阅读说明：本技术 用于心脏标测的系统和方法 (Systems and methods for cardiac mapping ) 是由 D·J·摩根 D·C·德诺 E·K·戴维斯 T·P·哈特利 M·哈格福什 于 2020-05-22 设计创作，主要内容包括：可以使用电生理信号的子区间来标测电生理活动。电解剖标测系统接收多个电生理信号(402),每个电生理信号跨越一激活区间。对于每个信号,系统识别激活区间内的初始事件时间,例如通过识别最大信号能量的时间(404),并定义围绕初始事件时间的子区间(406)。系统然后分析子区间以识别电生理信号的一个或多个电生理特征(408)并将相应的电生理数据点添加到电生理标测图(410)。有利地,子区间可以延伸到激活区间的外部,使得本教导允许捕获和分析在激活区间的边界处或附近发生的偏转。(The sub-intervals of the electrophysiological signals can be used to map the electrophysiological activity. The electroanatomical mapping system receives a plurality of electrophysiological signals (402), each electrophysiological signal spanning an activation interval. For each signal, the system identifies an initial event time within the activation interval, such as by identifying a time of maximum signal energy (404), and defines a subinterval around the initial event time (406). The system then analyzes the subintervals to identify one or more electrophysiological characteristics of the electrophysiological signal (408) and adds corresponding electrophysiological data points to the electrophysiological map (410). Advantageously, the subintervals may extend outside of the activation interval, such that the present teachings allow for the capture and analysis of deflections occurring at or near the boundaries of the activation interval.)

1. A method of mapping electrophysiological activity, comprising:

receiving a plurality of electrophysiological signals at an electroanatomical mapping system, wherein each electrophysiological signal spans an activation interval; and

for each electrophysiological signal of the plurality of electrophysiological signals, the electroanatomical mapping system:

identifying an initial event time within the activation interval of the electrophysiological signal;

defining a subinterval around the initial event time;

analyzing the subintervals to identify one or more electrophysiological characteristics of the electrophysiological signal; and

adding an electrophysiology data point to the electrophysiology map, wherein the electrophysiology data point comprises one or more electrophysiology features of the electrophysiology signal associated with the location at which the electrophysiology signal was measured.

2. The method according to claim 1, further comprising the electroanatomical mapping system outputting a graphical representation of the electrophysiology map on an anatomical model.

3. The method of claim 1, wherein identifying an initial event time within the activation interval of the electrophysiological signal comprises using an energy function to identify the initial event time.

4. The method of claim 3, wherein identifying the initial event time using an energy function comprises identifying a time of maximum signal energy of the energy function as the initial event time.

5. The method of claim 1, wherein identifying an initial event time within the activation interval of the electrophysiological signal comprises using template matching to identify the initial event time.

6. The method of claim 5, wherein identifying the initial event time using template matching comprises identifying a time of maximum morphological correlation between the electrophysiological signal and a template signal as the initial event time.

7. The method of claim 1, wherein identifying an initial event time within the activation interval of the electrophysiological signal comprises using a weighted window function to identify the initial event time.

8. The method of claim 1, wherein the electrophysiological signal comprises an omnipolar signal.

9. The method of claim 8, wherein the omnipolar signal comprises an omnipolar electrogram defined by at least two bipolar electrograms, and wherein identifying an initial event time within the activation interval of the electrophysiological signal comprises calculating a root mean square of derivatives of the at least two bipolar electrograms to identify the initial event time.

10. The method of claim 8, wherein the omnipolar signal comprises an omnipolar electrogram defined by at least two bipolar electrograms, and wherein identifying an initial event time within the activation interval of the electrophysiological signal comprises calculating a mean absolute value transformation of a derivative of the at least two bipolar electrograms to identify the initial event time.

11. The method of claim 8, wherein the omnipolar signal comprises an omnipolar electrogram defined by two orthogonal bipolar electrograms, and wherein identifying an initial event time within the activation interval of the electrophysiological signal comprises calculating a norm of a derivative of the two orthogonal bipolar electrograms to identify the initial event time.

12. The method of claim 11, wherein identifying an initial event time within the activation interval of the electrophysiological signal further comprises at least one of:

high pass filtering the derivatives of the two orthogonal bipolar electrograms prior to calculating the norm of the derivatives of the two orthogonal bipolar electrograms; and

low pass filtering the computed norm of the derivatives of the two orthogonal bipolar electrograms.

13. The method of claim 1, wherein defining a subinterval around the initial event time comprises defining the subinterval as an interval of a preset duration centered at the initial event time.

14. The method of claim 1, wherein defining a subinterval around the initial event time comprises:

the electroanatomical mapping system receiving user input defining a duration of the subinterval; and

defining the subinterval as an interval of user-defined duration centered at the initial event time.

