Patent Description:
Catheters are used for an ever-growing number of procedures. To name just a few examples, catheters are used for various electrophysiology procedures, including diagnostic, therapeutic, and ablative procedures. Typically, the catheter is manipulated through the patient's vasculature and/or body organs to the intended site, for example, within the patient's heart.

It is often desirable to provide a practitioner with a visualization (that is, an image) of the catheter within the heart. Although such images can be provided using ionizing radiation, it is also known to visualize the site of interest with ultrasound. In many such applications, an ultrasound transducer is mounted in a catheter that, analogous to the foregoing description of an electrophysiology catheter, can be navigated through a patient's vasculature and/or body organs to the site of interest.

One application of ultrasound imaging is intracardiac echocardiography (ICE). ICE techniques can be used to generate a three-dimensional volumetric image of a patient's heart or other anatomy from a plurality of two-dimensional ultrasound images taken from within the patient's heart. Advantageously, the ICE imaging modality can provide high-resolution real-time visualization of cardiac structures and continuous monitoring of catheter location within the heart, and can also aid in early recognition of potential complications.

It should be understood, however, that, in any given position and orientation, an ICE catheter can only image a certain volume (referred to herein as the "field of view" of the ICE catheter). Thus, if the medical device (e.g., electrophysiology catheter), anatomical structure, or other object of interest moves outside the field of view of the ICE catheter, the practitioner must manipulate the ICE catheter until the object of interest is reacquired (that is, the practitioner must manipulate the ICE catheter until the field of view once again encompasses the object of interest).

<CIT> relates to a method and apparatus for automated control and multidimensional positioning of medical devices with a single interventional remote navigation system.

The instant disclosure provides an electroanatomical mapping system according to claim <NUM>. Optional features are described in the dependent claims.

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.

While multiple embodiments are disclosed, still other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments.

The instant disclosure provides systems, apparatuses, and methods for tracking and visualizing medical devices, as may be desirable during an electrophysiology study. For purposes of illustration, aspects of the disclosure will be described with reference to tracking and visualizing an ablation catheter, such as the FlexAbility™ Ablation Catheter, Sensor Enabled™, from Abbott Laboratories (Abbott Park, Illinois), using an ICE catheter, such as Abbott Laboratories' ViewFlex™ Xtra ICE catheter. Further, exemplary embodiments will be described in the context of an electrophysiology procedure carried out using an electroanatomical mapping system, such as the EnSite Precision™ cardiac mapping system or the Ensite™ X EP System, both also from Abbott Laboratories. Those of ordinary skill in the art will understand, however, how to apply the teachings herein to good advantage in other contexts and/or with respect to other devices.

<FIG> shows a schematic diagram of an exemplary electroanatomical mapping system <NUM> for conducting cardiac electrophysiology procedures, such as electrophysiological mapping and ablation. System <NUM> can be used, for example, to create an anatomical model of the patient's heart <NUM> using one or more electrodes. System <NUM> 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, for example to create a diagnostic data map of the patient's heart <NUM>.

As one of ordinary skill in the art will recognize, system <NUM> determines the location, and in some aspects the orientation, of objects, typically within a three-dimensional space, and expresses those locations as position information determined relative to at least one reference. This is referred to herein as "localization.

As depicted in <FIG> and described herein, system <NUM> can be a hybrid system that incorporates both impedance-based and magnetic field-based localization capabilities. In some embodiments, system <NUM> is the EnSite™ Velocity™ or EnSite Precision™ cardiac mapping system or the Ensite™ X EP System, all from Abbott Laboratories. Other electroanatomical mapping systems, however, may be used in connection with the present teachings, including, for example, the RHYTHMIA HDX™ mapping system of Boston Scientific Corporation (Marlborough, Massachusetts), the CARTO navigation and location system of Biosense Webster, Inc. (Irvine, California), the AURORA® system of Northern Digital Inc. (Waterloo, Ontario, Canada), and Stereotaxis, Inc. Louis, Missouri) NIOBE® Magnetic Navigation System.

The localization and mapping systems described in the following patents can also be used with the instant teachings: <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; <CIT>; and <CIT>.

