US6761716B2
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US
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System and method for assessing electrode-tissue contact and lesion quality during RF ablation by measurement of conduction time
Assignee: Cardiac Pacemakers Inc
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Filing: 2001-09-18
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Granted: 2004-07-13
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Expires: 2021-09-18
Abstract
Abstract The efficacy of a lesion produced between a pair of ablation electrodes is assessed by analyzing the time it takes for a pulse of energy to travel from one electrode to the other. During a first time period, a first pulse of energy is applied to a first electrode. The time it takes for the pulse to conduct through the tissue to a second electrode is determined. During a time period subsequent to the first time, a subsequent pulse of energy is applied to the first electrode and the time it takes for the subsequent pulse to conduct through the tissue to the second electrode is determined. Changes in the conduction times are monitored by calculating the difference between consecutive conduction times and comparing the difference to a preset value. If the difference is below the preset value the lesion is considered adequate.
Inventors
- 👤 Veerichetty A. Kadhiresan
- 👤 Marshall L. Sherman
- 👤 Wade A. Bowe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 04:22
CPC Classifications
A; A61; A61B; A61B18/00; A61B18/04; A61B18/12; A61B18/1206; A61B2018/00636; A61B2018/00642; A61B2018/0066
Claims Analysis
Total Claims: 36
Claim 1
Independent Claim
168 words
In an ablation procedure using a catheter system having a catheter with a plurality of electrodes and a generator system for providing ablation power and energy pulses to the electrodes, a method of assessing the efficacy of a biological tissue lesion between a pair of the electrodes, said method comprising: a) during a first time period: applying a first pulse of energy to a first electrode; determining a first conduction time based on the time it takes for the pulse to conduct through the tissue to a second electrode; b) during a time period subsequent to the first time period, applying ablation power to at least one of the first electrode and the second electrode; c) during a time period subsequent to the application of ablation power: applying a subsequent pulse of energy to the first electrode; determining a subsequent conduction time based on the time it takes for the subsequent pulse to conduct through the tissue to the second electrode; d) monitoring changes in the conduction times.
Claim 2
Dependent Claim
168 words
In an ablation procedure using a catheter system having a catheter with a plurality of electrodes and a generator system for providing ablation power and energy pulses to the electrodes, a method of assessing the efficacy of a biological tissue lesion between a pair of the electrodes, said method comprising: a) during a first time period: applying a first pulse of energy to a first electrode; determining a first conduction time based on the time it takes for the pulse to conduct through the tissue to a second electrode; b) during a time period subsequent to the first time period, applying ablation power to at least one of the first electrode and the second electrode; c) during a time period subsequent to the application of ablation power: applying a subsequent pulse of energy to the first electrode; determining a subsequent conduction time based on the time it takes for the subsequent pulse to conduct through the tissue to the second electrode; d) monitoring changes in the conduction times.
Claim 3
Dependent Claim
43 words
The method of claim 1 wherein monitoring changes in the conduction times comprises: calculating a difference between consecutive conduction times; comparing the difference to a preset value; and if the difference is below the preset value, providing an indication of an adequate lesion.
Claim 4
Dependent Claim
26 words
The method of claim 2 wherein the difference comprises the percentage change between consecutive conduction times and the preset value is between approximately 5% and 10%.
Claim 5
Dependent Claim
16 words
The method of claim 2 wherein the indication of an adequate lesion comprise a visual indication.
Claim 6
Dependent Claim
61 words
The method of claim 1 wherein monitoring changes in the conduction times comprises: calculating a difference between consecutive conduction times; comparing the difference to a preset value; and if the difference is at least as great as the preset value, applying ablation power to the electrodes to improve the efficacy of the lesion between the first electrode and a second electrode.
Claim 7
Dependent Claim
27 words
The method of claim 1 wherein monitoring changes in the conduction times comprises displaying a graph of the consecutive conduction times as a function of pulse-application time.
Claim 8
Dependent Claim
19 words
The method of claim 1 further comprising repeating steps c) and d) for a plurality of subsequent time periods.
Claim 9
Dependent Claim
23 words
The method of claim 1 wherein the second electrode comprises at least one of the plurality of electrodes other than the first electrode.
Claim 10
Dependent Claim
49 words
The method of claim 1 wherein the plurality of electrodes are arranged in a linear array, the first electrode comprises one of either the most proximal electrode or the most distal electrode and the second electrode comprises the other of the most proximal electrode and the most distal electrode.
Claim 11
Dependent Claim
44 words
The method of claim 1 wherein the plurality of electrodes are arranged in either one of a circular array and an orthogonal array, the first electrode comprises one of the electrodes and the second electrode comprises the electrode most diametrically opposite the first electrode.