15. The method of claim 1, wherein the subinterval extends outside of the activation interval.

16. A method of mapping electrophysiological activity, comprising:

receiving a plurality of electrophysiological signals at an electroanatomical mapping system; and

for each electrophysiological signal of the plurality of electrophysiological signals, the electroanatomical mapping system:

processing the electrophysiological signals to define a subinterval comprising a deflection of interest;

analyzing only the subintervals to identify one or more electrophysiological characteristics of the electrophysiological signal; and

adding an electrophysiology data point to the electrophysiology map, wherein the electrophysiology data point comprises one or more electrophysiology features of the electrophysiology signal associated with the location at which the electrophysiology signal was measured.

17. The method of claim 16, wherein the electrophysiological signal comprises a full polar electrogram defined by at least two bipolar electrograms.

18. The method of claim 17, wherein the at least two bipolar electrograms comprise a pair of orthogonal bipolar electrograms.

19. The method according to claim 16, further comprising the electroanatomical mapping system outputting a graphical representation of the electrophysiology map on an anatomical model.

20. The method of claim 16, wherein the subintervals are centered at the deflection of interest.

21. An electroanatomical mapping system, comprising:

a subinterval definition processor configured to:

receiving an electrophysiological signal spanning an activation interval;

identifying a deflection of interest within the activation interval of the electrophysiological signal; and

defining a subinterval around the deflection of interest; and

a mapping processor configured to:

analyzing the subintervals to identify one or more electrophysiological characteristics of the electrophysiological signal; and

adding an electrophysiology data point to the electrophysiology map, wherein the electrophysiology data point comprises one or more electrophysiology features of the electrophysiology signal associated with the location at which the electrophysiology signal was measured.

Technical Field

The present disclosure relates generally to cardiac mapping such as may be performed in cardiac diagnostic and therapeutic procedures. In particular, the present disclosure relates to systems, devices, and methods for generating cardiac geometry and/or electrophysiology maps from data acquired by an roving electrophysiology probe, such as a high density ("HD") mesh catheter or other multi-electrode device.

Background

Cardiac mapping, including generation of cardiac geometry and electrocardiographic mapping, is part of many cardiac diagnostic and therapeutic procedures. However, as the complexity of such procedures increases, the geometries and electrophysiology maps used must increase in quality, density, and the speed and ease with which they are generated.

Electrocardiographic mapping typically involves analyzing intracardiac electrograms over a particular time interval (referred to in the art as the "itinerant activation interval" or "RAI"). However, because of the multiple deflections present within the RAI, the electrogram analysis may be complex.

Disclosure of Invention

A method of mapping electrophysiological activity is disclosed herein. The method includes receiving a plurality of electrophysiological signals at an electroanatomical mapping system, wherein each electrophysiological signal spans an activation interval. For each electrophysiological signal of the plurality of electrophysiological signals, the electroanatomical mapping system: identifying an initial event time within an activation interval of the electrophysiological signal; defining a subinterval around the initial event time; analyzing the subintervals to identify one or more electrophysiological characteristics of the electrophysiological signal; and adding an electrophysiology data point to the electrophysiology map, wherein the electrophysiology data point includes one or more electrophysiology features of the electrophysiology signal associated with the location at which the electrophysiology signal was measured. The electroanatomical mapping system may also output a graphical representation of the electrophysiology map on the anatomical model.

In aspects of the present disclosure, the step of identifying an initial event time within an activation interval of the electrophysiological signal comprises identifying the initial event time using an energy function, for example by identifying a time of maximum signal energy of the energy function as the initial event time.

In other aspects of the disclosure, the step of identifying an initial event time within the activation interval of the electrophysiological signal comprises identifying the initial event time using template matching, for example by identifying a maximum morphology-related time between the electrophysiological signal and the template signal as the initial event time.

In a further aspect of the disclosure, the step of identifying an initial event time within an activation interval of the electrophysiological signal comprises using a weighted window function to identify the initial event time.

The teachings herein may be applied to a bipolar electrophysiological signal, such as a bipolar electrogram defined by at least two bipolar electrograms. The step of identifying an initial event time within an activation interval of the electrophysiological signal may comprise calculating a root mean square of the derivatives of the at least two bipolar electrograms to identify the initial event time. Alternatively, the step of identifying an initial event time within an activation interval of the electrophysiological signal may comprise calculating a mean absolute value transformation of the derivatives of the at least two bipolar electrograms to identify the initial event time.

In some embodiments, the omnipolar electrogram is defined by two (or more) orthogonal bipolar electrograms, and the step of identifying an initial event time within an activation interval of the electrophysiological signal comprises calculating a norm (norm) of a derivative of the two (or more) orthogonal bipolar electrograms to identify the initial event time. The step of identifying an initial event time within an activation interval of the electrophysiological signal may further comprise at least one of: high pass filtering the derivatives of the two orthogonal bipolar electrograms prior to calculating the norm of the derivatives of the two orthogonal bipolar electrograms; and low pass filtering the norm of the calculated derivatives of the two orthogonal bipolar electrograms.

