Method and system for identifying disconnected catheter electrode

Abstract

To identify disconnected electrodes during a cardiac diagnostic operation, and use the information about electrodes identified as disconnected.SOLUTION: The invention provides a method, an apparatus and a computer program product, the method comprising: obtaining a plurality of electrical signals obtained from a plurality of electrodes distally disposed on a catheter inserted into one or more chambers of the heart of a patient, where one or more electrical signals obtained from one or more electrodes of the plurality of electrodes obtain electrical activity in one or more locations within the heart; identifying one or more signals from the plurality of electrical signals as being emitted from one or more disconnected electrodes, the identifying step utilizing a correlation with a reference signal measured within the heart, where the reference signal is associated with a reference electrode; and generating a map of electrical activity within the heart based upon the plurality of electrical signals, excluding one or more electrical signals originating from the disconnected electrodes.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates generally to methods for identifying disconnected electrodes during cardiac diagnostic procedures and using information regarding electrodes identified as disconnected. [Background technology]

[0002] Arrhythmias can be caused by problems with the electrical conduction system of the heart, particularly electrical activity at one or more points or regions in the walls of the heart chambers. Atrial fibrillation is an arrhythmia characterized by disorganized signals that cause the atria (left and / or right atria) to contract in a very rapid, asynchronous heart rhythm.

[0003] To assess a patient's condition and determine a treatment, such as applying one or more ablations, it may be necessary to assess electrical activity at multiple locations in the heart wall. This activity may be obtained from multiple electrodes located at the distal tip of an intracardiac catheter inserted into one or more chambers of the heart. The acquired signals may be displayed to a user, such as a surgeon performing a procedure. The acquired signals may also be used to generate a map of the electrical activity within the heart. [Brief description of the drawings]

[0004] A more complete understanding of the present disclosure will be obtained from the following detailed description of the embodiments of the present disclosure when read in conjunction with the drawings. [Figure 1] FIG. 1 is a schematic diagram of a catheter-based electrophysiological (EP) mapping and ablation system. [Diagram 2] FIG. 1 shows a detailed view of a basket-shaped catheter tip that may be used in accordance with some exemplary embodiments of the present disclosure. [Diagram 3] 1 is a flowchart of steps in a method for identifying a cutting electrode and using information about the cutting electrode, according to some exemplary embodiments of the present disclosure. [Figure 4]FIG. 1 is a schematic block diagram of a computing platform for identifying cutting electrodes and using information about the cutting electrodes, according to some exemplary embodiments of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0005] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known circuits, control logic, and details of computer program instructions for conventional algorithms and processes have not been shown in detail in order to avoid unnecessarily obscuring the present invention.

[0006] Software programming code embodying aspects of the invention 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 in any of a variety of known media for use with data processing systems, including, but not limited to, magnetic and optical storage devices, such as disk drives, magnetic tapes, compact discs (CDs), digital video discs (DVDs), and computer instruction signals embodied in a transmission medium, with or without a carrier wave upon which the signals are modulated. For example, the transmission medium may include a communications network, such as the Internet. Additionally, while the invention may be embodied in computer software, the functionality necessary to carry out the invention may alternatively be embodied, in part or in whole, using hardware components, such as application specific integrated circuits or other hardware, or some combination of hardware components and software.

[0007] Overview Arrhythmogenic tissue associated with atrial fibrillation may be identified by examining an intracardiac electrogram (IEGM) at one or more locations on the atrial wall, e.g., the inner wall, to detect local electrical potentials caused by depolarization at each of the one or more locations.

[0008] The IEGMs are typically detected with one or more electrodes on the distal tip of the intracardiac catheter. In some exemplary embodiments, the intracardiac catheter further includes a position sensor configured to track the position of the distal tip.

[0009] Modern catheters have multiple electrodes distributed across the catheter's multiple splines, and at any given time, each electrode samples the electrical activity at a location. For example, some catheters may have tens or even hundreds of electrodes. It is understood that multiple electrodes can allow for the collection of a significant amount of data and give a good overall picture of the electrical activity within the heart.

[0010] Typically, the signal output by each electrode includes the actual signal of electrical activity and noise generated in the environment, such as a far-field signal that represents noise in the blood pool within the heart chamber. Typically, the magnitude of the far-field signal is expected to be significantly larger than the magnitude of the actual signal of electrical activity. The actual signal is measured as the potential difference between the electrode and a reference that does not contact the heart wall and therefore captures only the far-field signal. The reference may be a reference electrode in the blood pool or the Wilson Central Terminal (WCT). The potential difference is therefore a signal indicative of the cardiac activity at the location of the electrode.

[0011] A problem that can occur with multi-electrode catheters is the physical disconnection of one or more electrodes when the wires connecting the electrodes to the Patient Interface Unit (PIU) become disconnected from the electrodes or break somewhere along the channel that runs along the shaft of the catheter. As detailed above, the output provided by a disconnected electrode, measured relative to a reference electrode, is dominated by the reference signal multiplied by minus one.

[0012] Incorporating these unrepresentative signals into an electrical map of the heart can compromise the integrity of such map and lead to erroneous decisions. Furthermore, if too many electrodes are disconnected, the heart will be mapped as a whole and thus motion may prove irrelevant, leading to unsafe decisions.

