System and method for gauging the amount of electrode-tissue contact using pulsed radio frequency energy

• US 6,264,653 B1
• Filed: 09/24/1999
• Issued: 07/24/2001
• Est. Priority Date: 09/24/1999
• Status: Expired due to Term

• Current Assignee: Boston Scientific Scimed (Boston Scientific Corporation)
• Original Assignee: C.R. Bard, Inc. (Becton, Dickinson & Co)
• Inventors: Falwell, Gary S.
• Primary Examiner(s): Dvorak, Linda C. M.
• Assistant Examiner(s): Ruddy, David M.
• Application Number:
  US09/405,246
• Time in Patent Office: 669 Days
• Field of Search: 606/32, 606/34, 606/41, 606/42, 606/49, 606/46, 606/38, 128/898
• US Class Current: 606/41
• CPC Class Codes: A61B 18/1206 Generators therefor
• CPC Class Codes: A61B 18/1492 having a flexible, catheter-like structure, e.g. for heart ablation A61B18/1477 takes precedence
• CPC Class Codes: A61B 2018/00815 measured by a thermistor
• CPC Class Codes: A61B 2018/00875 Resistance or impedance

Abstract

The system and methods of the invention gauge the amount or quality of the contact between body tissue and one or more electrodes supported on a catheter. In further aspects, the invention concerns methods for controlling power delivery to particular electrodes on a catheter in response to tissue contact data derived from that electrode or other electrodes during the ablation procedure. The invention monitors and processes information concerning the number of pulses of pulsed radio-frequency energy that are delivered during an ablation procedure. The amount or quality of tissue contact is gauged by comparing the number of pulses delivered to a particular electrode during the interval to either the number of pulses delivered to at least one other electrode of the plural electrodes or data derived during the ablation procedure. The system and method can provide a display of the gauge of tissue contact among the various electrodes and also can automatically control distribution of pulsed RF energy in response to the gauge of tissue contact.

Claims

1. A method for monitoring a catheter ablation procedure, comprising the steps of:

(a) providing a catheter having a plurality of electrodes supported along its length and at least one temperature sensor;

(b) providing pulsed radio-frequency energy to the plural electrodes from a source of RF energy;

(c) for each of the plural electrodes, monitoring the number of pulses delivered to that electrode during an interval of time; and

(d) gauging an amount of tissue contact by comparing the number of pulses delivered to a particular electrode during the interval to the number of pulses delivered to at least one other electrode of the plural electrodes.

2. The method as in claim 1, including the additional step of outputting the result of the comparison.

3. The method as in claim 1, including the additional step of controlling the number of pulses delivered to the particular electrode in response to the comparison.

4. The method as in claim 3, wherein the controlling step comprises:

i. locating an electrode among the plurality of electrodes which is making comparatively good tissue contact;

ii. identifying the total number of pulses that were delivered during the interval to the located electrode; and

iii. decreasing the number of pulses delivered to the particular electrode in the event that the number of pulses delivered to the particular electrode exceeds then number of pulses delivered to the located electrode by a predetermined factor.

5. The method as in claim 4, wherein the predetermined factor is one of a number and a percentage.

6. The method as in claim 5, wherein the predetermined factor is a percentage and wherein the number of pulses delivered to the particular electrode is decreased if the total number of pulses delivered to the particular electrode during the interval exceeds the total number of pulses delivered to the located electrode by about at least 25%.

7. The method as in claim 1, wherein the number of pulses delivered to the particular electrode during the interval is compared to an average number of pulses delivered to all of the plural electrodes.

8. The method as in claim 1, wherein the time interval is the same for each of the plural electrodes.

9. The method as in claim 1, further comprising a tip electrode at the tip of the length of the catheter and wherein the steps of providing pulsed energy and monitoring the number of pulses include providing pulsed energy to the tip electrode and monitoring the number of pulses provided to the tip electrode.

10. The method as in claim 1, wherein each of the plurality of electrodes has an associated temperature sensor.

11. A method for monitoring a catheter ablation procedure, comprising the steps of:

(a) providing a catheter having a plurality of electrodes supported along its length and at least one temperature sensor;

(b) providing pulsed radio-frequency energy to the plural electrodes from a source of RF energy;

(c) for each of the plural electrodes, monitoring the number of pulses delivered to that electrode during an interval of time; and

(d) gauging an amount of tissue contact by comparing the number of pulses delivered to a particular electrode during the interval to data derived during an ablation procedure.

12. A method for monitoring a catheter ablation procedure, comprising the steps of:

(a) providing a catheter having a plurality of electrodes supported along its length and a number of temperature sensors positioned along the catheter to sense the temperature at each of the electrodes;

(b) providing pulsed radio-frequency energy to the plural electrodes from a source of RF energy;

(c) for each of the plural electrodes, monitoring the number of pulses delivered to that electrode during an interval of time; and

(d) gauging an amount of tissue contact by comparing the number of pulses delivered to a particular electrode during the interval to data derived during an ablation procedure.

13. The method as in claim 12, where in there is one temperature sensor for each electrode.

14. A system for monitoring contact between one or more electrodes supported on a catheter and tissue within a patient during an ablation procedure in which energy is provided to the electrodes from a source of pulsed RF energy and in which each electrode has an associated temperature sensor, comprising:

(a) a controller coupled between the source of pulsed RF energy and each of the electrodes, the controller supplying pulsed RF energy to the electrodes using a gating signal and receiving temperature signals from the temperature sensors during the ablation procedure;

(b) a counter which registers the number of pulses of RF energy delivered to each electrode;

(c) a processor responsive to data gathered by the counter to generate a contact signal that gauges the amount or quality of tissue contact at each electrode.

15. The system as in claim 14, further comprising a continuously updated display of the gauge of tissue contact.

16. The system as in claim 14, wherein the processor governs the gating signal.

17. The system as in claim 16, wherein the gating signal for a particular electrode is altered to either limit or stop the supply of pulsed RF energy to that electrode based on the contact signals from other electrodes.