It is contemplated that the step of defining a subinterval around the initial event time may include defining the subinterval as an interval of a preset duration centered at the initial event time. It is also contemplated that the step of defining a subinterval around the initial event time may include: the electroanatomical mapping system receiving user input defining a duration of a subinterval; and defining the subintervals as intervals of user-defined duration centered at the initial event time.

In embodiments of the present disclosure, the subintervals extend outside of the activation interval (e.g., the roving activation interval, or RAI).

Also disclosed herein is a method of mapping electrophysiological activity, comprising: receiving a plurality of electrophysiological signals at an electroanatomical mapping system; and for each electrophysiological signal of the plurality of electrophysiological signals, the electroanatomical mapping system: processing the electrophysiological signals to define a subinterval comprising the deflection of interest; analyzing only the subintervals to identify one or more electrophysiological characteristics of the electrophysiological signal; and adding an electrophysiology data point to the electrophysiology map, wherein the electrophysiology data point includes one or more electrophysiology features of the electrophysiology signal associated with the location at which the electrophysiology signal was measured.

The electrophysiological signal may comprise a full-polar electrogram defined by at least two bipolar electrograms; in some embodiments, the at least two bipolar electrograms comprise a pair of orthogonal bipolar electrograms.

The method optionally includes the electroanatomical mapping system outputting a graphical representation of the electrophysiology map on the anatomical model.

According to aspects of the present disclosure, the subintervals are centered at the deflections of interest.

The present disclosure also provides an electroanatomical mapping system comprising a subinterval definition processor configured to: receiving an electrophysiological signal spanning an activation interval; identifying a deflection of interest within an activation interval of the electrophysiological signal; and defining a sub-interval around the deflection of interest. The electroanatomical mapping system also includes a mapping processor configured to: analyzing the subintervals to identify (e.g., quantify) one or more electrophysiological characteristics of the electrophysiological signals; and adding an electrophysiology data point to the electrophysiology map, wherein the electrophysiology data point includes one or more electrophysiology features of the electrophysiology signal associated with the location at which the electrophysiology signal was measured.

The foregoing and other aspects, features, details, utilities, and advantages of the present invention will be apparent from reading the following description and claims, and from reviewing the accompanying drawings.

Drawings

Fig. 1 is a schematic diagram of an exemplary electroanatomical mapping system.

Fig. 2 depicts an exemplary catheter that may be used in connection with aspects of the present disclosure.

Fig. 3A and 3B provide an electrode carried by a multi-electrode catheter and a bipolar alphanumeric labeling convention associated therewith.

Fig. 4 is a flowchart of representative steps that may be performed in accordance with exemplary embodiments disclosed herein.

Fig. 5 is an illustrative screen from an electroanatomical mapping system depicting a graphical representation of an electrophysiology map alongside an omnipolar electrogram trace.

Fig. 6 is a close-up view of a full-polar electrogram and the bipolar electrograms comprising it, labeled to show initial event times and subintervals, in accordance with aspects of the present disclosure.

Fig. 7 is a close-up view of an all-polar electrogram, its energy function, and the bipolar electrograms that make up it, labeled to show initial event times and subintervals, in accordance with aspects of the present disclosure.

While multiple embodiments are disclosed, other embodiments of the present disclosure will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not as restrictive.

Detailed Description

The present disclosure provides systems, devices, and methods for generating electrophysiology maps. For purposes of illustration, aspects of the present disclosure will be described with reference to cardiac electrophysiology procedures. More specifically, Advisor from the use of High Density (HD) grid conduits (e.g., Abbott Laboratories, Ardisia park, Ill.) will be used^TMHD mesh mapping catheter) in combination with an electroanatomical mapping system (e.g., EnSite Precision)^TMCardiac mapping system, also from yapei corporation) creates a cardiac electrophysiology map.

However, one of ordinary skill in the art will understand how to better apply the teachings herein in other situations and/or with respect to other devices. For example, the present teachings are equally applicable to other electrophysiological signals, such as from other electrophysiological catheters (including but not limited to flexiliity)^TM、Advisor^TM、Reflexion^TM、Inquiry^TMAnd/or Livewire^TMElectrophysiology catheters, all from yapei corporation) received unipolar and/or bipolar electrograms.

