Interference detection and removal of cardiac signals

Abstract

Systems and methods for detecting interference in cardiac signals are described herein. An electrode apparatus includes a plurality of external electrodes to be disposed proximate to a patient's skin. A computing apparatus includes processing circuitry. The computing apparatus is operably coupled to the electrode apparatus. The computing apparatus is configured to monitor electrical activity from a patient's tissue using the plurality of external electrodes to produce a plurality of electrical signals. At least one of the plurality of electrical signals is filtered. At least one interference in the at least one electrical signal is detected using the at least one filtered signal. A temporal location of the at least one interference in the at least one electrical signal is determined based on a time at which the at least one filtered signal exceeds a predetermined threshold.

Description

[0001] This disclosure relates to systems and methods for detecting and removing interference in cardiac signals using multiple external electrodes.

[0002] Implantable medical devices (IMDs), such as implantable pacemakers, cardioverter-defibrillators, or pacemaker-cardioverter-defibrillators, deliver therapeutic electrical stimulation to the heart. IMDs can provide pacing to resolve bradycardia, or pacing or shock to terminate rapid arrhythmias such as tachycardia or fibrillation. In some cases, the device can sense the heart's inherent depolarization, detect arrhythmias based on (or the absence of) inherent depolarization, and, if an arrhythmia is detected based on inherent depolarization, control the delivery of electrical stimulation to the heart.

[0003] IMD can also offer cardiac resynchronization therapy (CRT), a form of pacing. CRT involves delivering pacing pulses to the left ventricle or both the left and right ventricles. The timing and location of the pacing pulses delivered to the ventricles can be selected to improve the coordination and efficiency of ventricular contractions.

[0004] In addition to the implantable medical device itself, the system used for implanting the medical device may also include a workstation or other devices. In some cases, these other devices assist physicians or other technicians in placing the intracardiac lead at a specific location on the heart. In some cases, the device provides the physician with information about the heart's electrical activity and the location of the intracardiac lead. The device may perform functions similar to those of the medical device, including delivering electrical stimulation to the heart and sensing cardiac depolarization. In some cases, the device may include equipment for obtaining an electrocardiogram (ECG) via electrodes on the patient's surface or skin. More specifically, the patient may have multiple electrodes on an ECG belt or vest around the patient's torso. After the belt or vest has been secured to the torso, the physician may perform a series of tests to assess the patient's cardiac response. The assessment process may include detecting a baseline rhythm in which no electrical stimulation is delivered to the cardiac tissue and another rhythm following the delivery of electrical stimulation to the cardiac tissue.

[0005] ECG electrodes placed on a patient's body surface can be used for a variety of therapeutic purposes (e.g., cardiac resynchronization therapy), including optimizing lead placement, pacing parameters, etc., based on one or more metrics derived from signals captured by the ECG electrodes. For example, electrical heterogeneity information can come from the electrical activation time calculated from multiple electrodes on the body surface.

[0006] Additionally, signals from multiple electrodes on the body surface can be used to determine one or more specific ECG features across a series of heartbeats, such as QRS onset, peak, QRS offset, etc. These ECG features can be used to assess cardiac health and / or treatment, or to estimate or calculate activation time. However, in one or more cases, the signals on which activation time is based or calculated may contain various interferences that can, for example, lead to false detection of activation time. Detection and / or removal of these interferences can result in a more accurate determination of activation time. Summary of the Invention

[0007] The exemplary systems and methods described herein can be configured to assist users (e.g., physicians) in configuring cardiac treatments (e.g., cardiac treatments performed on a patient during and / or after implantation of a cardiac treatment device). The systems and methods can be described as non-invasive. For example, the systems and methods may not require implantable devices such as leads, probes, sensors, catheters, etc., to assess and configure cardiac treatments. Instead, the systems and methods can utilize non-invasive electrical measurements using, for example, multiple external electrodes attached to the patient's skin around the torso.

[0008] An exemplary system for cardiac assessment may include an electrode device comprising a plurality of external electrodes to be placed proximal to the patient's skin. A computing device includes a processing circuitry system. The computing device is operatively coupled to the electrode device. The computing device is configured to use the plurality of external electrodes to monitor electrical activity from patient tissue to generate a plurality of electrical signals. At least one of the plurality of electrical signals is filtered. At least one of the at least one filtered signal is used to detect at least one interference in the at least one electrical signal. The temporal location of at least one interference in the at least one electrical signal is determined based on the time for which the at least one filtered signal exceeds a predetermined threshold.

[0009] An exemplary system for cardiac assessment may include an electrode device comprising a plurality of external electrodes to be placed proximal to the patient's skin. A computing device includes a processing circuitry system. The computing device is operatively coupled to the electrode device. The computing device is configured to use the plurality of external electrodes to monitor electrical activity from the patient's tissue to generate a plurality of electrical signals. At least one interference is detected in at least one of the plurality of electrical signals. The temporal location of at least one interference in the at least one electrical signal is determined. The at least one interference is removed based on the temporal location of the at least one interference in the at least one electrical signal.

[0010] An exemplary method for cardiac assessment includes using multiple external electrodes to monitor electrical activity from patient tissue to generate multiple electrical signals. At least one of the multiple electrical signals is filtered. At least one of the filtered signals is used to detect at least one interference within the at least one electrical signal. The temporal location of at least one interference within the at least one electrical signal is determined based on the time the at least one filtered signal exceeds a predetermined threshold.

[0011] In one or more embodiments, the illustrative system and method can be described as utilizing a filtering algorithm that begins with sampling the signal. Next, a suitable threshold for the second derivative (or higher) of the pacing spike for a known pulse width or pulse width range can be determined using the sampling frequency. The signal can be processed or “passed through” the second derivative filter, and the resulting signal can be checked to see if the threshold is exceeded. If the threshold is identified as being exceeded, the time point at which the exceedance occurs is recorded. The original signal (or the typically filtered ECG signal) can then be examined at the recorded time point. The pacing spike can be removed from the original signal via smoothing through a window (e.g., by fixing and adjusting the pulse width, or by automatic extrapolation based on baseline deviation and return), said window starting slightly earlier than the time point and extending beyond the time point sufficiently to remove the pacing spike.

[0012] The above overview is not intended to describe every embodiment or every implementation of this disclosure. A more complete understanding will become apparent and understood by taking into account the accompanying drawings and the following detailed description and claims. Attached Figure Description

[0013] Figure 1 A diagram illustrating an exemplary system including electrode devices, display devices, and computing devices.

[0014] Figure 2-3 A diagram of an exemplary external electrode device for measuring the surface potential of the torso.

[0015] Figure 4 A block diagram of an exemplary method for detecting and removing interference.

[0016] Figure 5 for Figure 4 A detailed block diagram of the process of an exemplary method.

[0017] Figure 6A and 6B Examples of multiple sampled electrical signals are shown.

[0018] Figure 7 Examples illustrating filtered electrical signals.

[0019] Figure 8A This describes the instance signal after removing interference from some signals within the window.

[0020] Figure 8B Showing with additional filtering Figure 8A The signal.

[0021] Figure 9A This section describes an instance where an incorrect activation time was detected due to interference.

[0022] Figure 9B Show Figure 9A The same signal is shown, with interference removed.

[0023] Figure 10 This is a diagram of an illustrative system including an illustrative implantable medical device (IMD).

[0024] Figure 11A for Figure 10 An illustrative diagram of the IMD.

[0025] Figure 11B To be placed in Figure 11A An enlarged view of the distal end of the electrical lead in the left ventricle.

[0026] Figure 12A For example Figure 10-1 A block diagram of the illustrative IMD system.

[0027] Figure 12B To illustrate IMD (e.g., implantable pulse generator) circuitry systems and in Figure 10-1 Another block diagram of the associated leads used in the system of 1. Detailed Implementation

[0028] In the following detailed description of illustrative embodiments, reference is made to the accompanying drawings, which form a part of the detailed description, and specific embodiments that can be practiced are illustrated by way of illustration in the drawings. It should be understood that other embodiments may be utilized and structural changes may be made without departing from (e.g., still falling within) the scope of this disclosure herein.

[0029] Reference Figure 1-1 2. Description of Illustrative Systems and Methods. It will be apparent to those skilled in the art that elements or processes of one embodiment may be used in combination with elements or processes of other embodiments, and that possible embodiments of such systems, methods, and apparatuses using combinations of features set forth herein are not limited to the specific embodiments shown in the figures and / or described herein. Furthermore, it will be appreciated that the embodiments described herein may include many elements that are not necessarily shown to scale. Still further, it will be appreciated that the timing of the processes and the size and shape of the various elements herein may be modified but still fall within the scope of this disclosure; however, certain timings, one or more shapes and / or sizes, or element types may be preferred over others.

[0030] Multiple external electrodes positioned on or around the patient's surface or skin can be used to measure or monitor multiple electrocardiogram (ECG) signals (e.g., trunk surface potential). ECG signals can be used to evaluate and configure cardiac therapies, such as those provided by implantable medical devices performing cardiac resynchronization therapy (CRT). As described herein, ECG signals can be acquired or obtained non-invasively because, for example, implantable electrodes may not be used to measure ECG signals. Furthermore, ECG signals can be used to determine cardiac electrical activation time, which can be used to generate various metrics (e.g., electrical heterogeneity information) that can be used by a user (e.g., a physician) to optimize one or more settings or parameters of a cardiac therapy (e.g., pacing therapy) (such as CRT).

[0031] Various illustrative systems, methods, and graphical user interfaces can be configured to noninvasively assist users (e.g., physicians) in assessing cardiac health and / or configuring (e.g., optimizing) cardiac therapies using electrode devices, display devices, and computing devices, including external electrodes. Figure 1 An illustrative system 100 is described, comprising an electrode device 110, a computing device 140, and a remote computing device 160.

[0032] The electrode device 110 shown in the figure includes a plurality of electrodes incorporated or included within a bandage wrapped around the chest or torso of the patient 14. The electrode device 110 is operatively coupled to a computing device 140 (e.g., via a wired or wireless connection) to provide the computing device 140 with electrical signals from each of the electrodes for analysis, evaluation, etc. An illustrative electrode device can be described in U.S. Patent No. 9,320,446, entitled “Bioelectric Sensor Device and Methods,” filed March 27, 2014, and published March 26, 2016. Further reference will be made to… Figure 2-3 A more detailed description of the illustrative electrode device 110.

