System and method for detecting electrode-tissue contact
First Claim
Patent Images
1. A system for detecting contact of an electrode with tissue, said system comprising:
- a) a catheter comprising;
i) a body having a proximal end and a distal end, said distal end having a distal tip;
ii) a contact electrode adapted for contact with tissue, wherein said contact electrode is positioned at said catheter distal tip;
iii) a location sensor for determining a position of said distal end;
b) a reference electrode, wherein said reference electrode is positioned on said catheter;
c) a return electrode, said return electrode functioning as a sink for said test signals to said distal tip electrode and to said reference electrode; and
d) a contact detection circuit comprising;
i) a signal generator for sending test signals to said contact electrode and to said reference electrode; and
ii) a circuit to measure a differential electrical response to said test signals, said differential electrical response being indicative of contact of said contact electrode with tissue;
wherein said circuit to measure a differential electrical response to said test signals comprises;
(a) a first differential amplifier to measure a first electrical difference signal between said distal tip electrode and said return electrode; and
(b) a second differential amplifier to measure a second electrical difference signal between said reference electrode and said return electrode.
2 Assignments
0 Petitions
Accused Products
Abstract
A system for detecting electrode-tissue contact comprises a catheter having a location sensor and a distal tip electrode. The catheter preferably further comprises a reference electrode that is preferably protected from making contact with tissue. The system further comprises a signal generator to transmit test signals to the distal tip and reference electrodes. Tissue contact is detected by comparing the signals across the tip electrode to a return electrode versus the signal across the reference electrode to a return electrode. Ablation energy may be delivered to the distal tip electrode if contact of the electrode with tissue is detected.
584 Citations
57 Claims
-
1. A system for detecting contact of an electrode with tissue, said system comprising:
-
a) a catheter comprising;
i) a body having a proximal end and a distal end, said distal end having a distal tip;
ii) a contact electrode adapted for contact with tissue, wherein said contact electrode is positioned at said catheter distal tip;
iii) a location sensor for determining a position of said distal end;
b) a reference electrode, wherein said reference electrode is positioned on said catheter;
c) a return electrode, said return electrode functioning as a sink for said test signals to said distal tip electrode and to said reference electrode; and
d) a contact detection circuit comprising;
i) a signal generator for sending test signals to said contact electrode and to said reference electrode; and
ii) a circuit to measure a differential electrical response to said test signals, said differential electrical response being indicative of contact of said contact electrode with tissue;
wherein said circuit to measure a differential electrical response to said test signals comprises;
(a) a first differential amplifier to measure a first electrical difference signal between said distal tip electrode and said return electrode; and
(b) a second differential amplifier to measure a second electrical difference signal between said reference electrode and said return electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32)
-
-
33. A method of detecting contact of an electrode with tissue, said method comprising the steps of:
-
a) providing a catheter comprising i) a body having a proximal end and a distal end, said distal end having a distal tip;
ii) a contact electrode adapted for contact with tissue, wherein said contact electrode is positioned at said catheter distal tip;
iii) a location sensor for determining a position of said distal end;
b) providing a reference electrode, wherein said reference electrode is positioned on said catheter;
c) providing test signals to said contact electrode and to said reference electrode;
d) measuring a differential electrical response to said test signals, wherein said differential electrical response is indicative of contact of said contact electrode with tissue by;
i) measuring a first electrical difference signal between said distal tip electrode and a return electrode and a second electrical difference signal between said reference electrode and said return electrode; and
ii) comparing said first electrical difference signal with said second electrical difference signal to detect contact of said distal tip electrode with tissue. - View Dependent Claims (34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54)
a) providing a bridge circuit comprising a first resistive element and a second resistive element, said resistive elements each having a first side and a second side, said first side of said first resistive element connected with said first side of said second resistive-element, said second side of said first resistive element connected with said reference electrode, said second side of said second resistive element connected with said distal tip electrode, said bridge having a first input between said first resistive element and said second resistive element and a second resistive element and a second input connected to said return electrode, and a first output between said first resistive element and said reference electrode and a second output between said second resistive element and said distal tip electrode; and
b) measuring a signal across said bridge outputs to detect contact of said distal tip electrode with tissue.