Fig. 1 shows a schematic diagram of an exemplary electroanatomical mapping system 8, the exemplary electroanatomical mapping system 8 being used for conducting a cardiac electrophysiology study by navigating a cardiac catheter and measuring electrical activity occurring in a heart 10 of a patient 11 and mapping the electrical activity in three dimensions and/or information related to or representative of the electrical activity so measured. The system 8 may be used, for example, to create an anatomical model of a patient's heart 10 using one or more electrodes. The system 8 may also be used to measure electrophysiological data at a plurality of points along the surface of the heart and store the measured data in association with location information for each measurement point at which the electrophysiological data was measured, for example, to create a diagnostic data map of the patient's heart 10.

As one of ordinary skill in the art will appreciate, the system 8 determines the location of objects generally within a three-dimensional space and, in some aspects, determines the orientation of the objects and expresses these locations as positional information determined relative to at least one reference.

For simplicity of illustration, the patient 11 is schematically depicted as an oval. In the embodiment shown in fig. 1, three sets of surface electrodes (e.g., patch electrodes) are shown applied to the surface of the patient 11, which define three substantially orthogonal axes, referred to herein as the x-axis, y-axis, and z-axis. In other embodiments, the electrodes may be positioned in other arrangements, such as multiple electrodes on a particular body surface. As another alternative, the electrodes need not be on the surface of the body, but may be positioned inside the body.

In fig. 1, the x-axis surface electrodes 12, 14 are applied to the patient along a first axis, such as to the sides of the patient's chest region (e.g., to the skin under each arm of the patient), and may be referred to as left and right electrodes. The y-axis electrodes 18, 19 are applied to the patient along a second axis that is generally orthogonal to the x-axis, such as along the medial thigh and neck regions of the patient, and may be referred to as left leg and neck electrodes. The z-axis electrodes 16, 22 are applied along a third axis that is substantially orthogonal to both the x-axis and the y-axis, such as along the sternum and spine in the chest region of the patient, and may be referred to as chest and back electrodes. Heart 10 is located between these pairs of surface electrodes 12/14, 18/19, and 16/22.

An additional surface reference electrode (e.g., a "belly patch") 21 provides a reference and/or ground electrode for the system 8. The abdominal patch electrode 21 may be an alternative to the fixed intracardiac electrode 31, as described in further detail below. It should also be understood that, in addition, the patient 11 may have most or all of the conventional electrocardiogram ("ECG" or "EKG") system lead wires in place. In certain embodiments, for example, a standard set of 12 ECG lead wires may be used to sense an electrocardiogram on the patient's heart 10. This ECG information is available to the system 8 (e.g., it may be provided as input to the computer system 20). To the extent that the ECG lead wires are well understood, and in order to make the drawing clearer, only a single lead wire 6 and its connection to the computer 20 are shown in fig. 1.

Also shown is a representative catheter 13 having at least one electrode 17. Throughout the specification, this representative catheter electrode 17 is referred to as a "roving electrode", a "moving electrode", or a "measurement electrode". Typically, a plurality of electrodes 17 on the catheter 13 or on a plurality of such catheters will be used. For example, in one embodiment, system 8 may include sixty-four electrodes disposed on twelve catheters within a patient's heart and/or vasculature. In other embodiments, system 8 may utilize a single catheter that includes multiple (e.g., eight) splines, each spline in turn including multiple (e.g., eight) electrodes.

However, the foregoing embodiments are merely exemplary, and any number of electrodes and/or catheters may be used. For example, for purposes of this disclosure, one section of an exemplary multi-electrode catheter, particularly an HD mesh catheter, is shown in fig. 2. HD mesh catheter 13 includes a catheter body 200 coupled to a paddle 202. The catheter body 200 may also include a first body electrode 204 and a second body electrode 206. Paddle 202 may include a first spline 208, a second spline 210, a third spline 212, and a fourth spline 214 coupled to catheter body 200 by a proximal coupler 216, and to each other by a distal coupler 218. In one embodiment, first spline 208 and fourth spline 214 may be one continuous segment, and second spline 210 and third spline 212 may be another continuous segment. In other embodiments, each spline 208, 210, 212, 214 may be separate sections coupled to each other (e.g., by proximal coupler 216 and distal coupler 218, respectively). It should be understood that the HD catheter 13 may comprise any number of splines; the arrangement of four splines shown in fig. 2 is merely exemplary.

As described above, splines 208, 210, 212, 214 may include any number of electrodes 17; in fig. 2, sixteen electrodes 17 are shown arranged in a four by four array. It should also be appreciated that the electrodes 17 may be evenly and/or unevenly spaced, both as measured along the splines 208, 210, 212, 214 and between the splines 208, 210, 212, 214. For ease of reference in this specification, figure 3A provides alphanumeric indicia for electrodes 17.

