Fast anatomical mapping (FAM) reconstruction using surface update restrictions

A method includes presenting, on a display, an electroanatomical (EA) map of a surface of a cavity of an organ. Input is received from a user, and, in response to the user input, a region of the EA map is locked to subsequent updates.

FIELD OF THE INVENTION

The present invention relates generally to electroanatomical (EA) mapping, and particularly to editing of cardiac EA maps.

BACKGROUND OF THE INVENTION

Software-based editing tools for assisting the analysis of an electroanatomically mapped organ were previously proposed in the patent literature. For example, U.S. Patent Application Publication 2017/0325891 describes methods directed to generating three-dimensional surface representations of an anatomic structure such as a heart cavity. More specifically, a three-dimensional surface representation of the anatomic structure is constrained relative to one or more anchor portions corresponding to received input regarding the location of anatomic features of the anatomic structure. The resulting three-dimensional surface representation includes salient features of the anatomic structure and, therefore, can be useful as a visualization tool during any of various different medical procedures, including, for example, cardiac ablation.

SUMMARY OF THE INVENTION

An embodiment of the present invention that is described hereinafter provides a method including presenting, on a display, an electroanatomical (EA) map of a surface of a cavity of an organ. Input is received from a user, and, in response to the user input, a region of the EA map is locked to subsequent updates.

In some embodiments, locking the region includes preventing subsequent manual editing of the EA map.

In some embodiments, locking the region includes ignoring subsequently acquired data points belonging to the region.

In other embodiments, locking the region includes preventing subsequent updates in prespecified proximity of an anatomical feature in the EA map.

In an embodiment, the EA map includes an EA map of a left atrium, and wherein the anatomical feature is a pulmonary vein.

In another embodiment, locking the region is performed in response to identifying that data points in the region were obtained by a probe while applying excessive force to the surface.

In some embodiments, the method further includes manually editing unlocked regions of the EA map to remove irrelevant data points therein.

In some embodiments, the method further includes unlocking the locked region. The unlocked region of the EA map is manually edited to remove irrelevant data points therein, and the manually edited region is re-locked.

There is additionally provided, in accordance with another embodiment of the present invention, a system including a display and a processor. The display is configured to present an electroanatomical (EA) map of a surface of a cavity of an organ. The processor is configured to receive input from a user, and, in response to the user input, to lock a region of the EA map to subsequent updates.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1is a schematic, pictorial illustration of a system for electroanatomical (EA) mapping, in accordance with an exemplary embodiment of the present invention;

FIG. 2is a schematic, pictorial illustration of a reconstructed electroanatomical (EA) map of a left atrium generated using surface update restrictions, in accordance with an exemplary embodiment of the present invention; and

FIG. 3is a flow chart that schematically describes a method for generating the reconstructed electroanatomical (EA) map ofFIG. 2, in accordance with an exemplary embodiment of the present invention.

Detailed Description of Embodiments

Overview

An interior of an organ of a patient, such as a cardiac cavity, can be mapped using a mapping catheter (e.g., electroanatomically mapped) having one or more suitable sensors fitted at its distal end for mapping within the organ. Using location signals generated by the various sensors, a processor may calculate the sensor locations within the organ (e.g., the cardiac cavity). Using the calculated locations, the processor may further derive an anatomical map of the cavity surface.

For example, in a fast-anatomical mapping (FAM) of a heart chamber, point positions on an inner surface of the cavity are drawn using acquired electroanatomical (EA) data. However, undesired catheter positions may also be acquired and automatically added to the FAM-constructed cavity surface during FAM reconstruction. Examples of such undesired data points include cavity wall positions distorted by being pushed outwards by the catheter, wrong wall positions due to respiration-induced movement, positions measured erroneously in the interior of the cavity instead of on the surface, and irrelevant catheter positions, e.g., outside a mapping area of interest.

The accumulation of such undesired positions affect the accuracy of the reconstructed EA map. To address these inaccuracies, during or after acquisition, a physician, or a specialist helping the physician, may manually edit the surface generated from the acquired points to correct for the errors. This manual editing typically involves erasing data points and/or removing (“shaving”) entire portions from the computed surface. However, this manual editing is a time-consuming process.

