Patent Publication Number: US-2017367615-A1

Title: System and Method for Electrophysiology Procedures

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. provisional application No. 62/353,252, filed 22 Jun. 2016, which is hereby incorporated by reference as though fully set forth herein. 
    
    
     BACKGROUND 
     The instant disclosure relates to electrophysiology procedures, such as cardiac diagnostic (e.g., mapping) and therapeutic (e.g., ablation) procedures. In particular, the instant disclosure relates to systems, apparatuses, and methods for the creation of anatomical models and for conducting electrophysiology studies. 
     It is desirable to create anatomical models in connection with various medical procedures. For example, cardiac models are often created in connection with cardiac electrophysiology studies. Those of ordinary skill in the art will be familiar with numerous ways to acquire and display cardiac models for use in cardiac electrophysiology studies (e.g., using a roving catheter to gather a cloud of geometry points to which a surface is fit). 
     Once a cardiac model is created, that model can be used, for example, to display one or more electrophysiology maps. In general, electrophysiology maps are created from a plurality of electrophysiology data points, each of which includes both measured electrophysiology data and location data, allowing the measured electrophysiology information to be associated with a particular location in space (that is, allowing the measured electrophysiology information to be interpreted as indicative of electrical activity at a point on the patient&#39;s heart), and therefore displayed at the proper location on the cardiac model. 
     In certain extant approaches to non-contact electrophysiological mapping, a non-contact, multi-electrode mapping catheter is first introduced into the heart. Once the mapping catheter is placed, a roving catheter is introduced in order to create the cardiac model. The presence of the mapping catheter, however, can complicate the creation of the cardiac model, for example by impeding access by the roving catheter to portions of the heart. Moreover, the cardiac model can be invalidated if the mapping catheter moves during creation of the cardiac model. 
     BRIEF SUMMARY 
     Disclosed herein is a method of performing a cardiac electrophysiology procedure, including the steps of: inserting a catheter including at least one magnetic localization sensor into a patient&#39;s heart; generating a cardiac model using the catheter, wherein the cardiac model includes magnetic localization data measured using the at least one magnetic localization sensor; removing the catheter from the patient&#39;s heart; and, after removing the catheter from the patient&#39;s heart: inserting an electrophysiology catheter including at least one magnetic localization sensor into the patient&#39;s heart; placing the electrophysiology catheter in an initial location within the patient&#39;s heart; localizing the electrophysiology catheter within a coordinate system common to the cardiac model using the at least one magnetic localization sensor of the electrophysiology catheter; and performing the electrophysiology procedure using the electrophysiology catheter. The at least one magnetic localization sensor of the electrophysiology catheter can be positioned on a shaft of the electrophysiology catheter. 
     The electrophysiology procedure can be a diagnostic procedure, such as an electrophysiology mapping procedure, a therapeutic procedure, such as an ablation procedure, or a combination of both. 
     The electrophysiology device can be a multi-electrode electrophysiology mapping catheter, such as a non-contact electrophysiology mapping catheter. 
     In embodiments, the method can also include: monitoring for movement of the electrophysiology catheter from the initial location to a subsequent location; and re-localizing the electrophysiology catheter within the coordinate system common to the cardiac model using the at least one magnetic localization sensor of the electrophysiology catheter. 
     It is also contemplated that localizing the electrophysiology catheter within the coordinate system common to the cardiac model using the at least one magnetic localization sensor of the electrophysiology catheter can include determining a rotation angle of the at least one magnetic localization sensor of the electrophysiology catheter. For example, the electrophysiology catheter can include at least one radiopaque marker that is used to determine the rotation angle of the at least one magnetic localization sensor of the electrophysiology catheter. As another example, the rotation angle of the at least one magnetic localization sensor of the electrophysiology catheter can be determined using multiple electrodes on an electrophysiology mapping catheter. 