[0013] Furthermore, displaying electrograms of unrelated signals in addition to other signals to a user provides inaccurate information to the user and clutters the display, thus preventing the user from examining accurate relevant information.

[0014] The challenge, therefore, is to identify these electrodes so that the signals associated with them can be ignored, not used in computing electrical activity maps of the heart, not displayed to users such as physicians, or used in any other way.

[0015] Known techniques for detecting cutting electrodes require the injection of an additional signal dedicated to this purpose into the patient's heart, which is undesirable. For example, some techniques involve driving a current between two electrodes so that a potential difference is created. If one of the electrodes is cut, the resistance, and therefore the potential difference, approaches infinity, thus providing the discovery of the cutting electrode. However, this technique requires the driving of a significant current into the body, which is undesirable.

[0016] The electrical activity captured by the electrodes may be examined in the form of unipolar signals (U1, U2, U3, ...) and / or in the form of bipolar signals (B1, B2, B3...). A unipolar signal represents the potential difference between the output from an electrode and the output from a reference, as described herein above. A bipolar signal represents the potential difference between a pair of electrodes configured to sense the electrical activity of the heart. A bipolar signal is the unipolar signal from one electrode (of a pair of sensing electrodes) minus the unipolar signal from the other electrode (of the pair of sensing electrodes). For example, B1 may represent the difference between the unipolar signals on electrodes 1 and 2, e.g., U2-U1.

[0017] When unipolar signals are used to obtain output from each electrode, the electrode signals, including cardiac activity and far-field signals, are measured against a reference signal measured by a reference electrode, thus outputting cardiac activity at the electrode location.

[0018] If the wire is disconnected from the electrode, the electrode signal measured relative to the reference electrode will be dominated by the reference signal multiplied by minus one.

[0019] Correlating this purported cardiac activity signal with a reference signal provides an output that is substantially close to -1, for example within the range of [(-1.1)...(-0.9)], [(-1.05)...(-0.95)], etc.

[0020] Thus, by correlating the output of each electrode with the signal of a reference electrode that is known not to be in contact with the heart wall, the ablation electrode may be identified.

[0021] When bipolar methodology is used, assume that U1, U2, and U3 are signals representing cardiac activity at three electrodes in close proximity to one another, e.g., consecutive electrodes located on the same spline of the catheter. B1 denotes the voltage difference between U1 and U2, and B2 denotes the voltage difference between U2 and U3.

[0022] Therefore, B1=U1-U2 and B2=U2-U3, and each U signal is measured relative to the reference signal as above.

[0023] If the electrode associated with U2 is disconnected, then its measured signal will be dominated by (-reference signal) as above, and B1 and B2 will be: B1=U1-U2=U1-(-reference signal)=~U1+reference signal B2=U2-U3=-Reference signal-U3=~-U3-Reference signal

[0024] Because U1 and U3 are significantly lower than the reference signal, correlating B1, which is substantially the same as the reference signal, with B2, which is substantially the same as (-reference signal), gives approximately (-1) as above.

[0025] Therefore, by examining the bipolar signals of three consecutive electrodes, one can identify whether the middle electrode of the three electrodes is disconnected.

[0026] Thus, the present disclosure provides for identifying the cutting electrode using an electrocardiogram (ECG) signal rather than by applying an additional signal to identify the cutting electrode based on resistance changes. Because the full range of electrical signals provided to the heart is limited, using the available ECG signal is advantageous as it eliminates the need to add an extra signal.

[0027] It should be appreciated that if a reference signal is not available, a Wilson Center Terminal (WCT) signal, which averages signals captured across the user's body, may be used instead.

[0028] The identification of the disconnected electrode or electrodes may be used in a number of ways.

[0029] In some embodiments, signals associated with cutting electrodes may be excluded when generating the electrical map of the heart so that inaccurate information does not affect the results. Additionally, the number or percentage of cutting electrodes among all electrodes may be calculated and if a certain threshold is exceeded, operation may be discontinued since the results do not provide a sufficient picture of the electrical activity of the heart.

[0030] In some embodiments, eliminating the display of irrelevant and inaccurate electrograms, such as those associated with cutting electrodes, provides for displaying only true, relevant information, reducing clutter in the display and therefore making it easier for the user to inspect the true information.

[0031] In some embodiments, electrodes identified as being disconnected may be reported to the user or another person, such as a doctor, technician, etc.

[0032] System Description Please refer to FIG. 1, which shows an exemplary catheter-based electrophysiology mapping and ablation system 10. The system 10 includes multiple catheters that can be percutaneously inserted by a physician 24 through the vascular system of a patient 23 and into a heart chamber or vasculature of a heart 12. Typically, a delivery sheath catheter is inserted into the left or right atrium near a desired location of the heart 12. One or more catheters can then be inserted into the delivery sheath catheter to reach a desired location within the heart 12. The multiple catheters can include catheters dedicated to sensing Intracardiac Electrogram (IEGM) signals, catheters dedicated to ablation, and / or catheters dedicated to both sensing and ablation. An exemplary catheter 14 configured to sense IEGMs is illustrated herein. The physician 24 can place an electrode assembly 28 of the catheter 14 in contact with the heart wall to sense a target site in the heart 12. For ablation, the physician 24 can similarly place a distal end of an ablation catheter in contact with a target site for tissue ablation.

