Patent Description:
A wide range of medical procedures involve placing probes, such as catheters, within a patient's body. Location sensing systems have been developed for tracking such probes. Magnetic location sensing is one of the methods known in the art. In magnetic location sensing, magnetic field generators are typically placed at known locations external to the patient. A magnetic field sensor within the distal end of the probe generates electrical signals in response to these magnetic fields, which are processed to determine the coordinate locations of the distal end of the probe. These methods and systems are described in <CIT>, <CIT>, <CIT>, <CIT>, <CIT> and <CIT>, in <CIT>, and in <CIT> and <CIT> and <CIT>. Locations may also be tracked using impedance or current based systems.

One medical procedure in which these types of probes or catheters have proved extremely useful is in the treatment of cardiac arrhythmias. Cardiac arrhythmias and atrial fibrillation in particular, persist as common and dangerous medical ailments, especially in the aging population.

Diagnosis and treatment of cardiac arrhythmias include mapping the electrical properties of heart tissue, especially the endocardium and the heart volume, and selectively ablating cardiac tissue by application of energy. Such ablation can cease 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. Various energy delivery modalities have been disclosed for forming lesions, and include use of microwave, laser, pulsed field, and more commonly, radiofrequency energies to create conduction blocks along the cardiac tissue wall. In a two-step procedure, mapping followed by ablation, electrical activity at points within the heart is typically sensed and measured by advancing a catheter containing one or more electrical sensors into the heart, and acquiring data at a multiplicity of points. These data are then utilized to select the endocardial target areas at which the ablation is to be performed.

Electrode catheters have been in common use in medical practice for many years. They are used to stimulate and map electrical activity in the heart and to ablate sites of aberrant electrical activity. In use, the electrode catheter is inserted into a major vein or artery, e.g., femoral vein, and then guided into the chamber of the heart of concern. A typical ablation procedure involves the insertion of a catheter having a one or more electrodes at its distal end into a heart chamber. A reference electrode may be provided, generally taped to the skin of the patient or by means of a second catheter that is positioned in or near the heart. RF (radio frequency) current is applied between the tip electrode(s) of the ablating catheter, and the reference electrode, flowing through the media between the electrodes it, i.e., blood and tissue. The distribution of current depends on the amount of electrode surface in contact with the tissue as compared to blood, which has a higher conductivity than the tissue. Heating of the tissue occurs due to its electrical resistance. The tissue is heated sufficiently to cause cellular destruction in the cardiac tissue resulting in formation of a lesion within the cardiac tissue which is electrically non-conductive.

<CIT> teaches a method, consisting of presenting on a display screen a graphical image of a heart of a patient, including icons representing a catheter that is positioned within the heart and an electrode on the catheter, while the electrode is in contact with tissue at a location in the heart. The method further includes acquiring, using the electrode, electrical signals from the tissue at the location, and processing the acquired signals so as to detect an occurrence of a predefined signal feature in the acquired signals. The method also includes, upon detecting the occurrence of the predefined signal feature, modifying a visual feature of at least one of the icon representing the electrode and the icon representing the catheter on the display screen.

<CIT> teaches a medical system that includes a catheter including electrodes, and that is configured to be inserted into a chamber of a heart and maneuvered among sampling sites to sample electrical activity, a display, and processing circuitry to receive signals provided by the catheter, and compute, for each sampling site, a sampling position of the catheter and respective electrode positions of the catheter electrodes, render to the display a 3D representation of the chamber including respective sampling-site markers indicating the computed sampling position of the catheter at respective ones of the sampling sites, receive a user input selecting one sampling-site marker, and update the 3D representation to include electrode markers indicating the respective electrode positions of the respective catheter electrodes while the catheter was sampling the electrical activity of the tissue at the sampling site corresponding to the selected sampling-site marker.

<CIT>teaches a system that includes a mapping catheter including a plurality of mapping electrodes, each mapping electrode configured to sense signals associated with an anatomical structure. The catheter system further includes a processor operatively coupled to the plurality of mapping electrodes and configured to receive the signals sensed by the plurality of mapping electrodes, characterize the signals sensed by the plurality of mapping electrodes based on amplitudes of the sensed signals, and generate an output of a quality of contact of the plurality of mapping electrodes with the anatomical structure based on the signal characterization.

