Pulmonary vein isolation for patients with atrial fibrillation

Abstract

The present invention is titled "Pulmonary Vein Isolation for Patients with Atrial Fibrillation". The present invention discloses a method for ablating a patient, the method including ascertaining the CHA2DS2-VASc score of the patient and inserting a probe into the patient to contact the pulmonary veins of the patient. The method further includes applying energy via the probe to ablate the pulmonary veins until pulmonary vein isolation (PVI) is achieved. When PVI is achieved and the CHA2DS2-VASc score is less than a preset value, ablation of the pulmonary veins is stopped. When PVI is achieved and the CHA2DS2-VASc score is greater than or equal to the preset value, energy is applied to perform additional ablation.

Description

[0001] Cross - Reference to Related Applications

[0002] This application claims priority to U.S. Provisional Patent Application Serial No. 62 / 843,779, filed May 6, 2019, which is hereby incorporated by reference in its entirety as if fully set forth herein. Field of the Invention

[0003] The present invention generally relates to atrial fibrillation and, more particularly, to treating atrial fibrillation by pulmonary vein isolation and additional left atrial ablation. Background of the Invention

[0004] Pulmonary vein isolation (PVI) is the cornerstone of treating atrial fibrillation and is used for both paroxysmal AF (PAF) and persistent AF (PsAF). However, while the results of PVI in PAF patients have been consistently good, the results in PsAF patients have been more variable. Thus, some PsAF patients respond well to PVI alone, but other patients in this category require more treatment than PVI alone. Summary of the Invention

[0005] Embodiments of the present invention provide a method for ablating a patient, the method comprising:

[0006] Detecting the CHA 2 DS 2 -VASc score of the patient;

[0007] Inserting a probe into the patient to contact the patient's pulmonary veins;

[0008] Applying energy via the probe to ablate the pulmonary veins until pulmonary vein isolation (PVI) is achieved;

[0009] When PVI is achieved and the CHA 2 DS 2 -VASc score is less than a preset value, stopping ablation of the pulmonary veins; and

[0010] When PVI is achieved and the CHA 2 DS 2 -VASc score is greater than or equal to the preset value, applying the energy to perform additional ablation.

[0011] In an embodiment disclosed herein, the preset value is 1 when the patient is male and 2 when the patient is female.

[0012] In another embodiment disclosed herein, the probe comprises a balloon catheter.

[0013] In yet another embodiment disclosed by the present invention, the probe includes a focal catheter.

[0014] In an alternative embodiment, the energy includes radiofrequency energy.

[0015] In another alternative embodiment, additional ablation is adjacent to the pulmonary vein. Generally, the additional ablation includes rotor ablation, and / or ablation for isolating the posterior wall of the atrium, and / or ablation for isolating the left atrial appendage, and / or ablation at another location of arrhythmogenic activity.

[0016] According to an embodiment of the present invention, there is also provided a device for ablating a patient, the device comprising:

[0017] a probe configured to be inserted into the patient's body to contact the patient's pulmonary vein;

[0018] and a processor configured to:

[0019] detect the patient's CHA 2 DS 2 -VASc score,

[0020] apply energy via the probe to ablate the pulmonary vein until pulmonary vein isolation (PVI) is achieved,

[0021] when PVI is achieved and CHA 2 DS 2 -VASc score is less than a preset value, stop ablating the pulmonary vein, and

[0022] when PVI is achieved and CHA 2 DS 2 -VASc score is greater than or equal to the preset value, apply energy to perform additional ablation.

[0023] In conjunction with the accompanying drawings, the present disclosure will be more fully understood through the following detailed description of the embodiments of the present disclosure, wherein: Brief Description of the Drawings

[0024] Figure 1 is a schematic illustration of a medical system according to an embodiment of the present invention;

[0025] Figure 2 is a schematic illustration of the distal end of a medical probe for use in a system according to an embodiment of the present invention;

[0026] Figure 3 is a schematic illustration of the distal end of a medical probe for use in a system according to an alternative embodiment of the present invention;

[0027] Figure 4Schematic diagram showing CHA 2 DS 2 -VASc; and

[0028] Figure 5 Flow chart of steps of an algorithm stored in a module of a system according to an embodiment of the present invention. DETAILED DESCRIPTION

[0029] Overview

[0030] To date, there has generally not been a tool for classifying patients with atrial fibrillation as requiring only PVI (pulmonary vein isolation) or more than just PVI for patients with persistent atrial fibrillation (PsAF).