Claim 12
Dependent Claim
47 words
The method of claim 1 wherein the plurality of electrodes are arranged in either one of a linear array, a circular array and a orthogonal array, the first electrode comprises any one of the electrodes and the second electrode comprises an electrode immediately adjacent the first electrode.
Claim 13
Independent Claim
165 words
A system for assessing the efficacy of a biological tissue lesion between a first electrode and a second electrode positioned proximal to the biological tissue, said system comprising: a generator system adapted to output ablation power and pulses of energy; and a processor adapted to: (a) control the generator such that an energy pulse is provided to the first electrode at a first pulse-application time; (b) monitor electrical activity at the second electrode for an indication that the energy pulse has been sensed by the second electrode and record the time at which the pulse was sensed; (c) determine a conduction time based on the difference between the pulse-application time and the pulse-sense time; and (d) control the generator such that ablation power is applied to at least one of the first electrode and the second electrode; (e) repeat (a), (b) and (c) at least once, at a time subsequent to the the application of ablation power; and (f) monitor changes in the conduction times.
Claim 14
Independent Claim
165 words
A system for assessing the efficacy of a biological tissue lesion between a first electrode and a second electrode positioned proximal to the biological tissue, said system comprising: a generator system adapted to output ablation power and pulses of energy; and a processor adapted to: (a) control the generator such that an energy pulse is provided to the first electrode at a first pulse-application time; (b) monitor electrical activity at the second electrode for an indication that the energy pulse has been sensed by the second electrode and record the time at which the pulse was sensed; (c) determine a conduction time based on the difference between the pulse-application time and the pulse-sense time; and (d) control the generator such that ablation power is applied to at least one of the first electrode and the second electrode; (e) repeat (a), (b) and (c) at least once, at a time subsequent to the the application of ablation power; and (f) monitor changes in the conduction times.
Claim 15
Dependent Claim
49 words
The system of claim 12 wherein to monitor changes in the conduction times the processor is adapted to: calculate a difference between consecutive conduction times; compare the difference o a preset value; and provide an indication of an adequate lesion when the difference is less than the preset value.
Claim 16
Dependent Claim
26 words
The system of claim 13 wherein the difference comprises the percentage change between consecutive conduction times and the preset value is between approximately 5% and 10%.
Claim 17
Dependent Claim
22 words
The system of claim 13 wherein the processor comprises a display and the indication of an adequate lesion comprises a visual indication.
Claim 18
Dependent Claim
66 words
The system of claim 12 wherein to monitor changes in the conduction times the processor is adapted to: calculate a difference between consecutive conduction times; compare the difference to a preset value; and if the difference is at least as great as the preset value, apply ablation power to the electrodes to improve the efficacy of the lesion between the first electrode and a second electrode.
Claim 19
Dependent Claim
34 words
The system of claim 12 wherein the processor comprises a display and the processor is adapted to provide a graph of the consecutive conduction times as a function of pulse-application time on the display.
Claim 20
Independent Claim
168 words
A method of ablating biological tissue using a catheter system having a catheter with a plurality of electrodes and a generator system for providing ablation power and energy pulses to the electrodes, said method comprising: a) positioning the plurality of electrodes proximal to the biological tissue; b) during a first time period applying ablation power to the electrodes to form a lesion between a first electrode and a second electrode; c) during an initial time period subsequent to the first time period: applying an initial pulse of energy to the first electrode; determining an initial conduction time based on the time it takes for the pulse to conduct through the tissue to the second electrode; d) during a time period subsequent to the initial time period: applying a subsequent pulse of energy to the first electrode; determining a subsequent conduction time based on the time it takes for the subsequent pulse to conduct through the tissue to the second electrode; and e) monitoring changes in the conduction times.
Claim 21
Independent Claim
168 words
A method of ablating biological tissue using a catheter system having a catheter with a plurality of electrodes and a generator system for providing ablation power and energy pulses to the electrodes, said method comprising: a) positioning the plurality of electrodes proximal to the biological tissue; b) during a first time period applying ablation power to the electrodes to form a lesion between a first electrode and a second electrode; c) during an initial time period subsequent to the first time period: applying an initial pulse of energy to the first electrode; determining an initial conduction time based on the time it takes for the pulse to conduct through the tissue to the second electrode; d) during a time period subsequent to the initial time period: applying a subsequent pulse of energy to the first electrode; determining a subsequent conduction time based on the time it takes for the subsequent pulse to conduct through the tissue to the second electrode; and e) monitoring changes in the conduction times.
