Medical device and method of operating the same

Abstract

To provide a medical apparatus.SOLUTION: A medical apparatus includes a probe configured for insertion into a body of a patient. The probe includes electrodes configured to contact tissue in a region within the body. The apparatus further includes a display screen, a position-tracking system configured to acquire position coordinates of the electrodes within the body, and a processor. The processor is configured to acquire electrophysiological signals from the electrodes while the electrodes are held stationary in the region, extract electrophysiological parameters from the signals, compute a measure of consistency of the parameters, and render to the display screen a three-dimensional (3D) map of the tissue while superimposing on the map, responsively to the position coordinates, a visual indication of the extracted parameters at the locations for which the measure of consistency satisfies a consistency criterion, and automatically discarding from the map the parameters for which the measure of consistency does not satisfy the consistency criterion.SELECTED DRAWING: Figure 1

Description

[Technology field]

[0001] The present invention relates generally to electrophysiological measurements, and more particularly to devices and methods for automated mapping of electrophysiological parameters. [Background technology]

[0002] An electrophysiological (EP) map of a patient's tissue is generated by placing one or more electrodes over a region of the tissue, acquiring the EP signal in that region, and then repeating this process for a different region. EP parameters are extracted from the EP signal in each region of measurement and then displayed on an image of the tissue. Summary of the Invention [Means for solving the problem]

[0003] DETAILED DESCRIPTION OF THE INVENTION The embodiments of the present invention described hereinafter provide improved methods and apparatus for mapping electrophysiological parameters.

[0004] Thus, according to an embodiment of the present invention, there is provided a medical device including a probe configured for insertion into a patient's body, the probe including one or more electrodes configured to contact tissue at a region within the body. The device further includes a display screen, a position tracking system configured to acquire position coordinates of the one or more electrodes within the body, and a processor. The processing unit is configured to acquire individual electrophysiological signals from the one or more electrodes while the one or more electrodes are held fixed at individual locations in the region for at least a preset length of time, extract individual electrophysiological parameters from the electrophysiological signals acquired by the one or more electrodes at the individual locations, and calculate individual consistency measures of the individual electrophysiological parameters extracted from the electrophysiological signals acquired by the electrodes at each of the individual locations over the preset length of time.

[0005] The processing unit is further configured to display a three-dimensional (3D) map of the tissue on a display screen while superimposing a visual representation of the extracted electrophysiological parameters at each location for which the individual consistency measures met a predetermined consistency criterion on the map in response to the location coordinates, and to automatically discard from the map those electrophysiological parameters for which the individual consistency measures did not meet the predetermined consistency criterion.

[0006] In disclosed embodiments, the electrophysiological parameter includes a local activation time (LAT) in the patient's heart, and the consistency measure indicates variability in the LAT. Additionally or alternatively, the consistency measure includes peak-to-peak variability in the LAT at any given location, and the consistency criterion requires that the peak-to-peak variability in the LAT does not exceed a predetermined limit.

[0007] In another embodiment, the electrophysiological parameter includes an electrophysiological voltage and the consistency measure is indicative of the variability of the electrophysiological voltage. Additionally or alternatively, the consistency measure includes the peak-to-peak variability of the electrophysiological voltage at any given location, and the consistency criterion requires that the peak-to-peak variability of the electrophysiological voltage does not exceed a predetermined limit.

[0008] In yet another embodiment, the 3D map is displayed against a background color and the visual display includes other colors superimposed on the background color at individual locations to indicate the values ​​of the extracted electrophysiological parameters.

[0009] According to an embodiment of the present invention, there is also provided a method of electrophysiological mapping. The method includes acquiring individual electrophysiological signals from one or more electrodes on a probe in contact with tissue of a region within a patient's body while holding one or more electrodes fixed at individual locations in the region and acquiring position coordinates of the one or more electrodes for at least a predetermined length of time. Individual electrophysiological parameters are extracted from the electrophysiological signals acquired by the one or more electrodes at the individual locations, and individual consistency measures are calculated for the individual electrophysiological parameters extracted from the electrophysiological signals acquired by the electrodes over the predetermined length of time at each of the individual locations. The method further includes displaying a three-dimensional (3D) map of tissue while superimposing on the map a visual representation of the extracted electrophysiological parameters at individual locations whose individual consistency measures meet a predetermined consistency criterion in response to the position coordinates, and automatically discarding from the map electrophysiological parameters whose individual consistency measures do not meet the predetermined consistency criterion.