[0033] Although not described herein, the illustrative system 100 may further include an imaging device. The imaging device can be any type of imaging device configured to non-invasively image or provide an image of at least a portion of a patient. For example, in addition to non-invasive tools such as contrast solutions, the imaging device may provide an image of the patient without using any components or parts that may be located within the patient's body. It should be understood that the illustrative systems, methods, and interfaces described herein may further utilize the imaging device to provide non-invasive assistance to a user (e.g., a physician) to position or place one or more pacing electrodes near a patient's heart in conjunction with a cardiac therapy configuration.

[0034] For example, illustrative systems and methods can provide image-guided navigation for navigating leads, including electrodes, leadless electrodes, wireless electrodes, catheters, etc., within a patient's body, while also providing non-invasive cardiac therapy configurations, including determining effective or optimal pre-excitation intervals, such as the AV interval and VV interval. Illustrative systems and methods using imaging devices and / or electrode devices can be described in U.S. Patent Application Publication No. 2014 / 0371832, published December 18, 2014 by Ghosh; U.S. Patent Application Publication No. 2014 / 0371833, published December 18, 2014 by Ghosh et al.; U.S. Patent Application Publication No. 2014 / 0323892, published October 30, 2014 by Ghosh et al.; and U.S. Patent Application Publication No. 2014 / 0323882, published October 20, 2014 by Ghosh et al.

[0035] The imaging device can be configured to capture X-ray images and / or any other alternative imaging modalities. For example, the imaging device can be configured to capture images or image data using isocentric fluoroscopy, biplane fluoroscopy, ultrasound, computed tomography (CT), multi-slice computed tomography (MSCT), magnetic resonance imaging (MRI), high-frequency ultrasound (HIFU), optical coherence tomography (OCT), intravascular ultrasound (IVUS), two-dimensional (2D) ultrasound, three-dimensional (3D) ultrasound, four-dimensional (4D) ultrasound, intraoperative CT, intraoperative MRI, etc. Furthermore, it should be understood that the imaging device can be configured to capture multiple consecutive images (e.g., sequentially) to provide video frame data. In other words, multiple images captured by the imaging device over time can provide video frame data or motion picture data. Exemplary systems employing ultrasound can be found in U.S. Patent Application Publication No. 2017 / 0303840, entitled "Noninvasive Assessment of Cardiac Resynthesis Therapy" by Stadler et al. Furthermore, images can be obtained and displayed in two, three, or four dimensions. In a more advanced form, four-dimensional surface rendering of the heart or other areas of the body can also be achieved by incorporating cardiac data or other soft tissue data from images captured via MRI, CT, or echocardiography modalities. Image datasets from mixed modalities, such as positron emission tomography (PET) combined with CT or single-photon emission computed tomography (SPECT) combined with CT, can also provide functional image data overlaid on anatomical data, for example, for navigating implanted devices to target locations within the heart or other areas of interest.

[0036] Systems and / or imaging devices that can be used in conjunction with the illustrative systems and methods described herein are described in U.S. Patent Application Publication No. 2005 / 0008210, published January 13, 2005, by Evron et al.; U.S. Patent Application Publication No. 2006 / 0074285, published April 6, 2006, by Zakh et al.; U.S. Patent No. 8,731,642, published May 20, 2014, by Zakh et al.; U.S. Patent No. 8,861,830, published October 14, 2014, by Brada et al.; U.S. Patent No. 6,980,675, published December 27, 2005, by Evron et al.; and Okerlun et al. U.S. Patent No. 7,286,866, issued October 23, 2007 by d et al.; U.S. Patent No. 7,308,297, issued December 11, 2011 by Reddy et al.; U.S. Patent No. 7,308,299, issued December 11, 2011 by Burrell et al.; U.S. Patent No. 7,321,677, issued January 22, 2008 by Evron et al.; U.S. Patent No. 7,346,381, issued March 18, 2008 by Okerlund et al.; U.S. Patent No. 7,454,248, issued November 18, 2008 by Burrell et al.; and U.S. Patent No. 7,454,248, issued November 18, 2008 by Vass et al. U.S. Patent No. 7,499,743, issued March 3, 2009; U.S. Patent No. 7,565,190, issued July 21, 2009, by Okerlund et al.; U.S. Patent No. 7,587,074, issued September 8, 2009, by Zakh et al.; U.S. Patent No. 7,599,730, issued October 6, 2009, by Hunter et al.; U.S. Patent No. 7,613,500, issued November 3, 2009, by Vass et al.; U.S. Patent No. 7,742,629, issued June 22, 2010, by Zakh et al.; and U.S. Patent No. 7,742,629, issued June 29, 2010, by Okerlund et al. U.S. Patent No. 7,747,047, Evron et al., issued August 17, 2010; U.S. Patent No. 7,778,685, Vass et al., issued August 17, 2010; U.S. Patent No. 7,813,785, Okerlund et al., issued October 12, 2010; U.S. Patent No. 7,996,063, Vass et al., issued August 9, 2011; U.S. Patent No. 8,060,185, Hunter et al., issued November 15, 2011; and U.S. Patent No. 8,401,616, Verard et al., issued March 19, 2013.

[0037] The computing device 140 and the remote computing device 160 may each include display devices 130 and 170, respectively, which can be configured to display and analyze data, such as electrical signals (e.g., electrocardiogram data), electrical activation time, electrical heterogeneity information, etc. For example, one cardiac cycle or heartbeat represented by electrical signals collected or monitored by the electrode device 110 can be analyzed and evaluated for one or more metrics, including activation time and electrical heterogeneity information, which may be related to the therapeutic nature of one or more parameters involving cardiac therapy, such as pacing parameters, lead position, etc. More specifically, for example, the QRS complex of a single cardiac cycle can be evaluated against one or more measures, such as, for example, QRS onset, QRS deviation, QRS peak, electrical heterogeneity information (EHI), electrical activation time known as the earliest activation time, left ventricular or chest standard deviation (LVED) of electrical activation time, standard deviation of activation time (SDAT), mean left ventricular or chest alternative electrical activation time (LVAT) referenced to the earliest activation time, QRS duration (e.g., the interval between QRS onset and QRS deviation), the difference between mean left alternative activation time and mean right alternative activation time, relative or absolute QRS morphology, the difference between the higher and lower percentiles of activation time (the higher percentile can be 90%, 80%, 75%, 70%, etc., and the lower percentile can be 10%, 15%, 20%, 25%, and 30%, etc.), central tendency (e.g., median or mode), other statistical measures of deviation (e.g., mean deviation, standard deviation, variance, interquartile deviation, range), etc. Furthermore, each of the one or more measures can be location-specific. For example, some measures can be calculated based on signals recorded or monitored from electrodes located around selected areas of the patient (e.g., the patient's left side, the patient's right side, etc.).

[0038] In at least one embodiment, one or both of the computing device 140 and the remote computing device 160 may be a server, a personal computer, a tablet computer, a mobile device, and a cellular phone. The computing device 140 may be configured to receive input from an input device 142 (e.g., a keyboard) and transmit output to a display device 130, and the remote computing device 160 may be configured to receive input from an input device 162 (e.g., a touchscreen) and transmit output to a display device 170. One or both of computing device 140 and remote computing device 160 may include data storage that allows access to processing programs or routines and / or one or more other types of data, such as for analyzing multiple electrical signals captured by electrode device 110, for determining QRS initiation, QRS offset, median, mode, average, peak or maximum, trough or minimum, for determining electrical activation time, and for driving a graphical user interface configured to noninvasively assist the user in configuring one or more pacing parameters or settings, such as, for example, pacing rate, ventricular pacing rate, AV interval, VV interval, pacing pulse width, pacing vector, multi-point pacing vector (e.g., left ventricular vector four-lead), pacing voltage, pacing configuration (e.g., biventricular pacing, right ventricular pacing only, left ventricular pacing only, etc.), as well as arrhythmia detection and treatment, heart rate adaptive settings and performance, etc.

[0039] Computing device 140 can be operatively connected to input device 142 and display device 130 to transmit data to and from each of the input devices 142 and 130, for example, and remote computing device 160 can be operatively connected to input device 162 and display device 170 to transmit data to and from each of the input devices 162 and 170, for example,. For example, computing device 140 and remote computing device 160 can be electrically connected to input devices 142, 162 and display devices 130, 170 using, for example, analog electrical connections, digital electrical connections, wireless connections, bus-based connections, network-based connections, Internet-based connections, etc. As further described herein, a user can provide input to input devices 142, 162 to view and / or select one or more configuration information related to cardiac therapy delivered by a cardiac therapy device, such as, for example, an implantable medical device.

[0040] Although input device 142 is a keyboard and input device 162 is a touchscreen as depicted, it should be understood that input devices 142 and 162 may include any device capable of providing input to computing device 140 and computing device 160 to perform the functions, methods, and / or logic described herein. For example, input devices 142 and 162 may include a keyboard, mouse, trackball, touchscreen (e.g., capacitive touchscreen, resistive touchscreen, multi-touch touchscreen, etc.), etc. Similarly, display devices 130 and 170 may include any device capable of displaying information to a user, such as graphical user interfaces 132 and 172, including electrode status information, electroactive graphical representations, multiple signals of external electrodes on one or more heartbeats, QRS complexes, selection areas for various cardiac therapy options, rankings of various cardiac therapy options, various pacing parameters, electrical heterogeneity information (EHI), text commands, graphical depictions of the anatomy of the human heart, images or graphical depictions of a patient's heart, graphical depictions of the location of one or more electrodes, graphical depictions of the human torso, images or graphical depictions of a patient's torso, graphical depictions or actual images of implanted electrodes and / or leads, etc. Furthermore, the display devices 130 and 170 may include liquid crystal displays, organic light-emitting diode screens, touch screens, cathode ray tube displays, etc.

