Methods and apparatus for multi-catheter tissue ablation
Catheter systems, tools and methods are disclosed for the selective and rapid application of DC voltage to drive irreversible electroporation, with the system controller configurable to apply voltages to an independently selected subsets of electrodes, such that voltages of one polarity are applied to a multiplicity of electrodes on a first medical device and voltages of the opposite polarity to a multiplicity of electrodes on a second medical device. The first and second medical devices can be epicardial catheters positioned such that their opposing distal tips are approximately aligned and whose segments with electrodes collectively wrap around the pulmonary veins.
1. A system for delivering electrical energy to a target tissue of a patient, the energy configured to achieve ablation by irreversibly electroporation so as to treat a cardiac arrhythmia, the system comprising:
a first flexible catheter having a first distal end portion including a first magnet having a first magnetic polarity, the first flexible catheter including a first plurality of electrodes;
a second flexible catheter having a second distal end portion including a second magnetic having a second magnetic polarity opposite to the first magnetic polarity and configured to couple to the first magnet at the first distal end portion, the second flexible catheter including a second plurality of electrodes;
wherein the first and second flexible catheters are configured to be disposed at least partially around a cardiac chamber adjacent the target tissue when coupled together at the first and second end portions by the first and second magnets;
a voltage pulse generator configured to produce a pulsed voltage waveform; and
an electrode controller configured to be operably coupled to the voltage pulse generator, the electrode controller including a first output port and a second output port, the first output port configured to be operatively coupled to the first plurality of electrodes, the second output port configured to be operatively coupled to the second plurality of electrodes, the electrode controller configured to determine an impedance between a first subset of electrodes drawn solely from the first plurality of electrodes and a second subset of electrodes drawn solely from the second plurality of electrodes, and to select from the first and second subsets of electrodes at least one paired electrode subset for electrical pairing based on a pre-determined range of impedance values selected for ablation, and to deliver first and second output signals having opposite electrical polarities and associated with a pulsed voltage waveform respectively to the first and second output ports for respective application to the first and second subsets of electrodes of the at least one paired electrode subset, wherein the first and second output signals are configured to generate an electric field sufficient to achieve irreversible electroporation to ablate the target tissue.
2. The system of claim 1 , wherein an amplitude of each of the first output signal and the second output signal is up to 5 kV.
3. The system of claim 1 , wherein:
an amplitude of each of the first output signal and the second output signal is up to 5 kV; and
the first flexible catheter includes a plurality of leads, each lead of the plurality of leads coupled to an electrode from the first plurality of electrodes, each lead from the plurality of leads including an outer insulating layer having a thickness from about 0.02 mm to about 0.06 mm.
4. The system of claim 1 , wherein:
an amplitude of each of the first output signal and the second output signal is up to 5 kV;
the first plurality of electrodes includes at least four electrodes; and
the first flexible catheter includes a plurality of leads, each lead of the plurality of leads coupled to an electrode from the first plurality of electrodes, the first flexible catheter having a diameter of less than about 3 mm.
5. The system of claim 1 , wherein the electrode controller is configured to deliver the first output signal for application to the first electrode subset of the paired electrode subsets and to deliver the second output signal for application to the second electrode subset of the paired electrode subsets according to a sequential pattern wherein each electrode of the second electrode subset is adjacent each electrode of the first electrode subset.
6. The system of claim 1 , wherein the electrode controller is configured to select the at least one pair of electrode subsets further based on a predetermined schedule of the plurality of electrodes.
7. The system of claim 1 , wherein the electrode controller is configured to select the at least one pair of electrode subsets further based on at least one of: a distance between the first electrode subset and the second electrode subset of each pair of electrode subsets, and a characteristic associated with the target tissue.
8. The system of claim 1 , wherein the electrode controller is configured to generate an impedance map associated with the first plurality of electrodes and the second plurality of electrodes and to select the at least one pair of electrode subsets based on the impedance map.