As one of ordinary skill in the art will recognize, any two adjacent electrodes 17 define a dipole. Thus, the 16 electrodes 17 on the catheter 13 define a total of 42 bipoles-12 along the splines (e.g., between electrodes 17a and 17b, or between electrodes 17c and 17 d), 12 across the splines (e.g., between electrodes 17a and 17c, or between electrodes 17b and 17 d), and 18 between the diagonal splines (e.g., between electrodes 17a and 17d, or between electrodes 17b and 17 c).

For ease of reference in this specification, fig. 3B provides alphanumeric indicia along the splines and across the dipoles of the splines. The alphanumeric labels for the diagonal dipole are omitted from fig. 3B, but this is for clarity in illustration only. It is expressly contemplated that the teachings herein are also applicable to diagonal bipoles.

Conversely, any bipole may be used to generate a bipolar electrogram, according to techniques that will be familiar to those of ordinary skill in the art. Furthermore, by calculating the electric field or voltage loops of the electrode clusters, these bipolar electrograms may be combined (e.g., linearly combined) to generate an electrogram in any direction of the plane of catheter 13, also including activation timing information. Details of computing E-field rings for an electrode ensemble on an HD mesh catheter are disclosed in U.S. patent application publication No.2018/0296111 (' 111 publication), which is incorporated herein by reference as if fully set forth herein.

In any case, the catheter 13 may be used to simultaneously acquire a plurality of electrophysiology data points for each bipole defined by the electrodes 17 thereon, each such electrophysiology data point including localization information (e.g., the position and orientation of the selected bipole) and an electrogram signal for the selected bipole. For purposes of illustration, the method according to the present disclosure will be described with reference to various electrophysiology data points acquired by catheter 13. However, it should be understood that the teachings herein may be applied to multiple electrophysiology data points acquired by catheter 13 in series and/or in parallel.

The catheter 13 (or a plurality of such catheters) is typically introduced into the patient's heart and/or vasculature via one or more introducers and using familiar procedures. Indeed, various methods of introducing the catheter 13 into the heart of a patient, such as transseptal methods, will be familiar to those of ordinary skill in the art and need not be described further herein.

Because each electrode 17 is located within the patient, system 8 can acquire position data for each electrode 17 simultaneously. Similarly, each electrode 17 may be used to acquire electrophysiological data from the surface of the heart (e.g., a surface electrogram). One of ordinary skill will be familiar with various ways for the acquisition and processing of electrophysiology data points (including, for example, contact and non-contact electrophysiology mapping), such that further discussion thereof is unnecessary for an understanding of the techniques disclosed herein. Likewise, a graphical representation of cardiac geometry and/or cardiac electrical activity may be generated from a plurality of electrophysiology data points using various techniques familiar in the art. Further, to the extent that one of ordinary skill would understand how to create an electrophysiology map from electrophysiology data points, aspects herein are described only to the extent necessary to understand the present disclosure.

Returning now to fig. 1, in some embodiments, an optional fixed reference electrode 31 (e.g., attached to the wall of heart 10) is shown on second catheter 29. For calibration purposes, this electrode 31 may be fixed (e.g., attached to or near the heart wall) or disposed in a fixed spatial relationship to the roving electrode (e.g., electrode 17), and thus may be referred to as a "navigational reference" or a "local reference". In addition to or instead of the surface reference electrode 21 described above, a fixed reference electrode 31 may be used. In many cases, the coronary sinus electrode or other fixed electrode in the heart 10 may be used as a reference for measuring voltages and displacements; that is, the fixed reference electrode 31 may define the origin of a coordinate system, as described below.

Each surface electrode is coupled to a multiplexing switch 24 and the pair of surface electrodes is selected by software running on a computer 20, which computer 20 couples the surface electrodes to a signal generator 25. Alternatively, the switch 24 may be omitted and multiple (e.g., three) instances of the signal generator 25 may be provided, one instance for each measurement axis (i.e., each surface electrode pair).

The computer 20 may comprise, for example, a conventional general purpose computer, a special purpose computer, a distributed computer, or any other type of computer. The computer 20 may include one or more processors 28, such as a single central processing unit ("CPU") or multiple processing units, commonly referred to as a parallel processing environment, which may execute instructions to practice aspects described herein.

Typically, three nominally orthogonal electric fields are generated by a series of driven and sensed electric dipoles (e.g., surface electrode pairs 12/14, 18/19, and 16/22) to effect catheter navigation in a biological conductor. Alternatively, the orthogonal fields can be decomposed and any pairs of surface electrodes can be driven as dipoles to provide effective electrode triangulation. Likewise, the electrodes 12, 14, 18, 19, 16, and 22 (or any number of electrodes) may be positioned in any other effective arrangement for driving current to or sensing current from the electrodes in the heart. For example, multiple electrodes may be placed on the back, sides, and/or abdomen of the patient 11. Furthermore, this non-orthogonal approach increases the flexibility of the system. For any desired axis, the potentials measured across the roving electrodes resulting from a set of predetermined drive (source-sink) configurations can be algebraically combined to yield the same effective potential as would be obtained by simply driving a uniform current along the orthogonal axes.