There is provided in accordance with an embodiment of the present disclosure, a medical system according to claim <NUM>, including a catheter configured to be inserted into a chamber of a heart of a living subject, and including catheter electrodes configured to contact tissue at respective locations within the chamber of the heart, a display, and a processing circuitry configured to receive respective signals from the catheter captured by respective ones of the electrodes, assess conformity of each of the respective signals to at least one signal characteristic, find a given one of the signals of a given one of the electrodes not conforming to the at least one signal characteristic for a given time period, and render to the display an indication that the given signal of the given electrode does not conform to the at least one signal characteristic for the given time period.

Further in accordance with an embodiment of the present disclosure the processing circuitry is configured to render to the display a representation of the catheter with the indication that the given signal of the given electrode does not conform to the at least one signal characteristic for the given time period, wherein the indication is linked to the given electrode on the representation of the catheter.

Still further in accordance with an embodiment of the present disclosure the processing circuitry is configured to render to the display a representation of the catheter with the indication that the given signal of the given electrode does not conform to the at least one signal characteristic for the given time period, wherein the indication is disposed on the given electrode on the representation of the catheter.

Additionally in accordance with an embodiment of the present disclosure the processing circuitry is configured to render to the display the indication disposed on the given electrode on the representation of the catheter for a given time interval, remove the indication from the given electrode on the representation of the catheter, and repeat rendering to the display of the indication disposed on the given electrode on the representation of the catheter responsively to finding that the given signal of the given electrode does not conform to the at least one signal characteristic for a subsequent time period.

Moreover, in accordance with an embodiment of the present disclosure the processing circuitry is configured to render to the display the indication disposed on the given electrode on the representation of the catheter so that the indication repeatedly flashes on and off responsively to multiple detections of the given signal of the given electrode not conforming to the at least one signal characteristic for respective subsequent time periods.

Further in accordance with an embodiment of the present disclosure the respective subsequent time periods correspond to respective windows of interest of respective cardiac cycles.

Still further in accordance with an embodiment of the present disclosure the processing circuitry is configured to receive a user input requesting display of an electrogram captured by the given electrode, and render to the display the electrogram captured by the given electrode.

Additionally in accordance with an embodiment of the present disclosure the given time period is equal to a window of interest in one cardiac cycle.

Moreover, in accordance with an embodiment of the present disclosure the given time period is equal to multiple windows of interest of respective cardiac cycles.

Further in accordance with an embodiment of the present disclosure the processing circuitry is configured to save the given signal to a memory for future rendering to the display.

There is also provided in accordance with another embodiment of the present disclosure a computer-implemented medical method according to claim <NUM>, including receiving respective signals from a catheter inserted into a chamber of a heart of a living subject captured by respective electrodes of the catheter contacting tissue at respective locations within the chamber of the heart, assessing conformity of each of the respective signals to at least one signal characteristic, finding a given one of the signals of a given one of the electrodes not conforming to the at least one signal characteristic for a given time period, and rendering to the display an indication that the given signal of the given electrode does not conform to the at least one signal characteristic for the given time period.

Still further in accordance with an embodiment of the present disclosure the rendering includes rendering to the display a representation of the catheter with the indication that the given signal of the given electrode does not conform to the at least one signal characteristic for the given time period, wherein the indication is linked to the given electrode on the representation of the catheter.

Additionally in accordance with an embodiment of the present disclosure the rendering includes rendering to the display a representation of the catheter with the indication that the given signal of the given electrode does not conform to the at least one signal characteristic for the given time period, wherein the indication is disposed on the given electrode on the representation of the catheter.

Moreover in accordance with an embodiment of the present disclosure the rendering includes rendering to the display the indication disposed on the given electrode on the representation of the catheter for a given time interval, the method further including removing the indication from the given electrode on the representation of the catheter, and repeating rendering to the display of the indication disposed on the given electrode on the representation of the catheter responsively to finding that the given signal of the given electrode does not conform to the at least one signal characteristic for a subsequent time period.

Further in accordance with an embodiment of the present disclosure the rendering includes rendering to the display the indication disposed on the given electrode on the representation of the catheter so that the indication repeatedly flashes on and off responsively to multiple detections of the given signal of the given electrode not conforming to the at least one signal characteristic for respective subsequent time periods.

Still further in accordance with an embodiment of the present disclosure the respective subsequent time periods correspond to respective windows of interest of respective cardiac cycles.

Additionally in accordance with an embodiment of the present disclosure, the method includes receiving a user input requesting display of an electrogram captured by the given electrode, and wherein the rendering includes rendering to the display the electrogram captured by the given electrode.