[0033] The catheter 14 is an exemplary catheter that is basket-shaped and includes one, preferably multiple electrodes 26, optionally distributed across multiple splines 22 in an electrode assembly 28, and configured to sense IEGM signals. Each electrode 26 is connected via a wire (not shown) that passes through or is attached to the splines 22 to a patient interface unit (PIU) 30, which will be described in more detail below. The splines 22 may be directly or indirectly attached to a central longitudinal axis of the electrode assembly 28. The longitudinal axis may have an electrode 17 coupled thereto. By design, even when the electrode assembly 28 is in a heart chamber and one or more electrodes 26 are in contact with the heart wall, the electrode 17 is in a position within the heart chamber and cannot be in contact with the heart wall. Thus, the electrode 17 measures a far-field signal that is representative of noise in the blood pool.

[0034] The catheter 14 may additionally include a position sensor 29 embedded in or near the electrode assembly 28 for tracking the position and orientation of the electrode assembly 28. Optionally and preferably, the position sensor 29 is a magnetic-based position sensor including three magnetic coils for sensing three-dimensional (3D) position and orientation. The electrode assembly 28 is described in further detail in connection with FIG. 2 below.

[0035] The magnetic-based position sensor 29 may operate in conjunction with a location pad 25 that includes a plurality of magnetic coils 32 configured to generate a magnetic field within a predetermined working volume. The real-time position of the electrode assembly 28 of the catheter 14 may be tracked based on the magnetic field generated by the location pad 25 and sensed by the magnetic-based position sensor 29. Details of magnetic-based position sensing technology are described in U.S. Patent Nos. 5,5391,199; 5,443,489; 5,558,091; 6,172,499; 6,239,724; 6,332,089; 6,484,118; 6,618,612; 6,690,963; 6,788,967; and 6,892,091.

[0036] Additionally or alternatively, the system 10 may include one or more electrode patches 38 positioned for skin contact on the patient 23 to establish a position reference for the location pads 25 and impedance-based tracking of the electrodes 26. For impedance-based tracking, a current is directed to the electrodes 26 and sensed at the electrode skin patch 38, so that the position of each electrode can be triangulated via the electrode patch 38. Details of impedance-based position tracking techniques are described in U.S. Patent Nos. 7,536,218, 7,756,576, 7,848,787, 7,869,865, and 8,456,182.

[0037] System 10 displays multiple electrograms 21 captured by electrodes 26 of catheter 14 and / or body surface ECG electrodes 18 on display device 27. Recorder 11 may include pacing capability for pacing the cardiac rhythm and / or may be electrically connected to a stand-alone pacer.

[0038] The PIU 30 may be configured to establish electrical communications between the catheters, other electrophysiological equipment, a power source, and a workstation 55 that controls the operation of the system 10. The electrophysiological equipment of the system 10 may include, for example, multiple catheters, location pads 25, body surface ECG electrodes 18, electrode patches 38, an ablation energy generator 50, and a recorder 11. Optionally and preferably, the PIU 30 additionally includes processing capabilities for implementing real-time calculations of catheter positions and performing ECG calculations.

[0039] The workstation 55 includes a processor unit having a memory, a memory or storage device having suitable operating software stored therein, and a user interface function. The workstation 55 may provide multiple functions, optionally including: (1) modeling the endocardial anatomy in three dimensions (3D) based on signals received from the electrodes 26 and rendering the model or anatomical map 20 for display on the display device 27; (2) displaying activation sequences (or other data) compiled from the recorded electrograms 21 on the display device 27 with representative visual indicia or images superimposed on the rendered anatomical map 20; and (3) displaying real-time positions and orientations of multiple catheters within the heart chambers. One commercially available product embodying elements of the system 10 is available as the CARTO™ 3 system, available from Biosense Webster, Inc., 31A Technology Drive, Irvine, CA 92618.

[0040] As can be seen, multiple electrograms 21 may be displayed, which may include one or more electrograms associated with the cutting electrode, and therefore these electrograms are inaccurate and irrelevant.

[0041] Reference is now made to Figure 2, which shows a more detailed view of the basket-shaped electrode assembly 28 of Figure 1. An example of a basket-type catheter is the CLARYSENSE™ catheter available from Biosense Webster, Inc. (31A Technology Drive, Irvine, CA 92618).

[0042] An electrode assembly 28 may be attached to the distal end of the catheter 14. The electrode assembly 28 may include electrode-carrying splines 22, which may be made from flexible polymer circuit strips, each carrying a plurality of electrodes 26, e.g., ten arms carrying ten electrodes 26 each, providing a total of 100 electrodes. In other embodiments, the electrode assembly 28 may carry from about five to about ten splines, e.g., about eight splines. In some embodiments, the electrodes 26 may not be located on the proximal portion of the splines 22, or may be more sparsely located.

[0043] The splines 22 may be attached to a central longitudinal axis of the electrode assembly 28, for example, the splines 22 may be connected to a connector 19 disposed along the axis. The splines 22 may be generally equally spaced about the axis. The splines 22 may be actuated by relative longitudinal movement of their ends along the axis. The axis may include a pusher 16 such that the pusher 16 pushes into the connector 19. When the pusher 16 is pushed distally into the connector 19, the splines 22 bend. While the electrode assembly 28 is within the heart chamber, the bending causes the electrodes 26 to spread within the heart chamber such that at least some of the electrodes can contact the heart chamber wall and sense IEGM signals, and other electrodes 26 can assume positions within the heart chamber.