Thus, any two of the surface electrodes 12, 14, 16, 18, 19, 22 may be selected as dipole sources and drains with respect to a ground reference (such as the belly patch 21), while the unexcited electrodes measure voltages with respect to the ground reference. The roving electrodes 17 placed in the heart 10 are exposed to the field from the current pulses and measurements are taken with respect to ground, such as an abdominal patch 21. In practice, a catheter within the heart 10 may contain more or fewer than the sixteen electrodes shown, and each electrode potential may be measured. As previously described, at least one electrode may be secured to the interior surface of the heart to form a fixed reference electrode 31, the fixed reference electrode 31 also being measured relative to ground (such as the abdominal patch 21), and the fixed reference electrode 31 may be defined as the origin of the coordinate system of the system 8 relative to its measurement location. The data sets from each of the surface, internal, and virtual electrodes may be used to determine the position of the roving electrode 17 within the heart 10.

The system 8 may use the measured voltages to determine the position of an electrode within the heart, such as the roving electrode 17, in three-dimensional space relative to a reference position, such as the reference electrode 31. That is, the voltage measured at the reference electrode 31 may be used to define the origin of the coordinate system, and the voltage measured at the roving electrode 17 may be used to express the position of the roving electrode 17 relative to the origin. In some embodiments, the coordinate system is a three-dimensional (x, y, z) cartesian coordinate system, but other coordinate systems are contemplated, such as polar, spherical, and cylindrical coordinate systems.

It should be clear from the foregoing discussion that when a surface electrode pair applies an electric field across the heart, data is measured that is used to determine the position of the electrode within the heart. The electrode data may also be used to create a breathing compensation value that is used to improve the raw position data for the electrode position, as described, for example, in U.S. Pat. No.7,263,397, which is incorporated by reference herein in its entirety. The electrode data may also be used to compensate for changes in the patient's body impedance, as described, for example, in U.S. Pat. No.7,885,707, which is also incorporated herein by reference in its entirety.

Thus, in one representative embodiment, system 8 first selects a set of surface electrodes and then drives them with current pulses. While delivering the current pulse, electrical activity, such as voltage measured with at least one of the remaining surface and intracorporeal electrodes, is measured and stored. As described above, compensation for artifacts such as respiration and/or impedance shifts may be performed.

In aspects of the present disclosure, the system 8 may be a hybrid system that combines impedance-based (e.g., as described above) and magnetic-based positioning capabilities. Thus, for example, the system 8 may further include a magnetic source 30 coupled to one or more magnetic field generators. For clarity, only two magnetic field generators 32 and 33 are depicted in fig. 1, but it should be understood that additional magnetic field generators (e.g., a total of six magnetic field generators, defining three substantially orthogonal axes, similar to those defined by patch electrodes 12, 14, 16, 18, 19, and 22) may be used without departing from the scope of the present teachings. Also, one of ordinary skill in the art will appreciate that one or more magnetic positioning sensors (e.g., coils) may be included for positioning the catheter 13 within the magnetic field so generated.

In some embodiments, system 8 is EnSite of Yapei corporation^TM Velocity^TMOr EnSite Precision^TMA cardiac mapping and visualization system. However, other positioning systems may be used in conjunction with the present teachings, including, for example, RYTHMIA HDX from Boston Scientific Corporation (Markov, Mass.)^TMMapping system, Webster bioscience Inc. (Biosense Webster, Inc.), CARTO navigation and positioning system (Lkawa, Calif.), North Digital Inc. (Northern Digital Inc.) (ludison, Ontario)Systematic, Sterotaxis IncMagnetic navigation systems (St. Louis, Mo.) and Mediguide from Yapei corporation^TMProvided is a technique.

The localization and mapping systems described in the following patents (all of which are incorporated herein by reference in their entirety) may also be used with the present invention: U.S. Pat. Nos. 6,990,370; 6,978,168, respectively; 6,947,785, respectively; 6,939,309; 6,728,562, respectively; 6,640,119, respectively; 5,983,126; and 5,697,377.

Aspects of the present disclosure relate to generating electrophysiology maps, and in particular to generating electrophysiology maps using subintervals of electrophysiology signals. A graphical representation of such an electrophysiology map may also be output, for example, on display 23. The system 8 may thus include a subinterval definition module 58, which may further include a mapping module to generate an electrophysiology map and optionally output a graphical representation of the electrophysiology map (e.g., to the display 23).