     According to another embodiment of the disclosure, a method of performing an electrophysiology procedure includes: generating a model of an anatomical region using a probe, wherein the probe includes at least one magnetic localization sensor, and wherein the model includes magnetic localization data measured using the at least one magnetic localization sensor; placing an electrophysiology device within the anatomical region, wherein the electrophysiology device includes at least one magnetic localization sensor; localizing the electrophysiology device within a coordinate system common to the model using the at least one magnetic localization sensor of the electrophysiology device; and performing the electrophysiology procedure using the electrophysiology device. 
     The method can include compensating for movement of the electrophysiology device during the electrophysiology procedure using the at least one magnetic localization sensor of the electrophysiology device. For example, the localizing step can be repeated if and when the electrophysiology device moves. 
     The electrophysiology procedure can include a diagnostic procedure and/or a therapeutic procedure. 
     The electrophysiology device can include a plurality of electrodes, and localizing the electrophysiology device within the coordinate system common to the model using the at least one magnetic localization sensor of the electrophysiology device can include using the plurality of electrodes to determine a rotation angle of the electrophysiology device. 
     Alternatively, the electrophysiology device can include a radiopaque marker, and localizing the electrophysiology device within the coordinate system common to the model using the at least one magnetic localization sensor of the electrophysiology device can include using the radiopaque marker to determine a rotation angle of the electrophysiology device. 
     In still other embodiments of the instant disclosure, a method of performing an electrophysiology procedure includes: inserting a probe carrying at least one magnetic localization sensor into an anatomical region; generating a model of the anatomical region by measuring a plurality of positions of the at least one magnetic localization sensor as it moves through the anatomical region; removing the probe from the anatomical region; and, after removing the probe from the anatomical region: positioning an electrophysiology device including at least one magnetic localization sensor at an initial position within the anatomical region; localizing the initial position of the electrophysiology device within a coordinate system common to the model of the anatomical region using the at least one magnetic localization sensor of the electrophysiology device; and performing the electrophysiology procedure using the electrophysiology device. 
     The method can include: monitoring for movement of the electrophysiology device from the initial position to a subsequent position; and localizing the subsequent position of the electrophysiology device within the coordinate system common to the model of the anatomical region using the at least one magnetic localization sensor of the electrophysiology device. 
     It is also contemplated that localizing the initial position of the electrophysiology device within the coordinate system common to the model of the anatomical region using the at least one magnetic localization sensor of the electrophysiology device can include determining a rotation angle of the electrophysiology device. 
     The foregoing and other aspects, features, details, utilities, and advantages of the present invention will be apparent from reading the following description and claims, and from reviewing the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a localization system, such as may be used in an electrophysiology procedure. 
         FIG. 2  depicts an exemplary catheter, such as may be used to create a cardiac geometry as described herein. 
         FIG. 3  depicts an exemplary electrophysiology catheter, such as may be used to carry out an electrophysiology procedure as disclosed herein. 
         FIG. 4  is a flowchart of representative steps that can be carried out in the performance of an electrophysiology procedure as disclosed herein. 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure provides methods, apparatuses, and systems for the creation of anatomical models in connection with electrophysiology studies. For purposes of illustration, exemplary embodiments will be described in detail herein in the context of a cardiac electrophysiology mapping procedure. It is contemplated, however, that the methods, apparatuses, and systems described herein can be utilized in other contexts including, without limitation, cardiac ablation. 
       FIG. 1  shows a schematic diagram of a system  8  for conducting cardiac electrophysiology studies by navigating and localizing one or more medical devices (e.g., one or more catheters  13 ), creating one or more cardiac models, measuring electrical activity occurring in a heart  10  of a patient  11  (depicted schematically as an oval), and/or mapping and displaying the measured electrical activity and/or information related to or representative of the measured electrical activity on the cardiac model(s). System  8  can also be used to deliver therapy (e.g., ablation) to heart  10 . 
     Thus, system  8  can determine the location, and in some aspects the orientation, of objects, typically within a three-dimensional space, and express those locations as position information determined relative to at least one reference (e.g., belly patch  21  and/or fixed reference  31 ). This data can, in turn, be used to create a model of the patient&#39;s heart  10  using one or more roving localization elements, as will be familiar to those of ordinary skill in the art. 
