Abstract:
While obtaining electrophysiologic data from a cardiac catheter a series of visual displays are presented. The displays include a respective current image of the heart and the distal portion of the cardiac catheter therein and further include a catheter icon that represents the distal portion of the cardiac catheter, The catheter icon is separated from the image of the heart in the displays. The catheter icon has indicia that represent functional elements of the cardiac catheter.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This Application claims the benefit of U.S. Provisional Application No. 61/867,664, which is herein incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    This invention relates to medical imaging systems. More particularly, this invention relates to improvements in cardiac catheterization. 
         [0004]    2. Description of the Related Art 
         [0005]    Cardiac arrhythmias, such as atrial fibrillation, occur when regions of cardiac tissue abnormally conduct electric signals to adjacent tissue, thereby disrupting the normal cardiac cycle and causing asynchronous rhythm. 
         [0006]    Procedures for treating arrhythmia include locating and surgically disrupting the origin of the signals causing the arrhythmia, as well as disrupting the conducting pathway for such signals. By selectively ablating cardiac tissue by application of energy via a catheter, it is sometimes possible to interrupt or modify the propagation of unwanted electrical signals from one portion of the heart to another. The ablation process destroys the unwanted electrical pathways by formation of non-conducting lesions. 
       SUMMARY OF THE INVENTION 
       [0007]    Electrical activity in the heart is typically measured by advancing a multiple-electrode catheter to measure electrical activity at multiple points in the heart chamber simultaneously. A graphical user interface integrated with modern imaging systems for monitoring cardiac catheterization presents an abundance of dynamically changing information from the multiple electrodes to the operator, and facilitates efficient processing of the information by the operator. 
         [0008]    There is provided according to embodiments of the invention a method for guiding a medical procedure, which is carried out by inserting a cardiac catheter into of a heart of a living subject, and thereafter obtaining electrophysiologic data from the cardiac catheter relating to the heart. While obtaining electrophysiologic data, the method is further carried out by presenting a series of visual displays, the displays including a respective current image of the heart and the distal portion of the cardiac catheter therein and further including a catheter icon that represents the distal portion of the cardiac catheter, The catheter icon is separated from the image of the heart in the displays. The catheter icon has indicia that represent functional elements of the cardiac catheter. 
         [0009]    According to one aspect of the method, the catheter icon has an orientation that matches a current orientation of the distal portion of the cardiac catheter in the heart. 
         [0010]    According to another aspect of the method, presenting a series of visual displays includes enlarging the catheter icon with respect to the image of the heart. 
         [0011]    According to a further aspect of the method, presenting a series of visual displays includes applying respective visual cues to the indicia of the catheter icon, wherein the visual cues encode a status of respective functional elements of the cardiac catheter. 
         [0012]    According to yet another aspect of the method, the visual cues comprise at least one of a color and a pattern that is associated with one of the functional elements. 
         [0013]    According to yet another aspect of the method, the visual cues comprise a numerical descriptor that is associated with one of the functional elements. 
         [0014]    According to still another aspect of the method, the visual cues comprise a shape that is associated with one of the functional elements. 
         [0015]    According to an additional aspect of the method, the visual cues comprise a de-emphasis of one of the functional elements. 
         [0016]    According to still another aspect of the method, the image of the heart is a functional electroanatomic image. 
         [0017]    There is further provided according to embodiments of the invention a data processing system, including a processor, a visual display screen, and a memory accessible to the processor storing programs and data objects therein, The programs include a graphical user interface generator configured to present graphical information on the visual display screen, wherein execution of the programs cause the processor to present a series of visual displays, the displays including a respective current image of the heart and a distal portion of the cardiac catheter and further including a catheter icon that represents the distal portion of the cardiac catheter, the catheter icon being separated from the image of the heart, the catheter icon and having indicia that represent functional elements of the cardiac catheter. 
     
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
         [0018]    For a better understanding of the present invention, reference is made to the detailed description of the invention, by way of example, which is to be read in conjunction with the following drawings, wherein like elements are given like reference numerals, and wherein: 
           [0019]      FIG. 1  is a pictorial illustration of a system for performing medical procedures in accordance with an embodiment of the invention; 
           [0020]      FIG. 2  is a screen display in accordance with an embodiment of the invention; 
           [0021]      FIG. 3  is a screen display in accordance with an embodiment of the invention; 
           [0022]      FIG. 4  is a screen display in accordance with an alternate embodiment of the invention; 
           [0023]      FIG. 5  is a screen display in accordance with an alternate embodiment of the invention; 
           [0024]      FIG. 6  is a screen display in accordance with an alternate embodiment of the invention; 
           [0025]      FIG. 7  is a screen display in accordance with an alternate embodiment of the invention; 
           [0026]      FIG. 8  is a screen display in accordance with an alternate embodiment of the invention; and 
           [0027]      FIG. 9 , is an exemplary screen display produced during a cardiac catheterization in accordance with an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0028]    In the following description, numerous specific details are set forth in order to provide a thorough understanding of the various principles of the present invention. It will be apparent to one skilled in the art, however, that not all these details are necessarily needed for practicing the present invention. In this instance, well-known circuits, control logic, and the details of computer program instructions for conventional algorithms and processes have not been shown in detail in order not to obscure the general concepts unnecessarily. 