The foregoing systems, and the modalities they employ to localize a medical device, will be familiar to those of ordinary skill in the art. Insofar as the ordinarily-skilled artisan will appreciate the basic operation of such systems, therefore, they are only described herein to the extent necessary to understand the instant disclosure.

For simplicity of illustration, the patient <NUM> is depicted schematically as an oval. In the embodiment shown in <FIG>, three sets of surface electrodes (e.g., patch electrodes) <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> are shown applied to a surface of the patient <NUM>, pairwise defining three generally orthogonal axes, referred to herein as an x-axis (<NUM>, <NUM>), a y-axis (<NUM>, <NUM>), and a z-axis (<NUM>, <NUM>). In other embodiments the electrodes could be positioned in other arrangements, for example multiple electrodes on a particular body surface. As a further alternative, the electrodes do not need to be on the body surface, but could be positioned internally to the body. Regardless of configuration, the patient's heart <NUM> lies within the electric field generated by patch electrodes <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>.

<FIG> also depicts a magnetic source <NUM>, which is coupled to magnetic field generators. In the interest of clarity, only two magnetic field generators <NUM> and <NUM> are depicted in <FIG>, 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 <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>) can be used without departing from the scope of the present teachings.

An additional surface reference electrode (e.g., a "belly patch") <NUM> provides a reference and/or ground electrode for the system <NUM>. The belly patch electrode <NUM> may be an alternative to a fixed intra-cardiac electrode <NUM>, described in further detail below. A magnetic patient reference sensor - anterior ("PRS-A") can also be positioned on the patient's chest to serve as a reference, analogous to surface reference electrode <NUM> and/or intracardiac reference electrode <NUM>, for magnetic field-based localization modalities.

It should also be appreciated that, in addition, the patient <NUM> may have most or all of the conventional electrocardiogram ("ECG" or "EKG") system leads in place. In certain embodiments, for example, a standard set of <NUM> ECG leads may be utilized for sensing electrocardiograms on the patient's heart <NUM>. This ECG information is available to the system <NUM> (e.g., it can be provided as input to computer system <NUM>). Insofar as ECG leads are well understood, and for the sake of clarity in the figures, only a single lead <NUM> and its connection to computer <NUM> is illustrated in <FIG>.

Representative catheters <NUM>, <NUM> are also shown schematically in <FIG>. In aspects of the disclosure, catheter <NUM> can be an ablation catheter, such as the Abbott Laboratories FlexAbility™ Ablation Catheter, Sensor Enabled™, and catheter <NUM> can be an intracardiac echocardiography (ICE) catheter, such as the Abbott Laboratories ViewFlex™ Xtra ICE catheter. Catheters <NUM>, <NUM> each respectively include one or more sensors <NUM>, <NUM> for sensing the electric fields generated by patch electrodes <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> and/or the magnetic fields generated by magnetic field generators <NUM>, <NUM>.

In some embodiments, an optional fixed reference electrode <NUM> (e.g., attached to a wall of the heart <NUM>) is shown on yet another catheter <NUM>. Often, reference electrode <NUM> is placed in the coronary sinus and defines the origin of a coordinate system with reference to which catheters <NUM>, <NUM> can be localized by system <NUM>.

The computer <NUM> may comprise, for example, a conventional general-purpose computer, a special-purpose computer, a distributed computer, or any other type of computer. The computer <NUM> may comprise one or more processors <NUM>, 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 described herein.

Amongst other things, computer system <NUM> can interpret measurements by sensors <NUM>, <NUM> of the magnetic and/or electrical fields generated by magnetic field generators <NUM>, <NUM> and patch electrodes <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM>, respectively, to determine the position and orientation of catheters <NUM>, <NUM> within heart <NUM>. The term "localization" is used herein to describe the determination of the position and orientation of an object, such as catheter <NUM>, within such fields.

Ultrasound imaging catheter <NUM> can be used to generate a three-dimensional volumetric image of heart <NUM> (or other anatomic structure) from a plurality of two-dimensional images using any of several techniques, including those disclosed in <CIT>. In certain embodiments of the disclosure, field of view <NUM> of ultrasound imaging catheter <NUM> (depicted in <FIG>) is about <NUM> degrees by about <NUM> degrees by about <NUM>, though these dimensions are merely exemplary, and it is contemplated that the size of field of view <NUM> can vary without departing from the scope of the instant disclosure.