     System  8  can also be used to measure electrophysiology data at a plurality of points along a cardiac surface and store the measured data in association with location information for each measurement point at which the electrophysiology data was measured. These electrophysiology data points can be used to create one or more electrophysiology maps of the patient&#39;s heart  10  according to known techniques. 
     As depicted in  FIG. 1  and described herein, system  8  is a hybrid system that incorporates both impedance-based and magnetic-based localization capabilities. In some embodiments, system  8  includes the EnSite™ Velocity™ cardiac mapping and visualization system of St. Jude Medical, Inc., which generates electrical fields, or another localization system that relies upon electrical localization fields. Other localization systems, may be used in connection with the present teachings, including, without limitation, the CARTO navigation and location system of Biosense Webster, Inc., the AURORA® system of Northern Digital Inc., Sterotaxis&#39; NIOBE® Magnetic Navigation System, as well as MediGuide™ Technology and the EnSite Precision™ system, both from St. Jude Medical, Inc. Insofar as the ordinarily skilled artisan will appreciate the basic operation of such localization systems, they are only described herein to the extent necessary to understand the instant disclosure. 
     Computer  20  may comprise a conventional general-purpose computer, a special-purpose computer, a distributed computer, or any other type of computer. The computer  20  may comprise one or more processors  28 , such as a single central processing unit (CPU), or a plurality of processing units, commonly referred to as a parallel processing environment, which may execute instructions to practice the various aspects disclosed herein. 
     For simplicity of illustration, the patient  11  is depicted schematically as an oval. In the embodiment shown in  FIG. 1 , three sets of surface electrodes (e.g., patch electrodes  12 ,  14 ,  16 ,  18 ,  19 , and  22 ) are shown coupled to a current source  25 . 
       FIG. 1  also depicts a magnetic source  30 , which is coupled to magnetic field generators. In the interest of clarity, only two magnetic field generators  32  and  33  are depicted in  FIG. 1 , but it should be understood that additional magnetic field generators (e.g., a total of six magnetic field generators, defining three generally orthogonal axes analogous to those defined by patch electrodes  12 ,  14 ,  16 ,  18 ,  19 , and  22 ) can be used without departing from the scope of the present teachings. 
     As mentioned above, system  8  can be used to create cardiac models, for example using a representative catheter  13  having at least one localization sensor. It should be understood that catheter  13  (or multiple such catheters) are typically introduced into the heart and/or vasculature of the patient via one or more introducers and using familiar procedures. For purposes of this disclosure, a segment of an exemplary catheter  13  is shown in  FIG. 2 . In  FIG. 2 , catheter  13  extends into the left ventricle  50  of the patient&#39;s heart  10  through a transseptal sheath  35 . The use of a transseptal approach to the left ventricle is well known and need not be further described herein. Catheter  13  can also be introduced into the heart  10  in any other suitable manner. 
       FIG. 2  also depicts multiple elements  17 ,  52 ,  54 ,  56  carried by catheter  13 . According to aspects of the instant disclosure, at least one of elements  17 ,  52 ,  54 , and  56  is a magnetic sensor that allows localization of catheter  13  within a magnetic localization field, such as may be generated by magnetic source  30  operating in conjunction with magnetic field generators  32 ,  33 . Similarly, at least one of elements  17 ,  52 ,  54 ,  56  is an electrode that allows localization of catheter  13  within an impedance-based localization field, such as may be generated by current source  25  operating in conjunction with patch electrodes  12 ,  14 ,  16 ,  18 ,  19 ,  22 . 
     In any event, those of ordinary skill in the art will be familiar with the use of such a catheter to create a cardiac model from a plurality of geometry points collected as catheter  13  moves through a heart chamber. As described in detail below, in embodiments of the disclosure, magnetic localizations of catheter  13  are used to generate the plurality of geometry points and the resultant cardiac model. 