[0044] As mentioned above, the structure of the electrode assembly 28 ensures that the splines 22 surround the central shaft, and in particular the electrode 17 mounted on the central shaft, so that the electrode 17 cannot contact the heart wall and its output contains only the far-field signal present in the blood pool, also referred to as the reference signal.

[0045] Referring now to FIG. 3, a flowchart of steps in a method for identifying a cutting electrode and using information about the cutting electrode is shown, according to some exemplary embodiments of the present disclosure.

[0046] Electrograms taken by a plurality of electrodes positioned distally on a catheter inserted into one or more chambers of a patient's heart are obtained, step 300. At least some of the electrodes each acquire electrograms at one or more locations within one or more chambers of the heart.

[0047] In step 304, the electrogram may be examined to identify at least one electrode that is disconnected, i.e., the wire is disconnected from the electrode or broken somewhere along the channel.

[0048] Step 304 may be performed by applying unipolar and / or bipolar techniques to obtain signals associated with the electrodes.

[0049] Step 308 may be applied when using a unipolar technique to obtain the electrode signal.

[0050] Using this technique, the measured signal consists of an actual signal and a noise signal. The actual signal may therefore be estimated as the measured signal minus a noise signal provided by a reference electrode, such as electrode 17. If the tested electrode is disconnected, the measured signal will be close to 0 and therefore the actual signal will be close to the minus of the reference signal. Thus, if the correlation between the reference signal and the actual signal is close to -1, e.g. deviating from -1 by a predefined threshold, it may be assumed that the associated electrode is disconnected.

[0051] Step 312 may be applied when using a unipolar technique to obtain electrode signals.

[0052] In bipolar techniques, a potential difference is measured between two consecutive or otherwise adjacent electrodes, for example electrodes located on the same spline.

[0053] Using this technique, one can obtain the potential difference between two pairs of electrodes that have one electrode in common, e.g., B1=U1-U2 and B2=U2-U3, where U1, U2 and U3 are signals indicative of the difference between the cardiac activity at the locations of the two electrodes.

[0054] If the electrode associated with U2 is disconnected, then B1 and B2 become as given by the following equations: B1=U1-U2=U1-(~0-reference signal)=~U1+reference signal B2=U2-U3=(~0-Reference signal-U3=-(-U3-Reference signal)

[0055] Since each of U1 and U3 has a magnitude significantly smaller than the reference signal, correlating B1, which is substantially the same as the reference signal, with B2, which is substantially the same as (-reference signal), results in approximately -1, e.g., deviating from -1 by up to a predetermined threshold.

[0056] It is understood that the extreme electrodes on each spline cannot be checked using bipolar techniques.

[0057] The calculations may be repeated for all electrodes. For example, the calculations may be repeated every predetermined period of time, only when the catheter is in the heart, upon user command, or according to any other condition or protocol. In some embodiments, repeating the process may be omitted for electrodes that have already been detected as disconnected in a previous check.

[0058] In step 316, once the cutting electrode is identified, one or more actions may be taken.

[0059] For example, in step 320, a map of the cardiac electrical activity may be generated based on signals obtained from all electrodes, excluding signals associated with electrodes identified as disconnected.

[0060] Additionally, the ratio between cutting electrodes and total electrodes may be calculated in step 324. If the ratio or number of cutting electrodes exceeds a predetermined threshold, map generation may be avoided since the collected data is insufficient to provide a reliable map.

[0061] In another example, in step 328, electrograms of signals acquired from all electrodes may be displayed, excluding electrodes identified as disconnected.

[0062] In yet another example, a user, such as a physician, technician, etc., may be notified of the cut electrode in step 332. The notification may take the form of sending a message, updating a database, displaying an alert on a display device, etc.

[0063] Referring now to FIG. 4, a block diagram of a computing platform 400 for detecting cutting electrodes and using information about these electrodes is shown, in accordance with certain exemplary embodiments of the present disclosure.

[0064] It will be appreciated that the computing platform 400 may be embedded within the workstation 55, but may also be a stand-alone computing platform, or may be embedded elsewhere and in operative communication with the workstation 55.

[0065] Computing platform 400 may be implemented as one or more computing platforms that may be operatively connected to one another. For example, one or more remote computing platforms may be implemented, for example, on a cloud computer. The other computing platforms may be part of an associated organizational computer network. In other embodiments, all functionality may be provided by one or more computing platforms that are all part of the organizational network.

[0066] Computing platform 400 may include one or more processors 404, which may or may not be located on the same computing platform, and which may be one or more central processing units (CPUs), microprocessors, electronic circuits, integrated circuits (ICs), etc. Processor 404 may be configured to provide necessary functionality by loading into memory and activating software modules stored in a memory unit, such as storage device 412, which will be described in more detail below.

[0067] The computing platform 400 may also include a communications device 408 for communicating with other devices or other computing platforms as needed, e.g., obtaining information indicative of position and electrical measurements from a catheter procedure controller, storing data on a remote storage device, etc. The communications module 408 may be adapted to interface with any communications channel, such as a local area network (LAN), a wide area network (WAN), a cellular network, etc., and to use any associated communications protocol.