Moreover, in accordance with an embodiment of the present disclosure the given time period is equal to a window of interest in one cardiac cycle.

Further in accordance with an embodiment of the present disclosure the given time period is equal to multiple windows of interest of respective cardiac cycles.

Still further in accordance with an embodiment of the present disclosure, the method includes saving the given signal to a memory for future rendering to the display.

There is also provided in accordance with still another embodiment of the present disclosure a software product according to claim <NUM>, including a non-transient computer-readable medium in which program instructions are stored, which instructions, when read by a central processing unit (CPU), cause the CPU to receive respective signals from a catheter inserted into a chamber of a heart of a living subject captured by respective electrodes of the catheter contacting tissue at respective locations within the chamber of the heart, assess conformity of each of the respective signals to at least one signal characteristic, find a given one of the signals of a given one of the electrodes not conforming to the at least one signal characteristic for a given time period, and render to the display an indication that the given signal of the given electrode does not conform to the at least one signal characteristic for the given time period.

During the mapping process, unexpected signals that do not fit into the category of expected mapping signals may be captured by catheter electrodes. These unexpected signals may be due to noise and/or physiological factors leading to complex signals including late activations, or double/multiple activations per cardiac cycle. Although these unexpected signals may be interesting for the physician, these unexpected signals are difficult to treat algorithmically (and may cause errors in the mapping process) and are generally filtered out as non-mapping signals and ignored by the mapping algorithm. Nevertheless, complex signals may be the most interesting signals for the physician and may indicate a heart defect which should be treated. However, as mentioned above these complex signals are generally excluded from the mapping process.

Embodiments of the invention use the signals filtered out as non-mapping signals and provide respective indications to the physician that such non-mapping signals exist. The physician may then select the non-mapping signals for viewing to determine if the signals are physiologically relevant.

In some embodiments, a mapping system assesses conformity of each signal to one or more signal characteristics for a given time period (e.g., for a window of interest of each signal in one or more cardiac cycles). The signals for a given time period may also be referred to as signal segments for the given time period. According to the present invention, the signal characteristics for classifying a signal segment (for a given time period) as a valid mapping signal include a signal having a single activation early enough in the cardiac cycle. Signal segments with late, double, multiple, or unclear activations may be excluded as not conforming with the signal characteristics. In some embodiments, peaks above a given threshold are considered as possible activations, whereas peaks below the given threshold are not considered as possible activations for determining how many activations a signal segment has in the window of interest and how late the activations are in the window of interest. The activation time may be defined by the steepest negative slope of a candidate peak or any other suitable criteria. The definition of "early enough" in the cardiac cycle, the window of interest, and the given threshold for identifying peaks may be implementation specific and/or physician defined. In some embodiments, the physician defines the "window of interest". For example, in atrial procedures, the "window of interest" may be defined by setting limits around the P wave, which may be identified based on the R peak of the QRS complex. The definition of late activation may be dependent on the region on the map. In some embodiments, "late" may be considered to be about <NUM> milliseconds later than all the points surrounding the specific map region under consideration. With regards to the given threshold for identifying peaks, the threshold may be set to any suitable level, for example, <NUM> micro-Volts.

The mapping system then finds the signal segments not conforming to the signal characteristic(s) for the given time period and saves non-conforming signal segments to a memory for future retrieval and inspection by the physician. The non-conforming signal segments may be saved with metadata such as the electrode which captured the signal segment, the time of capture, and optionally the nature of the non-conformity (e.g., late activation, double activation etc.). The mapping system may then render an indication to a display indicating that an electrode captured the non-conforming signal segment optionally with an identification of the capturing electrode.

In some embodiments, the indication may be implemented by highlighting or otherwise coloring or shading the relevant electrode on a representation of the catheter. In some embodiments, the indication remains visible until removed by the physician.

In other embodiments, the indication may be removed automatically after a time-out (e.g., within a cardiac cycle). If the same electrode is still capturing a non-conforming signal segment for the next time period, the indication is rendered again. In this manner if the non-conforming signal segment is a one-off occurrence (or repeating a few times for example) e.g., due to noise, the indication will disappear, whereas if the non-conforming signal segment is repetitive (e.g., due to a physiological effect) then the indication will flash on and off repetitively thereby alerting the physician that a non-conforming signal segment has been captured. The physician may then request rendering of the non-conforming signal segment on the display for inspection.