[0041] The processing programs or routines stored and / or executed by computing device 140 and remote computing device 160 may include programs or routines for computational mathematics, matrix mathematics, decomposition algorithms, compression algorithms (e.g., data compression algorithms), calibration algorithms, image construction algorithms, signal processing algorithms (e.g., various filtering algorithms, Fourier transform, fast Fourier transform, etc.), normalization algorithms, comparison algorithms, vector mathematics, or any other processing that implements one or more of the illustrative methods and / or processes described herein. The data stored and / or used by computing device 140 and remote computing device 160 may include, for example, electrical signal / waveform data (e.g., multiple QRS groups) from electrode device 110, electrical activation time from electrode device 110, heart sound / signal / waveform data from acoustic sensors, graphics (e.g., graphic elements, icons, buttons, windows, dialog boxes, drop-down menus, graphics areas, graphics regions, 3D graphics, etc.), graphical user interfaces, results of one or more processing programs or routines employed according to this disclosure (e.g., electrical signals, electrical heterogeneity information, etc.), or any other data used to perform one or more of the processes or methods described herein.

[0042] In one or more embodiments, the illustrative systems, methods, and interfaces may be implemented using one or more computer programs that execute on a programmable computer (e.g., a computer including, for example, processing power, data storage devices (e.g., volatile or non-volatile memory and / or storage elements), input devices, and output devices). The program code and / or logic described herein may be applied to input data to perform the functions described herein and generate desired output information. The output information may be applied as input to one or more other means and / or methods described herein or to be applied in a known manner.

[0043] Any programmable language can be used to provide one or more programs for implementing the systems, methods, and / or interfaces described herein, such as high-level programs and / or object-oriented programming languages ​​suitable for communicating with computer systems. For example, any such program can be stored on any suitable means, such as a storage medium, readable by a general or special-purpose program that runs on a computer system (e.g., including a processing device) to configure and operate the computer system to perform the programs described herein when read by a suitable device. In other words, at least in one embodiment, the illustrative systems, methods, and interfaces can be implemented using a computer-readable storage medium configured with computer programs, wherein such a storage medium causes a computer to operate in a specific and predefined manner to perform the functions described herein. Further, in at least one embodiment, the illustrative systems, methods, and / or interfaces can be described as being implemented by logic (e.g., object code) encoded in one or more non-transitory media, said logic including code for execution and operable, when executed by a processor or processing circuitry system, to perform operations such as the methods, processes, and / or functions described herein.

[0044] Computing device 140 and remote computing device 160 can be, for example, any fixed or mobile computer system (e.g., controller, microcontroller, personal computer, microcomputer, tablet computer, etc.). The exact configuration of computing device 140 and remote computing device 160 is not limiting, and any device capable of providing suitable computing and control capabilities (e.g., signal analysis, mathematical functions such as median, mode, average, maximum value determination, minimum value determination, slope determination, minimum slope determination, maximum slope determination, graphics processing, etc.) can be used. As described herein, digital files can be any medium (e.g., volatile or non-volatile memory, CD-ROM, punched card, magnetically recordable magnetic tape, etc.) containing digital bits (e.g., encoded in binary or ternary) that can be read and / or written by computing device 140 and remote computing device 160 as described herein. Moreover, as described herein, a user-readable format file can be any representation of data (e.g., ASCII text, binary numbers, hexadecimal numbers, decimal numbers, graphics, etc.) that can be presented on any medium (e.g., paper, monitor, etc.) that can be read and / or understood by a user.

[0045] In view of the foregoing, it will be apparent that the functions described in one or more embodiments of this disclosure can be implemented in any manner known to those skilled in the art. Thus, the computer language, computer system, or any other software / hardware intended for implementing the processes described herein should not be limited to the scope of the systems, processes, or programs described herein (e.g., the functions provided by such systems, processes, or programs).

[0046] The illustrative electrode device 110 can be configured to measure the surface potential of the patient 14's body and, more specifically, the surface potential of the patient 14's torso. For example... Figure 2 As shown, the illustrative electrode device 110 may include an external electrode 112, an assembly or array of strips 113, and an interface / amplifier circuitry system 116. The electrode 112 may be attached to or coupled to the strip 113, and the strip 113 may be configured to wrap around the torso of the patient 14 such that the electrode 112 surrounds the patient's heart. As further shown, the electrode 112 may be positioned around the circumference of the patient 14, including posterior, lateral, posterolateral, anterolateral, and anterior positions of the patient 14's torso.

[0047] The illustrative electrode device 110 can be further configured to measure or monitor at least one or both sounds from the patient 14. For example... Figure 2As shown, the illustrative electrode device 110 may include an array or collection of acoustic sensors 120 attached to or coupled to a strip 113. The strip 113 may be configured to wrap around the torso of the patient 14 such that the acoustic sensors 120 surround the patient's heart. As further shown, the acoustic sensors 120 may be positioned around the circumference of the patient 14, including posterior, lateral, posterolateral, anterolateral, and anterior positions of the patient 14's torso.

[0048] Furthermore, electrode 112 and acoustic sensor 120 can be electrically connected to interface / amplifier circuitry 116 via wired connection 118. Interface / amplifier circuitry 116 can be configured to amplify signals from electrode 112 and acoustic sensor 120 and provide the signals to one or both of computing device 140 and remote computing device 160. Other illustrative systems may use wireless connections (e.g., as data channels) to transmit signals sensed by electrode 112 and acoustic sensor 120 to interface / amplifier circuitry 116, and further to one or both of computing device 140 and remote computing device 160. In one or more embodiments, interface / amplifier circuitry 116 may be electrically connected to computing device 140 using, for example, analog electrical connections, digital electrical connections, wireless connections, bus-based connections, network-based connections, Internet-based connections, etc.

[0049] Despite Figure 2In one example, electrode device 110 includes a strip 113, but in other examples, any of a variety of mechanisms, such as tape or adhesive, can be used to assist in the spacing and placement of electrodes 112 and acoustic sensors 120. In some examples, strip 113 may include elastic band, tape strip, or cloth. Further, in some examples, strip 113 may be part of or integrated with a garment (e.g., a T-shirt). In other examples, electrodes 112 and acoustic sensors 120 may be placed separately on the torso of patient 14. Further, in other examples, one or both of electrodes 112 (e.g., arranged in an array) and acoustic sensors 120 (e.g., also arranged in an array) may be part of or within a patch, vest, and / or other means of securing electrodes 112 and acoustic sensors 120 to the torso of patient 14. Still further, in other examples, one or both of electrodes 112 and acoustic sensors 120 may be two parts of a material or part of or within two patches. One of the two patches may be located on the front of the patient 14's torso (to monitor, for example, electrical signals representing the front of the patient's heart, measure the electrical activation time of an alternative heart representing the front of the patient's heart, monitor or measure sound in the front of the patient, etc.), and the other patch may be located on the back of the patient 14's torso (to monitor, for example, electrical signals representing the back of the patient's heart, measure the electrical activation time of an alternative heart representing the back of the patient's heart, monitor or measure sound in the back of the patient, etc.). Furthermore, in other embodiments, one or both of the electrode 112 and the acoustic sensor 120 may be arranged in top and bottom rows extending from the front of the patient 14, across the left side of the patient 14, to the back of the patient 14. Still further, in other embodiments, one or both of the electrode 112 and the acoustic sensor 120 may be arranged in a curve around the axillary region, and the electrode / sensor density on the right chest may be lower than the density in the other remaining areas.

[0050] Electrodes 112 can be configured to surround the heart of patient 14 and record or monitor electrical signals associated with cardiac depolarization and repolarization after the signal has propagated through the torso of patient 14. Each electrode in 112 can be used in a monopolar configuration to sense the torso surface potential reflecting cardiac signals. Interface / amplifier circuitry 116 can also be coupled to a return electrode or an unrelated electrode (not shown) that can be used in combination with each electrode 112 for monopolar sensing.

[0051] In some instances, there may be approximately 12 to approximately 50 electrodes 112 spatially distributed around the patient's torso, and approximately 12 to approximately 50 acoustic sensors 120. Other configurations may have more or fewer electrodes 112 and more or fewer acoustic sensors 120. It should be understood that the electrodes 112 and acoustic sensors 120 may not be arranged or may be distributed in an array that extends all the way around or completely around the patient 14. Instead, the electrodes 112 and acoustic sensors 120 may be arranged in an array that extends only around a portion or partially around the patient 14. For example, the electrodes 112 and acoustic sensors 120 may be distributed on the front, back, and left sides of the patient, with fewer or no electrodes and acoustic sensors near the right side (including the posterior and anterior regions of the patient's right side).

[0052] The computing device 140 can record and analyze torso surface potential signals sensed by electrode 112 and sound signals sensed by acoustic sensor 120, which are amplified / modulated by interface / amplifier circuitry system 116. The computing device 140 can be configured to analyze electrical signals from electrode 112 to provide electrocardiogram (ECG) signals, information, or data from the patient's heart, as will be further described herein. The computing device 140 can also be configured to analyze electrical signals from acoustic sensor 120 to provide sound signals, information, or data from the patient's body and / or implanted devices (such as left ventricular assist devices).

[0053] Additionally, computing device 140 and telecomputing device 160 can be configured to provide graphical user interfaces 132, 172 that depict various information associated with electrode device 110 and data collected or sensed using electrode device 110. For example, graphical user interfaces 132, 172 can depict ECG data including QRS complexes obtained using electrode device 110 and acoustic data including sound waves obtained using acoustic sensor 120, along with other related information. The illustrative system and method can noninvasively use the electrical information collected using electrode device 110 and the acoustic information collected using acoustic sensor 120 to assess a patient's cardiac health and to evaluate and configure cardiac therapies delivered to the patient.

[0054] Furthermore, the electrode device 110 may further include, for example, reference electrodes and / or drive electrodes positioned around the lower torso of the patient 14, which may be further used by the system 100. For example, the electrode device 110 may include three reference electrodes, and signals from the three reference electrodes may be combined to provide a reference signal. Further, the electrode device 110 may use three tail-end reference electrodes (e.g., instead of the standard reference used in the Wilson Central Terminal) to obtain a “true” monopolar signal with less noise by averaging the three tail-end positioned reference signals.