[0068] The computing platform 400 may include a storage device 412, such as a hard disk drive, a flash disk, a random access memory (RAM), a memory chip, etc. In some demonstrative embodiments, the storage device 412 may hold program code operable to cause the processor 404 to perform operations associated with any of the modules listed below or steps of the method of Figure 3 above. The program code may include one or more executable units, such as functions, libraries, stand-alone programs, etc., adapted to execute instructions, as detailed below.

[0069] Alternatively or additionally, the instructions provided may be stored on a non-transitory, tangible computer readable medium, such as a magnetic, optical, or electronic memory.

[0070] The storage device 412 may include an I / O module 416 for rendering displays to a user to be displayed on the display device 27, such as a map of the heart, plots of selected electrograms, etc. The display and I / O module 416 may also be operable in receiving commands and operating parameters from a user, for example, in highlighting locations assessed by any of the displayed electrograms, in displaying groups of electrograms, etc.

[0071] The storage device 412 may include a communications module 420 for transmitting and receiving data such as catheter positions, associated electrograms, user preferences, histograms, etc., to and from other parts of the system or other systems via the communications device 408.

[0072] The storage device 412 may comprise a monopolar cut electrode finding module 424 for calculating a correlation between a signal purportedly output by an electrode and a reference signal. The monopolar cut electrode finding module 424 may be further adapted to determine whether the correlation value is closer to −1 than a predefined threshold, in which case the electrode may be identified as cut.

[0073] The storage device 412 may comprise a bipolar cut electrode finding module 428 for calculating a correlation between two signals, each signal referencing two electrodes including a common electrode associated with the two signals. The bipolar cut electrode finding module 428 may be further adapted to determine whether the correlation value is closer to −1 than a predefined threshold, in which case the electrode common to the two signals may be identified as cut.

[0074] The storage device 412 may include an electrical map generation module 432 for generating an electrical activity map of the heart, where signals associated with the cutting electrodes are not considered when generating the map. If the number of cutting electrodes or the percentage of cutting electrodes out of the total number of electrodes exceeds a predetermined threshold, map generation may be disabled due to insufficient associated data.

[0075] The storage device 412 may include an electrogram selection module 436 for selecting electrograms to be displayed, which may exclude electrograms associated with cutting electrodes.

[0076] The storage device 412 may also include an additional action taking module 440 for taking additional actions associated with the cutting electrode, such as notifying a user.

[0077] It will be understood that the steps and modules disclosed above may be in addition to software, hardware, firmware, or other modules required to operate the catheter, display the catheter procedure process, perform other calculations such as signal analysis, particularly complex fractionated electrogram (CFE) analysis, generate cardiac maps, etc. Further details on methods and systems may be found, for example, in U.S. Patent Nos. 8,676,305 and 9,629,567, which are incorporated herein by reference in their entirety for any purpose.

[0078] The present invention may be a system, a method, and / or a computer program product. The computer program product may include a computer readable storage medium having computer readable program instructions for causing a processor to perform aspects of the present invention.

[0079] A computer-readable storage medium may be a tangible device capable of holding and storing instructions for use by an instruction execution device. A computer-readable storage medium may be, for example, but not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of computer-readable storage media includes portable computer diskettes, hard disks, random access memories (RAMs), read-only memories (ROMs), erasable programmable read-only memories (EPROMs or flash memories), static random access memories (SRAMs), portable compact disk read-only memories (CD-ROMs), digital versatile disks (DVDs), memory sticks, floppy disks, mechanically encoded devices such as punch cards or ridges in grooves with instructions recorded on them, and any suitable combination of the above. A computer-readable storage medium as used herein should not be construed as being a signal that is itself ephemeral, such as an electric wave or other freely propagating electromagnetic wave, an electromagnetic wave propagating through a wave guide or other transmission medium (e.g., light pulses passing through a fiber optic cable), or an electric signal transmitted through a flow line.

[0080] The computer-readable program instructions described herein can be downloaded from a computer-readable storage medium to each computing / processing device or to an external computer or external storage device via a network, such as the Internet, a local area network, a wide area network, and / or a wireless network. The network can include copper transmission cables, optical transmission fiber, wireless transmission, routers, firewalls, switches, gateway computers, and / or edge servers. A network adapter card or network interface of each computing / processing device receives the computer-readable program instructions from the network and transfers the computer-readable program instructions to a computer-readable storage medium within the respective computing / processing device for storage.

[0081] The computer readable program instructions for carrying out the operations of the present invention may be either assembler instructions, instruction set architecture instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state setting data, or source or object code written in any combination of one or more programming languages, such as Java, C, C++, Python, etc. The computer readable program instructions may be executed entirely on the user's computer, partially on the user's computer, as a standalone software package, partially on the user's computer, partially on a remote computer, or entirely on a remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer via any type of network, including a local area network (LAN) or a wide area network (WAN), or may be connected to an external computer (e.g., via the Internet using an Internet Service Provider). In some embodiments, electronic circuitry, including, for example, programmable logic circuits, field programmable gate arrays (FPGAs), or programmable logic arrays (PLAs), may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to individualize the electronic circuitry to carry out aspects of the present invention.

[0082] Aspects of the present invention are described herein with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer readable program instructions.

