Balloon catheter with diagnostic electrodes, far field electrodes, and guidewire

1. A medical apparatus, comprising:

a shaft for insertion into an organ of a patient;

an expandable frame coupled to a distal end of the shaft, the expandable frame extending along a longitudinal axis, wherein the expandable frame comprises a plurality of expandable spines disposed about the longitudinal axis to define an internal lumen; and

a membrane disposed inside the internal lumen defined by the plurality of expandable spines;

each expandable spine of the plurality of expandable spines comprising:

a plurality of diagnostic electrodes disposed on an external surface of the expandable spine, wherein the plurality of diagnostic electrodes is configured to sense diagnostic signals when in contact with tissue; and

a reference electrode disposed on a surface of the expandable spine opposite the diagnostic electrode such that the reference electrode is disposed between the expandable spine and the membrane and in direct contact with the membrane, the reference electrode extending from about a proximal end of the expandable spine to about a distal end of the expandable spine, wherein the reference electrode is electrically insulated from the tissue and is configured to sense interfering signals, and

wherein the reference electrode defines a gap between the expandable spine and the membrane, the gap configured to permit blood to flow to the reference electrode to detect interfering signals conducted by the blood.

2. The medical apparatus of claim 1 , wherein the reference electrode is in contact with blood flow but not in contact with tissue.

3. The medical apparatus according to claim 1 , wherein at least an expandable spine from among the plurality of expandable spines is made of flexible printed circuit board (PCB), and wherein the diagnostic electrode and the reference electrode are disposed on opposing facets of the flexible PCB.

4. The medical apparatus according to claim 1 , wherein the shaft and the membrane are hollow along a longitudinal axis thereof, and wherein the medical probe further comprises a guidewire configured to be inserted through the shaft and the membrane, and to guide the membrane toward a target location in the organ.

5. The medical apparatus according to claim 1 , wherein the interfering signals comprise far-field bio-electrical signals.

6. The medical apparatus of claim 1 , further comprising:

a processor, which is configured to:

receive the diagnostic signals sensed by the diagnostic electrode;

receive the interfering signals sensed by the reference electrode;

calculate corrected diagnostic signals by subtracting the interfering signals from the diagnostic signals.

7. The medical apparatus according to claim 1 , wherein the reference electrode is at least partially encapsulated in an electrically insulating material.

8. The medical apparatus according to claim 7 , wherein the electrically insulating material comprises a water-resistant seal.

9. A method, comprising:

inserting into an organ of a patient a medical probe, comprising an expandable frame coupled to a distal end of a shaft, the expandable frame extending along a longitudinal axis, wherein the expandable frame comprises a plurality of expandable spines disposed about the longitudinal axis to define an internal lumen, and wherein a membrane is disposed inside the internal lumen;

sensing diagnostic signals with a plurality of diagnostic electrodes disposed on an external surface of an expandable spine of the plurality of expandable spines, wherein the plurality of diagnostic electrodes are configured to sense diagnostic signals when in contact with tissue;

sensing interfering signals with a reference electrode, which is disposed on a surface of the expandable spine opposite the diagnostic electrode such that the reference electrode is disposed between the expandable spine and the membrane and in direct contact with the membrane, the reference electrode extending from about a proximal end of the expandable spine to about a distal end of the expandable spine, wherein the reference electrode is electrically insulated from the tissue and configured to sense interfering signals, and wherein the reference electrode defines a gap between the expandable spine and the membrane, the gap configured to permit blood to flow to the reference electrode to detect interfering signals conducted by the blood;

in a processor, receiving the diagnostic signals sensed by the diagnostic electrode;

receiving the interfering signals sensed by the reference electrode; and

calculating corrected diagnostic signals by subtracting the interfering signals from the diagnostic signals.

10. The method according to claim 9 , wherein sensing interfering signals comprises sensing interfering signals with the reference electrode that is in contact with blood flow but not in contact with tissue to detect interfering signals conducted by blood.

11. The method according to claim 9 , wherein at least an expandable spine from among the expandable spines is made of flexible printed circuit board (PCB), and wherein the plurality of diagnostic electrodes and the reference electrode are disposed on opposing facets of the flexible PCB.

12. The method according to claim 9 , further comprising inserting a guidewire through the shaft and the membrane, wherein the shaft and the membrane are hollow along a longitudinal axis thereof, and guiding the membrane toward a target location in the organ.

13. The method according to claim 9 , wherein the step of sensing interfering signals comprises sensing far-field bio-electrical signals.

14. The method according to claim 9 , wherein the reference electrode is at least partially encapsulated in an electrically insulating material.

15. The method according to claim 14 , wherein the electrically insulating material comprises a water-resistant seal.