     System  8  can also be used to create one or more electrophysiology maps. In general, electrophysiology maps are created from a plurality of electrophysiology data points, each of which includes both measured electrophysiology data and location data, allowing the measured electrophysiology information to be associated with a particular location in space (that is, allowing the measured electrophysiology information to be interpreted as indicative of electrical activity at a point on the patient&#39;s heart  10 ). 
       FIG. 3  depicts a representative electrophysiology catheter  60 , such as the EnSite™ Array™ non-contact mapping catheter of St. Jude Medical, Inc., placed into left ventricle  50  to carry out an electrophysiology procedure (e.g., an electrophysiology mapping procedure) according to the teachings herein. Electrophysiology catheter  60  includes an electrode array  62  and an inflatable balloon  63  that can be expanded, such as through the use of a stylet  64  or via inflation of balloon  63  interior to array  62 , to place electrode array  62  into a stable and reproducible geometric shape. 
     Electrode array  62  includes a braid of insulated wires  66 . The insulation can be removed from wires  66  at predetermined locations to form a plurality of electrodes  68 . Additional details of representative electrophysiology catheter  60  are described in U.S. Pat. No. 6,240,307, which is hereby incorporated by reference as though fully set forth herein. 
     According to aspects of the disclosure, electrophysiology catheter  60  also includes a magnetic localization sensor  70 , which allows electrophysiology catheter  60  to be magnetically localized by magnetic source  30  operating in conjunction with magnetic field generators  32 ,  33 . In embodiments, magnetic localization sensor  70  is positioned on shaft  72  of electrophysiology catheter  60  near electrode array  62 . In the embodiment shown in  FIG. 3 , magnetic localization sensor  70  is embedded within shaft  72  at a location proximal of electrode array  62 . In other embodiments, magnetic localization sensor  70  can be positioned at other locations along the length of shaft  72 . For example, magnetic localization sensor  70  can be embedded within a portion of shaft  72  that is co-radial with balloon  63  such that sensor  70  is centrally located relative to array  62 . 
     Various aspects of the instant disclosure will now be described with reference to  FIG. 4 , which is a flowchart depicting representative steps of an exemplary method  400  for carrying out a cardiac electrophysiology procedure according to aspects of the instant disclosure. In some embodiments, for example,  FIG. 4  may represent several exemplary steps that can be carried out by the computer  20  of  FIG. 1  (e.g., by one or more processors  28  executing one or more specialized modules as further described below). 
     It should be understood that the teachings herein can be software- and/or hardware-implemented, and that they may be executed on a single CPU, which may have one or more threads, or distributed across multiple CPUs, each of which may have one or more threads, in a parallel processing environment. 
     In block  402  of  FIG. 4 , a magnetically-localizable catheter (that is, a catheter including at least one magnetic localization sensor) is inserted into a patient&#39;s heart. For example, as described above, catheter  13 , carrying one or more magnetic localization sensors as shown in  FIG. 2  (e.g., one or more of  17 ,  52 ,  54 ,  56 ), can be navigated into the patient&#39;s ventricle  50  via a transseptal introducer  35 . 
     In block  404 , the magnetically-localizable catheter is used to generate a cardiac model. For example, as described above, catheter  13  can be moved through ventricle  50  in order to collect a cloud of geometry points by periodically detecting the position of the magnetic localization sensor(s) within a magnetic localization field generated by magnetic source  30  in conjunction with magnetic field generators  32 ,  33 . Various approaches are known for creating a three-dimensional model of the cardiac geometry from such a cloud of geometry points. The resultant model includes magnetic localization data measured using the magnetic sensor(s) on catheter  13 . 
     In block  406 , the magnetically-localizable catheter is removed from the patient&#39;s heart. For example, catheter  13  can be withdrawn back through transseptal introducer  35 . Introducer  35 , on the other hand, can be left in place for further steps in the electrophysiology procedure as described below. 
     In block  408 , electrophysiology catheter  60  is inserted into the patient&#39;s heart, for example as shown in  FIG. 3 . As described above, electrophysiology catheter  60  includes at least one magnetic localization sensor  70  such that it is magnetically localizable. This enables electrophysiology catheter  60  to be localized within the cardiac model created in block  404 , as described in further detail below. 