An exemplary method of mapping electrophysiological activity will be explained with reference to a flowchart 400 of representative steps as shown in fig. 4. For example, in some embodiments, the flow chart 400 may represent several exemplary steps that may be performed by the electro-anatomical mapping system 8 of fig. 1 (e.g., by the processor 28 and/or the subinterval definition module 58). It should be understood that the representative steps described below may be hardware or software implemented. For purposes of explanation, the term "signal processor" is used herein to describe both hardware-based and software-based implementations of the teachings herein.

In block 402, the system 8 receives a plurality of electrophysiological signals. For purposes of illustration, aspects of the present disclosure will be described with reference to an all-polar electrogram. In this regard, fig. 5 depicts a representative output 500 of the system 8 to the display 23, including a plurality of traces 502. Each trace depicts a full-pole electrogram of a conglomerate of three electrodes 17 on the HD mesh catheter 13, as calculated, for example, according to the teachings of the' 111 publication. The RAI of each electrophysiological signal is an unshaded area between the carats 504, 506.

In block 404, the system 8 identifies a deflection of interest within an activation interval of a given electrophysiological signal. The term "initial event time" is used herein to refer to the timing (timing) of the deflection of interest so identified.

In aspects of the present disclosure, the system 8 uses an energy function of a given electrophysiological signal to identify an initial event time. For example, the initial event time may be identified as the time at which the energy function of the electrophysiological signal has the largest signal energy, which may be determined, for example, by wavelet domain transformation and analysis of a given electrophysiological signal. Other methods of identifying the time of maximum signal energy are described below.

In other aspects of the disclosure, system 8 uses template matching to identify an initial event time. For example, the initial event time may be identified as the time of maximum morphological correlation between a given electrophysiological signal and a template signal exhibiting the deflection of interest. By way of illustration only, U.S. patent application publication No.2015/0057507, which is incorporated herein by reference as if fully set forth herein, describes an exemplary method of calculating morphological similarities between electrophysiological signals.

In other aspects of the disclosure, system 8 uses a weighted window function to identify the initial event time. For example, it may be desirable to characterize late potentials (late potentials) during certain electrophysiological studies (e.g., in reentrant arrhythmias where regular mapping is possible, the deflection that occurs after activation of most chambers may be of particular interest to a medical practitioner). In such studies, a voltage weighting function that increases over time may be applied to a given electrophysiological signal within the RAI in order to identify the late deflections of interest.

One of ordinary skill in the art will also recognize from the foregoing discussion that a weighted window function may also be employed to identify the early potential (early potential). Thus, it is contemplated that the window function may be time-aligned with the edges of the RAI (e.g., carat 504 or 506 in fig. 5, depending on whether early or late potentials are of interest), surface electrocardiogram deflection, and/or particular intracardiac electrogram features.

The' 111 publication describes another suitable method of identifying the initial event time in an all-polar electrogram by identifying the time of maximum energy of the all-polar electrogram within the RAI. Because the deflections of interest are typically characterized by high slew rates, high amplitudes, and high frequency components within a given electrophysiological signal, the' 111 publication describes distinguishing between two or more bipolar electrograms that define an all-polar electrogram.

According to some aspects of the present disclosure, the time of maximum energy may be identified by calculating a root mean square of a derivative of a bipolar electrogram defining a full-polar electrogram. In an alternative aspect of the present disclosure, the time of maximum energy may be identified by calculating a root mean square or simply a mean square of the bipolar electrograms that define the full-polar electrogram.

According to other aspects of the disclosure, the time of maximum energy may be identified by calculating an absolute value transformation of the derivative of the bipolar electrogram defining the full-pole electrogram.

In other aspects of the present disclosure, particularly where a full-polar electrogram is defined by orthogonal pairs of bipolar electrograms (as in the case of the HD mesh catheter shown in fig. 2), the time of maximum energy may be identified by calculating the norm of the derivative of the bipolar electrogram. To further emphasize the desired deflection in the omnipolar electrogram, the derivative of the bipolar electrogram may be high pass filtered prior to calculating the norm of the derivative and/or the calculated norm may be low pass filtered.

Fig. 6 depicts identification of initial event times in an all-polar electrogram for cliques of electrodes a1, B1, and B2 (see fig. 3A). In the lower portion of FIG. 6 are two bipolar electrograms 602, 604 corresponding to bipolar B1-B2 and A1-B1 (see FIG. 3B), respectively. The top of fig. 6 shows a corresponding full-pole electrogram 606 for a three-electrode cluster. By calculating the norm of the derivative of the bipolar electrograms 602, 604 (optionally including high-pass and/or low-pass filtering as described above), the system 8 may generate the energy function of the all-polar electrogram 606 and identify therefrom the time of maximum signal energy and designate that time as the initial event time, represented in fig. 6 by the marker 608.