         [0029]    Aspects of the present invention may be embodied in software programming code, which is typically maintained in permanent storage, such as a computer readable medium. In a client/server environment, such software programming code may be stored on a client or a server. The software programming code may be embodied on any of a variety of known non-transitory media for use with a data processing system, such as a USB memory, hard drive, electronic media or CD-ROM. The code may be distributed on such media, or may be distributed to users from the memory or storage of one computer system over a network of some type to storage devices on other computer systems for use by users of such other systems. 
         [0030]    Although the disclosed embodiments relate specifically to intracardiac catheters and ablation procedures, the principles of the present invention may similarly be applied, mutatis mutandis, to probes of other types, for use in substantially any sort of invasive thermal treatment. 
       Overview 
       [0031]    Turning now to the drawings, reference is initially made to  FIG. 1 , which is a pictorial illustration of a system  10  for performing diagnostic and therapeutic procedures on a heart  12  of a living subject, which is constructed and operative in accordance with a disclosed embodiment of the invention. The system comprises a catheter  14 , which is percutaneously inserted by an operator  16  through the patient&#39;s vascular system into a chamber or vascular structure of the heart  12 . The operator  16 , who is typically a physician, brings the catheter&#39;s distal tip  18  into contact with the heart wall at an ablation target site. Functional electroanatomic maps, e.g., electrical activation maps may then be prepared, according to the methods disclosed in U.S. Pat. Nos. 6,226,542, and 6,301,496, and in commonly assigned U.S. Pat. No. 6,892,091, whose disclosures are herein incorporated by reference. One commercial product embodying elements of the system  10  is available as the CARTO® 3 System, available from Biosense Webster, Inc., 3333 Diamond Canyon Road, Diamond Bar, Calif. 91765. This system may be modified by those skilled in the art to embody the principles of the invention described herein. 
         [0032]    Areas determined to be abnormal, for example by evaluation of the electrical activation maps, can be ablated by application of thermal energy, e.g., by passage of radiofrequency electrical current through wires in the catheter to one or more electrodes at the distal tip  18 , which apply the radiofrequency energy to the myocardium. The energy is absorbed in the tissue, heating it to a point (typically about 50° C.) at which it permanently loses its electrical excitability. When successful, this procedure creates non-conducting lesions in the cardiac tissue, which disrupt the abnormal electrical pathway causing the arrhythmia. The principles of the invention can be applied to different heart chambers to treat many different cardiac arrhythmias. 
         [0033]    The catheter  14  typically comprises a handle  20 , having suitable controls on the handle to enable the operator  16  to steer, position and orient the distal end of the catheter as desired for the ablation. To aid the operator  16 , the distal portion of the catheter  14  contains position sensors (not shown) that provide signals to a position processor  22 , located in a console  24 . 
         [0034]    Ablation energy and electrical signals can be conveyed to and from the heart  12  through one or more electrodes  32  located at or near the distal tip  18  via cable  34  to the console  24 . Pacing signals and other control signals may be conveyed from the console  24  through the cable  34  and the electrodes  32  to the heart  12 . One or more sensing electrodes  33 , also connected to the console  24 , are disposed near the ablation electrode  32  and have connections to the cable  34 . 
         [0035]    Wire connections  35  link the console  24  with body surface electrodes  30  and other components of a positioning sub-system. The electrodes  32  and the body surface electrodes  30  may be used to measure tissue impedance at the ablation site as taught in U.S. Pat. No. 7,536,218, issued to Govari et al., which is herein incorporated by reference. A temperature sensor such as thermocouples  31 , may be mounted on or near the ablation electrode  32  and optionally or near the sensing electrodes  33 . The thermocouples  31  are connected to the electrode circuit as described in further detail below. 
         [0036]    The console  24  typically contains one or more ablation power generators  25 . The catheter  14  may be adapted to conduct ablative energy to the heart using any known ablation technique, e.g., radiofrequency energy, ultrasound energy, and laser-produced light energy. Such methods are disclosed in commonly assigned U.S. Pat. Nos. 6,814,733, 6,997,924, and 7,156,816, which are herein incorporated by reference. 
         [0037]    The positioning processor  22  is an element of a positioning subsystem in the system  10  that measures location and orientation coordinates of the catheter  14 . 
