DISTAL BALLOON IMPEDANCE AND TEMPERATURE RECORDING TO MONITOR PULMONARY VEIN ABLATION AND OCCLUSION
First Claim
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1. A method of assessing lesion quality in pulmonary vein ostium tissue, the method comprising:
- recording a first set of impedance measurements from an electrode on a balloon catheter having a treatment element at a distal portion;
recording a second set of impedance measurements from the electrode;
determining a first impedance slope using the first set of impedance measurements and determining a second impedance slope using the second set of impedance measurements;
comparing the first slope to a first reference slope and comparing the second slope to a second reference slope;
determining whether the balloon catheter is creating a permanent lesion in the pulmonary vein ostium based on the comparison of the first slope to the first reference slope and the second slope to the second reference slope; and
repositioning the treatment element when it is determined that the balloon catheter is not creating a permanent lesion in the pulmonary vein ostium tissue.
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Abstract
A cryoablation method, system, and device that allows for real-time and accurate assessment and monitoring of PV occlusion and lesion formation without the need for expensive imaging systems and without patient exposure to radiation. The system includes a cryoballoon catheter with a cryoballoon, a distal electrode, a proximal electrode, and a temperature sensor. Impedance measurements recorded by the electrodes may be used to predict ice formation, quality of pulmonary vein occlusion, and lesion formation.
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Citations
21 Claims
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1. A method of assessing lesion quality in pulmonary vein ostium tissue, the method comprising:
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recording a first set of impedance measurements from an electrode on a balloon catheter having a treatment element at a distal portion; recording a second set of impedance measurements from the electrode; determining a first impedance slope using the first set of impedance measurements and determining a second impedance slope using the second set of impedance measurements; comparing the first slope to a first reference slope and comparing the second slope to a second reference slope; determining whether the balloon catheter is creating a permanent lesion in the pulmonary vein ostium based on the comparison of the first slope to the first reference slope and the second slope to the second reference slope; and repositioning the treatment element when it is determined that the balloon catheter is not creating a permanent lesion in the pulmonary vein ostium tissue. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of assessing pulmonary vein ostium lesion quality, the method comprising:
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positioning a balloon catheter proximate a pulmonary vein ostium, the balloon catheter including a longitudinal axis and a balloon; reducing the temperature of the balloon to a temperature sufficient to ablate the pulmonary vein ostium; recording a first set of impedance measurements from each of a plurality of electrodes radially disposed about the longitudinal axis immediately distal to the balloon; recording a second set of impedance measurements from each of the plurality of electrodes; determining a first impedance slope using the first set of impedance measurements from each of the plurality of electrodes and determining a second impedance slope using the second set of impedance measurements from each of the plurality of electrodes; comparing the first impedance slope and the second impedance slope for each of the plurality of electrodes to generate an impedance curve for each of the plurality of electrodes; comparing the impedance curves of the plurality of electrodes to each other; determining, based on the comparison between the impedance curves, at least one of; whether the balloon catheter is creating a permanent lesion in the pulmonary vein ostium; whether the balloon catheter is not occluding the pulmonary vein; whether the balloon catheter is partially occluding the pulmonary vein; and whether the balloon catheter is completely occluding the pulmonary vein; determining, when the comparison indicates that the balloon catheter is partially occluding the pulmonary vein, a radial position of an area of the treatment element that is not in contact with tissue; and repositioning the treatment element until a determination of at least one of complete occlusion and the creation of a permanent lesion is made.
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18. A method of determining cryoablation lesion quality, the method comprising:
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positioning a cryoballoon coupled to an ablation catheter in contact with a pulmonary vein ostium, the ablation catheter further including; a first electrode immediately distal to the cryoballoon; a second electrode distal to the first electrode; and at least one thermocouple proximate the first electrode, the first and second electrodes being within the pulmonary vein; initiating a flow of coolant within the cryoballoon to cool the cryoballoon to a temperature sufficient to ablate the pulmonary vein ostium; continuously recording impedance measurements from the first electrode; continuously recording impedance measurements from the second electrode; continuously recording temperature measurements from the thermocouple; and determining that a circumferential ablation lesion will be formed around the pulmonary vein ostium when the first electrode measures an impedance of at least 2000Ω and
the thermocouple measures a temperature of −
37.8±
3.3°
C. within 120±
30 sec from the onset of the flow of coolant within the cryoballoon.
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19. A system for cryoablating tissue, the system comprising:
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a cryoablation device, the device including; a balloon coupled to a distal portion of the device; a first electrode immediately distal to the balloon; a second electrode a distance from the first electrode; and at least one thermocouple proximate the first electrode; a source of coolant in fluid communication with the balloon; and a console including a processor, the processor programmed to; receive impedance measurements recorded by the first and second electrodes; receive temperature measurements recorded by the thermocouple; and determine whether the balloon is creating a permanent lesion in a pulmonary vein ostium, the determination based on at least one of the impedance measurements from the first electrode, impedance measurements from the second electrode, and temperature measurements from the at least one thermocouple. - View Dependent Claims (20, 21)
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Specification