[0055] Figure 3 Another illustrative electrode device 110 is shown, comprising multiple electrodes 112 and multiple acoustic sensors 120. The electrodes are configured to surround the heart of a patient 14 and record or monitor electrical signals associated with the depolarization and repolarization of the heart after the signal has propagated through the torso of the patient 14. The acoustic sensors are configured to surround the heart of the patient 14 and record or monitor sound signals associated with the heart after the signal has propagated through the torso of the patient 14. The electrode device 110 may include a vest 114 to which the multiple electrodes 112 and multiple acoustic sensors 120 may be attached, or the electrodes 112 and acoustic sensors 120 may be coupled to the vest. In at least one embodiment, the multiple electrodes 112 or an array of the electrodes may be used to collect electrical information, such as alternative electrical activation time. Similar to... Figure 2 Electrode equipment 110, Figure 3 The electrode device 110 may include an interface / amplifier circuitry 116 electrically connected to each of the electrodes 112 and acoustic sensors 120 via a wired connection 118 and configured to transmit signals from the electrodes 112 and acoustic sensors 120 to a computing device 140. As shown, the electrodes 112 and acoustic sensors 120 may be distributed on the torso of the patient 14, including, for example, posterior, lateral, posterolateral, anterolateral, and anterior positions of the patient 14's torso.

[0056] Vest 114 may be formed of fabric, with electrodes 112 and acoustic sensors 120 attached to the fabric. Vest 114 may be configured to maintain the positioning and spacing of electrodes 112 and acoustic sensors 120 on the torso of patient 14. Further, vest 114 may be marked to aid in determining the position of electrodes 112 and acoustic sensors 120 on the surface of the torso of patient 14. In some instances, approximately 25 to approximately 256 electrodes 112 and approximately 25 to approximately 256 acoustic sensors 120 may be distributed around the torso of patient 14, although other configurations may have more or fewer electrodes 112 and more or fewer acoustic sensors 120.

[0057] The illustrative systems and methods can be used to provide noninvasive assistance to users in the assessment of a patient's cardiac health and / or in the assessment and configuration of cardiac treatments currently being delivered to the patient (e.g., via implantable medical devices for pacing therapy, via LVAD, etc.). Furthermore, it should be understood that computing device 140 and remote computing device 160 can be operatively coupled to each other in a variety of different ways to perform or execute the functions described herein. For example, in the depicted embodiments, computing device 140 can be operatively wirelessly coupled to remote computing device 160, as depicted by the wireless signal lines emanating therebetween. Alternatively, in contrast to wireless connectivity, one or more of computing device 140 and remote computing device 160 can be operatively coupled via a single or wired electrical connection.

[0058] According to the embodiments described herein, an ECG band is used in conjunction with a CRT system to calculate the SDAT of the cardiac cycle (or heartbeat). According to various embodiments, the ECG band is used to calculate the SDAT of the cardiac cycle after CRT pacing. For example, the ECG band can be used to calculate the SDAT of the cardiac cycle during biventricular and / or left ventricular pacing. The embodiments described herein can be used for non-CRT pacing. If the SDAT is inaccurate, the output of the ECG band may be misleading and may affect lead placement (e.g., leads not being placed in the optimal position) and / or optimal device programming. For example, if the SDAT is inaccurate, it may be artificially lowered, causing the leads to remain in their current position instead of being repositioned for a better response. Interference in the signal detected by the ECG band can cause the detection of incorrect activation times, resulting in inaccurate SDAT. Detecting and / or removing interference can reduce the risk of inaccurate SDAT.

[0059] Figure 4 An exemplary method 400 for detecting interference in an electrical signal is described herein. As shown, method 400 includes monitoring electrical activity 410 to generate multiple electrical signals. According to various embodiments, multiple electrodes are used to monitor the electrical activity. The multiple electrodes may be outer surface electrodes configured on a belt or vest, similar to those described herein. Figure 1-3As described. Each electrode may be positioned or set around the patient's torso to monitor electrical activity (e.g., acquire torso potential) from multiple different locations around the patient's torso. Each of the different locations where the electrodes are located may correspond to the electrical activation of a different part or region of the cardiac tissue of the patient's heart.

[0060] More than 420 electrical signals are filtered. According to the embodiments described herein, for example, higher-order filters, such as second-order filters, are used to filter the electrical signals. In some embodiments, the filter may be a second-order difference filter. According to various implementations, the filter may be a second-order derivative filter. More specifically, each of the multiple electrical signals can be filtered individually, thereby generating multiple filtered signals. Furthermore, in some embodiments, each of the multiple electrical signals may be filtered by the same filter. Therefore, multiple electrical signals can be processed to make them suitable for detecting interference.

[0061] At least one interference is detected in the filtered electrical signal. For example, interference can be detected by determining that the filtered signal exceeds a predetermined threshold. Interference may include one or more of pacing spikes and / or muscle-generated noise. Other types of interference may include artifacts caused by movement, breathing, etc. The detection method described herein can be used to detect the His potential used in His bundle pacing or the left bundle potential used for target lead placement to capture the left bundle in patients with conduction system disorders such as left bundle branch block.

[0062] In one or more embodiments, the time location of at least one interference in at least one of the at least four 440 electrical signals is determined based on the time it takes for the absolute value of the amplitude of at least one filtered signal to exceed a predetermined amplitude threshold. The predetermined threshold may be based on the sampling rate of the at least one electrical signal. In some cases, the threshold may be determined based on a predetermined number of electrical signal samples. According to various embodiments, the time location of the interference is determined by the predetermined threshold. The predetermined threshold may be based on a measurement of the amplitude of the electrical signal. More specifically, the predetermined threshold may be determined by determining the time it takes for the filtered signal to reach the predetermined amplitude.

[0063] According to one or more embodiments, interference detected at 450 can be removed from at least one of a plurality of electrical signals. Various methods can be used to remove 450 interference. For example, 450 interference can be removed by smoothing the electrical signals within a window using the determined temporal location of the interference. Any known smoothing algorithm or technique can be used to perform or execute the smoothing of the electrical signals within the window. For example, the electrical signals within a window can be smoothed by replacing one or more signals within the window with lines to connect the signals at the start and end points within the window. In some cases, a best-fit line can replace the electrical signals in the window and / or the window can be blanked during interference so that it is not used for activation time determination.

[0064] The window in which interference can be removed may begin or have a start time, i.e., a predetermined time period before the time position of the interference. Similarly, the window may end or have an end time after the time position of the interference. In other words, the window may begin a predetermined time period before at least one time position of the interference and extend for a predetermined amount of time after the time position. For example, the predetermined time period before the time position of the interference (used to determine the window) may be between about 0.5 milliseconds (ms) and about 2 milliseconds. In at least one embodiment, the predetermined time period before the time position of the interference is about 1 ms. Furthermore, for example, the predetermined time period after the time position of the interference (used to determine the window) may be between about 5 ms and about 15 ms. In at least one embodiment, the predetermined time period after the time position of the interference is about 10 ms.

[0065] Furthermore, in at least one embodiment, the window may be a fixed length starting from a predetermined starting point. For example, the window length may range from approximately 5 ms to approximately 15 ms. In some cases, the window length is approximately 10 ms. The window start time and end time may be determined based on a baseline deviating from the threshold amplitude and a return to the threshold amplitude. In other words, the window start time may be based on a first threshold exceeding the threshold and the end time may be based on a second threshold exceeding the threshold after the first threshold has been exceeded.

[0066] After removing at least one interference, the electrical signal can be used to determine multiple activation times. Additionally, information on electrical heterogeneity can be determined based on multiple cardiac activation times.

[0067] In some embodiments, more than one interference is detected and / or removed. For example, a first interference may be detected, and a second interference occurring after the first interference may also be detected. The first and / or second interferences can be removed by smoothing an electrical signal within a window that begins a predetermined amount of time before the time position of the first interference and extends for a predetermined amount of time after the second interference. Although two interferences are described herein, it should be understood that more interferences may be detected and / or removed from the electrical signal. Furthermore, in some embodiments, each of the first and second interferences, as well as any other additional interferences, may be removed individually, each within its own window.

[0068] According to one or more embodiments, interference is detected in at least one electrical signal. In some cases, the detected interference is removed only when it is sensed in a predetermined number of electrical signals out of a plurality of electrical signals. Figure 5A process 500 for removing interference from electrical signals based on interference detected in a predetermined number of electrical signals according to embodiments described herein is illustrated. Multiple electrical signals are sensed using multiple electrodes. At least one interference is detected 510. It is determined whether interference exists in at least a predetermined number of sensed electrical signals. The predetermined number of signals for which interference needs to be detected may range from about three to about ten. In some cases, the predetermined number of signals for which interference needs to be detected is four. If it is determined 510 that no interference is detected in at least a predetermined number of electrical signals, then the interference is not removed 520. If it is determined 510 that interference is detected in at least a predetermined number of electrical signals, then the interference is removed from at least a predetermined number of electrical signals 530. In some cases, if it is determined 510 that interference is detected in at least a predetermined number of electrical signals, then the interference is removed from all of the multiple electrical signals 530. In some embodiments, if interference is detected in a predetermined number of electrical signals, then the interference is removed from more than a predetermined number but less than all of the electrical signals.

[0069] According to various implementations, interference can only be removed if it is sensed in a predetermined number of electrical signals derived from a predetermined set of electrodes. For example, interference can only be removed if it is sensed in at least four electrical signals derived from four electrodes in a subset of electrodes. For example, the electrode subset may be approximately 12 electrodes located anteriorly on the top and left side of the sternum and posteriorly on the left side of the spine.

[0070] Figure 6A and 6B Examples of multiple sampled electrical signals according to embodiments described herein are shown. As shown, a portion of the electrical signal or electrical activity is plotted along time axis 605. As described herein, the sampled electrical signals can be filtered and the activation time can be determined based on the filtered signal. According to various embodiments, the activation time can be determined based on the slope of the filtered signal. Figure 6B Explanation in Figure 6A A close-up view of the signal in the vertical direction.

[0071] In this example, the sensed signals include cardiac activity 610 in response to pacing. A first interference 612 and a smaller second interference 620 occur prior to the sensed cardiac response activity 610. The first interference 612 and / or the second interference 620 have slopes that can indicate the activation time of the signal. This can lead to false detection of the activation time, resulting in inaccurate data. More specifically, the reference point used to determine the activation time of each signal may be the time location of the maximum slope within each signal, and interference can cause or create the maximum slope within each signal, resulting in inaccurate activation time data.