         [0038]    In one embodiment, the positioning subsystem comprises a magnetic position tracking arrangement that determines the position and orientation of the catheter  14  by generating magnetic fields in a predefined working volume and sensing these fields at the catheter, using field generating coils  28 . The positioning subsystem may employ impedance measurement, as taught, for example in U.S. Pat. No. 7,756,576, which is hereby incorporated by reference, and in the above-noted U.S. Pat. No. 7,536,218. 
         [0039]    As noted above, the catheter  14  is coupled to the console  24 , which enables the operator  16  to observe and regulate the functions of the catheter  14 . Console  24  includes a processor, preferably a computer with appropriate signal processing circuits. The processor is coupled to execute a graphical user interface program that is operative to produce the visual displays described below by driving a monitor  29 . The signal processing circuits typically receive, amplify, filter and digitize signals from the catheter  14 , including signals generated by the above-noted sensors and a plurality of location sensing electrodes (not shown) located distally in the catheter  14 . The digitized signals are received and used by the console  24  and the positioning system to compute the position and orientation of the catheter  14 , and to analyze the electrical signals from the electrodes. 
         [0040]    Typically, the system  10  includes other elements, which are not shown in the figures for the sake of simplicity. For example, the system  10  may include an electrocardiogram (ECG) monitor, coupled to receive signals from one or more body surface electrodes, to provide an ECG synchronization signal to the console  24 . As mentioned above, the system  10  typically also includes a reference position sensor, either on an externally-applied reference patch attached to the exterior of the subject&#39;s body, or on an internally-placed catheter, which is inserted into the heart  12  maintained in a fixed position relative to the heart  12 . Conventional pumps and lines for circulating liquids through the catheter  14  for cooling the ablation site are provided. 
         [0041]    In order to accurately ablate tissue, for example according to known procedures in which tissue temperature is an important variable, it is desirable to understand and model the behavior of the ablation catheter in actual operation. 
         [0042]    With modern imaging systems used for monitoring cardiac catheterization, an increasing abundance of dynamically changing information is presented to the operator, to the extent that efficient processing of the information by the operator is impaired. Modern navigation and ablation catheters typically have multiple sensors, sensing electrodes, and ablation electrodes, which can be active in many combinations. Each of these has its own time-varying status, which is important for the operator to evaluate concurrently with extensive electroanatomic information regarding cardiac function. The graphical image in the example of  FIG. 9  illustrates the nature of the difficulties confronting the operator using a known imaging system. An iconic representation of the catheter is embedded within an electroanatomic or functional map of the heart. The catheter has a plurality of elements, e.g., sensors and electrodes. Some of which are numbered and others of which are emphasized with visual cues such as circles and geometric patterns imposed on the elements. The visual cues encode the current status of the particular element and are meaningful to the operator. However, the cues are partially obscured by the functional map, and are sometimes difficult for the operator to appreciate. 
       User Interface 
       [0043]    Reference is now made to  FIG. 2 , which is a screen display  37 , in accordance with an embodiment of the invention. This and the following screen displays may appear on the monitor  29  during a catheterization procedure. Heart  39  is outlined in broken lines. A representation of the distal portion of a catheter  41  is shown within the heart  39  in a particular location and orientation. A separate icon  43  appears in the upper left portion of the screen, and contains a scaled-up catheter image  45  of the distal portion of the catheter  41 . In  FIG. 2 , the catheter image  45  matches the orientation and perspective of the catheter  41 . This is not essential, however. A freewheeling mode of operation may be chosen by the operator, in which case the catheter image  45  may be rotated in any axis to an operator-selected orientation independently of the orientation of the catheter  41 . Because the catheter  41  and the icon  43  are separated from the image of the heart  39 , the icon  43  is not obscured by the heart. This contrasts to the difficulty of appreciating details of the catheter  41  within the superimposed image of the heart  39  in the central part of the screen display  37 . As noted above, this is particularly true of information regarding the status of functional elements of the catheter  41  that may be required to represent the anatomy and electrical events in the heart  39 . Such information, while not seen in the figures for clarity of presentation, can in practice be quite extensive and detailed, e.g., pseudocolors, data points, numerical information. The presentation of the heart  39 , while desirable and indeed, necessary, nevertheless obscures the catheter  41 , whose detailed status information needs to be presented to the operator. The matching orientations of the catheter  41  and the icon  43  may be referenced to a 3-dimensional coordinate system  47   
         [0044]    The position of the icon  43  in the upper left corner is exemplary. The actual position and scaling factor are configurable or controllable by the operator, such that the icon  43  is conveniently placed, yet does not interfere with the representation of the heart. Optional visual emphasis, indicated in  FIG. 2  by shaded region  49 , may be provided for the icon  43  to aid the operator. 
