CN110996776B - Method for combining heart mapping and model - Google Patents

Abstract

Various embodiments provide a method of cardiac mapping and model merging comprising: generating a PVC activation of the heart based on a three-dimensional (3D) heart model and PVC electrocardiogram (ECG) data recordings during premature ventricular systoles (PVCs) of the heart Figure; generating a 3D inner surface model of the heart by triangulating point-by-point contact data collected during electrophysiological (EP); merging the 3D activation map and the 3D inner surface model to form a PVC activation surface model; and in the first To pace the heart at the pacing site, the first pacing site is set in the earliest activated region identified in the PVC activation surface model.

Description

Cardiac Mapping and Model Merging Method

Cross References to Related Applications

This application claims priority to the following patent applications: U.S. Provisional Patent Application No. 62/539,740, filed August 1, 2017, entitled "Methods for Cardiac Mapping and Orientation Guidance"; Provisional Patent Application No. 62/539,787, entitled "Methods for Cardiac Mapping and Orientation Guidance"; Methods"; and U.S. Provisional Patent Application No. 62/711,777, filed July 30, 2018, entitled "Cardiac Mapping Systems, Methods, and Kits Containing Fiducial Markers," all of which are incorporated herein by reference in their entirety .

Background technique

Some heart defects in the conduction system cause asynchronous contractions of the heart (arrhythmias) and are sometimes called conduction disorders. As a result, the heart does not pump enough blood, which can eventually lead to heart failure. Conduction disorders have a variety of causes, including age, heart (muscle) damage, medications, and genetics.

A premature ventricular contraction (PVC) is an abnormal or irregular heartbeat that begins somewhere in the ventricles rather than in the upper chambers of the heart as a normal sinus beat does. PVCs often result in reduced cardiac output as the ventricles contract before they have a chance to completely fill with blood. PVC may also trigger ventricular tachycardia (VT or V-Tach).

Ventricular tachycardia (VT or V-Tach) is another arrhythmia disorder caused by abnormal electrical signals in the ventricles of the heart. In VT, abnormal electrical signals cause the heart to beat faster than normal, usually more than 100 beats per minute, with the beating starting in the ventricles. VT usually occurs in people with underlying heart abnormalities. VT sometimes occurs in a structurally normal heart, and in these patients, the source of the abnormal electrical signal can be in multiple locations in the heart. A common location is the right ventricular outflow tract (RVOT), which is the path of blood flow from the right ventricle to the lungs. In patients with a heart attack, scarring from the heart attack creates an intact myocardial environment and scarring that predisposes the patient to VT.

Other common causes of conduction disorders include defects in the rapidly activating fibers of the left and/or right ventricle, the His-Purkinje system, or scar tissue. As a result, the left and right ventricles may become out of sync. This is called left bundle branch block (LBBB) or right bundle branch block (RBBB).

Cardiac resynchronization therapy (CRT), also known as biventricular pacing or multipoint ventricular pacing, is a known method of improving cardiac function in LBBB or RBBB situations. CRT involves simultaneous pacing of the right ventricle (RV) and left ventricle (LV) with a pacemaker. To achieve CRT, coronary sinus (CS) leads were placed for LV pacing in addition to conventional RV endocardial leads (with or without right atrial (RA) leads). The basic goal of CRT is to improve LV mechanical function by restoring LV synchrony and an enlarged QRS period in patients with dilated cardiomyopathy, which is primarily a consequence of LBBB.

Catheter ablation is the treatment of choice for patients with VT and/or symptomatic PVC. Ablation targets the site in the heart where a PVC occurs or where a VT attack occurs. To determine an appropriate ablation location, the treating physician may first stimulate the proposed location using electrical leads in order to determine whether ablation at the proposed location will provide the desired electrical activation pattern stimulation of the heart.

Currently, determining the correct placement of the leads for maximum cardiac synchrony or the desired pattern of electrical activation requires a degree of guesswork by the surgeon.

However, current methods do not allow the determination of the optimal placement of the electrical lead on a patient-by-patient basis. Further, current methods do not provide directional guidance for adjusting lead positions to provide an improved activation pattern if the desired activation pattern is not achieved when the heart is stimulated at a given location. Therefore, there is a need for improved guidance in determining the correct location of the electrical leads of a CRT and in determining the location of ablation.

Contents of the invention

Various embodiments provide a method of cardiac mapping and model merging comprising: generating a PVC activation of the heart based on a three-dimensional (3D) heart model and PVC electrocardiogram (ECG) data recordings during premature ventricular systoles (PVCs) of the heart Figure; Generate a 3D inner surface model of the heart by triangulating point-by-point contact data collected during electrophysiology (EP); Merge the 3D activation map and the 3D inner surface model to form a PVC activation surface model; use EP The catheter paces the heart at a first pacing site, which is positioned in the earliest activation region identified in the PVC activation surface model.