Those of ordinary skill in the art will appreciate that various echographic imaging modalities, such as B-mode ultrasound and color Doppler echocardiography, may be employed to acquire the two-dimensional image slices that are then assembled into the three-dimensional volumetric image. In this regard, ultrasound imaging catheter <NUM> may be coupled to an ultrasound console <NUM>, such as Abbott Laboratories' ViewMate™ Ultrasound Console, which may in turn be coupled to system <NUM> as shown in <FIG>.

The foregoing discussion of ICE imaging is general, insofar as numerous aspects of ICE imaging, including the use of ICE imaging in connection with electrophysiology procedures, are well-understood by those of ordinary skill in the art and need not be described in detail herein. See, e.g., <NPL>). Thus, ICE imaging will only be described herein to the extent necessary to understand the instant disclosure.

Aspects of the disclosure relate to tracking and visualizing (e.g., on display <NUM> and/or ultrasound console <NUM>) catheter <NUM> as it moves relative to the field of view of ultrasound imaging catheter <NUM>. System <NUM> can therefore include a tracking and visualization module <NUM>. According to some embodiments of the disclosure, tracking and visualization module <NUM> operates to automatically track and visualize catheter <NUM> as it moves relative to the field of view of ultrasound imaging catheter <NUM>.

One exemplary method according to aspects of the instant disclosure will be explained with reference to the flowchart <NUM> of representative steps presented as <FIG>. In some embodiments, for example, flowchart <NUM> may represent several exemplary steps that can be carried out by electroanatomical mapping system <NUM> of <FIG> (e.g., by processor <NUM> and/or tracking and visualization module <NUM>). It should be understood that the representative steps described below can be either hardware- or software-implemented. For the sake of explanation, the term "signal processor" is used herein to describe both hardware- and software-based implementations of the teachings herein.

In block <NUM>, system <NUM> localizes catheter <NUM> within the electrical and/or magnetic fields generated by patch electrodes <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> and/or magnetic field generators <NUM>, <NUM>. Localization of catheter <NUM> is described above and will also be familiar to those of ordinary skill in the art.

In decision block <NUM>, system <NUM> uses the localization of catheter <NUM> to determine whether catheter <NUM> is inside or outside field of view <NUM> of ICE catheter <NUM>. For instance, in certain embodiments of the disclosure, system <NUM> can localize ICE catheter <NUM> within the electrical and/or magnetic fields generated by patch electrodes <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> and/or magnetic field generators <NUM>, <NUM>, again as described above. The localization of ICE catheter <NUM>, in turn, allows system <NUM> to determine the extent of field of view <NUM> relative to the coordinate system of system <NUM> (referred to herein as the "coordinate envelope" of field of view <NUM>). This, in turn, allows system <NUM> to determine whether the localization of catheter <NUM> is inside or outside field of view <NUM> (e.g., if the localization coordinates of catheter <NUM> are within the coordinate envelope of field of view <NUM>, then catheter <NUM> is inside field of view <NUM>; otherwise, it is outside field of view <NUM>).

Upon determining that catheter <NUM> is outside field of view <NUM> (the "NO" exit from decision block <NUM>), system <NUM> can output a notification that catheter <NUM> is not within field of view <NUM> (block <NUM>). This notification is referred to herein as a "negative imaging notification" and can be audible (e.g., sounded as an alarm), tactile (e.g., a vibration output in the handle of catheter <NUM>), visual (e.g., shown on display <NUM>), or any other suitable notification or combination of notifications to a practitioner.

If desired, the practitioner can adjust the position and/or orientation of ICE catheter <NUM> until field of view <NUM> includes catheter <NUM>. According to the herein claimed invention, system <NUM> provides cues to the practitioner to aid in such adjustments (e.g., provide an indication on display <NUM> directing the practitioner to rotate and/or deflect ICE catheter <NUM> a certain amount in a certain direction).