[0010] The present invention will be more fully understood from the following detailed description when considered in conjunction with the drawings in which: [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a schematic, pictorial illustration of a medical device for mapping EP parameters in a patient's heart, in accordance with an embodiment of the present invention; [Figure 2] FIG. 1 is a flow chart diagram that schematically illustrates a method for automated EP mapping, in accordance with an embodiment of the present invention. [Figure 3A] 1A-1C are schematic illustrations of electroanatomical maps including a 3D map of the heart chambers with overlaid visual display of EP parameters during measurement and after automatic discarding of inconsistent EP parameters, in accordance with an embodiment of the present invention. [Figure 3B] 1A-1C are schematic illustrations of electroanatomical maps including a 3D map of the heart chambers with overlaid visual display of EP parameters during measurement and after automatic discarding of inconsistent EP parameters, in accordance with an embodiment of the present invention. [Figure 3C] 1A-1C are schematic illustrations of electroanatomical maps including a 3D map of the heart chambers with overlaid visual display of EP parameters during measurement and after automatic discarding of inconsistent EP parameters, in accordance with an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] Overview Generating an electrophysiological (EP) map of a patient's tissue involves placing one or more electrodes on a tissue region, acquiring a signal in that region, and then repeating the process for a different region. When a small number of electrodes are used, this process allows a physician to observe the acquired signals and simply receive a "good" signal (as determined by the physician) to map, thereby generating an accurate map of EP parameters extracted from these signals. Good signals are typically only generated when the electrodes are in good contact with the tissue. However, using a small number of electrodes has the disadvantage that mapping takes a long time.

[0013] Catheters with multiple electrodes reduce mapping time but accuracy because it is impossible for a physician to properly review all of the simultaneously occurring signals within the available time. The task of identifying good signals (and rejecting others) can be facilitated by displaying the signal analysis results, i.e., the values ​​of EP parameters across the entire measurement area, to the physician. (For brevity, "EP parameter values" will hereafter be referred to simply as "EP parameters.") This task can be further facilitated by displaying these values ​​in a graphical format, such as a map of these values. However, physicians are still required to use their subjective judgment in accepting or rejecting the analysis results, with inherent variability due to subjectivity. Furthermore, the physician's need to judge the quality of these results may further burden the physician's time and attention during the mapping procedure, especially when multiple electrodes are used.

[0014] The embodiments of the invention described herein address these problems by providing a medical device that includes a probe, a display screen, a position tracking system, and a processor. A probe with one or more electrodes is inserted into a patient's body so that the probe contacts tissue within the body. While the probe and its electrodes are held stationary against the tissue for a preset length of time, the position tracking system requires the position coordinates of the electrodes, and the processor requires the EP signals from the electrodes. The processor extracts individual EP parameters from the signals and calculates a consistency measure of the values ​​at each electrode location. The processor displays a three-dimensional (3D) map of the tissue on the display screen while overlaying on the map a visual representation of the extracted EP parameters at locations where the consistency measure meets a predetermined consistency criterion. The processor automatically discards from the map EP parameters whose individual consistency measures do not meet the predetermined criterion.

[0015] This approach facilitates rapid, automated determination of the points on the tissue where the acquired EP parameters are valid, without having to rely on subjective and time-consuming evaluation by a physician.

[0016] In a disclosed embodiment, the processor displays a 3D map of the heart chamber onto which the EP parameters are mapped. The 3D map is displayed in a neutral or monotone color, such as gray. EP parameters can include, for example, local activation time (LAT) measured at the muscle layer, or bipolar or unipolar peak voltage. LAT is the time interval between a reference time, determined, for example, from a surface ECG or intracardiac electrogram, and the time of a local depolarization event. Other useful scalar functions of physiological parameters can be calculated and displayed and superimposed on a display combining LAT (as false colors) and conduction velocity (as arrows). One such useful scalar function is the range of voltage measured at each sampling point (displayed as false colors); an abnormally low range is diagnostic of scar tissue, and conduction velocity can then be displayed as an arrow. LAT can be determined manually (and usually automatically by the CARTO® system) by noting one or more of: (a) the most negative slope (-dV / dt) of the voltage of the unipolar recording; (b) the highest absolute voltage of the bipolar recording; (c) the absolute maximum slope dV / dt of the bipolar recording; or (d) the lowest voltage of the bipolar recording.