Exemplary embodiments of the present invention that are described herein reduce the amount of manual editing needed by “locking” regions (e.g., areas) of a surface of an EA map presented to a user, wherein those areas are not to be further edited (e.g., to prevent automatically made updates and/or manual edits of the region of the EA map).

In the disclosed exemplary embodiments, a user interface is provided that enables the user to provide an input, such as to command the mapping system to lock a region of the EA map shown on a display to subsequent updates. For example, in response to the user input, a processor of the system ignores subsequently acquired data points belonging to the region. In some exemplary embodiments, FAM-generated surface areas of the map that are deemed good enough are “locked” by the user so as not to be further updated automatically by the mapping application, thus preventing accumulation of new errors in these areas.

Examples of locked regions include:A surface portion that has already been manually edited. Further automatic acquisitions in that region are ignored, though the region may still be manually edited.Acquisitions for which a measured catheter contact force is deemed above a predefined threshold (indicating that the catheter is pushing wall tissue locally to a distorted position). Acquired points are ignored and are not used to construct the surface.Certain areas on the map that, after an initial FAM mapping, are deemed sufficiently representative of the anatomy. An example of such an area is around an ostium of pulmonary veins in an EA map of the left atrium of the heart.

In some exemplary embodiments, the disclosed user interface includes controls configured to undo existing update restrictions. For example, a special editing mode is activated (e.g., as a keyboard button) to enable data point updates even in locked areas, for example, in the most recent locked area. An editing mode may also be provided as a new acquisition mode in the FAM tool user interface. Another control (e.g., a computer mouse) can be activated, as another example, to manually select “locked” areas on the surface and disable (“unlock”) its update restrictions. A further control knob, such as another keyboard button, may be used to toggle the entire update restriction mode on or off.

The disclosed FAM surface update restriction techniques may assist the physician to prepare an EA map, and thus ease, expedite and improve the quality of complicated diagnostic tasks performed during diagnostic catheterizations, which rely on an accurate EA map generated during the procedures. Another advantage of the disclosed FAM surface update restriction techniques is reducing the editing (e.g., shaving) time of portions of the map or the acquired data (e.g., volume) that is used to build the map.

System Description

FIG. 1is a schematic, pictorial illustration of a system21for electroanatomical (EA) mapping, in accordance with an exemplary embodiment of the present invention.FIG. 1depicts a physician27using a Pentaray® EA mapping catheter29to perform an EA mapping of a heart23of a patient25. Catheter29comprises, at its distal end, one or more arms20, which may be mechanically flexible, each of which is coupled with one or more electrodes22. During the mapping procedure, electrodes22acquire and/or inject unipolar and/or bipolar signals from and/or to the tissue of heart23.

A processor28in a console30receives these signals via an electrical interface35, and uses information contained in these signals to construct an EA map40that processor28stores in a memory33. During and/or following the procedure, processor28may display EA map40on a display26. User controls32of a user interface100enable physician27to communicate with processor28to lock portions of EA map40to prevent further updating, as described above. Controls32may include, for example, a trackball and control knobs, as well as a keyboard. Other elements of user interface100may include touch screen functionality of display26.

During the procedure, a tracking system is used to track the respective locations of sensing-electrodes22, such that each of the signals may be associated with the location at which the signal was acquired. For example, the Active Current Location (ACL) system, made by Biosense-Webster (Irvine, Calif.), which is described in U.S. Pat. No. 8,456,182, whose disclosure is incorporated herein by reference, may be used. In the ACL system, a processor estimates the respective locations of the electrodes based on impedances measured between each of the sensing electrodes22, and a plurality of surface electrodes24, that are coupled to the skin of patient25. For example, three surface electrodes24may be coupled to the patient's chest, and another three surface electrodes may be coupled to the patient's back. For ease of illustration, only one surface electrode24is shown inFIG. 1. Electric currents are passed between electrodes22inside heart23of the patient25and surface electrodes24. Processor28calculates an estimated location of all electrodes22within the patient's heart23based on the ratios between the resulting current amplitudes measured at surface electrodes24(or between the impedances implied by these amplitudes) and the known positions of electrodes24on the patient's body. The processor28may thus associate any given impedance signal received from electrodes22with the location at which the signal was acquired.