[0031] The present inventors have found that the CHA 2 DS 2 -VASc score can be used as a metric to determine whether PVI alone is sufficient for a patient or whether additional treatment, i.e., ablation outside the pulmonary veins, is required. (The score is described in detail in the DETAILED DESCRIPTION section of the embodiments below.) If the patient score is less than a preset value depending on the patient's gender, PVI alone may be sufficient to treat the patient's atrial fibrillation. If the patient score is greater than or equal to the preset value, additional treatment (i.e., ablation in addition to PVI alone) may be required to treat atrial fibrillation.

[0032] (It should be noted that the CHA 2 DS 2 -VASc score is currently used to predict / estimate the stroke risk in patients with atrial fibrillation. A high score corresponds to a higher stroke risk, such that in such cases, anticoagulation is typically required.)

[0033] In an embodiment of the present invention, a physician determines the patient's CHA 2 DS 2 -VASc score. The physician then inserts a probe into the patient and navigates the probe such that the distal end of the probe contacts the patient's pulmonary veins.

[0034] The physician then applies a suitable energy modality (usually radiofrequency energy or pulsed field ablation (also known as irreversible electroporation)) using the distal end to ablate the pulmonary veins, thereby achieving pulmonary vein isolation. The achievement of pulmonary vein isolation depends on the physician (who may also be the operator of the probe), who typically uses a mapping probe to detect the absence of electrical signals conducted between the atrium and the vein under examination or to pace the coronary sinus and detect the entrance block of the signal. When CHA 2 DS 2- When the VASc score is less than the preset value mentioned above, the physician may stop the ablation of the pulmonary veins and withdraw the probe from the vein. When CHA 2 DS 2 - When the VASc score is greater than or equal to the preset value, the physician may need to perform additional ablation outside the vein. The physician typically performs the above procedure sequentially on all of the patient's pulmonary veins. Detailed implementation manner

[0036] Figure 1 FIG. is a schematic illustration of a medical system 20 including a medical probe 22 and a console 24, and Figure 2 is a schematic illustration of the distal end 26 of a medical probe according to an embodiment of the present invention. The probe 22 is used as a catheter and is also referred to herein as catheter 22. The medical system 20 may be based on, for example, that produced by Biosense Webster Inc. (33 Technology Drive, Irvine, CA 92618 USA) system. In the embodiments described below, the medical probe 22 is used to ablate tissue in the heart 28 of a patient 30 (also referred to herein as a subject). Alternatively, the medical probe 22 may be used for other treatment and / or diagnostic purposes in the heart or other body organs with necessary modifications.

[0037] The probe 22 includes an insertion tube 32 and a handle 34 coupled to the proximal end of the insertion tube. During a medical procedure, a medical professional 36 may insert the probe 22 through the patient 30's vascular system via a pre-positioned sheath 72 such that the distal end 26 of the medical probe enters the chamber of the heart 28. When the distal end 26 enters the chamber of the heart 28, the medical professional 36 may deploy a balloon 38 attached to the distal end 26 described in more detail below, and the medical professional may manipulate the handle 34 to position the balloon so as to engage myocardial tissue at one or more desired locations. The balloon 38 is typically formed of a biocompatible material such as polyethylene terephthalate (PET), polyurethane, nylon, or silicone.

[0038] In Figure 1 the configuration shown, the console 24 is connected to body surface electrodes via a cable 40, which typically includes an adhesive skin patch 42 attached to the patient 30. The console 24 also includes a processor 44 coupled to a plurality of modules, which include software and / or hardware components. The details and functions of the modules are described below.

[0039] The processor 44 in combination with a current tracking module 46 is based on the microelectrode 48 and / or ablation electrode 74 attached to the balloon 38 and the adhesive skin patch 42 ( Figure 2)(The impedance and / or current measured between (usually gold covering the balloon) to determine the position coordinates of the distal end 26 within the heart 28. In addition to being used as a position sensor during a medical procedure, the microelectrodes 48 (also simply referred to herein as electrodes) can also perform other tasks, such as measuring the electrical activity of the heart 28 and / or pacing the heart.)