[0083] These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing device to generate a machine such that the instructions are executed by the processor of the computer or other programmable data processing device to create means for performing the functions / acts specified in one or more blocks of the flowcharts and / or block diagrams. These computer readable program instructions may also be stored on a computer readable storage medium that can cause a computer, programmable data processing apparatus, and / or other device to function in a particular manner, such that the computer readable storage medium on which the instructions are stored includes an article of manufacture that includes instructions that implement aspects of the functions / acts specified in one or more blocks of the flowcharts and / or block diagrams.

[0084] The computer-readable program instructions may be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus, or other device to generate a computer-implemented process such that the instructions executing on the computer, other programmable apparatus, or other device perform the functions / acts defined in the flowchart and / or block diagram blocks.

[0085] The flow charts and block diagrams in the figures illustrate the structure, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flow charts or block diagrams may represent a module, segment, or portion of instructions that includes one or more executable instructions for implementing the illustrated logical function. In some alternative implementations, the functions shown in the blocks may occur in an order other than that shown in the figures. For example, two blocks shown in succession may in fact be executed substantially simultaneously, or the blocks may sometimes be executed in the reverse order, depending on the functionality involved. It should also be noted that each block of the block diagrams and / or flow diagrams, as well as combinations of blocks in the block diagrams and / or flow diagrams, may be implemented by a dedicated hardware-based system that performs a particular function or operation, or may operate or execute a combination of dedicated hardware and computer instructions. EXAMPLES

[0086] Example 1 1. A method comprising: acquiring a plurality of electrical signals obtained from a plurality of electrodes distally positioned on a catheter inserted into one or more chambers of a patient's heart, wherein the at least one electrical signal acquired from at least one of the plurality of electrodes acquires electrical activity at at least one location within the heart; identifying at least one signal from the plurality of electrical signals as emanating from at least one ablation electrode, the identifying utilizing correlation with a reference signal measured within the heart, the reference signal being associated with the reference electrode; and generating a map of electrical activity within the heart based on the plurality of electrical signals, excluding the at least one electrical signal originating from the at least one ablation electrode.

[0087] Example 2 2. The method of example 1, wherein the plurality of electrical signals are electrocardiogram (ECG) signals.

[0088] Example 3 3. The method of any one of claims 1 to 2, further comprising displaying a representation of the plurality of electrical signals to a user, excluding at least one electrical signal resulting from the at least one cutting electrode.

[0089] Example 4 4. The method of any of claims 1 to 3, further comprising providing a notification to a user indicating the at least one cutting electrode.

[0090] Example 5 5. The method of any of claims 1 to 4, wherein the at least one signal is identified by comparing the at least one signal to a reference signal.

[0091] Example 6 6. The method of example 5, wherein the comparing includes correlating the at least one signal with a reference signal, and further includes indicating an electrode associated with the at least one signal as disconnected if the correlation provides a value within a predetermined distance from −1.

[0092] Example 7 7. The method of any of examples 1 to 6, wherein identifying the at least one signal includes correlating a first signal and a second signal, the first signal measuring a potential difference between a first electrode and a second electrode, and the second signal measuring a potential difference between the second electrode and a third electrode.

[0093] Example 8 The method of example 7, wherein the correlation is between the first signal and the second signal, and identifies that the second electrode is disconnected and that at least one signal is associated with the second electrode if the correlation provides a value within a predetermined distance from -1.

[0094] Example 9 The method of any of Examples 1 to 8, wherein the catheter comprises a basket-shaped catheter tip.

[0095] Example 10 The method according to any of Examples 1 to 9, wherein the method is repeated at predetermined intervals or according to a user's command or according to a condition or protocol for as long as the catheter remains within the heart.

[0096] Example 11 The method of example 10, wherein the method is omitted for electrodes detected as disconnected.

[0097] Example 12 1. A computerized apparatus having a processor coupled to a memory unit, the processor being adapted to perform the steps of acquiring a plurality of electrical signals obtained from a plurality of electrodes positioned distally on a catheter inserted into one or more chambers of a patient's heart, wherein the at least one electrical signal acquired from at least one of the plurality of electrodes acquires electrical activity at at least one location within the heart; identifying at least one signal from the plurality of electrical signals as emanating from at least one ablation electrode, the identifying utilizing a correlation with a reference signal measured within the heart, the reference signal being associated with the reference electrode; and generating a map of electrical activity within the heart based on the plurality of electrical signals, excluding the at least one electrical signal originating from the at least one ablation electrode.

[0098] Example 13 The apparatus of example 12, wherein the plurality of electrical signals are electrocardiogram (ECG) signals.

[0099] Example 14 The device of any one of claims 12 to 13, wherein the processor is further adapted to display a representation of the plurality of electrical signals to the user, excluding at least one electrical signal resulting from at least one cutting electrode.

[0100] Example 15 An apparatus described in any of Examples 12 to 14, wherein the processor is further adapted to provide a notification to the user indicating at least one cutting electrode.

[0101] Example 16 The apparatus of any of Examples 12 to 15, wherein the at least one signal is identified by correlating the at least one signal to a reference signal, and, conditional on the correlation providing a value within a predetermined distance from -1, the processor is further adapted to indicate the electrode associated with the at least one signal as disconnected.

[0102] (Example 17) 17. The apparatus of any of Examples 12 to 16, wherein identifying the at least one signal includes correlating the first signal with the second signal, the first signal measuring a potential difference between the first electrode and the second electrode and the second signal measuring a potential difference between the second electrode and the third electrode, and the processor is further adapted to identify, on condition that the correlation provides a value within a predetermined distance from -1, that the second electrode is disconnected and that the at least one signal is associated with the second electrode.