Various embodiments provide a method of cardiac mapping comprising: attaching 12 electrodes of an electrocardiogram (ECG) device to a patient's chest; recording ECG data using the electrocardiogram (ECG) device; based on the ECG data of the patient's heart, a 3D chest model and two-dimensional (2D) images to generate an activation map of the heart that contains the earliest activated regions; based on a comparison of the earliest activated regions in the activation model with the earliest predicted regions of activation, each electrode included in the 3D chest model is identified The offset between the actual position of each electrode and the ideal position of each electrode; and adjusting the activation map based on the determined offset. Some embodiments include applying fiducial markers to the patient's body (e.g., chest or torso) to identify anatomical locations, the markers being configured to appear in the image data by detecting light reflected from the fiducial markers contained in the image data. are identified so that a patient-specific three-dimensional (3D) anatomical model can be generated that aligns the image data with the 3D representation of the patient's chest by registering the identified anatomical locations with corresponding anatomical locations in imaging obtained from CT or MRI scans. Anatomical models merged.

Description of drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate exemplary embodiments of the invention and, together with the general description given above and the detailed description given below, explain features of the invention.

FIG. 1 is an example of a 3D model of a heart, according to various embodiments.

2A is a plan view of an electrically activated 3D model of a heart, according to various embodiments.

2B is a plan view of an electrically activated 3D model of a heart, according to various embodiments.

Figure 2C is a plan view of a synchronicity graph, according to various embodiments.

Figure 2D is a plan view of a synchronicity graph, according to various embodiments.

Figure 3 is a schematic representation of a cardiac imaging system, according to various embodiments.

4A and 4B are plan views of an electrically activated 3D model of a heart, according to various embodiments.

4C and 4D are plan views of synchronicity graphs according to various embodiments.

Figure 5 is a schematic representation of a cardiac imaging system, according to various embodiments.

Figure 6 is a flowchart illustrating a method according to various embodiments.

7A is a schematic representation of LAO and PA views of an electrically activated 3D model of a heart, according to various embodiments.

Figure 7B is a schematic representation of LAO and PA views of a synchronicity graph, according to various embodiments.

8A is a schematic representation of LAO and PA views of an electrically activated 3D model of a heart, according to various embodiments.

Figure 8B is a schematic representation of LAO and PA views of a synchronicity graph, according to various embodiments.

9 is a schematic diagram of a surgical imaging system, according to various embodiments.

Figure 10 is a flowchart of a method of using the system of Figure 9, according to various embodiments.

11A is a flowchart of a method of using the system of FIG. 9, according to various embodiments.

FIG. 11B shows an example of a reference heart image generated during the method of FIG. 11A .

11C and 11D illustrate activation maps that may be generated during the method of FIG. 11A.

Figure 12 is a flowchart of a method of using the system of Figure 9, according to various embodiments.

Figure 13 is a system block diagram of a cardiac imaging system according to various embodiments.

14A and 14B are 3D images of electrical leads and fiducial markers on a patient's torso, according to various embodiments.

Detailed ways

Various embodiments are described in detail with reference to the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. References made to particular examples and implementations are for purposes of illustration, and are not intended to limit the scope of the invention or the claims.

An electrocardiogram (ECG) is defined herein as any method that correlates (preferably non-invasively) the actual electrical activity of the myocardium with the measurement or derivation (electrical activity) of the heart. In the case of a classical ECG, the potential difference between electrodes on the body surface is related to the electrical activity of the heart. The derived ECG can also be obtained by other means, for example by measurement by a so called ICD (Implantable Cardioverter Defibrillator). In order to obtain such functional images, an estimate of the motion of the electrical activity must be provided.

Cardiac dyssynchrony has deleterious effects on cardiac function by reducing left ventricular (LV) mechanical properties while increasing myocardial oxygen consumption. In addition, cardiac dyssynchrony may lead to LV remodeling. Thus, cardiac dyssynchrony accelerates the progression of chronic congestive heart failure (CHF) and reduces patient survival.

During normal conduction, cardiac activation begins in the left ventricle (LV) and right ventricle (RV) endocardium. In particular, electrical impulses (ie, waves of depolarization) travel through the left and right ventricles substantially simultaneously. Bundle branch block (BBB) is a condition in which there is a delay or blockage along the path of electrical impulses. Delays or blockages can occur in the pathways that send electrical impulses to the left or right ventricle.

A left BBB is a condition in which the electrical impulse to the LV slows down and is one of the main causes of cardiac dyssynchrony. In particular, activation begins only in the RV and proceeds through the septum before reaching the LV endocardium.