[0072] To detect interference, the sampling frequency is used to determine a threshold for the second-order (or higher-order) difference of interference with a known pulse width or pulse width range. The signal is passed through a second-order filter, and the resulting filtered signal is checked to see if it exceeds the threshold. Figure 7 The figure illustrates an example of a sampled signal after filtering using a second-order filter. Signals 710 with amplitudes exceeding the threshold 720 are detected as interference. Once interference 710 is identified, its timing is determined. For example, this can be done by determining when the interference exceeds the threshold 720.

[0073] As described in this article, interference is removed from at least one signal within the window. Figure 8A This illustrates an example signal after interference has been removed from some signals within window 825. It can be observed that interference has been removed from signals with linear portions within window 825. Figure 8B Showing additional filters as described herein Figure 8A The signal. Here, it can be observed that interference has been removed. The activation time can now be determined based on these filtered signals, unaffected by interference.

[0074] As described in this article, inaccurate activation times can be detected without removing interference from the electrical signal. Figure 9A This illustrates an example of detecting erroneous activation time 930 based on the location of interference 925. Detecting and / or removing one or more interferences can be used to reduce the occurrence of erroneous activation time detection. For example, interference detection can be performed using a controller. In some cases, interference detection is performed using commercial chips. Figure 9B Show Figure 9A The same signal is shown, but interference 925 has been removed. As can be observed, the erroneous activation time 930 is no longer detected. Based on Figure 9A The electrical activation time of the electrical signal generates an SDAT of 46.0 ms, and based on Figure 9B The electrical activation time of the electrical signal produces an SDAT of 28.5 ms. Therefore, interference removal according to this disclosure can lead to measurable improvements in cardiac electrical heterogeneity, such as in the accuracy of SDAT measurement.

[0075] Illustrative cardiac treatment systems and devices can be referenced in this article. Figure 10-1 2. Further description, Figure 10-1 2. This article can be used to discuss... Figure 1 -9 describes the illustrative systems, interfaces, methods, and processes.

[0076] Figure 10The illustration is provided to illustrate a conceptual diagram of a therapeutic system 10, which can be used to deliver pacing therapy to a patient 14. The patient 14 can be, but is not necessarily, a person. The therapeutic system 10 may include an implantable medical device 16 (IMD) that can be coupled to leads 18, 20, 22. The IMD 16 may be, for example, an implantable pacemaker, cardioverter-defibrillator, and / or a defibrillator, which delivers or provides electrical signals (e.g., pacing, etc.) to the heart 12 of the patient 14 via electrodes coupled to one or more of leads 18, 20, 22 and / or senses electrical signals from the patient's heart.

[0077] Leads 18, 20, and 22 extend into the heart 12 of the patient 14 to sense the electrical activity of the heart 12 and / or deliver electrical stimulation to the heart 12. Figure 10 In the example shown, the right ventricle (RV) lead 18 extends through one or more veins (not shown), the superior vena cava (not shown), and the right atrium 26, and enters the right ventricle 28. The left ventricle (LV) coronary sinus lead 20 extends through one or more veins, the vena cava, and the right atrium 26, and enters the coronary sinus 30 to reach the region of the free wall of the left ventricle 32 adjacent to the heart 12. The right atrium (RA) lead 22 extends through one or more veins and the vena cava, and enters the right atrium 26 of the heart 12.

[0078] The IMD 16 can sense electrical signals, such as those associated with depolarization and repolarization of the heart 12, via electrodes coupled to at least one of leads 18, 20, and 22. In some instances, the IMD 16 delivers pacing therapy (e.g., pacing pulses) to the heart 12 based on electrical signals sensed within the heart 12. The IMD 16 is operable to adjust one or more parameters associated with the pacing therapy, such as AV delay and various other timing, pulse width, amplitude, voltage, burst length, etc. Furthermore, the IMD 16 is operable to deliver pacing therapy using various electrode configurations, which may be monopolar, bipolar, quadrupole, or further multipolar. For example, a multipolar lead system may include several electrodes that can be used to deliver pacing therapy. Thus, a multipolar lead system can provide or supply multiple electrical vectors for pacing from it. The pacing vector may include at least one cathode and at least one anode, the at least one cathode being at least one electrode located on at least one lead, and the at least one anode being at least one electrode located on at least one lead (e.g., the same lead or different leads) and / or on the housing or canister of the IMD. While improvements in cardiac function as a result of pacing therapy may depend primarily on the cathode, electrical parameters such as impedance, pacing threshold voltage, current consumption, and lifespan may be more dependent on the pacing vector, which includes both the cathode and anode. The IMD 16 may also provide defibrillation and / or cardioversion therapy via electrodes located on at least one of leads 18, 20, 22. Further, the IMD 16 may detect arrhythmias of heart 12, such as fibrillation of ventricles 28, 32, and provide defibrillation therapy to heart 12 in the form of electrical pulses. In some instances, the IMD 16 may be programmed to deliver a therapeutic process, such as pulses with increasing energy levels, until the fibrillation of heart 12 ceases.

[0079] Figure 11A-11B The following is a conceptual diagram of the IMD 16 and leads 18, 20, 22 of the treatment system 10 in Figure 13 for further explanation. Leads 18, 20, 22 can be electrically connected via connector block 34 to a therapy delivery module (e.g., for delivering pacing therapy), a sensing module (e.g., for sensing one or more signals from one or more electrodes), and / or any other module of the IMD 16. In some instances, the proximal ends of leads 18, 20, 22 may include electrical contacts that are electrically connected to corresponding electrical contacts within connector block 34 of the IMD 16. Additionally, in some instances, leads 18, 20, 22 may be mechanically connected to connector block 34 by means of a retaining screw, connecting pin, or other suitable mechanical coupling mechanism.

[0080] Each of leads 18, 20, and 22 includes an elongated insulated lead body capable of carrying multiple conductors (e.g., concentric coil conductors, straight conductors, etc.) separated from each other by insulation (e.g., a tubular insulating sheath). In the illustrated example, bipolar electrodes 40 and 42 are located near the distal end of lead 18. Additionally, bipolar electrodes 44, 45, 46, and 47 are located near the distal end of lead 20, and bipolar electrodes 48 and 50 are located near the distal end of lead 22.

[0081] Electrodes 40, 44, 45, 46, 47, and 48 may be in the form of ring electrodes, and electrodes 42 and 50 may be in the form of extendable spiral-tipped electrodes retractably mounted within insulated electrode heads 52, 54, and 56, respectively. A corresponding one of electrodes 40, 42, 44, 45, 46, 47, 48, and 50 may be electrically connected to a corresponding conductor within the lead body of its associated leads 18, 20, and 22 (e.g., coil conductors and / or straight conductors), and thereby connected to a corresponding electrical contact at the proximal end of leads 18, 20, and 22.

[0082] In addition, the surface area of ​​electrodes 44, 45, 46, and 47 can be approximately 5.3 mm². 2 up to approximately 5.8mm 2 Electrodes 44, 45, 46, and 47 may also be referred to as LV1, LV2, LV3, and LV4, respectively. The LV electrodes on lead 20 (i.e., left ventricular electrode 1 (LV1) 44, left ventricular electrode 2 (LV2) 45, left ventricular electrode 3 (LV3) 46, and left ventricular electrode 4 (LV4) 47, etc.) can be spaced apart at variable distances. For example, electrode 44 may be spaced from electrode 45 by, for example, approximately 21 millimeters (mm), electrodes 45 and 46 may be spaced apart by, for example, approximately 1.3 mm to approximately 1.5 mm, and electrodes 46 and 47 may be spaced apart by, for example, approximately 20 mm to approximately 21 mm.

[0083] Electrodes 40, 42, 44, 45, 46, 47, 48, and 50 can be further used to sense electrical signals (e.g., morphological waveforms within an electrogram (EGM)) accompanying depolarization and repolarization of the heart 12. The electrical signals are conducted to the IMD 16 via corresponding leads 18, 20, and 22. In some instances, the IMD 16 can also deliver pacing pulses via electrodes 40, 42, 44, 45, 46, 47, 48, and 50 to induce depolarization of the cardiac tissue of the patient's heart 12. In some instances, such as... Figure 11AAs described, the IMD 16 includes one or more housing electrodes, such as housing electrode 58, which may be integrally formed with or otherwise coupled to the outer surface of the housing 60 of the IMD 16 (e.g., a hermetically sealed housing). Any of electrodes 40, 42, 44, 45, 46, 47, 48, and 50 may be combined with housing electrode 58 for unipolar sensing or pacing. It will be understood by those skilled in the art that other electrodes may also be selected to define or be used for pacing and sensing vectors. Furthermore, any of electrodes 40, 42, 44, 45, 46, 47, 48, 50, and 58, when not used for pacing therapy, may be used to sense electrical activity during pacing therapy.

[0084] For reference Figure 11A In further detail, the housing 60 may encapsulate a treatment delivery module, which may include a stimulation generator for generating cardiac pacing pulses and defibrillation or cardioversion shocks, and a sensing module for monitoring electrical signals of the patient's heart (e.g., the patient's heart rhythm). Leads 18, 20, and 22 may also include elongated electrodes 62, 64, and 66, which may be in the form of coils. The IMD 16 can deliver defibrillation shocks to the heart 12 via any combination of the elongated electrodes 62, 64, and 66 and the housing electrode 58. Electrodes 58, 62, 64, and 66 may also be used to deliver cardiac cardioversion pulses to the heart 12. Furthermore, electrodes 62, 64, and 66 may be made of any suitable conductive material, such as, but not limited to, platinum, platinum alloys, and / or other materials known to be suitable for use in implantable defibrillation electrodes. Since electrodes 62, 64, and 66 are not typically configured for pacing therapy, any one of electrodes 62, 64, and 66 can be used to sense electrical activity and can be used in combination with any of electrodes 40, 42, 44, 45, 46, 47, 48, 50, and 58. In at least one embodiment, the RV elongated electrode 62 can be used to sense the electrical activity of a patient's heart during pacing therapy delivery (e.g., in combination with housing electrode 58 or a defibrillator electrode-to-housing electrode vector).