As described above, orientation-independent energy functions are generated for orientation-independent omnipolar electrograms (e.g., 606), which in turn are defined by two or more bipolar electrograms (e.g., orthogonal bipolar electrograms 602, 604). However, in the present teachings, the energy functions of the underlying bipolar electrogram are generated, which in turn can be combined into directionally independent energy functions.

Returning now to FIG. 4, once the initial event time is identified, system 8 next defines a subinterval around the initial event time in block 406. In an embodiment of the present disclosure, the subintervals are centered at the initial event time, as shown in fig. 6 at a 60ms wide caliper 610. However, it should be understood that the subintervals need not be centered on the initial event time; in fact, the practitioner may wish to adjust how many subintervals occur before the initial event time and how many subintervals occur after the initial event time.

The subintervals may have a preset width (i.e., a preset duration). Alternatively, the system 8 may allow the practitioner to adjust the width of the subinterval (e.g., by presenting controls on the graphical user interface on the display 23 that allow the user to change the width of the subinterval).

It should also be understood that while aspects of the present disclosure limit the initial event time to within the RAI, the subintervals need not be so limited and may extend outside of the RAI. Allowing the sub-intervals to extend outside of the RAI may facilitate identification of morphologies that may be excluded because they occur too close to the boundary of the RAI.

For example, when mapping regular reentry arrhythmias, the RAI may typically be set to approximate cycle length. However, a physiological but regular tachycardia may have a cycle length that varies between about 5ms and about 10 ms. By definition, in reentry arrhythmias there is always some portion of cardiac tissue that is depolarizing, each depolarization event lasting between about 7ms and about 70 ms. Some of these events may occur near the edges of the RAI. Thus, depending on the variability of the cycle length, the RAI may include no depolarization event, one complete depolarization event, one partial depolarization event, or two partial depolarization events. In such cases, the present teachings can be better applied to identify and then analyze depolarization events that are not entirely within the RAI.

For example, fig. 7 illustrates the identification of an initial event time in the case of atrial flutter. The bipolar electrograms 702, 704 corresponding to the bipolar C1-C2 and B1-C1, respectively, on the catheter 13 exhibit two deflections within the RAI (e.g., between the carats 504, 506). The full-polar electrogram 706 of electrode ensemble C1-C2-B1 also has two deflections within the RAI. However, the energy function 708 has its maximum energy at the earlier of the two deflections, and therefore the system 8 designates this earlier deflection as the initial event time 710. The resulting subinterval 712 extends (e.g., earlier than carat 504) before the beginning of the RAI.

In block 408, the system 8 analyzes the subintervals to identify one or more electrophysiological characteristics of the given electrophysiological signal. For example, rather than analyzing the entire full-pole electrogram 606 or 706 to determine peak-to-peak voltage, local activation time, etc., system 8 limits its analysis to subintervals 610 or 710 to identify these same features. Bipolar electrograms (e.g., 702, 704) may also be analyzed within the same subinterval, if desired. In block 410, the respective electrophysiology data point can be added to the electrophysiology map.

Decision block 412 initiates a loop back to block 404 to process the additional electrophysiological signals received in block 402. Once all signals have been processed, decision block 412 follows a "NO" exit to block 414, where system 8 may output a graphical representation of the electrophysiology map on the anatomical model (e.g., model 508 in FIG. 5 as an output on display 23).

Although several embodiments have been described above with a certain degree of particularity, those skilled in the art could make numerous alterations to the disclosed embodiments without departing from the spirit or scope of this invention.

For example, the teachings herein may be applied in real-time (e.g., during an electrophysiology study) or during post-processing (e.g., applied to electrophysiology data points acquired during an electrophysiology study performed at an earlier time).

As another example, it is contemplated that the width of the subintervals may be computationally determined by the system 8, for example, based on the deviation of the voltage or electric field loop from the isoelectric point.

As yet another example, a single subinterval duration may be used for all electrode cliques within a preset proximity distance. For example, the subinterval duration may be set for the centrally located four-electrode clique B2-C2-C3-B3, and this same subinterval duration may be used for all three-electrode cliques on catheter 13.

As a further example, the teachings of U.S. patent application publication No.2017/0156612, which is incorporated herein by reference as if fully set forth herein, may be better applied in conjunction with the present teachings (and in particular the initial event time identification in block 404).

All directional references (e.g., upper, lower, upward, downward, left, right, leftward, rightward, top, bottom, above, below, vertical, horizontal, clockwise, and counterclockwise) are only used for identification purposes to aid the reader's understanding of the present invention, and do not create limitations, particularly as to the position, orientation, or use of the invention. References made in conjunction (e.g., attached, coupled, connected, etc.) are to be construed broadly and may include intermediate members between a connection of elements and relative movement between elements. As such, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other.

It is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative only and not limiting. Changes in detail or structure may be made without departing from the spirit of the invention as defined in the appended claims.