[0017] During measurement, the processor continues to update the 3D map for each heartbeat by extracting EP parameters over several heartbeats (e.g., 3-7 heartbeats) and overlaying a display of the EP parameters on the map. This display can be, for example, color-coded, with the lowest EP parameter values ​​being blue, the highest values ​​being red, and intermediate values ​​being represented by colors in the visible spectrum between blue and red. The 3D map can be updated after each heartbeat based on the last measured EP parameters or based on a cumulative average value of the EP parameters. Alternatively, the 3D map can be updated only after the EP parameters have been measured over several heartbeats, and then updated with only points that pass consistency criteria, as described below.

[0018] The processor also calculates a consistency measure for the EP parameter over these several heartbeats to reflect the variation of the extracted value over heartbeats. The criteria applied to the consistency measure may, for example, require that the variation be below a certain threshold, such as a voltage threshold. If the variation exceeds this threshold at a given measurement point on the tissue, the EP parameter measured at this point is rejected and the corresponding region on the 3D map is displayed with its neutral background color.

[0019] System Description FIG. 1 is a schematic, pictorial illustration of a medical device 20 for mapping EP parameters in a heart 26 of a patient 28, in accordance with an embodiment of the present invention.

[0020] A physician 30 navigates a basket catheter 40, seen in detail in inset 45, to a target location in a patient's 28's heart 26 by manipulating the shaft 22 using a remote controller 32 near the catheter's proximal end and / or deflection from a sheath 23. In the embodiment seen in inset 25, the physician 30 uses the catheter 40 to perform electroanatomical mapping of the cardiac chambers. EP signals are acquired from the tissue by using electrodes 48 on the basket catheter 40 that are in contact with the tissue, as described in further detail below.

[0021] Catheter 40 is inserted from sheath 23 in a collapsed configuration, as shown in inset 45, and only expands to its intended functional shape after it exits sheath 23. Sheath 23 also serves to minimize vascular trauma on the way to the target location by housing catheter 40 in a collapsed configuration.

[0022] The basket catheter 40 incorporates a magnetic sensor 50A at the distal edge of the shaft 22 (i.e., at the proximal edge of the basket catheter 40), as shown in inset 45. Typically, but not necessarily, the sensor 50A is a triaxial sensor (TAS) and comprises three small coils oriented in different directions. In the illustrated embodiment, a second magnetic sensor 50B is incorporated at the distal edge of the basket catheter. The sensor 50B may be, for example, a single-axis sensor (SAS) or a triaxial sensor (TAS). Alternatively, the catheter 40 may include other types of magnetic sensors at these or other locations.

[0023] Catheter 40 further includes a plurality of expandable spines 55, which may be mechanically flexible, each coupled to a plurality of electrodes 48, e.g., 120 electrodes in total. Electrodes 48 are configured to contact tissue of patient 28 to detect EP signals. Magnetic sensors 50A and 50B and electrodes 48 are connected to various processing circuits in console 24 by wires routed along shaft 22.

[0024] Alternatively, device 20 may comprise other types of catheters containing other types of electrode arrays, such as an expandable balloon catheter with electrodes 48 on its outer surface.

[0025] The medical device 20 includes a magnetic sensing subsystem for determining the position and orientation of the basket catheter 40, and thus the positions of the electrodes 48. The patient 28 positions himself in a magnetic field generated by pads containing field-generating coils 42, driven by a tracking module 43 in the console 24. The magnetic field generated by the coils 42 produces electrical signals in the sensors 50A and 50B, which indicate the position and / or orientation of the sensors. The signals from the sensors 50A and 50B are transmitted back to the tracking module 43, which converts the signals into corresponding digital input values ​​for the processor 41. The processor 41 uses these input values ​​to calculate the position and orientation of the basket catheter 40, thus locating the individual positions of each of the electrodes 48.