[0085] Figure 10-1 The configuration of the illustrative treatment system 10 described in section 2 is only one example. In other examples, alternatives or additions... Figure 10 The described transvenous leads 18, 20, and 22 indicate that the treatment system may include epicardial leads and / or patch electrodes. Furthermore, in other instances, the treatment system 10 may have leads (e.g., leadless / wireless pacing systems) implanted (e.g., transvenous implantation or method of use) into the left chamber of the heart. Figure 10As described, the IMD 16 is implanted in / around the cardiac septum, except as a substitute for a transvenous lead placed in the right chamber of the heart. Further, in one or more embodiments, it is not necessary to implant the IMD 16 into the patient 14. For example, the IMD 16 can be used for various cardiac therapies via a percutaneous lead extending through the skin of the patient 14 to multiple locations within or outside the heart 12. In one or more embodiments, the system 10 can utilize wireless pacing (e.g., transmitting energy to one or more intracardiac pacing components via ultrasound, inductive coupling, RF, etc.) and sense cardiac activation using electrodes on the housing / shell and / or subcutaneous leads.

[0086] In other instances of therapeutic systems that provide electrical stimulation to the heart 12, such systems may include any suitable number of leads coupled to the IMD 16, and each of these leads may extend to any location within or near the heart 12. For example, as... Figure 10-1 As illustrated in section 2, other examples of the treatment system may include three venous leads positioned therein. Further still, other treatment systems may include a single lead extending from IMD 16 into the right atrium 26 or the right ventricle 28, or two leads extending into one of the corresponding right atrium 26 and right ventricle 28.

[0087] Figure 12A This is a functional block diagram illustrating one configuration of the IMD 16. As shown, the IMD 16 may include a control module 81, a therapy delivery module 84 (e.g., which may include a stimulation generator), a sensing module 86, and a power supply 90.

[0088] The control module or device 81 may include a processor 80, a memory 82, and a telemetry module, or a device 88. The memory 82 may include computer-readable instructions that, when executed by, for example, the processor 80, cause the IMD 16 and / or control module 81 to perform various functions belonging to the IMD 16 and / or control module 81 described herein. Further, the memory 82 may include any volatile, non-volatile, magnetic, optical, and / or electrical media, such as random access memory (RAM), read-only memory (ROM), non-volatile RAM (NVRAM), electrically erasable programmable ROM (EEPROM), flash memory, and / or any other digital media. An illustrative capture management module may be the left ventricular capture management (LVCM) module described in U.S. Patent No. 7,684,863, entitled "LV Threshold Measurement and Capture Management," published March 23, 2010.

[0089] The processor 80 of the control module 81 may include any one or more of the following: a microprocessor, a controller, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), and / or an equivalent discrete or integrated logic circuit system. In some instances, the processor 80 may include any combination of multiple components, such as one or more microprocessors, one or more controllers, one or more DSPs, one or more ASICs, and / or one or more FPGAs, as well as other discrete or integrated logic circuit systems. The functionality of the processor 80 as defined herein may be embodied in software, firmware, hardware, or any combination thereof.

[0090] The control module 81 can control the therapy delivery module 84 to deliver therapy (e.g., electrical stimulation therapy such as pacing) to the heart 12 according to one or more selected therapy programs that can be stored in the memory 82. More specifically, the control module 81 (e.g., processor 80) can control various parameters of the electrical stimulation delivered by the therapy delivery module 84, such as, for example, AV delay, VV delay, pacing pulses having amplitude, pulse width, frequency, or electrode polarity, which can be controlled by one or more selected therapy programs (e.g., AV and / or VV delay adjustment programs, pacing therapy programs, pacing recovery programs, capture management programs, etc.). As shown, the therapy delivery module 84 is electrically connected to electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66, for example, via conductors of corresponding leads 18, 20, 22 or, in the case of housing electrodes 58, via electrical conductors arranged within the housing 60 of the IMD 16. The therapy delivery module 84 can be configured to generate an electrical stimulation therapy, such as pacing therapy, using one or more of electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66 and deliver the electrical stimulation therapy to the heart 12.

[0091] For example, the therapy delivery module 84 can deliver pacing stimulation (e.g., pacing pulses) via ring electrodes 40, 44, 45, 46, 47, 48 and / or spiral tip electrodes 42, 50 of leads 18, 22. Further, for example, the therapy delivery module 84 can deliver defibrillation shocks to the heart 12 via at least two of electrodes 58, 62, 64, 66. In some instances, the therapy delivery module 84 can be configured to deliver pacing, cardioversion, or defibrillation stimulation in the form of electrical pulses. In other instances, the therapy delivery module 84 can be configured to deliver one or more of these types of stimulation in the form of other signals (such as sine waves, square waves, and / or other substantially continuous time signals).

[0092] The IMD 16 may further include a switching module 85, and the control module 81 (e.g., processor 80) may use the switching module 85 to select, for example via a data / address bus, which of the available electrodes are used for delivering therapy, such as pacing pulses for pacing therapy, or which of the available electrodes are used for sensing. The switching module 85 may include a switch array, switch matrix, multiplexer, or any other type of switching device suitable for selectively coupling the sensing module 86 and / or the therapy delivery module 84 to one or more selected electrodes. More specifically, the therapy delivery module 84 may include a plurality of pacing output circuits. Each of the plurality of pacing output circuits may, for example, be selectively coupled using the switching module 85 to one or more electrodes of electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66 (e.g., a pair of electrodes for delivering therapy to a bipolar or multipolar pacing vector). In other words, each electrode may be selectively coupled using the switching module 85 to one of the pacing output circuits of the therapy delivery module.

[0093] The sensing module 86 is connected (e.g., electrically connected) to a sensing device, which may include electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66 to monitor the electrical activity of the heart 12, such as electrocardiogram (ECG) / electrogram (EGM) signals. ECG / EGM signals can be used to measure or monitor activation time (e.g., ventricular activation time), heart rate (HR), heart rate variability (HRV), heart rate oscillation (HRT), deceleration / acceleration capacity, deceleration sequence morbidity, T wave alternation (TWA), P wave to P wave interval (also known as PP interval or AA interval), R wave to R wave interval (also known as RR interval or VV interval), P wave to QRS complex interval (also known as PR interval, AV interval or PQ interval), QRS complex morphology, ST segment (i.e., the segment connecting the QRS complex and the T wave), T wave changes, QT interval, electrical vectors, etc.

[0094] The switching module 85 can also be used with the sensing module 86 to select which of the available electrodes to use or enable, for example, to sense the electrical activity of a patient's heart (e.g., using one or more electrical vectors of the patient's heart using any combination of electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66). Similarly, the switching module 85 can also be used with the sensing module 86 to select which of the available electrodes to not use (e.g., disable), for example, to sense the electrical activity of a patient's heart (e.g., using one or more electrical vectors of the patient's heart using any combination of electrodes 40, 42, 44, 45, 46, 47, 48, 50, 58, 62, 64, 66), etc. In some instances, the control module 81 can select the electrodes acting as sensing electrodes by providing signals, for example, via a data / address bus, through the switching module within the sensing module 86.

[0095] In some instances, the sensing module 86 includes a channel comprising an amplifier having a relatively wider passband than an R-wave or P-wave amplifier. Signals from selected sensing electrodes can be supplied to a multiplexer and subsequently converted by an analog-to-digital converter into multi-bit digital signals for storage in memory 82, for example, as an electrogram (EGM). In some instances, such storage of an EGM in memory 82 can be under the control of direct memory access circuitry.

[0096] In some instances, the control module 81 can operate as an interrupt-driven device and can respond to interrupts from the pacemaker timing and control module, where the interruption may correspond to the occurrence of sensed P and R waves and the generation of cardiac pacing pulses. Any necessary mathematical calculations can be performed by the processor 80, and any updates to values ​​or intervals controlled by the pacemaker timing and control module can occur after such interruptions. A portion of the memory 82 can be configured as a plurality of recirculation buffers capable of holding one or more series of measurement intervals that can be analyzed by, for example, the processor 80 in response to the occurrence of a pacing or sensing interruption to determine whether the patient's heart 12 is currently exhibiting atrial or ventricular tachyarrhythmias.

[0097] The telemetry module 88 of the control module 81 may include any suitable hardware, firmware, software, or any combination thereof for communicating with another device, such as a programmer. For example, under the control of the processor 80, the telemetry module 88 may receive downlink telemetry from the programmer and send uplink telemetry to the programmer via an antenna (which may be internal and / or external). The processor 80 may, for example, provide, via an address / data bus, the data to be transmitted uplink to the programmer and control signals for the telemetry circuitry within the telemetry module 88. In some instances, the telemetry module 88 may provide the received data to the processor 80 via a multiplexer.

[0098] The various components of the IMD 16 are further coupled to a power source 90, which may include a rechargeable or non-rechargeable battery. A non-rechargeable battery may be selected to last for several years, while a rechargeable battery may be inductively charged from an external device, for example, daily or weekly.

[0099] Figure 15B is another embodiment of the functional block diagram of IMD 16, depicting a bipolar RA lead 22, a bipolar RV lead 18, and a bipolar LV CS lead 20 connected to an implantable pulse generator (IPG) circuit 31 without LA CS pacing / sensing electrodes. This implantable pulse generator circuit has programmable modes known in the pacing field and parameters of the biventricular DDD / R type. Furthermore, a sensor signal processing circuit 91 is indirectly connected to a timing circuit 43 and connected to a microcomputer circuit system 33 via a data and control bus. The IPG circuit 31 is shown in the functional block diagram, which is generally divided into the microcomputer circuit 33 and the pacing circuit 21. The pacing circuit 21 includes a digital controller / timer circuit 43, an output amplifier circuit 51, a sensing amplifier circuit 55, an RF telemetry transceiver 41, an activity sensor circuit 35, and many other circuits and components described below.

[0100] When battery 29 provides power, crystal oscillator circuit 89 provides a basic timing clock to pacing circuit 21. Power-on reset circuit 87 responds to the initial connection of the circuit with the battery to define initial operating conditions, and similarly resets the operating state of the device in response to the detection of a low battery condition. Reference mode circuit 37 generates a stable voltage reference and current for the analog circuitry within pacing circuit 21. Analog-to-digital converter (ADC) and multiplexer circuit 39 digitizes the analog signals and voltages to provide, for example, real-time telemetry of cardiac signals from sensing amplifier 55 for uplink transmission via RF transmitter and receiver circuit 41. Voltage reference and bias circuit 37, ADC and multiplexer 39, power-on reset circuit 87, and crystal oscillator circuit 89 may correspond to any of those used in illustrative implantable cardiac pacemakers.