A pacemaker is an electronic device, about the size of a pocket watch, that senses the inner heart rhythm and provides electrical stimulation when directed. Pacing can be temporary or permanent.

Permanent pacing is most commonly accomplished by transvenous placement of leads into the endocardium (i.e., the right atrium or ventricle) or epicardium (i.e., through the LV surface of the coronary sinus), which are subsequently connected to a subclavian Regional subcutaneous pacing generator. However, miniaturized pacemakers have been developed for direct cardiac surface grafting or implantation into the heart.

Cardiac resynchronization therapy (CRT) is a specialized pacemaker therapy that provides biventricular pacing. CRT is performed with or without the use of an implantable cardioverter-defibrillator (ICD), a medical device used to treat and prevent ventricular tachycardia (VT ) or patients at risk for ventricular fibrillation (VF).

In this application, areas of the heart that are electrically stimulated (eg, paced) by pacing electrodes, microcatheters, etc. may be referred to interchangeably as "pacing sites" or "stimulation sites."

Figure 1 shows a three-dimensional (3D) model of a heart 1 viewed from two different directions. The 3D model contains a mesh 6 representing the outer surface of the heart, here the surface of the myocardium. In this example, the model can also contain diaphragm walls. The mesh 6 has a plurality of nodes 8 . In this example, the mesh is a triangular mesh where the surface of the heart is approximated by adjacent triangles.

Figures 2A-2D are 3D models 4 of a heart showing the initial electrical activation of the heart 1 from various single stimulation locations 10. 2A-2C show the ventricular surface of the myocardium with the septal wall 2 . Typically, the 3D model 4 may comprise a mesh 6 representing the ventricular surface of the heart, here the outer surface of the ventricular myocardium with the septal wall as shown in FIG. 1 . The mesh 6 has a plurality of nodes 8 . In the example shown, heart 1 is electrically stimulated at stimulation site 10 . During electrical stimulation at the stimulation site 10, electrical signals will pass through the heart tissue. Therefore, different parts of the heart will be activated at different times. Each location on the heart has a specific delay relative to the initial stimulus. Each node 8 has associated therewith a value representing the time delay between stimulating the heart 1 at the stimulation location 10 and activating the heart at the corresponding node 8 . The locations sharing the same delay time are connected by an isochrone 12 in Figures 2A-2D. In this application, an isochrone is defined as a line drawn on a 3D surface model of the heart that connects points on the model where activations occur or are reached simultaneously. In this example, the latency of nodes passing through the surface of the heart is also shown by differently rendered shading. Vertical bars indicate the time delay (in milliseconds) associated with the corresponding color. It should be understood that the stimulation site 10 may be an intrinsic activation site of the heart 1 .

3 is a system block diagram of a system 100 for providing a representation of the synchrony of electrical activation of cardiac tissue. System 100 includes processing unit 102 and memory 104 .

A 3D electrical activation model 4 can be obtained by combining electrocardiogram and medical imaging data in the system 100 . This data may be stored in memory 104 . Processing unit 102 may be connected to electrocardiography system 106 and medical imaging system 108 for retrieving data and storing corresponding data in memory 104 . The processing unit 102 may apply an electrocardiographic imaging (ECGI) method capable of determining cardiac activation from a 12-lead ECG to determine a 3D model 4 of the electrical activation of the heart. In the ECGI method, to calculate the position of the isochrone of the heart, the ECG signal can be combined with a patient-specific 3D anatomical model of the heart, lungs and/or torso. The patient-specific 3D anatomical model may be obtained from magnetic resonance images (MRI) or computed tomography (CT) images received from the medical imaging system 108 . Alternatively or additionally, the 3D anatomical model exhibiting the closest conformity to the patient may be selected from a database containing a plurality of 3D anatomical models and optionally modified. The selected and optionally modified 3D anatomical model can be used as the patient-specific 3D anatomical model.

The 3D model 4 may also contain further information. In the example shown in Fig. 2A, the 3D model 4 may contain cardiac vessels 14 and/or veins on the myocardium. This information can be added to the 3D model 4 as nodes are indicated as being associated with such vessels. The blood vessel 14 can then be identified and optionally displayed in the 3D model 4 . Optionally, the processing unit 102 may comprise a first recognition unit 110 arranged for automatically retrieving information representative of the location of such blood vessels from a 3D anatomical model of the patient's heart. The processing unit 102 can then automatically insert this information into the 3D model 4 .