Reference is now made to <FIG>, which is a schematic, pictorial illustration of a catheter tracking system <NUM>, in accordance with an embodiment of the present invention. The system <NUM> includes a catheter <NUM> configured to be inserted into a body part (e.g., a chamber of a heart <NUM>) of a living subject (e.g., a patient <NUM>). A physician <NUM> navigates the catheter <NUM> (for example, a basket catheter produced by Biosense Webster, Inc. of Irvine, CA, USA), seen in detail in inset <NUM>, to a target location in the heart <NUM> of the patient <NUM>, by manipulating a deflectable segment of an insertion tube <NUM> of the catheter <NUM>, using a manipulator <NUM> near a proximal end <NUM> of the insertion tube <NUM>, and/or deflection from a sheath <NUM>. In the pictured embodiment, physician <NUM> uses catheter <NUM> to perform electro-anatomical mapping of a cardiac chamber.

The catheter <NUM> includes a distal end <NUM>. The distal end <NUM> of the catheter <NUM> includes an assembly <NUM> (e.g., a basket assembly as shown in <FIG> or a balloon assembly or any suitable distal end assembly, e.g., grid, flexible splines or a focal catheter) on which at least one (e.g., multiple) catheter electrode(s) <NUM> (only some labeled for the sake of simplicity) are disposed. The electrodes <NUM> are configured to contact tissue at respective locations with the chamber of the heart. The assembly <NUM> is disposed distally to the insertion tube <NUM> and may be connected to the insertion tube <NUM> via a coupling member of the insertion tube <NUM> at the distal end <NUM>. The coupling member of the insertion tube <NUM> may be formed as an integral part of the rest of the insertion tube <NUM> or as a separate element which connects with the rest of the insertion tube <NUM>.

The assembly <NUM> further comprises multiple flexible strips <NUM> (only two labeled for the sake of simplicity), to each of which are coupled the electrodes <NUM>. The assembly <NUM> may include any suitable number of electrodes <NUM>. In some embodiments, the assembly <NUM> may include ten flexible strips <NUM> and <NUM> electrodes, with twelve electrodes disposed on each flexible strip <NUM>.

The catheter <NUM> includes a pusher <NUM>. The pusher <NUM> is typically a tube that is disposed in a lumen of the insertion tube <NUM> and spans from the proximal end <NUM> to the distal end <NUM> of the insertion tube <NUM>. A distal end of the pusher <NUM> is connected to distal ends of the flexible strips <NUM>, typically via a coupling member of the pusher <NUM>. The coupling member of the pusher <NUM> may be formed as an integral part of the rest of the pusher <NUM> or as a separate element which connects with the rest of the pusher <NUM>. The distal end of the insertion tube <NUM> is connected to proximal ends of the flexible strips <NUM>, typically via the coupling member of the distal end <NUM>. The pusher <NUM> is generally controlled via the manipulator <NUM> to deploy the assembly <NUM> and change an ellipticity of the assembly <NUM> according to the longitudinal displacement of the pusher <NUM> with respect to the insertion tube <NUM>. The actual basket assembly <NUM> structure may vary. For example, flexible strips <NUM> may be made of a printed circuit board (PCB), or of a shape-memory alloy, or any suitable material.

Embodiments described herein refer mainly to a basket distal-end assembly <NUM>, purely by way of example. In alternative embodiments, the disclosed techniques can be used with a catheter having a balloon-based distal-end assembly or of any other suitable type of distal-end assembly.

Catheter <NUM> is inserted in a folded configuration, through sheath <NUM>, and only after the catheter <NUM> exits sheath <NUM> is catheter <NUM> able to change shape by retracting pusher <NUM>. By containing catheter <NUM> in a folded configuration, sheath <NUM> also serves to minimize vascular trauma on its way to the target location.

The distal end <NUM> of the catheter <NUM> comprises magnetic coil sensors 50A and 50B. The magnetic coil sensor 50A is shown in inset <NUM> at the distal edge of insertion tube <NUM> (i.e., at the proximal edge of basket assembly <NUM>). The sensor 50A may be a Single-Axis Sensor (SAS), or a Double-Axis Sensor (DAS) or a Triple-Axis Sensor (TAS). Similarly, the sensor 50B may be a SAS, DAS, or TAS. Magnetic coil sensors 50A and 50B and electrodes <NUM> are connected by wires running through insertion tube <NUM> to various driver circuitries in a console <NUM>.