[0101] If the IPG is programmed into a rate-response mode, signals output from one or more physiological sensors are used as rate control parameters (RCPs) to derive the physiological escape interval. For example, the escape interval is adjusted proportionally to the patient activity level generated in the patient activity sensor (PAS) circuit 35 within the illustrated IPG circuit 31. The patient activity sensor 27 is coupled to the IPG housing and may take the form of a piezoelectric crystal transducer. The output signal of the patient activity sensor 27 can be processed and used as the RCP. Sensor 27 generates an electrical signal in response to sensed body activity, which is processed by the activity circuit 35 and provided to the digital controller / timer circuit 43. The active circuit 35 and associated sensor 27 can correspond to the circuit systems disclosed in U.S. Patent No. 5,052,388, entitled "Method and Apparatus for Implicationing Activity Sensing in a Pulse Generator," published October 1, 1991, and U.S. Patent No. 4,428,378, entitled "Rate Adaptive Pacer," published January 31, 1984. Similarly, the illustrative systems, apparatus, and methods described herein can be practiced in conjunction with alternative types of sensors (such as oxygenation sensors, pressure sensors, pH sensors, and respiration sensors) to provide rate-responsive pacing capability. Alternatively, the QT time can be used as a rate indication parameter, in which case no additional sensor is required. Similarly, the illustrative embodiments described herein can also be practiced in non-rate-responsive pacemakers.

[0102] Data transmission to and from the external programmer is achieved via telemetry antenna 57 and an associated RF transceiver 41, which demodulates both received downlink telemetry and transmits uplink telemetry. Uplink telemetry capability may include the ability to transmit stored digital information, such as operating modes and parameters, EGM histograms and other events, as well as real-time EGM of atrial and / or ventricular electrical activity and marker channel pulses indicating the occurrence of sensed and paced depolarization in the atria and ventricles.

[0103] The microcomputer 33 includes a microprocessor 80 and an associated system clock, as well as on-processor RAM chips 82A and ROM chips 82B. Additionally, the microcomputer circuitry 33 includes a separate RAM / ROM chip 82C to provide additional memory capacity. The microprocessor 80 typically operates in a low-power mode and is interrupt-driven. The microprocessor 80 is awakened in response to defined interrupt events, which may include A-TRIG, RV-TRIG, and LV-TRIG signals generated by timers in the digital timer / controller circuitry 43, and A-EVENT, RV-EVENT, and LV-EVENT signals generated by the sense amplifier circuitry 55, etc. The specific values ​​of the timeout intervals and delays by the digital controller / timer circuitry 43 are controlled by the microcomputer circuitry 33 via data and control buses from programmed parameter values ​​and operating modes. Furthermore, if programmed to operate as a rate-responsive pacemaker, timing interrupts, such as every cycle or every two seconds, may be provided to allow the microprocessor to analyze active sensor data and update the basic AA, VA, or VV escape intervals (if applicable). In addition, the microprocessor 80 can also be used to define variable, operable AV delay intervals, VV delay intervals, and the energy delivered to each ventricle and / or atrium.

[0104] In one embodiment, microprocessor 80 is a custom microprocessor adapted to fetch and execute instructions stored in RAM / ROM unit 82 in a conventional manner. However, other embodiments are contemplated that may be suitable for practicing this disclosure. For example, readily available commercially available microprocessors or microcontrollers or custom-designed dedicated hardwired logic or state machine type circuitry can perform the functions of microprocessor 80.

[0105] The digital controller / timer circuit 43 operates under the general control of the microcomputer 33 to control timing and other functions within the pacing circuit 21, and includes a set of timing and associated logic circuits, some of which are depicted in relation to this disclosure. The depicted timing circuits include a URI / LRI timer 83A, a VV delay timer 83B, an intrinsic interval timer 83C for timing the elapsed V-EVENT to V-EVENT interval or V-EVENT to A-EVENT interval or VV conduction interval, an escape interval timer 83D for timing the AA, VA, and / or VV pacing escape interval, an AV delay interval timer 83E for timing the A-LVp delay (or A-RVp delay) from a previous A-EVENT or A-TRIG, a postventricular timer 83F for timing the postventricular time period, and a date / time clock 83G.

[0106] The AV delay interval timer 83E is loaded with an appropriate delay interval (e.g., A-RVp delay or A-LVp) for a ventricular chamber to time out from a previous A-PACE or A-EVENT. The interval timer 83E triggers pacing stimulus delivery and can be based on one or more previous cardiac cycles (or on a dataset derived empirically for a given patient).

[0107] The post-event timer 83F causes the post-ventricular time period following RV-EVENT, LV-EVENT, RV-TRIG, or LV-TRIG, and the post-atrial time period following A-EVENT or A-TRIG, to time out. The duration of the post-event time period can also be selected as a programmable parameter stored in the microcomputer 33. The post-ventricular time period includes PVARP, post-atrial ventricular blanking period (PAVBP), ventricular blanking period (VBP), post-ventricular atrial blanking period (PVARP), and ventricular refractory period (VRP), but other time periods can be appropriately defined, at least in part, according to the operating circuitry system employed in the pacemaker. The post-atrial time period includes the atrial refractory period (ARP) and atrial blanking period (ABP). During the atrial refractory period, A-EVENT is ignored for the purpose of resetting any AV delays, and during the atrial blanking period, atrial sensing is disabled. It should be noted that the onset of the post-atrial time interval and AV delay may begin substantially simultaneously with the start or end of each A-EVENT or A-TRIG, or in the latter case, at the end of an A-PACE that can follow an A-TRIG. Similarly, the onset of the post-ventricular time interval and VA escape interval may begin substantially simultaneously with the start or end of a V-EVENT or V-TRIG, or in the latter case, at the end of a V-PACE that can follow a V-TRIG. The microprocessor 80 also optionally calculates the AV delay, VV delay, post-ventricular time interval, and post-atrial time interval, which vary with sensor-based escape intervals and / or intrinsic atrial and / or ventricular rates established in response to one or more RCPs.

[0108] Output amplifier circuit 51 includes an RA pacing pulse generator (and an LA pacing pulse generator, if LA pacing is provided), an RV pacing pulse generator, an LV pacing pulse generator, and / or any other pulse generator configured to provide atrial and ventricular pacing. To trigger the generation of an RV-PACE or LV-PACE pulse, digital controller / timer circuit 43 generates an RV-TRIG signal when the A-RVp delay (in the case of RV pre-excitation) provided by AV delay interval timer 83E (or VV delay timer 83B) times out, or generates an LV-TRIG signal when the A-LVp delay (in the case of LV pre-excitation) times out. Similarly, digital controller / timer circuit 43 generates an RA-TRIG signal (or an LA-TRIG signal, if provided) that triggers the output of an RA-PACE pulse at the end of a VA escape interval timed by escape interval timer 83D.

[0109] Output amplifier circuit 51 includes a switching circuit for connecting selected pacing electrode pairs from the lead conductors and IND-CAN electrodes 20 to an RA pacing pulse generator (and an LA pacing pulse generator, if provided), an RV pacing pulse generator, and an LV pacing pulse generator. Pacing / sensing electrode pair selection and control circuit 53 selects the lead conductors and associated pacing electrode pairs for connection to the atrial and ventricular output amplifiers within output amplifier circuit 51 for RA, LA, RV, and LV pacing.

[0110] Sensing amplifier circuit 55 contains sensing amplifiers for atrial and ventricular pacing and sensing. High-impedance P-wave and R-wave sensing amplifiers can be used to amplify the voltage difference signal generated across the sensing electrode pair due to the passage of the cardiac depolarization wavefront. The high-impedance sensing amplifier uses high gain to amplify low-amplitude signals and relies on passband filtering, time-domain filtering, and amplitude threshold comparison to distinguish the P-wave or R-wave from background electrical noise. Digital controller / timer circuit 43 controls the sensitivity settings of atrial and ventricular sensing amplifier 55.

[0111] During the blanking period before, during, and after the delivery of a pacing pulse to any of the pacing electrodes in the pacing system, the sensing amplifier can be decoupled from the sensing electrode to avoid saturation of the sensing amplifier. Sensing amplifier circuit 55 includes a blanking circuit for decoupling selected lead conductor pairs and IND-CAN electrode 20 from the inputs of the RA sensing amplifier (and LA sensing amplifier, if provided), RV sensing amplifier, and LV sensing amplifier during ABP, PVABP, and VBP. Sensing amplifier circuit 55 also includes a switching circuit for connecting selected sensing electrode lead conductors and IND-CAN electrode 20 to the RA sensing amplifier (and LA sensing amplifier, if provided), RV sensing amplifier, and LV sensing amplifier. Similarly, sensing electrode selection and control circuit 53 selects the conductors and associated sensing electrode pairs to be coupled to the atrial and ventricular sensing amplifiers within output amplifier circuit 51 and sensing amplifier circuit 55 for RA, LA, RV, and LV sensing along desired unipolar and bipolar sensing vectors.

[0112] Right atrial depolarization or a P wave in the RA-SENSE signal sensed by the RA sensing amplifier results in an RA-EVENT signal being transmitted to the digital controller / timer circuit 43. Similarly, left atrial depolarization or a P wave in the LA-SENSE signal sensed by the LA sensing amplifier (if provided) results in an LA-EVENT signal being transmitted to the digital controller / timer circuit 43. Ventricular depolarization or an R wave in the RV-SENSE signal sensed by the ventricular sensing amplifier results in an RV-EVENT signal being transmitted to the digital controller / timer circuit 43. Similarly, ventricular depolarization or an R wave in the LV-SENSE signal sensed by the ventricular sensing amplifier results in an LV-EVENT signal being transmitted to the digital controller / timer circuit 43. The RV-EVENT, LV-EVENT, RA-EVENT, and LA-SENSE signals may be refractory or responsive and may be inadvertently triggered by electrical noise signals or abnormally conducted depolarization waves instead of genuine R or P waves.