[0040] Alternatively or in addition, the processor 44 determines the position coordinates of the distal end 26 based on signals received by the electromagnetic (EM) tracking module 88. The signals are generated by a magnetic sensor 76 incorporated within the tubular shaft 70 of the distal end 26, and the sensor generates its signal in response to a magnetic field passing through the sensor emitted by an alternating magnetic field radiator 78 positioned beneath the patient 30.)

[0041] The processor 44 may include a real-time noise reduction circuit 50 typically configured as a field programmable gate array (FPGA), followed by an analog-to-digital (A / D) signal conversion integrated circuit 52. The processor may pass the signals from the A / D circuit 52 to another processor and / or may be programmed to determine the position coordinates mentioned above.)

[0042] Position tracking techniques based on impedance and current are described, for example, in U.S. Patents 5,983,126, 6,456,864, and 5,944,022. Electromagnetic position tracking techniques are described, for example, in U.S. Patents 5,391,199, 6,690,963, and 6,892,091. The methods of position sensing described above are implemented in the system described above and are described in detail in the patents cited above.) system and are described in detail in the patents cited above.)

[0043] Before inserting the probe 22 into the patient 30, the processor 44 acquires an electroanatomical map 56 of the heart 28. Typically, data for the map is acquired using a probe other than the probe 22, such as a focal catheter, which is configured to be tracked by the module 46 and to acquire signals from the regions of the heart chambers contacted by the catheter. An example of a focal catheter is described below with reference to Figure 3 Typically, although not required, the processor 44 uses the signals to determine the local activation time (LAT) of the heart chambers and incorporates the LAT into the map 56. The map 56 is stored in a memory 60 accessible by the processor 44, and during the procedure, the processor can present the map 56 to the medical professional 36 on the display 58.)

[0044] During the procedure using the probe 22, the processor 44 can overlay an icon representing the position of the distal end 26 (determined in the manner described above) on the map 56, enabling the professional 36 to track the distal end.)

[0045] Memory 60 may include any suitable volatile and / or non-volatile memory, such as random access memory or a hard disk drive. In some embodiments, medical professional 36 may manipulate the mapping diagram 56 using one or more input devices 62. In an alternative embodiment, display 58 may include a touch screen that may be configured to receive input from medical professional 36 in addition to presenting mapping diagram 56.

[0046] In Figure 2 the configuration shown, balloon 38 (shown inflated) is attached to a tubular shaft 70 terminating at a distal end 26. Balloon 38 is configured to extend from a sheath 72 and be deployed into the left atrium 80 of heart 28 such that electrodes 74 contact the ostia 82 of pulmonary veins 84. The contact may be verified by any convenient means known in the art, such as by changes in impedance between the recording electrodes and patch 42.

[0047] Console 24 also includes an inflation module 64 and an ablation module 66. Ablation module 66 is configured to monitor and control ablation parameters, such as the level and duration of ablation power (e.g., radiofrequency (RF) energy) transmitted from ablation module 66 to ablation electrodes 74, and module 66 generally includes an RF generator 86 for this purpose.

[0048] Inflation module 64 is configured to monitor and control the inflation of balloon 38. In some embodiments, inflation module 64 may use a flush fluid to inflate balloon 38 and control the inflation of the balloon by controlling the flow rate of the flush fluid into the balloon. In these embodiments, balloon 38 generally includes a plurality of small apertures (not shown) that permit the flush fluid to exit the balloon. The diameter of these apertures is typically from 0.025 micrometers to 0.500 micrometers.

[0049] As described herein, probe 22 is used to ablate elements of PV 84. However, other methods of causing processor 44 to ablate elements of PV 84 are also considered to be within the scope of the present invention. For example, probe 22 having a distal end exemplified by distal end 26 functions as a balloon catheter, however, another type of probe such as a focal catheter may also be used for ablation. Examples of medical probes formed as focal catheters are provided in Figure 3 as follows.