In some embodiments, system <NUM> comprises a magnetic-sensing subsystem to estimate an ellipticity of the basket assembly <NUM> of catheter <NUM>, as well as its elongation/retraction state, inside a cardiac chamber of heart <NUM> by estimating the elongation of the basket assembly <NUM> from the distance between sensors 50A and 50B. Patient <NUM> is placed in a magnetic field generated by a pad containing multiple magnetic field generator coils <NUM>, which are driven by a unit <NUM>. The magnetic field generator coils <NUM> are configured to generate respective alternating magnetic fields, having respective different frequencies, into a region where a body-part (e.g., the heart <NUM>) of a living subject (e.g., the patient <NUM>) is located. The magnetic coil sensors 50A and 50B are configured to output electrical signals responsively to detecting the respective magnetic fields. For example, if there are nine magnetic field generator coils <NUM> generating nine respective different alternating magnetic fields with nine respective different frequencies, the electrical signals output by the magnetic coil sensors <NUM> will include components of the nine different frequency alternating magnetic fields. The magnitude of each of the magnetic fields varies with distance from the respective magnetic field generator coils <NUM> such that the location of the magnetic coil sensors <NUM> may be determined from the magnetic fields sensed by the magnetic coil sensors <NUM>. Therefore, the transmitted alternating magnetic fields generate the electrical signals in sensors 50A and 50B, so that the electrical signals are indicative of position and orientation of the magnetic coil sensors <NUM>.

The generated signals are transmitted to console <NUM> and become corresponding electrical inputs to processing circuitry <NUM>. The processing circuitry <NUM> may use the signals to compute: the elongation of the basket assembly <NUM>, in order to estimate basket ellipticity and elongation/retraction state from the calculated distance between sensors 50A and 50B; and compute a relative orientation between the axes of the sensors 50A and 50B to estimate a shape of the expandable distal end assembly <NUM> (e.g., a basket shape) responsively to the relative orientation, as described in more detail below.

The bow of the flexible strips <NUM> and/or the positions of the electrodes <NUM> (or other features) on the flexible strips <NUM> with respect to a fixed point on the catheter <NUM> (such as the distal tip of the insertion tube <NUM>) may be measured for various distances between the magnetic sensors 50A, 50B and for various relative orientation angles between the magnetic sensors 50A, 50B. For example, the positions of the electrodes <NUM> with respect to the fixed point on the catheter <NUM> may be measured for every <NUM> movement of the pusher <NUM> with respect to the insertion tube <NUM> and for every <NUM> degree of relative orientation between the magnetic sensors 50A, 50B (up to a maximum sideways movement of the assembly <NUM>). At each different distance/relative-orientation combination, the computed distance and computed relative orientation angle between the magnetic sensors 50A, 50B is recorded along with the position data of the electrodes <NUM>. This data may then be used to estimate the bow of the flexible strips <NUM> and/or the positions of the electrodes <NUM> (or other features) on the flexible strips <NUM> with respect to a fixed point on the catheter <NUM> (such as the distal tip of the insertion tube <NUM>) responsively to the computed distance and relative orientation angle between the magnetic sensors 50A, 50B.

Additionally, or alternatively, the bow of the flexible strips <NUM> may be estimated based on the following assumptions: (a) each of the flexible strips <NUM> is of a fixed and known length; (b) each of the flexible strips <NUM> is connected to the pusher <NUM> via a coupler, with the distal ends of the flexible strips <NUM> being substantially perpendicular (within an error of plus or minus <NUM> degrees) to the longitudinal axis of the insertion tube <NUM>; (c) each of the flexible strips <NUM> is connected to the insertion tube <NUM> via a coupler, which couples the proximal ends of the flexible strips <NUM> to the insertion tube <NUM>, substantially parallel (within an error of plus or minus <NUM> degrees) to the longitudinal axis of the insertion tube <NUM>. Based on the above assumptions (a)-(c), and the computed positions of the couplers based on the computed positions of the magnetic sensors 50A, 50B, the bow of each of the flexible strips <NUM> may be computed using a third-degree polynomial. In some embodiments, the bow of the flexible strips <NUM> and/or the positions of the electrodes <NUM> (or other features) on the flexible strips <NUM> with respect to a fixed point on the catheter <NUM> (such as the distal tip of the insertion tube <NUM>) may be computed based on the computed distance and orientation between the magnetic sensors 50A, 50B and a model of the catheter <NUM> which provides the bow of the flexible strips <NUM> and/or the positions of the electrodes <NUM> for the computed distance based on the mechanical properties and dimensions of the flexible strips <NUM>.