[0113] The techniques described in this disclosure (including those attributable to IMD 16, computing device 140, and / or various constituent components) can be implemented at least in part in the form of hardware, software, firmware, or any combination thereof. For example, aspects of the techniques can be implemented within one or more processors embodied in a programmer, stimulator, image processing device, or other apparatus, such as a physician or patient programmer, including one or more microprocessors, DSPs, ASICs, FPGAs, or any other equivalent integrated or discrete logic circuit systems, and any combination of such components. The terms “module,” “processor,” or “processing circuit system” generally refer to any circuit system, alone or in combination with other logic circuit systems, or any other equivalent circuit system.

[0114] Such hardware, software, and / or firmware may be implemented within the same device or in separate devices to support the various operations and functions described in this disclosure. Furthermore, any described unit, module, or component may be implemented together or individually as discrete but interoperable logical devices. Describing different features as modules or units is intended to highlight different functional aspects and does not necessarily imply that such modules or units must be implemented by separate hardware or software components. Rather, the functionality associated with one or more modules or units may be performed by separate hardware or software components, or integrated into common or separate hardware or software components.

[0115] When implemented in software, the functionality attributable to the systems, apparatus, and techniques described in this disclosure can be embodied in instructions on a computer-readable medium such as RAM, ROM, NVRAM, EEPROM, flash memory, magnetic data storage media, optical data storage media, etc. The instructions can be executed by a processing circuitry system and / or one or more processors to support one or more aspects of the functionality described in this disclosure.

[0116] Illustrative Examples

[0117] Example 1. A system for cardiac assessment, comprising:

[0118] i. An electrode device comprising multiple external electrodes to be placed proximal to the patient's skin; and

[0119] ii. A computing device comprising a processing circuitry system, said computing device being operatively coupled to an electrode device and configured to:

[0120] iii. Use multiple external electrodes to monitor electrical activity from patient tissues to generate multiple electrical signals;

[0121] i. Filter at least one electrical signal from a plurality of electrical signals;

[0122] ii. Detect at least one interference in at least one electrical signal using at least one filtered signal; and

[0123] iii. Determine the time location of at least one interference in at least one electrical signal based on the time during which at least one filtered signal exceeds a predetermined threshold.

[0124] Example 2. The system according to Example 1, wherein electrical activity includes an electrical activation time representing depolarization propagating through cardiac tissues of the patient's torso.

[0125] Example 3. The system according to any one of Examples 1 to 2, wherein the plurality of external electrodes comprises a plurality of surface electrodes to be positioned proximal to the patient's trunk skin.

[0126] Example 4. The system according to any one of Examples 1 to 3, wherein the predetermined threshold is based on the sampling rate of at least one electrical signal.

[0127] Example 5. The system according to any one of Examples 1 to 4, further wherein the computing device is configured to remove at least one interference.

[0128] Example 6. The system according to Example 5, wherein after removing at least one interference, the computing device is configured to use electrical signals to determine multiple cardiac activation times.

[0129] Example 7. The system according to any one of Examples 1 to 6, wherein the computing device is configured to smooth at least one electrical signal within a window, the window starting at a predetermined time period before at least one time position of interference and extending for a predetermined amount of time after at least one time position of interference.

[0130] Example 8. The system according to any one of Examples 1 to 7, wherein the computing device is configured to:

[0131] i. Determine the timing location of at least one interference in at least two electrical signals; and

[0132] ii. Smooth multiple electrical signals at the time location of at least one of at least two interfering signals.

[0133] Example 9. The system according to any one of Examples 1 to 8, wherein the computing device is configured to filter at least one electrical signal using a second differential filter.

[0134] Example 10. The system according to any one of Examples 1 to 9, wherein the computing device is configured to determine a predetermined threshold based on a predetermined pulse width range.

[0135] Example 11. The system according to any one of Examples 1 to 10, wherein a computing device is configured to determine the time position of at least one disturbance within a predetermined window, the predetermined window being based on the amplitude of at least one electrical signal.

[0136] Example 12. The system according to any one of Examples 1 to 11, wherein at least one interference comprises one or more of pacing spikes and muscle-generated noise.

[0137] Example 13. A system for cardiac assessment, comprising:

[0138] i. An electrode device comprising multiple external electrodes to be placed proximal to the patient's skin; and

[0139] i. A computing device comprising a processing circuitry system, said computing device being operatively coupled to an electrode device and configured to:

[0140] ii. Use multiple external electrodes to monitor electrical activity from patient tissues to generate multiple electrical signals;

[0141] iii. Detect at least one interference among multiple electrical signals;

[0142] iv. Determine the time location of at least one interference in at least one electrical signal; and

[0143] v. Remove at least one interference based on the time location of at least one interference in at least one electrical signal.

[0144] Example 14. The system according to Example 13, wherein the computing device is configured to remove at least one interference based on the time position of the at least one interference in at least one electrical signal if at least one interference is detected in at least a selected number of a plurality of signals.

[0145] Example 15. The system according to Example 14, wherein the selected quantity includes at least four electrical signals.

[0146] Example 16. The system according to any one of Examples 13 to 15, wherein the computing device is configured to smooth at least one electrical signal within a window that begins a predetermined time period before at least one time position of interference and extends for a predetermined amount of time after at least one time position of interference.

[0147] Example 17. The system according to any one of Examples 13 to 16, wherein after removing at least one interference, the computing device is configured to use electrical signals to determine multiple cardiac activation times.

[0148] Example 18. A method for cardiac assessment, comprising:

[0149] i. Use multiple external electrodes to monitor electrical activity from patient tissues to generate multiple electrical signals;

[0150] ii. Filter at least one electrical signal from a plurality of electrical signals;

[0151] iii. Detect at least one interference in at least one electrical signal using the at least one filtered signal; and

[0152] iv. Determine the time location of at least one interference in at least one electrical signal based on the time during which at least one filtered signal exceeds a predetermined threshold.

[0153] Example 19. The method according to Example 18, wherein the electrical activity includes an electrical activation time representing the depolarization propagating through cardiac tissue in the patient's torso.

[0154] Example 20. The method according to any one of Examples 18 to 19, wherein the plurality of external electrodes comprises a plurality of surface electrodes to be positioned proximal to the patient's trunk skin.

[0155] Example 21. The method according to any one of Examples 18 to 20, wherein the predetermined threshold is based on the sampling rate of at least one electrical signal.

[0156] Example 22. The method according to any one of Examples 18 to 21 further comprises removing at least one interference from at least one electrical signal.

[0157] Example 23. The method according to Example 22, wherein removing at least one interference includes smoothing at least one electrical signal within a window, the window starting at a predetermined time period before the time position of at least one interference and extending for a predetermined amount of time after the time position of at least one interference.

[0158] Example 24. The method according to any one of Examples 22 to 23, wherein detecting at least one interference in at least one electrical signal using at least one filtered signal includes detecting at least a first interference and a second interference in at least one electrical signal, the second interference occurring after the first interference.

[0159] i. Wherein determining the time position of at least one interference in at least one electrical signal includes determining the time positions of a first interference and a second interference.

[0160] ii. The method further includes removing a first interference and a second interference by smoothing at least one electrical signal within a window, the window starting a predetermined time period before the time position of the first interference and extending for a predetermined amount of time after the time position of the second interference.

[0161] Example 25. The method according to any one of Examples 22 to 24, further comprising, after removing at least one interference, using an electrical signal to determine multiple cardiac activation times.

[0162] Example 26. The method according to any one of Examples 18 to 25, wherein determining the time location of at least one interference comprises:

[0163] i. Determine the timing location of at least one interference in at least two electrical signals; and

[0164] ii. Smooth multiple electrical signals at the time location of at least one of at least two interfering signals.

[0165] Example 27. The method according to any one of Examples 18 to 26, wherein filtering at least one electrical signal comprises filtering at least one signal using a second differential filter.

[0166] This disclosure is provided with reference to illustrative embodiments and is not intended to be limiting. As previously described, those skilled in the art will recognize that various other illustrative applications can utilize the beneficial features of the devices and methods described herein using the techniques described herein. Various modifications to the illustrative embodiments and further embodiments of this disclosure will become apparent in this specification.

Claims

1. A system for cardiac assessment, comprising: an electrode apparatus comprising a plurality of external electrodes to be disposed proximal to the skin of a patient; and a computing apparatus comprising processing circuitry, the computing apparatus operably coupled to the electrode apparatus and configured to: monitor electrical activity from the tissue of a patient using the plurality of external electrodes to produce a plurality of electrical signals; filter at least one of the plurality of electrical signals; detect at least one disturbance in the at least one electrical signal using at least one filtered signal; and determine a temporal location of the at least one disturbance in the at least one electrical signal based on a time at which the at least one filtered signal exceeds a predetermined threshold, wherein the computing apparatus is configured to remove the at least one disturbance and, after removing the at least one disturbance, determine a plurality of cardiac activation times using the at least one filtered signal.

2. The system of claim 1, wherein the electrical activity comprises electrical activation times representing depolarization propagating through cardiac tissue of the patient torso.

3. The system of any of claims 1-2, wherein the plurality of external electrodes comprises a plurality of surface electrodes to be positioned proximal to the skin of the patient torso.

4. The system of any of claims 1-2, wherein the predetermined threshold is based on a sampling rate of the at least one electrical signal.

5. The system of any of claims 1-2, wherein the computing apparatus is configured to smooth the at least one electrical signal within a window that begins a predetermined period of time before the temporal location of the at least one disturbance and extends a predetermined amount of time after the temporal location of the at least one disturbance.

6. The system of any of claims 1-2, wherein the computing apparatus is configured to: determine a temporal location of the at least one disturbance in at least two electrical signals; and smooth the plurality of electrical signals at the temporal location of the at least one disturbance in the at least two electrical signals.

7. The system of any of claims 1-2, wherein the computing apparatus is configured to filter the at least one electrical signal using a second difference filter.

8. The system of any of claims 1-2, wherein the computing apparatus is configured to determine the predetermined threshold based on a predetermined pulse width range.

9. The system of any of claims 1-2, wherein the computing apparatus is configured to determine the temporal location of the at least one disturbance within a predetermined window, the predetermined window based on an amplitude of the at least one electrical signal.

10. The system of any of claims 1-2, wherein the at least one disturbance comprises one or more of a pacing spike and muscle-generated noise.

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