Multipurpose electrode
Multi-purpose electrodes for use during ablation are provided. The electrodes comprise a variable impedance region and a relatively constant impedance region. The relatively constant impedance region can be used for mapping, and both regions can be used for ablating. The mapping region can obtain low frequency electrophysiological signals during mapping, while both regions can conduct higher frequency ablation electrical signals to a patient during ablation.
1 . An electrode for use with an ablation catheter including a balloon having an irrigation aperture, the electrode comprising:
a conductive polymer layer coupled to the balloon and having an inner surface facing toward the balloon and an outer surface facing away from the balloon, the conductive polymer layer defining an irrigation aperture; and
an outer layer of dielectric material disposed radially outward from the conductive polymer layer in a direction extending from a center of the balloon and having a thickness, the outer layer of dielectric material defining an opening larger than the irrigation aperture, so as to define an overlap region where the outer layer overlaps the conductive polymer layer and a non-overlap region adjacent to the irrigation aperture where the conductive polymer layer is exposed;
wherein the overlap region defines a variable impedance region having a first exposed surface area, wherein the variable impedance region has a first impedance when a first electrical signal having a first frequency is applied thereto, and a second impedance when a second electrical signal having a second frequency is applied thereto, the second impedance being different than the first impedance; and
wherein the non-overlap region defines a substantially constant impedance region having a second exposed surface area less than the first exposed surface area of the variable impedance region;
wherein the thickness of the outer layer of dielectric material is such that the overlap region conducts an ablation energy at the second frequency through the entirety of the outer layer so as to treat tissue with the ablation energy.
2 . The electrode of claim 1 , wherein the first impedance is higher than the second impedance when the first electrical signal has a lower frequency than the second electric signal.
3 . The electrode of claim 1 , wherein the first electrical signal has a frequency of about 1000 Hz or less, and the second electrical signal has a frequency of at least about 50 KHz.
4 . The electrode of claim 1 , wherein the substantially constant impedance region is adapted so that an impedance of the substantially constant impedance region does not vary based on the frequency of an electrical signal applied thereto.
5 . The electrode of claim 1 , wherein the non-overlap region is disposed in a central portion of the electrode.
6 . The electrode of claim 1 , wherein the overlap region is disposed in a peripheral region of the electrode.
7 . The electrode of claim 1 , wherein the variable impedance region includes a layer of high dielectric material.
8 . The electrode of claim 1 , wherein the electrode includes more than one variable impedance region.
9 . The electrode of claim 1 , wherein the variable impedance region is disposed in a peripheral region of the electrode.
10 . The electrode of claim 1 , wherein the substantially constant impedance region is disposed within a central portion of the electrode.
11 . The electrode of claim 1 , wherein the electrode is individually addressable.
12 . The electrode of claim 1 , wherein a periphery of the electrode defines an uninterrupted electrode surface area that can be exposed to tissue to deliver an electrical signal to the tissue.
13 . The electrode of claim 1 , wherein the substantially constant impedance region has an impedance lower than the first impedance or the second impedance.
14 . The electrode of claim 1 , wherein the electrode is configured to pass ablation energy at an ablation frequency through its entirety.
15 . An electrode comprising:
a physiological signal mapping section comprising a substantially constant impedance region having a constant impedance surface area; and
a tissue ablating section comprising the substantially constant impedance region and a variable impedance region having a variable impedance surface area greater than the constant impedance surface area, wherein the variable impedance region has a first impedance when a first frequency is applied thereto, and a second impedance when a second frequency is applied thereto, the second impedance being different than the first impedance,
wherein the variable impedance region includes a first layer of material disposed radially outward in a direction extending from a center of a conductive polymer conductive electrode layer of material coupled to a balloon, the first layer of material having a thickness,
wherein the thickness is such that the variable impedance region conducts an ablation energy at the second frequency that passes through the first layer so as to treat tissue with the ablation energy, and
wherein the first layer defines an opening such that the first layer overlaps with only a portion of the conductive polymer electrode layer of material, to create an overlap region defining the variable impedance region where the first layer and the conductive polymer electrode layer overlap, and a non-overlap region defined by the opening and defining the substantially constant impedance region where the first layer and the conductive polymer electrode layer do not overlap.