A method of position and/or direction sensing using external magnetic fields and magnetic coil sensors, such as sensors 50A and 50B, is implemented in various medical applications, for example, in the CARTO® system, produced by Biosense-Webster, and is described in detail in <CIT>, <CIT>, <CIT> <CIT>,<CIT> and <CIT>, in <CIT>, and in <CIT>, <CIT> and <CIT>.

In some embodiments, the processing circuitry <NUM> uses position-signals received from the electrodes <NUM> or body surface electrodes <NUM>, and the magnetic sensor <NUM> to estimate a position of the assembly <NUM> inside a body part, such as inside a cardiac chamber. In some embodiments, the processing circuitry <NUM> correlates the position signals received from the electrodes <NUM>, <NUM> with previously acquired magnetic location-calibrated position signals, to estimate the position of the assembly <NUM> inside the body part. The position coordinates of the electrodes <NUM> may be determined by the processing circuitry <NUM> based on, among other inputs, measured impedances, voltages or on proportions of currents distribution, between the electrodes <NUM> and the body surface electrodes <NUM>.

The method of position sensing using current distribution measurements and/or external magnetic fields is implemented in various medical applications, for example, in the Carto® system, produced by Biosense Webster Inc. (Irvine, California), and is described in detail in <CIT>, <CIT>, <CIT>, <CIT>,<CIT>,<CIT>,<CIT>, <CIT>, and <CIT>, in <CIT>, and in <CIT>, <CIT> and <CIT>.

The Carto®<NUM> system applies Active Current Location (ACL) which is a hybrid current-distribution and magnetic-based position-tracking technology. In some embodiments, using ACL, the processing circuitry <NUM> estimates the positions of the electrodes <NUM>. In some embodiments, the signals received from the electrodes <NUM>, <NUM> are correlated with a current-to-position matrix (CPM) which maps current distribution ratios (or another electrical value) with a position that was previously acquired from magnetic location-calibrated position signals. The current distribution ratios are based on measurements of the body surface electrodes <NUM> of current flowing from the electrodes <NUM> to the body surface electrodes <NUM>.

In some embodiments, to visualize catheters which do not include a magnetic sensor, the processing circuitry <NUM> may apply an electrical signal-based method, referred to as Independent Current Location (ICL) technology. In ICL, the processing circuitry <NUM> calculates a local scaling factor for each voxel of the volume in which catheters are visualized. The factor is determined using a catheter with multiple electrodes having a known spatial relationship, such as a lasso-shaped catheter. However, although yielding accurate local scaling (e.g., over several millimeters), ICL is less accurate when applied to a volume of a whole heart chamber, whose size is in the order of centimeters. The ICL method, in which positions are calculated based on current distribution proportions can have errors and may yield a distorted shape of the assembly <NUM>, due to the non-linear nature of the current-based ICL space. In some embodiments, the processing circuitry <NUM> may apply the disclosed ICL method to scale ICL space and the assembly <NUM> shape into a correct one, based on known smaller scale distances between electrodes of a lasso-shaped catheter, for example, as well as based on larger scale distances, themselves based on the known distance between the electrodes <NUM> at the ends of the assembly <NUM>.

Processing circuitry <NUM>, typically part of a general-purpose computer, is further connected via a suitable front end and interface circuits <NUM>, to receive signals from body surface-electrodes <NUM>. Processing circuitry <NUM> is connected to surface-electrodes <NUM> by wires running through a cable <NUM> to the chest of patient <NUM>. The catheter <NUM> includes a connector <NUM> disposed at the proximal end <NUM> of the insertion tube <NUM> for coupling to the processing circuitry <NUM>.

In some embodiments, processing circuitry <NUM> renders to a display <NUM>, a representation <NUM> of at least a part of the catheter <NUM> and a body-part, (e.g., from a mapping process or from a scan (e.g., CT or MRI) of the body-part previously registered with the system <NUM>), responsively to computed position coordinates of the insertion tube <NUM> and the flexible strips <NUM>.

Processing circuitry <NUM> is typically programmed in software to carry out the functions described herein. 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. The system <NUM> may also include a memory <NUM> used by the processing circuitry <NUM>.

The example illustration shown in <FIG> is chosen purely for the sake of conceptual clarity. <FIG> shows only elements related to the disclosed techniques for the sake of simplicity and clarity. System <NUM> typically comprises additional modules and elements that are not directly related to the disclosed techniques, and thus are intentionally omitted from <FIG> and from the corresponding description. The elements of system <NUM> and the methods described herein may be further applied, for example, to control an ablation of tissue of heart <NUM>.