         [0045]    Generating the catheter image  45  within the icon  43  may be accomplished by rendering the catheter a first time in the main window (within a 3-dimensional view of the heart  39 ), then rendering the catheter a second time as the catheter image  45  within the icon  43 , preserving its axial rotation and longitudinal orientation. The catheter image  45  is scaled such that the catheter&#39;s bounding box (the largest main diagonal of the bounding box of the catheter  41 ) fits within the icon view. 
         [0046]    Reference is now made to  FIG. 3 , which is a screen display  51  in accordance with an embodiment of the invention. The screen display  51  is similar to the screen display  37  ( FIG. 2 ), except that the catheter  41  has a different orientation with respect to the coordinate system  47 . The new orientation is reflected in the orientation of catheter image  53  of the distal portion of the catheter  41  in icon  55 . 
       First Alternate Embodiment 
       [0047]    Reference is now made to  FIG. 4 , which is a screen display  57  in accordance with an embodiment of the invention. The screen display  51  is similar to the screen display  37  ( FIG. 2 ), except that catheter  59  is a loop or lasso having multiple ring electrodes, as best seen in a catheter image  61  in icon  63 . Ring electrodes  65 ,  67  (shown in hatched pattern) are visually apparent as being actively in use as bipolar sensors. 
         [0048]    Reference is now made to  FIG. 5 , which is a screen display  69  in accordance with an embodiment of the invention. The screen display  69  is similar to the screen display  57  ( FIG. 4 ), except that the catheter  59  has a different orientation, having a partial spiral twist. In the catheter image  71  within icon  73 , one ring electrode  75  is currently active, and is readily distinguished from its fellows by a visual effect, indicated here by a hatching pattern. Status information ( 328 . 3 ) is displayed with respect to another ring electrode  77 . It will be appreciated that such detail would be less well seen by the operator if it were shown only on the catheter  59 . 
       Second Alternate Embodiment 
       [0049]    Reference is now made to  FIG. 6 , which is a screen display  79  in accordance with an alternate embodiment of the invention. This embodiment is similar to the embodiment shown in  FIG. 5 , except now in icon  81  the ring electrodes  65 ,  67  in catheter image  83  are visually emphasized by visual cues (circles). Alternatively, when the cued elements are sensors, such cues could indicate a normal or abnormal functional status; e.g., insufficient or excessive pressure or temperature. As the status of the electrodes and sensors changes dynamically during the procedure, it is important that the operator be alerted to abnormal conditions. 
       Third Alternate Embodiment 
       [0050]    Reference is now made to  FIG. 7 , which is a screen display  85  in accordance with an alternate embodiment of the invention. This embodiment is similar to the embodiment shown in  FIG. 4 . Icon  87  includes catheter image  89  However ring electrodes  91 ,  93 ,  95 ,  97 ,  99  are now associated with numbers. Numerical indicia of this sort may be correlated with tabular information or the like that is external to the screen display. Additionally or alternatively, such numbers may indicate actual readings of sensors or the current passing through an ablation electrode. Many types of useful sensors may be incorporated in the catheter and their condition represented on the catheter image  89 . 
       Fourth Alternate Embodiment 
       [0051]    Reference is now made to  FIG. 8 , which is a screen display  101  in accordance with an alternate embodiment of the invention. Icon  103  includes catheter image  105 . This embodiment is similar to the embodiment shown in  FIG. 7 . Ring electrodes  91 ,  93 ,  95 ,  97 ,  99  are associated with numerical indicia as in  FIG. 7 . Ring electrode  107  is emphasized by a visual cue as in  FIG. 6 . This embodiment illustrates the versatility that is possible when presenting the icon  103 . Many other visual cues will occur to those skilled in the art, e.g., emphasis of catheter elements by highlighting, flashing, and de-emphasis by graying-out. 
       Example 
       [0052]    Reference is now made to  FIG. 9 , which is an exemplary screen display  109  produced by the above-referenced CARTO 3 system during a cardiac catheterization in accordance with an embodiment of the invention. A functional electroanatomic map of the heart is displayed in pseudocolors, in which local activation times are represented by different hatching and shading patterns in  FIG. 9 . The screen display  109  includes icon  111  and catheter image  113  in accordance with an embodiment of the invention. Lasso catheter  115  within heart  117  is partially obscured by the electroanatomic map detail and a data point cloud (dots  119 ) previously obtained during mapping by ring electrodes of the catheter  115 . The orientation of the catheter  115  and indications of the status of its ring electrodes can be appreciated by the orientation and the various visual cues in the catheter image  113 . 
         [0053]    It will be appreciated by persons skilled in the art that the present invention is not limited to what has been particularly shown and described hereinabove. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described hereinabove, as well as variations and modifications thereof that are not in the prior art, which would occur to persons skilled in the art upon reading the foregoing description.