[0026] Position and / or orientation detection methods using external magnetic fields and magnetic sensors such as sensors 50A and 50B have been implemented in a variety of medical applications, for example, in the CARTO® system available from Biosense Webster, Inc. (Irvine, California). Such methods are described in detail in U.S. Patent Nos. 5,391,199, 6,690,963, 6,484,118, 6,239,724, 6,618,612, and 6,332,089, PCT Patent Publication WO 96 / 05768, and U.S. Patent Application Publication Nos. 2002 / 0065455(A1), 2003 / 0120150(A1), and 2004 / 0068178(A1), the disclosures of which are all incorporated herein by reference.

[0027] Alternatively, or in addition, device 20 may use other methods of position detection to locate electrodes 48. For example, processor 41 may map the location of electrodes 48 by measuring the impedance between electrodes 48 placed on the chest of patient 28 and connected to console 24 by leads 39 and body surface electrodes 49.

[0028] Processor 41 additionally receives electrophysiological signals via electrical interface 44 and utilizes the information contained in these signals, along with the coordinates provided by magnetic sensors 50A and 50B, to construct an electroanatomical map 31 of heart chamber 26 in which catheter 40 is positioned. During and / or after the procedure, processor 41 can display electroanatomical map 31 on display screen 27.

[0029] The processor 41 is typically programmed in software to perform the functions described herein. The software may be downloaded to the computer in electronic form, for example over a network, or alternatively or additionally may be provided and / or stored on a non-transitory tangible medium, such as magnetic, optical, or electronic memory. In particular, the processor 41 runs dedicated algorithms that enable the processor to perform the disclosed steps, as described below.

[0030] The illustration shown in Figure 1 has been selected solely for conceptual clarity. For simplicity and clarity, Figure 1 shows only elements relevant to the disclosed techniques. Medical device 20 typically includes additional modules and elements not directly related to the disclosed techniques, and thus are intentionally omitted from Figure 1 and the corresponding description. The elements of medical device 20 and the methods described herein may be further applied, for example, to control the ablation of tissue in heart 26.

[0031] 2 is a flowchart 200 that generally illustrates an automated process for EP mapping, according to an embodiment of the present invention. In this method, only EP parameters that meet certain consistency criteria are incorporated into the map. The embodiment shown in flowchart 200 refers to an example of acquiring EP signals from heart chamber 26 (see FIG. 1). In alternative embodiments, EP parameter values ​​may be acquired not only from the heart but also from other organs and tissues using other types of mapping devices, as will be apparent to those skilled in the art after reading this description.

[0032] The process illustrated by flowchart 200 begins at start step 202. In map generation step 204, a solid gray (or other suitable background color) 3D map of the heart chamber is generated by processor 41 and displayed on display screen 27. The 3D map may be generated, for example, from images of heart 26 previously stored in the processor or based on position measurements acquired by the catheter. Alternatively, the 3D map may be generated simultaneously with the display of EP parameters. In acquisition step 206, processor 41 receives signals from electrodes 48 in contact with myocardial tissue in a portion of heart chamber 26 over a preset number of consecutive heartbeats. Typically, signals are acquired over three to seven consecutive heartbeats, although more heartbeats may alternatively be sampled. In a tracking step, processor 41 receives signals from tracking module 43 and calculates individual position coordinates of electrodes 48.

[0033] In a calculation and display step 208, the processor 41 extracts EP parameters for each heartbeat individually from the signals received in the acquisition step 206. The processor displays the parameters by applying a corresponding color code to appropriate regions of the 3D map generated in step 204 based on the location coordinates received in the tracking step 207. The color coding may include, for example, showing the lowest EP parameter value as blue, the highest value as red, and intermediate values ​​between the lowest and highest values ​​as colors in the visible spectrum in the same order. However, other color coding schemes and shadings or symbols, such as those known in the art, may alternatively be used. The EP parameters may be displayed in this step either as the last measurement or as a cumulative average. Alternatively, color coding may be superimposed on the 3D map after the EP parameters have been measured over several heartbeats, using only those points that pass consistency criteria applied in the following steps.