[0050] Figure 3 Schematic illustration of the distal end 126 of a probe 122 according to an alternative embodiment of the present invention. Except for the differences described below, the operation of distal end 126 is generally similar to the operation of distal end 26 ( Figure 1 and Figure 2 ), and elements indicated by the same reference numerals in both distal ends 26 and 126 are generally similar in construction and operation.

[0051] Compared to the distal end 26 of probe 22, the distal end 126 of probe 122 does not include a balloon. Instead, the distal end 126 is formed as a generally cylindrical extension 128 of shaft 70. At the distal end of the extension 128, an electrode 130, which is generally cup-shaped, is formed to cover the distal end. Typically, one or more other electrodes 132 (generally in the form of a ring) surround the extension 128. Like electrode 74, electrode 130 is configured to act as an ablation electrode by being coupled to ablation module 66. Additionally, although electrodes 132 can also be configured to act as ablation electrodes by being coupled to module 66, they are typically configured to be similar to electrode 48, i.e., to act as position sensors by being coupled to a current tracking module, and / or to measure electrical activity and / or provide pacing.

[0052] It should be understood that probe 122 utilizes the distal end 126 to act as a focal catheter, and the distal end can be tracked using module 46. Alternatively or in addition, the distal end 126 can include a magnetic sensor 134 that is generally similar to sensor 76, in which case the distal end 126 can be tracked using EM tracking module 88.

[0053] In an embodiment of the present invention, in addition to probe 22 or probe 122 for ablating patient 30, processor 44 is coupled to a pulmonary vein isolation (PVI) module 138. Module 138 in particular stores the value of the CHA 2 DS 2 -VASc score of patient 30, and the CHA Figure 4 is described below with reference to 2 DS 2 -VASc score. The other functions of PVI module 138 are described with reference to the flowchart of Figure 5 .

[0054] Figure 4 FIG. is a schematic diagram of a graph 68 of CHA 2 DS 2 -VASc presented to physician 36 on display 58 according to an embodiment of the present invention.

[0055] CHA 2 DS 2 -VASc graph shows eight conditions of patient 30 that physician 36 considers before performing ablation on the patient. Each of these conditions is assumed to be present or absent. If absent, the condition is assigned a value of zero (0). If present, the condition has a value given by Table I:

[0056]

[0057]

[0058] Table I

[0059] To evaluate the CHA 2 DS 2 -VASc score of patient 30, the physician sums the values for all conditions. For example, if patient 30 is a 60-year-old male with diabetes, then the CHA 2 DS 2 -VASc score is 1.

[0060] The physician can use control 62 to input the value of the CHA 2 DS 2 -VASc score into the PVI module 138. As Figure 5 described in the flowchart of, which shows the steps of the algorithm stored in the PVI module 138, the PVI module uses the CHA 2 DS 2 -VASc score to determine how ablation of patient 30 can be performed.

[0061] The algorithm also uses the gender of patient 30, and the physician can input the patient's gender into the processor 40 in any convenient way, such as by using the touchscreen buttons 90 or 92, or by selecting the appropriate button using control 62.

[0062] Figure 5 is a flowchart of the steps of the algorithm stored in the PVI module 138 according to an embodiment of the present invention. The algorithm is implemented by the processor 40 and includes the steps of the protocol to be followed for ablation of patient 30, and this specification assumes that the probe 22 (i.e., the balloon catheter) having the distal end 26 is used for this protocol. This specification can be modified with the necessary changes for other probes such as the probe 122 (i.e., the focal catheter), and the use of such other probes is considered to be included within the scope of the present invention.

[0063] In an initial step 150, the physician 36 evaluates the CHA 2 DS 2 -VASc score of patient 30 and stores the score in the module 138, as referred to above Figure 4 described. In the initial step, the physician also inputs the patient's gender into the processor 40 as described above, and the processor uses the patient's gender to specify and record the patient's preset value. If the patient is male, the preset value is specified as 1; if the patient is female, the preset value is specified as 2. The preset value is used in the comparison step 170 described below.

[0064] The physician repeats the remaining steps of the flowchart for each pulmonary vein in turn until all of the patient's pulmonary veins have been treated.

[0065] In the probe insertion step 154, the physician inserts the probe 22 into the patient 30 and navigates the distal end 26 until the electrodes 74 of the distal end contact the ostium 82 of the pulmonary vein 84. Navigation can be performed using the current tracking module 46 and / or the EM tracking module 88, and contact can be verified by observing, for example, changes in impedance between the electrodes 74 and the patch 42 as described above.