Claim 22
Dependent Claim
51 words
The method of claim 18 wherein the generator system provides power having a duty cycle with alternating on periods and off periods, the first time period occurs during an on period of the duty cycle, and the initial time and subsequent time occur during an off period of the duty cycle.
Claim 23
Dependent Claim
19 words
The method of claim 19 wherein the initial time period and subsequent time period occur during different off periods.
Claim 24
Dependent Claim
19 words
The method of claim 19 wherein the initial time period and subsequent time period occur during consecutive off periods.
Claim 25
Dependent Claim
43 words
The method of claim 18 wherein monitoring changes in the conduction times comprises: calculating a difference between consecutive conduction times; comparing the difference to a preset value; and if the difference is below the preset value, providing an indication of an adequate lesion.
Claim 26
Dependent Claim
61 words
The method of claim 18 wherein monitoring changes in the conduction times comprises: calculating a difference between consecutive conduction times; comparing the difference to a preset value; and if the difference is at least as great as the preset value, applying ablation power to the electrodes to improve the efficacy of the lesion between the first electrode and a second electrode.
Claim 27
Dependent Claim
26 words
The method of claim 23 wherein the difference comprises the percentage change between consecutive conduction times and the preset value is between approximately 5% and 10%.
Claim 28
Dependent Claim
19 words
The method of claim 18 further comprising repeating steps c) and d) for a plurality of subsequent time periods.
Claim 29
Independent Claim
186 words
A system for ablating biological tissue comprising: a catheter having a plurality of electrodes adapted to be positioned proximal to the biological tissue; a power generator adapted to output power having a duty cycle with alternating on periods and off periods; a pulse generator adapted to output energy pulses; and a processor adapted to: (a) during a first time period, control the power generator such that power is applied to the electrodes to form a lesion between a first electrode and a second electrode; (b) control the pulse generator such that an energy pulse is provided to the first electrode during an initial time period subsequent to the first time period; (c) monitor electrical activity at the second electrode for an indication that the energy pulse has been sensed by the second electrode and record the time at which the pulse was sensed; (d) determine a conduction time based on the difference between the pulse-application time and the pulse-sense time; (e) repeat (b), (c) and (d) at least once, during a time period subsequent to the initial time period; (f) monitor changes in the conduction times.
Claim 30
Independent Claim
186 words
A system for ablating biological tissue comprising: a catheter having a plurality of electrodes adapted to be positioned proximal to the biological tissue; a power generator adapted to output power having a duty cycle with alternating on periods and off periods; a pulse generator adapted to output energy pulses; and a processor adapted to: (a) during a first time period, control the power generator such that power is applied to the electrodes to form a lesion between a first electrode and a second electrode; (b) control the pulse generator such that an energy pulse is provided to the first electrode during an initial time period subsequent to the first time period; (c) monitor electrical activity at the second electrode for an indication that the energy pulse has been sensed by the second electrode and record the time at which the pulse was sensed; (d) determine a conduction time based on the difference between the pulse-application time and the pulse-sense time; (e) repeat (b), (c) and (d) at least once, during a time period subsequent to the initial time period; (f) monitor changes in the conduction times.
Claim 31
Dependent Claim
43 words
The system of claim 26 wherein the processor controls the power generator such that the first time period occurs during an on period of the duty cycle, and the initial time and subsequent time occur during an off period of the duty cycle.
Claim 32
Dependent Claim
17 words
The system of claim 27 wherein the initial time and subsequent time occur during different off periods.
Claim 33
Dependent Claim
17 words
The system of claim 27 wherein the initial time and subsequent time occur during consecutive off periods.
Claim 34
Dependent Claim
68 words
The system of claim 26 wherein to monitor changes in the conduction times the processor is adapted to: calculate a difference between consecutive conduction times; compare the difference to a preset value; and if the difference is above the preset value, control the power generator such that power is applied to the electrodes to improve the efficacy of the lesion between the first electrode and a second electrode.
Claim 35
Dependent Claim
26 words
The system of claim 30 wherein the difference comprises the percentage change between consecutive conduction times and the preset value is between approximately 5% and 10%.
Claim 36
Dependent Claim
19 words
The system of claim 26 further comprising repeating steps c) and d) for a plurality of subsequent time periods.
References Cited (Backward Citations)
US20020143326A1
Cited
US20030045871A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
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| 3.5 Years (Year 4) | 2007-07-13 | 2008-01-12 | 2008-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2011-07-13 | 2012-01-12 | 2012-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2015-07-13 | 2016-01-12 | 2016-07-13 | $7700.00 | Window Closed / Lapsed |