[0034] In consistency evaluation step 210, processor 41 evaluates the consistency measure of the beat-to-beat EP parameters against a predetermined consistency criterion. For simplicity, EP parameters whose consistency measure meets the consistency criterion are also referred to as "concordant EP parameters" in the following description, while such parameters that do not meet the consistency criterion are referred to as "inconsistent EP parameters." The consistency measure and consistency criterion are defined in this embodiment in terms of the peak beat-to-beat variability of the EP parameters.

[0035] In a first determination step 212, processor 41 determines whether the EP parameter satisfies a consistency criterion based on the results of consistency evaluation step 210. For example, if the EP parameter calculated in step 208 is local activation time (LAT), the consistency criterion may be adopted as a range of ±10 ms, i.e., if the LATs measured for each heartbeat over three to seven heartbeats are within 20 ms of each other, they are considered to satisfy the consistency criterion. In another example, if the EP parameter is the bipolar or unipolar maximum voltage in the signal detected by electrodes 48, the consistency criterion may be adopted as a range of 20 mV, such that a maximum voltage measured within this range is considered to satisfy the consistency criterion. Alternatively, a larger or smaller range of the parameter may be adopted as the consistency criterion.

[0036] Further alternatively, other types of consistency criteria may be applied: for example, processor 41 may calculate the mean value of the EP parameter in question and the variance of the parameter over a series of heartbeats, and define the consistency criterion in terms of the maximum acceptable variance.

[0037] If the processor 41 determines in step 212 that the EP parameters meet the consistency criteria, the processor automatically incorporates the color-coded area in the 3D map in an incorporation step 214. Alternatively, if the consistency criteria are not met, the processor reverts the problematic area of ​​the map to the background color in an exclusion step 216.

[0038] In a second decision step 218, the physician 30 determines whether EP signals need to be sampled from additional regions of the heart chamber. If the answer is yes, the physician moves the basket catheter 40 to another region and measures the EP signal from that region, beginning the acquisition step 206. Alternatively, if the EP value was rejected in the initial decision step 212, the physician 30 may decide to resample the signal from that region. If no more EP signals need to be sampled, the process ends at final step 222.

[0039] 3A, 3B, and 3C are schematic illustrations of electroanatomical map 31, including a 3D map 300 of heart chamber 26, including an overlaid visual display of EP parameters during measurement and after automatic exclusion of non-concordant EP parameters, in accordance with an embodiment of the present invention. Map 300 is initially colored gray on display screen 27, and this color is updated according to the method of FIG. 2 at various stages of measurement using basket catheter 40, as described in more detail below.

[0040] In Figure 3A, a colored overlay 302 is superimposed on the 3D map 300 as a visual representation of the EP parameters resulting from the calculation and display step 208. In Figure 3A, the colored overlay 302 may include both matching and non-matching values. The basket catheter 40 is positioned over a region 304, the gray color of which indicates that the EP parameters have not yet been measured in this region.

[0041] FIG. 3B shows a 3D map 300 with a colored overlay 306 superimposed directly on the region 304 of FIG. 3A, showing the values ​​of the measured EP parameters.

[0042] 3C shows 3D map 300 with only the concordant EP parameters superimposed thereon as colored overlay 308. The non-concordant values ​​of the measured EP parameters are now excluded from region 310 in exclusion step 216 (FIG. 2), so that this region is displayed in gray in map 300. Thus, physician 30 sees only colored overlay 308 displaying the concordant EP parameters. The rejection of the non-concordant EP parameters is performed automatically by processor 41 without any intervention by physician 30.

[0043] In the disclosed embodiment, EP parameters are measured from the heart 26, however, in alternative embodiments, the described methods of automatic acceptance or rejection of EP parameters may be applied to other tissues in the body of the patient 28. Furthermore, in alternative embodiments, more than one type of EP parameter may be measured and displayed simultaneously.

[0044] It will be understood that the above-described embodiments are given by way of example, and that the present invention is not limited to what has been particularly shown and described above. Rather, the scope of the present invention includes both combinations and sub-combinations of the various features described in the foregoing specification, as well as variations and modifications thereof not disclosed in the prior art which will occur to those skilled in the art upon reading the foregoing description.