Reference is now made to <FIG>, which is a flowchart <NUM> including steps in a method of operation of the system <NUM> of <FIG>. Reference is also made to <FIG>.

The processing circuitry <NUM> is configured to receive respective signals from the catheter <NUM> captured by respective ones of the electrodes <NUM> (block <NUM>). The processing circuitry <NUM> is configured to assess conformity of each of the respective signals to at least one signal characteristic for a given time period (block <NUM>). The signal characteristic for a given time period may be a predetermined signal characteristic that is used for comparative purposes with the signals recorded by the electrodes.

The "given time period" may include a complete cardiac cycle, multiple cardiac cycles, a predefined time interval within a cardiac cycle, any time intervals that may include any portion of the P-wave, QRS complex or T-wave in one cardiac cycle or from one cardiac cycle to subsequent cardiac cycles. The given time period may be any suitable length. In some embodiments, the given time period is equal to a window of interest in current or most recent cardiac cycle. In other embodiments, the given time period is equal to multiple windows of interest of respective most recent cardiac cycles and therefore an indication (described in more detail below) is provided after several successive cardiac cycles of detecting non-conformity with the signal characteristics.

The signals (collected by the electrodes) for a given time period may also be referred to as signal segments for the given time period. According to the invention, the "signal characteristics" for classifying a collected or recorded signal segment (for a given time period) as a valid mapping signal include a signal having a single activation early enough in the cardiac cycle. The term "single activation" is defined herein as a single peak below a given threshold. With regards to the given threshold for identifying peaks in the recorded signals or signal segments, the threshold may be set to any suitable level, for example, approximately <NUM> micro-Volts. Signal segments with late activation, double activation, multiple activation, or unclear activations may be excluded as not conforming with the signal characteristics. In some embodiments, peaks of the recorded signals or signal segments above a given threshold are considered as possible activations (i.e., signals considered to be in conformity for step <NUM>), whereas peaks of the recorded signals or signal segments below the given threshold are not considered as possible activations (i.e., not conforming as in step <NUM>) for determining how many activations a signal segment has in the window of interest and how late the activations are in the window of interest. The activation time of the measured or recorded signals may be defined by the steepest negative slope of a candidate peak or any other suitable criteria of the recorded signals or signal segments. The definition of "early enough" in the cardiac cycle, the window of interest, and the given threshold for identifying peaks may be implementation specific and/or physician defined. In some embodiments, the physician defines the "window of interest". For example, in atrial procedures, the "window of interest" may be defined by setting limits around the P wave, which may be identified based on the R peak of the QRS complex. The definition of late activation may be dependent on the region on the map. In some embodiments, "late" may be considered to be about <NUM> milliseconds later than all the points surrounding the specific map region under consideration. With regards to the given threshold for identifying peaks in the recorded signals or signal segments, the threshold may be set to any suitable level, for example, approximately <NUM> micro-Volts.

The processing circuitry <NUM> is configured to find a given one of the signals (e.g., signal segment) of a given one of the electrodes <NUM> not conforming to the signal characteristic(s) for the given (current or most recent) time period (block <NUM>). It may happen that more than one of the recorded signals of more than one corresponding electrode <NUM> may not conform to the pre-defined signal characteristic(s) for the given time period. The processing circuitry <NUM> is configured to save the given signal (which may be non-conforming or non-standard) to the memory <NUM> for future rendering to the display <NUM> (block <NUM>).

Reference is now made to <FIG>, which is a schematic view of a representation <NUM> of the catheter <NUM> in an anatomical map <NUM> with an indication <NUM> that least one of the electrodes <NUM> is capturing (or captured) a non-standard signal rendered in the system <NUM> of <FIG>. Reference is also made to <FIG>.

The processing circuitry <NUM> is configured to render to the display <NUM> the indication <NUM> that the given signal of the given electrode <NUM> does not conform to the signal characteristic(s) for the given time period (block <NUM>). The indication <NUM> may include rendering the identification (e.g., electrode number(s) and/or letter(s)) of the given electrode <NUM> on the display <NUM> with an optional explanation that the given electrode <NUM> captured a non-conforming signal (not shown in <FIG>).