[0103] (Example 18) 18. The device of any of Examples 12 to 17, wherein the catheter comprises a basket-shaped catheter tip.

[0104] (Example 19) The apparatus of any of Examples 12 to 18, wherein the processor is adapted to repeat the steps at predetermined intervals, or according to a user's command, or according to a condition or protocol, for as long as the catheter is within the heart.

[0105] (Example 20) 1. A computer program product comprising a non-transitory computer-readable medium bearing program instructions that, when read by a processor, cause the processor to perform the steps of acquiring a plurality of electrical signals obtained from a plurality of electrodes distally positioned on a catheter inserted into one or more chambers of a patient's heart, wherein the at least one electrical signal acquired from at least one of the plurality of electrodes acquires electrical activity at at least one location within the heart; identifying at least one signal from the plurality of electrical signals as emanating from at least one ablation electrode, the identifying utilizing correlation with a reference signal measured within the heart, the reference signal being associated with the reference electrode; and generating a map of electrical activity within the heart based on the plurality of electrical signals, excluding the at least one electrical signal originating from the at least one ablation electrode.

[0106] Although the embodiments described herein primarily address cardiac diagnostic applications, the methods and systems described herein may also be used in other medical applications.

[0107] It will be understood that the embodiments described above are given by way of example, and that the present disclosure is not limited to what is particularly shown and described hereinabove. Rather, the scope of the present disclosure includes both combinations and subcombinations of the various features described hereinabove, as well as variations and modifications thereof not disclosed in the prior art that would occur to one skilled in the art upon reading the foregoing description.

[0108] [Embodiment] (1) A method for identifying a disconnected intracardiac electrogram (IEGM) electrode (26) on a catheter (14) while mapping electrical activity of a heart chamber of a patient, the catheter (14) including a plurality of IEGM electrodes (26) and a reference electrode (17), the reference electrode (17) configured to be maintained within a blood pool of the heart chamber, and the plurality of IEGM electrodes (26) configured to contact a wall of the heart chamber while the catheter (14) is positioned within the heart chamber, the method comprising: simultaneously sampling the IEGM outputs (21) from the plurality of IEGM electrodes (26) and a reference output from the reference electrode (17); calculating a correlation between the IEGM output (21) and the reference output; determining a correlation coefficient for the plurality of IEGM electrodes based on the calculation; and identifying that a first IEGM electrode of the plurality of IEGM electrodes (26) has a break in electrical connection based on identifying a lack of correlation between an output from the first IEGM electrode and the reference output; updating the pool of IEGM outputs (21) applied to calculate an electro-anatomical map (20) by removing the IEGM output from the first IEGM electrode from the pool of IEGM outputs (21); calculating a map of electrical activity within the heart chamber based on the updated pool of IEGM outputs (21); and rendering the map (20) on a display (27). (2) The method of claim 1, wherein identifying the absence of correlation is based on determining that the correlation coefficient for the first IEGM electrode is between -0.9 and -1. (3) The method of embodiment 1, further comprising the step of displaying a notification to a user on the display indicating that the first IEGM electrode is disconnected. (4) The method of claim 1, wherein the IEGM output (21) is defined between a bipolar pair of the IEGM electrodes, and the correlation calculated is between the IEGM output from the bipolar pair of the IEGM electrodes and the reference output. (5) The method of embodiment 4, wherein the first IEGM electrode is identified based on comparing correlations from two different bipolar pairs, each of which includes the first IEGM electrode.

[0109] (6) The method of embodiment 4, wherein the first IEGM electrode is identified based on a correlation from a bipolar pair defined by an output from a second IEGM electrode subtracted from the output from the first IEGM electrode. (7) The method of embodiment 1, wherein the method is repeated at predetermined intervals for as long as the catheter (14) remains within the heart chamber. (8) A computerized device (400) configured to identify disconnected intracardiac electrogram (IEGM) electrodes (26) on a catheter (14) mapping electrical activity of a heart chamber of a patient, the catheter (14) including a plurality of IEGM electrodes (26) and a reference electrode (17), the reference electrode (17) configured to be maintained within a blood pool of the heart chamber, and the plurality of IEGM electrodes (26) configured to contact a wall of the heart chamber while the catheter (14) is positioned within the heart chamber, the device (400) comprising: A processor (404) coupled to a memory unit (412), the processor (404) comprising: receiving an IEGM output from the plurality of IEGM electrodes (26) and a reference output from the reference electrode (17), wherein the IEGM output (21) and the reference output are sampled simultaneously; calculating a correlation between the IEGM output (21) and the reference output; determining a correlation coefficient for the plurality of IEGM electrodes (26) based on the calculation; identifying that a first IEGM electrode of the plurality of IEGM electrodes has a break in electrical connection based on identifying a lack of correlation between an IEGM output (21) from the first IEGM electrode of the plurality of IEGM electrodes (26) and the reference output; updating the pool of IEGM outputs (21) applied to calculate an electro-anatomical map by removing the IEGM output from the first IEGM electrode from the pool of IEGM outputs (21); calculating a map (20) of electrical activity within the heart chamber based on the updated pool of IEGM outputs (21); and rendering the map on a display. (9) The apparatus of embodiment 8, wherein the process is configured to identify no correlation based on determining that the correlation coefficient of the first IEGM is between -0.9 and -1. (10) The device of embodiment 8, wherein the processor (404) is configured to provide a notification to a user on a display indicating the first IEGM electrode.