[0045] [Embodiment] (1) A medical device, a probe configured for insertion into a patient's body, the probe comprising one or more electrodes configured to contact tissue in an area within the body; A display screen; a position tracking system configured to acquire position coordinates of the one or more electrodes within the body; 1. A processor, comprising: acquiring individual electrophysiological signals from the one or more electrodes while the one or more electrodes are held fixed at individual locations in the region for at least a predetermined length of time; extracting individual electrophysiological parameters from the electrophysiological signals acquired by the one or more electrodes at the individual locations; calculating individual consistency measures of the individual electrophysiological parameters extracted from the electrophysiological signals acquired by the electrodes at each of the individual locations over the preset time period; displaying a three-dimensional (3D) map of the tissue on the display screen while superimposing a visual representation of the extracted electrophysiological parameters at each of the locations for which the individual consistency measures met a predetermined consistency criterion on the map in response to the location coordinates, and automatically discarding from the map those electrophysiological parameters for which the individual consistency measures did not meet the predetermined consistency criterion. a processor configured to: A medical device comprising: (2) The medical device of embodiment 1, wherein the electrophysiological parameter includes a local activation time (LAT) in the patient's heart, and the consistency measure indicates a variation in the LAT. (3) The medical device of embodiment 2, wherein the consistency measure includes the peak-to-peak variation of the LAT at any given location, and the consistency criterion requires that the peak-to-peak variation of the LAT does not exceed a predetermined limit value. (4) The medical device of embodiment 1, wherein the electrophysiological parameter includes an electrophysiological voltage and the consistency measure indicates a variation in the electrophysiological voltage. (5) The medical device of embodiment 4, wherein the consistency measure includes a peak-to-peak variation of the electrophysiological voltage at any given location, and the consistency criterion requires that the peak-to-peak variation of the electrophysiological voltage does not exceed a predetermined limit value.

[0046] (6) A medical device as described in embodiment 1, wherein the 3D map is displayed with a background color and the visual display includes other colors superimposed on the background color at the individual locations to indicate the values ​​of the extracted electrophysiological parameters. (7) A method for electrophysiological mapping, comprising: acquiring individual electrophysiological signals from one or more electrodes on a probe in contact with tissue of a patient's body at individual locations in the region for at least a predetermined length of time, while holding the one or more electrodes stationary at the individual locations in the region and while acquiring position coordinates of the one or more electrodes; extracting individual electrophysiological parameters from the electrophysiological signals acquired by the one or more electrodes at the individual locations; calculating individual consistency measures of the individual electrophysiological parameters extracted from the electrophysiological signals acquired by the electrodes at each of the individual locations over the preset length of time; displaying a three-dimensional (3D) map of the tissue in response to the location coordinates while superimposing on the map a visual representation of the extracted electrophysiological parameters at each of the locations for which the individual consistency measures met a predetermined consistency criterion, and automatically discarding from the map the electrophysiological parameters for which the individual consistency measures did not meet the predetermined consistency criterion; A method comprising: (8) The method of embodiment 7, wherein extracting electrophysiological parameters includes extracting a local activation time (LAT) in the patient's heart, and calculating the consistency measure includes calculating a measure indicative of variability in the LAT. (9) The method of embodiment 8, wherein calculating the measure includes calculating the peak-to-peak variation of the LAT at any given location, and the consistency criterion requires that the peak-to-peak variation of the LAT does not exceed a predetermined limit. (10) The method of embodiment 7, wherein extracting electrophysiological parameters includes extracting electrophysiological voltages in the patient's heart, and calculating the individual consistency measures includes calculating measures indicative of variability in the electrophysiological voltages.

[0047] (11) The method of embodiment 10, wherein calculating the measure includes calculating the peak-to-peak variation of the electrophysiological voltage at any given location, and wherein the consistency criterion requires that the peak-to-peak variation of the electrophysiological voltage does not exceed a predetermined limit. (12) The method of embodiment 7, wherein displaying the 3D map includes displaying the 3D map in a background color, and overlaying the visual display includes overlaying another color on the background color at each of the locations to indicate each value of the extracted electrophysiological parameter.