-
-
43. The method of claim 42 wherein said first resistive element comprises a first resistor and said second resistive element comprises a second resistor.
-
44. The method of claim 42 wherein said first resistive element comprises a first high output impedance buffer and said second resistive element comprises a second high output impedance buffer.
-
45. The method of claim 42 wherein said signal across said bridge outputs is measured with a differential amplifier.
-
46. The method of claim 45 wherein said signal across said bridge outputs is adjusted to provide a null signal from said differential amplifier when said distal tip electrode and said reference electrode are both in blood and neither electrode is in contact with tissue.
-
47. The method of claim 42 wherein said location sensor is an electromagnetic sensor.
-
48. The method of claim 33 wherein measuring a differential electrical response to said test signals comprises measuring current to said reference electrode with a first current sensor and measuring current to said distal tip electrode with a second current sensor, said first current sensor and said second current sensor having outputs connected to a differential amplifier, said amplifier measuring a voltage indicative of contact of said distal tip electrode with tissue.
-
49. The method of claim 48 wherein said current sensors are selected from current transformers and Hall effect sensors.
-
50. The method of claim 48 wherein said current sensors have output signals, said signals being adjusted to provide a null signal from said differential amplifier when said distal tip electrode and said reference electrode are both in blood and neither electrode is in contact with tissue.
-
51. The method of claim 48 wherein said location sensor is an electromagnetic location sensor.
-
52. The method of claim 33 wherein measuring a differential electrical response to said test signals comprises:
-
a) measuring a first impedance between said distal tip electrode and a return electrode and a second impedance between said reference electrode and said return electrode; and
b) comparing said first and second impedances to detect contact of said catheter distal tip electrode with tissue.
-
-
53. The method of claim 52 wherein said location sensor is an electromagnetic location sensor.
-
54. The method of claim 53 which further comprises delivering ablation energy to said distal tip electrode in accordance with said distal tip electrode being in contact with tissue.
-
55. A method of detecting contact of an electrode with tissue, said method comprising the steps of:
-
a) providing a catheter comprising;
i) a body having a proximal end and a distal end, said distal end having a distal tip;
ii) a contact electrode adapted for contact with tissue, wherein said contact electrode is positioned at said catheter distal tip; and
iii) a location sensor for determining a position of said distal end;
b) providing a reference electrode, wherein said reference electrode is positioned on said catheter;
c) providing test signals to said contact electrode and to said reference electrode;
d) measuring a differential electrical response to said test signals, said differential electrical response being indicative of contact of said contact electrode with tissue;
e) collecting electrical information from said distal tip electrode and location information from said location sensor at a plurality of points on said tissue; and
f) generating an electrical map of said tissue from said electrical and location information, said electrical and location information at each of said points being weighted in said map in accordance with contact being detected between said distal tip electrode and said tissue at said points.
-
-
56. A method of detecting contact of an electrode with tissue, said method comprising the steps of:
-
a) providing a catheter comprising;
i) a body having a proximal end and a distal end, said distal end having a distal tip;
ii) a contact electrode adapted for contact with tissue, wherein said contact electrode is positioned at said catheter distal tip; and
iii) a location sensor for determining a position of said distal end;
b) providing a reference electrode, wherein said reference electrode is positioned on said catheter;
c) providing test signals to said contact electrode and to said reference electrode;
d) measuring a differential electrical response to said test signals, said differential electrical response being indicative of contact of said contact electrode with tissue;
e) collecting electrical information from said distal tip electrode and mechanical information from said location sensor at a plurality of points on said tissue; and
f) generating an electromechanical map of said tissue from said electrical and mechanical information, said electrical and mechanical information at each of said points being weighted in said map in accordance with contact being detected between said distal tip electrode and said tissue at said points. - View Dependent Claims (57)
-
Specification