[0110] (11) The device of embodiment 8, wherein the IEGM output is defined between a bipolar pair of the IEGM electrodes and the correlation calculated is between the IEGM output from the bipolar pair of the IEGM electrodes and the reference output. (12) The device of embodiment 11, wherein the first IEGM electrode is identified based on comparing correlations from two different bipolar pairs that include the first IEGM electrode. (13) The apparatus of embodiment 11, wherein the first IEGM electrode is identified based on a correlation from a bipolar pair defined by an output from a second IEGM electrode subtracted from the output from the first IEGM electrode.

Claims

1. 1. A computerized device (400) configured to identify disconnected intracardiac electrogram (IEGM) electrodes (26) on a catheter (14) mapping electrical activity of a patient's heart chamber, the catheter (14) including a plurality of IEGM electrodes (26) and a reference electrode (17), the reference electrode (17) configured to be maintained within a blood pool of the heart chamber, the plurality of IEGM electrodes (26) configured to contact a wall of the heart chamber while the catheter (14) is positioned within the heart chamber, the device (400) comprising: A processor (404) coupled to a memory unit (412), the processor (404) comprising: receiving an IEGM output from the plurality of IEGM electrodes (26) and a reference output from the reference electrode (17), wherein the IEGM output (21) and the reference output are sampled simultaneously; calculating a correlation between the IEGM output (21) and the reference output; determining a correlation coefficient for the plurality of IEGM electrodes (26) based on said calculation; identifying that a first IEGM electrode of the plurality of IEGM electrodes has a broken electrical connection based on identifying a lack of correlation between an IEGM output (21) from the first IEGM electrode of the plurality of IEGM electrodes (26) and the reference output; updating the pool of IEGM outputs (21) applied to compute an electro-anatomical map by removing the IEGM output from the first IEGM electrode from the pool of IEGM outputs (21); calculating a map (20) of electrical activity within the heart chamber based on the updated pool of IEGM outputs (21); and rendering the map (20) on a display (27).

2. The apparatus of claim 1 , wherein the process is configured to identify no correlation based on determining that the correlation coefficient of the first IEGM is between −0.9 and −1.

3. The apparatus of claim 1 , wherein the processor (404) is configured to provide a notification to a user on a display indicating the first IEGM electrode.

4. The apparatus of claim 1 , wherein the IEGM output is defined between a bipolar pair of the IEGM electrodes, and the correlation calculated is between the IEGM output from the bipolar pair of IEGM electrodes and the reference output.

5. The apparatus of claim 4 , wherein the first IEGM electrode is identified based on comparing correlations from two different bipolar pairs that include the first IEGM electrode.

6. 5. The apparatus of claim 4, wherein the first IEGM electrode is identified based on a correlation from a bipolar pair defined by an output from a second IEGM electrode subtracted from the output from the first IEGM electrode.

7. 1. A method of identifying a disconnected intracardiac electrogram (IEGM) electrode (26) on a catheter (14) while mapping electrical activity of a patient's heart chamber, the catheter (14) including a plurality of IEGM electrodes (26) and a reference electrode (17), the reference electrode (17) configured to be maintained within a blood pool of the heart chamber, the plurality of IEGM electrodes (26) configured to contact a wall of the heart chamber while the catheter (14) is positioned within the heart chamber, the method comprising: simultaneously sampling IEGM outputs (21) from the plurality of IEGM electrodes (26) and a reference output from the reference electrode (17); calculating a correlation between the IEGM output (21) and the reference output; determining a correlation coefficient for the plurality of IEGM electrodes based on the calculation; and identifying that a first IEGM electrode of the plurality of IEGM electrodes (26) has a broken electrical connection based on identifying a lack of correlation between an output from the first IEGM electrode and the reference output; updating the pool of IEGM outputs (21) applied to compute an electro-anatomical map (20) by removing the IEGM output from the first IEGM electrode from the pool of IEGM outputs (21); calculating a map of electrical activity within the heart chamber based on the updated pool of IEGM outputs (21); and rendering said map (20) on a display (27).

8. The method of claim 7 , wherein identifying no correlation is based on determining that the correlation coefficient for the first IEGM electrode is between −0.9 and −1.

9. 8. The method of claim 7, further comprising the step of displaying a notification to a user on the display indicating that the first IEGM electrode has been disconnected.

10. 8. The method of claim 7, wherein the IEGM output (21) is defined between a bipolar pair of the IEGM electrodes, and the correlation calculated is between the IEGM output from the bipolar pair of IEGM electrodes and the reference output.

11. The method of claim 10 , wherein the first IEGM electrode is identified based on comparing correlations from two different bipolar pairs, each of which includes the first IEGM electrode.

12. The method of claim 10 , wherein the first IEGM electrode is identified based on a correlation from a bipolar pair defined by an output from a second IEGM electrode subtracted from the output from the first IEGM electrode.

13. 8. The method of claim 7, wherein the method is repeated at predetermined intervals for as long as the catheter (14) remains within the heart chamber.

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