On the other hand, upon determining that catheter <NUM> is inside field of view <NUM> (the "YES" exit from decision block <NUM>), system <NUM> can display (e.g., on display <NUM> and/or on ultrasound console <NUM>) a region of field of view <NUM> including catheter <NUM>. The displayed region can include a single two-dimensional image slice (e.g., the two-dimensional image slice that passes through the localization of catheter <NUM>) or a plurality of adjacent two-dimensional image slices assembled into a three-dimensional volumetric image.

<FIG> schematically represents the display of a single two-dimensional image slice including catheter <NUM>. As shown in <FIG>, catheter <NUM> is inside field of view <NUM> at location a, intersected by two-dimensional image slice <NUM>. Thus, system <NUM> displays two-dimensional image slice <NUM>.

<FIG> illustrates the display of a plurality of two-dimensional image slices <NUM> as a three-dimensional volumetric image. As shown in <FIG>, each of the displayed image slices <NUM> intersects catheter <NUM>. It is also contemplated, however, that additional two-dimensional slices that do not intersect catheter <NUM> may be displayed for context or reference (e.g., to show the position and orientation of catheter <NUM> relative to certain anatomical structures that may be of interest to the practitioner). The plurality of slices may, as shown in <FIG>, be displayed as a volumetric image <NUM>.

The ordinarily-skilled artisan will appreciate that system <NUM> can monitor catheter <NUM> as it moves through the patient. Accordingly, in embodiments of the invention and consistent with the teachings above, system <NUM> can detect when catheter <NUM> has moved to a new location inside field of view <NUM> or has exited field of view <NUM>.

In the latter case (e.g., catheter <NUM> has moved outside field of view <NUM>), system <NUM> can output a negative imaging notification and, optionally, guide the practitioner to reposition and/or reorient ICE catheter <NUM> to reacquire catheter <NUM> within field of view <NUM>.

In the former case (e.g., catheter <NUM> has moved, but remains inside field of view <NUM>), system <NUM> can display an updated region of field of view <NUM> including the new location of catheter <NUM>. As described above, the updated displayed region can include one or more two-dimensional image slices. Referring to <FIG>, for example, if catheter <NUM> moves from location "a" to location "b," system <NUM> can switch from displaying two-dimensional image slice <NUM> to displaying two-dimensional image slice <NUM>.

Although several embodiments 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 scope of this invention as defined in the appended claims.

For example, the teachings herein can not only be applied to track and visualize an electrophysiology catheter or other medical device within the field of view of an ICE catheter, but also to track and visualize other objects of interest, including anatomical structures, within the field of view of an ICE catheter. To the extent the object of interest is not directly localizable by system <NUM> (e.g., it is an anatomical structure, and therefore does not include electrodes, magnetic coils, or other sensors usable for localization), it can be identified by the practitioner through a graphical user interface (e.g., on display <NUM>). For instance, the practitioner can use a mouse or other input device to "click" on an anatomical structure of interest (e.g., a pulmonary vein ostium), and system <NUM> can use image recognition algorithms to track the "clicked" structure as it moves (e.g., as the heart beats and/or as the patient breathes).

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'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.

Claim 1:
An electroanatomical mapping system for tracking a medical device (<NUM>) within a non-ionizing localization field, the system comprising:
a medical device (<NUM>);
an intracardiac echocardiography catheter (<NUM>);
a display (<NUM>); and
a tracking and visualization module (<NUM>) configured to:
localize the medical device (<NUM>) within the non-ionizing localization field;
determine whether or not the medical device (<NUM>) falls within a field of view (<NUM>) of the intracardiac echocardiography catheter (<NUM>); and
display a region (<NUM>) of the field of view containing the medical device (<NUM>) upon determining that the medical device (<NUM>) falls within the field of view, characterized in that the tracking and visualization module (<NUM>) is further configured to output a negative imaging notification upon determining that the medical device (<NUM>) does not fall within the field of view, and
wherein the system is configured to provide cues to the practitioner to aid in adjusting the position and/or orientation of the intracardiac echocardiography catheter (<NUM>) until the field of view (<NUM>) includes the medical device (<NUM>).