The example illustration shown inFIG. 1is chosen purely for the sake of conceptual clarity. Other tracking methods can be used, such as those based on measuring voltage signals. Other types of sensing catheters, such as the Lasso® Catheter (produced by Biosense Webster) may equivalently be employed. Contact sensors may be fitted at the distal end of EA mapping catheter29. As noted above, other types of electrodes, such as those used for ablation, may be utilized in a similar way and fitted to electrodes for acquiring the needed position data. Thus, an ablation electrode used for collecting position data is regarded, in this case, as a sensing electrode. In an optional exemplary embodiment, processor28is further configured to indicate the quality of physical contact between each of the electrodes22and an inner surface of the cardiac chamber during measurement.

Processor28typically comprises a general-purpose computer with software programmed to carry out the functions described herein. In particular, processor28runs a dedicated algorithm as disclosed herein, including inFIG. 3, which enables processor28to perform the disclosed steps, as further described below. The software may be downloaded to the computer in electronic form, over a network, for example, or it may, alternatively or additionally, be provided and/or stored on non-transitory tangible media, such as magnetic, optical, or electronic memory.

FAM Reconstruction Using Surface Update Restrictions

FIG. 2is a schematic, pictorial illustration of a reconstructed electroanatomical (EA) map40of a left atrium generated using surface update restrictions, in accordance with an exemplary embodiment of the present invention. Map40comprises different areas, some of which, such as areas in a region50, being open to automatic updating according to new data points acquired during the mapping procedure shown inFIG. 1. Areas60, which are EA-mapped surfaces of ostia of pulmonary veins, are locked for further editing by the physician because areas60of EA map40are deemed sufficiently representative of the anatomy. Map50further comprises areas55which were locked after being previously manually edited.

As seen, areas with a different status (e.g., locked or actively updated) can be emphasized graphically, for example, with different shades or textures, so that the physician may readily follow the progress of the EA mapping.

FIG. 2is brought purely for clarity of description. In other exemplary embodiments, for example, EA map40may include additional information, such as values of electrophysiological potentials and cardiac activation times.

FIG. 3is a flow chart that schematically describes a method for generating the reconstructed electroanatomical (EA) map40ofFIG. 2(i.e., using surface update restrictions), in accordance with an exemplary embodiment of the present invention. The algorithm, according to the presented embodiment, carries out a process that begins with processor28presenting to a user an EA map40that also undergoes automatic updates by processor28as the processor analyzes newly acquired data points and adds these to EA map40at step70.

At a manual editing step72, using user interface100, physician27edits a region of map40, for example by erasing erroneous data points that distort the presented anatomical shape. Next, at a locking step74, physician27locks the edited area, such as area55, to avoid it being updated with newly acquired erroneous data points. To lock the region, physician27uses control tools32of user interface100to select an area and change its status.

At an additional locking step76, physician27turns to a map area being actively updated. In order to avoid extensive manual editing to erase distortive data points (such as taken in step72), the physician locks the area to updates with data points that processor28determines were erroneous, since they were acquired while the catheter applied excessive contact force on wall tissue (e.g., a force above a prespecified value being applied to the surface of the cavity). Finally, at step78, physician27locks editing in regions60in proximity of ostia of pulmonary veins, after deciding that additional data points in those areas are not important enough to justify a potential need to manually edit those regions of the EA map.

The example flow chart shown inFIG. 3is chosen purely for the sake of conceptual clarity. In optional exemplary embodiments, various additional steps may be performed, for example to automatically register additional layers, such as of medical images.

Although the embodiments described herein mainly address cardiac applications, the methods and systems described herein can also be used in other applications, such as in anatomical mapping of cavities of other organs of the body. In general, the disclosed update restrictions techniques can be used in any application that utilizes a geometrical map reconstruction algorithm that is incremental, i.e., supports local reconstruction updates.