation in the tissue; and

apply a second sequence of electrical pulses to the inner electrode to induce cell necrosis in the tissue by irreversible electroporation.

13. The computer-implemented system of claim 12 , further comprising a ground pad adjacent the tissue and instructions to be executed by the processor to apply a ground potential to the ground pad.

14. The computer-implemented system of claim 12 , wherein the first sequence of electrical pulses comprises a first energy dose that is less than the necrotic threshold, and wherein the second sequence of electrical pulses comprises a second energy dose that is equal to or greater than the necrotic threshold.

15. The computer-implemented system of claim 12 , further comprising an energy source electrically coupled to the plurality of outer electrodes and the inner electrode.

16. The computer-implemented system of claim 15 , further comprising at least one of a temperature sensor for measuring temperature in the tissue and a pressure sensor for measuring pressure in the tissue.

17. The computer-implemented system of claim 16 , wherein the energy source is operative to:

generate and deliver the first sequence of electrical pulses until at least one of a predetermined temperature and a predetermined pressure is achieved; and

generate and deliver the second sequence of electrical pulses when the at least one of a predetermined temperature and a predetermined pressure is achieved.

18. A computer-implemented system for delivering energy to tissue having a necrotic threshold, the system comprising:

an electrode array comprising a plurality of electrodes;

a central electrode positioned intermediate the plurality of electrodes; and

a controller configured to:

apply a first sequence of electrical pulses to the electrode array to induce thermal heating in the tissue and reduce the necrotic threshold of the tissue; and

apply a second sequence of electrical pulses to the central electrode to induce cell necrosis in the tissue by irreversible electroporation.

19. The computer-implemented system of claim 18 , wherein the plurality of electrodes and the central electrode are configured for insertion into the tissue.

20. The computer-implemented system of claim 18 , wherein the controller is configured to apply the first sequence of electrical pulses to thermally heat the tissue to a predetermined threshold to realize a reduced necrotic threshold of the tissue.