     Electrophysiology catheter  60  is placed in an initial location and prepared to collect electrophysiology data points in block  410 . The precise sequence of events encompassed by block  410  may differ from one electrophysiology catheter to another. In the case of the EnSite™ Array™ catheter, for example, once electrophysiology catheter  60  is positioned, electrode array  62  can be expanded, which positions electrodes  68  to record electrical activity on the surface of the heart. 
     In block  412 , electrophysiology catheter  60  is localized within the cardiac model created in block  404  using at least the localization of the at least one magnetic localization sensor  70  on electrophysiology catheter  60  and the magnetic localization data in the cardiac model. For example, one or more fiducial points (e.g., the left ventricle apex) can be identified, and the localization thereof using both the at least one magnetic sensor  70  of electrophysiology catheter  60  and the localization data in the cardiac model can be used to confirm the initial localization of electrophysiology catheter  60  within the cardiac model. 
     The initial localization of electrophysiology catheter  60  in block  412  can also include determining a rotation angle of electrophysiology catheter  60 . More particularly, block  412  can include determining a rotation angle of the at least one magnetic localization sensor  70  carried by electrophysiology catheter  60 . In embodiments of the disclosure, electrophysiology catheter  60  includes a radiopaque marker  74 , and the position of radiopaque marker  74 , as determined using fluoroscopy, is used to determine the rotation angle of electrophysiology catheter  60 . 
     In other embodiments of the disclosure, such as embodiments that utilize a multi-electrode electrophysiology catheter  60 , an electric field created by the electrodes can be used to determine the rotation angle of electrophysiology catheter  60 . 
     In still other embodiments, magnetic sensor  70  can be a six-degree-of-freedom magnetic sensor that can be used independently to determine the rotation angle of electrophysiology catheter  60 . 
     In further embodiments, two magnetic sensors  70  can be used in conjunction to determine the rotation angle of electrophysiology catheter  60 . 
     Once electrophysiology catheter  60  has been localized within the cardiac model, including any determination of the rotation angle of electrophysiology catheter  60 , the electrophysiology procedure can be carried out in block  414 . For example, electrophysiology catheter  60  can be used to perform a diagnostic procedure, such as electrophysiological mapping (e.g., calculating electrical signals from raw signals sensed by electrophysiology catheter  60  and, in embodiments, displaying the calculated electrical signals over the cardiac model) and/or to perform a therapeutic procedure, such as an ablation procedure. 
     In contrast to many extant electrophysiology procedures, which are carried out with multiple catheters in the heart, the electrophysiology procedure described above is carried out with only a single catheter (namely, electrophysiology catheter  60 ) within the heart chamber. This minimizes the risk that electrophysiology catheter  60  will move from its initial location during the electrophysiology procedure. 
     Nonetheless, it should be understood that electrophysiology catheter  60  may be moved, either deliberately or accidentally, during the electrophysiology procedure. According to aspects of the disclosure, therefore, block  416  monitors for movement of electrophysiology catheter  60 , for example from the initial location (block  410 ) to a subsequent location. 
     If movement is detected, block  418  can adjust (e.g., compensate) for the new localization of electrophysiology catheter  60 , thereby minimizing or eliminating the invalidation of previously collected data and ensuring that the electrophysiology procedure can continue substantially uninterrupted. 
     Although several embodiments of this invention have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention. 
     For example, in the embodiments described above a first magnetically-localizable catheter (e.g., catheter  13 ) is used to generate the geometry, and a second magnetically-localizable catheter (e.g., catheter  60 ) is used to carry out the electrophysiology procedure. In other embodiments, however, a single magnetically-localizable catheter (e.g., catheter  60 ) can be used both to generate the geometry and to carry out the electrophysiology procedure. 
     All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader&#39;s understanding of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention. Joinder references (e.g., attached, coupled, connected, and the like) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other. 
     It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.