In some embodiments, the processing circuitry <NUM> is configured to render to the display <NUM> the representation <NUM> of the catheter <NUM> with the indication <NUM> that the given signal of the given electrode <NUM> does not conform to the signal characteristic(s) for the given time period, wherein the indication <NUM> is linked to the given electrode <NUM> on the representation <NUM> of the catheter <NUM>, for example, by pointing to the given electrode with an arrow (not shown in <FIG>).

In some embodiments, the processing circuitry <NUM> is configured to render to the display <NUM> the representation <NUM> of the catheter <NUM> with the indication <NUM> that the given signal of the given electrode <NUM> does not conform to the signal characteristic(s) for the given time period, wherein the indication <NUM> is disposed on the given electrode <NUM> on the representation <NUM> of the catheter <NUM> as shown in <FIG>. The indication <NUM> may be any suitable color and/or shading and/or pattern and/or a border around the given electrode on the representation <NUM>.

In some embodiments, the indication <NUM> is rendered until a request is received from the physician <NUM> to remove the indication <NUM>. In other embodiments, the processing circuitry <NUM> is configured to render to the display <NUM> the indication <NUM> disposed on the given electrode <NUM> on the representation <NUM> of the catheter <NUM> for a given time interval (for example, equal to a duration about the length of the given time period). The processing circuitry <NUM> is configured to remove the indication <NUM> from the given electrode <NUM> on the representation <NUM> of the catheter <NUM> (after expiration of the given time interval). The steps of blocks <NUM>-<NUM> are repeated for a subsequent time period, which may lead to the processing circuitry <NUM> repeating rendering to the display <NUM> the indication <NUM> disposed on the given electrode <NUM> on the representation <NUM> of the catheter <NUM> responsively to finding that the given signal of the given electrode <NUM> does not conform to the signal characteristic(s) for the subsequent time period. The steps of blocks <NUM>-<NUM> are repeated for more time periods and different electrodes may be found to be capturing signal segments not conforming to the signal characteristic(s).

In some embodiments, the processing circuitry <NUM> is configured to render to the display <NUM> the indication <NUM> disposed on the given electrode <NUM> on the representation <NUM> of the catheter <NUM> so that the indication <NUM> repeatedly flashes on and off responsively to multiple detections of the given signal of the given electrode <NUM> not conforming to the signal characteristic(s) for respective subsequent time periods. In some embodiments, the respective subsequent time periods correspond to respective windows of interest of respective cardiac cycles (i.e., each subsequent time period corresponds to a window of interest in a cardiac cycle). In this manner, the physician <NUM> may observe the flashing on and off of the indication <NUM>, and if the flashing continues long enough (as determined by the physician <NUM>), the physician <NUM> may realize that the signal being captured by the given electrode <NUM> is not just capturing an occasional noisy signal but is probably capturing a complex signal that should be displayed and examined in more detail.

Reference is now made to <FIG>, which is a schematic view of the representation <NUM> of the catheter <NUM> of <FIG> with an electrogram <NUM>. Reference is also made to <FIG>. In response to seeing the indication <NUM> (e.g., the indication <NUM> flashing on and off), the physician <NUM> may request the electrogram <NUM> to be displayed. The processing circuitry <NUM> is configured to receive a user input (from the physician <NUM>) requesting display of the electrogram <NUM> captured by the given electrode <NUM> (block <NUM>). The processing circuitry <NUM> is configured to render to the display <NUM> the electrogram <NUM> captured by the given electrode (block <NUM>).

More specifically, "about" or "approximately" may refer to the range of values ±<NUM>% of the recited value, e.g., "about <NUM>%" may refer to the range of values from <NUM>% to <NUM>%.

Various features of the invention which are, for clarity, described in the contexts of separate embodiments may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment may also be provided separately or in any suitable sub-combination.

Claim 1:
A medical system (<NUM>), comprising:
a catheter (<NUM>) configured to be inserted into a chamber of a heart of a living subject, and including catheter electrodes (<NUM>) configured to contact tissue at respective locations within the chamber of the heart;
a display (<NUM>); and
a processing circuitry (<NUM>) configured to:
receive respective signals from the catheter captured by respective ones of the electrodes;
assess conformity of each of the respective signals to at least one signal characteristic, the at least one signal characteristic consisting of a single activation early enough in a cardiac cycle;
find a given one of the signals of a given one of the electrodes not conforming to the at least one signal characteristic for a given time period; and
render to the display an indication that the given signal of the given electrode does not conform to the at least one signal characteristic for the given time period.