Claims

1. A medical device comprising: a probe configured for insertion into a patient's body, the probe comprising one or more electrodes configured to contact tissue in an area within the body; A display screen; a position tracking system configured to acquire position coordinates of the one or more electrodes within the body; 1. A processor, comprising: acquiring individual electrophysiological signals from the one or more electrodes while the one or more electrodes are held fixed at individual locations in the region for at least a predetermined length of time; extracting individual electrophysiological parameters from the electrophysiological signals acquired by the one or more electrodes at the individual locations; calculating individual consistency measures of the individual electrophysiological parameters extracted from the electrophysiological signals acquired by the electrodes at each of the individual locations over the preset time period; displaying a three-dimensional (3D) map of the tissue on the display screen while superimposing a visual representation of the extracted electrophysiological parameters at each of the locations for which the individual consistency measures met a predetermined consistency criterion on the map in response to the location coordinates, and automatically discarding from the map those electrophysiological parameters for which the individual consistency measures did not meet the predetermined consistency criterion. a processor configured to: A medical device comprising:

2. The medical device of claim 1 , wherein the electrophysiological parameter comprises a local activation time (LAT) in the patient's heart, and the consistency measure indicates variability in the LAT.

3. 3. The medical device of claim 2, wherein the consistency measure includes a peak-to-peak variation of the LAT at any given location, and the consistency criterion requires that the peak-to-peak variation of the LAT does not exceed a predetermined limit.

4. The medical device of claim 1 , wherein the electrophysiological parameter comprises an electrophysiological voltage and the consistency measure indicates a variation in the electrophysiological voltage.

5. 5. The medical device of claim 4, wherein the consistency measure includes a peak-to-peak variation of the electrophysiological voltage at any given location, and the consistency criterion requires that the peak-to-peak variation of the electrophysiological voltage does not exceed a predetermined limit.

6. 2. The medical device of claim 1, wherein the 3D map is displayed with a background color and the visual display includes other colors superimposed on the background color at the individual locations to indicate values ​​of the extracted electrophysiological parameters.

7. 1. A method of electrophysiological mapping, comprising: acquiring individual electrophysiological signals from one or more electrodes on a probe in contact with tissue of a patient's body at individual locations in the region for at least a predetermined length of time, while holding the one or more electrodes stationary at the individual locations in the region and while acquiring position coordinates of the one or more electrodes; extracting individual electrophysiological parameters from the electrophysiological signals acquired by the one or more electrodes at the individual locations; calculating individual consistency measures of the individual electrophysiological parameters extracted from the electrophysiological signals acquired by the electrodes at each of the individual locations over the preset length of time; displaying a three-dimensional (3D) map of the tissue in response to the location coordinates while superimposing on the map a visual representation of the extracted electrophysiological parameters at each of the locations for which the individual consistency measures met a predetermined consistency criterion, and automatically discarding from the map the electrophysiological parameters for which the individual consistency measures did not meet the predetermined consistency criterion; A method comprising:

8. 8. The method of claim 7, wherein extracting an electrophysiological parameter comprises extracting a local activation time (LAT) in the patient's heart, and calculating the consistency measure comprises calculating a measure indicative of variability in the LAT.

9. 9. The method of claim 8, wherein calculating the measure includes calculating a peak-to-peak variation of the LAT at any given location, and the consistency criterion requires that the peak-to-peak variation of the LAT does not exceed a predetermined limit.

10. 8. The method of claim 7, wherein extracting electrophysiological parameters comprises extracting electrophysiological voltages in the patient's heart, and wherein calculating the individual consistency measures comprises calculating measures indicative of variability in the electrophysiological voltages.

11. 11. The method of claim 10, wherein calculating the measure comprises calculating peak-to-peak variation of the electrophysiological voltage at any given location, and the consistency criterion requires that the peak-to-peak variation of the electrophysiological voltage does not exceed a predetermined limit.

12. 8. The method of claim 7, wherein displaying the 3D map comprises displaying the 3D map in a background color, and wherein overlaying the visual representation comprises overlaying another color on the background color at the individual locations to indicate individual values ​​of the extracted electrophysiological parameters.

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