[0066] In the ablation step 158, and using the first comparison step 162, the physician ablates the annulus around the ostium using the RF generator 86. During ablation, the physician checks whether the pulmonary vein has been isolated. Checks for isolation typically include measuring changes in impedance of the ablated tissue and / or observing changes in signals by signal pacing and / or passive signal acquisition. In the case of using pacing, if a signal injected on one side of the ablation annulus is not observed on the other side, it indicates isolation. In the case of using passive signal acquisition, if a signal that was present before ablation is no longer present, it may indicate isolation.

[0067] If the comparison step 162 returns a negative value, the physician continues ablation in step 158.

[0068] If the comparison step 162 returns a positive value, i.e., the physician has determined that the pulmonary vein is isolated, the control flow proceeds to the notification step 166, where the physician uses the control 62 to notify the processor 44 to record the isolation.

[0069] In the second comparison step 170, the processor checks the CHA 2 DS 2 -VASc score of the patient 30 stored in the PVI module to see if it is less than a preset value recorded in step 150.

[0070] If the comparison returns a positive value, i.e., the score is less than the preset value, the embodiments of the present invention assume that no additional ablation is required based on this score and the achievement of isolation. In this case, the control flow proceeds to the probe withdrawal step 174, where the physician may be advised to stop ablation and withdraw the probe from the vein because pulmonary vein isolation has been achieved and the score is less than 2. In one embodiment, the advice is in the form of a notification to the physician, such as the notification 190 presented on the display 58 ( Figure 4 ).

[0071] If the comparison 170 returns negative, i.e., the score is at or above the preset value, the embodiments of the present invention assume that even though the achievement of isolation has been completed, additional ablation outside the pulmonary vein is still required based on this score. In this case, the control flow proceeds to the additional ablation step 178, where the physician may be advised to continue ablation. In one embodiment, the advice is in the form of a notification to the physician, such as the notification 194 presented on the display 58 ( Figure 4 ).

[0072] The additional ablations required are adjacent to the pulmonary veins and may include rotor ablations (e.g., focal triggers with a repetitive activation pattern), ablations to isolate the posterior atrial wall, and ablations to isolate the left atrial appendage, and / or ablations of additional locations of arrhythmogenic activity. It should be understood that this list is not intended to be complete, and other ablations that may be required are also considered to be within the scope of the present invention.

[0073] It should be understood that the above embodiments are cited by way of example, and the present invention is not limited to what is specifically shown and described above. On the contrary, the scope of the present invention includes combinations and sub-combinations of the various features described above, as well as variations and modifications thereof, which should occur to those skilled in the art when reading the above description, and which are not disclosed in the prior art.

Claims

1. An apparatus for ablating a patient, comprising: a probe configured to be inserted into the patient to contact the patient's pulmonary vein; and a processor configured to: Detect the CHA of the patient 2 DS 2 -VASc score apply energy via the probe to ablate the pulmonary vein until pulmonary vein isolation (PVI) is achieved, When PVI is achieved and the CHA 2 DS 2 -VASc score is less than a preset value, ablation of the pulmonary vein is stopped, and When PVI is achieved and the CHA 2 DS 2 -VASc score is greater than or equal to the preset value, apply the energy to perform additional ablation; wherein the preset value is 1 when the patient is male and 2 when the patient is female.

2. The apparatus according to claim 1, wherein the probe comprises a balloon catheter.

3. The apparatus according to claim 1, wherein the probe comprises a focal catheter.

4. The apparatus according to claim 1, wherein the energy comprises radiofrequency energy.

5. The apparatus according to claim 1, wherein the additional ablation is adjacent to the pulmonary vein.

6. The apparatus according to claim 5, wherein the additional ablation comprises rotor ablation.

7. The apparatus according to claim 5, wherein the additional ablation comprises ablation for isolating the posterior wall of the atrium.

8. The apparatus according to claim 5, wherein the additional ablation comprises ablation for isolating the left atrial appendage.

9. The apparatus according to claim 5, wherein the additional ablation comprises ablation at another location of arrhythmogenic activity.

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