The 3D model 4 may also contain information about scar tissue. Scar tissue locations can be obtained from delayed-enhanced magnetic resonance imaging (MRI) images and added to the 3D model4. Scar tissue can be simulated in 3D Model 4 by reducing the propagation speed of electrical signals. Scar tissue can also be explained by selling very slow or non-transitional transitions from one node to another in areas of the heart wall where there is scar tissue. Optionally, the processing unit 102 may comprise a second recognition unit 112 configured and arranged for automatically retrieving information representative of the location of such scar tissue from a patient-specific 3D anatomical model of the heart. The processing unit 102 can automatically insert this information into the 3D model 4 .

In various embodiments, the obtained 3D model 4 can be used to obtain further information about the electrical activation of the heart. For example, a time delay of activation from one node to another can be determined. This can be used to generate other views based on the 3D model 4 resulting from initial stimuli at other nodes of the mesh 6 . To achieve this, the processing unit 102 may comprise an interpolation unit 114, which may take the 3D model 4 and define a certain node as a stimulus location. It should be understood that the 3D model 4 may assume stimulation at predetermined nodes. The interpolation unit 114 may remove stimuli at predetermined nodes for computational purposes.

Fig. 2B shows an example of a 3D model 4 resulting from an initial stimulation at another stimulation location 10'. It will be appreciated that for each node of the mesh 6 a view resulting from an initial stimulus at other nodes of the mesh 6 may be generated.

A specific sequence of electrical activations throughout the heart 1 resulting from stimulation at specific nodes can be summarized into a single parameter, cardiac activation synchrony. Cardiac activation synchrony provides an indication of how the entire heart is activated in synchrony. For the common case, a more synchronized activation of the heart is believed to be beneficial. The measure of cardiac activation synchrony in this example is the standard deviation (std) of the depolarization (dep) times of the heart. Cardiac activation synchrony thus provides an indication of the synchrony of activation of the entire heart as a result of stimulation at the corresponding node. The processing unit 102 may comprise a synchrony determination unit 116 configured to determine cardiac activation synchrony.

In various embodiments, cardiac activation synchrony may be determined separately for stimulation at each node. Thus, a measure of cardiac activation synchrony can be provided for each node of the mesh. The processing unit 102 may comprise a synchrony map generation unit 118 configured to generate a synchrony map based on the calculation of the cardiac activation synchrony of each node by the synchrony determination unit 116 . The processing unit 102 may be connected to an output unit 120 arranged to output the synchronization map 15 and/or the substitute data to a user. The output unit may be a display unit, a printer, a message unit, and the like.

FIG. 2C shows an example of the cardiac synchrony graph 15 . In the example shown in FIG. 2C , cardiac activation synchrony is indicated for each node in FIG. 15 . In this example, the indication may be displayed by providing false colors and/or isochronous lines 16 . Isosynchrony lines 16 connect nodes with the same cardiac activation synchrony. Cardiac Synchronization Figure 15 provides a single 3D overview showing locations on the heart that lead to good cardiac activation synchrony, and, if the heart is stimulated at these locations, locations on the heart that result in poor cardiac activation synchrony. In the example shown in Fig. 2C, it can be seen that the original stimulation locations 10 do not provide particularly good synchronization, with cardiac activation synchrony values around 45 ms standard deviation of cardiac depolarization times. The most unfavorable stimulation position (here the position with the highest cardiac activation synchrony value) is indicated by S-. In this example, the most favorable stimulation location where the lowest cardiac activation synchrony values occur is indicated by S+. In some cases, as shown in Fig. 2D, the most favorable stimulation position S+ can be best seen when looking at the synchronicity diagram 15 from the other direction.

Another example of a cardiac activation synchrony measure is the range of depolarization times (maximum depolarization time - minimum depolarization time). The range of depolarization times can be corrected for cycle length. Another example of a measure of cardiac activation synchrony is the standard deviation of left ventricular (LV) depolarization times alone. Another example of a measure of cardiac activation synchrony is the delay between stimulation and diaphragm activation. Another example of a measure of cardiac activation synchrony is AV latency. Another example of a measure of cardiac activation synchrony is VV latency. It should be appreciated that the measure of cardiac activation synchrony may be selected according to the task at hand and/or according to a particular condition or abnormality experienced by the patient.

Fig. 4A shows a second example in which a second stimulation position 18 is defined. The electrical activation of the heart is calculated using the 3D model 4 and the simultaneous stimulation at the first stimulation location 10 and the second stimulation location 18 . In this example, the interpolation unit 114 does not remove the stimulus at the first location 8 for computational purposes. FIG. 4A shows the calculated resulting electrical activation of the heart 1 . In the example shown in Figure 4A, the total activation time is reduced due to the addition of the second stimulation location 18. In this example, the first stimulation site 10 represents the site of intrinsic activation of the heart, or a first selected stimulation site, or stimulation produced by a pacemaker lead already present in the heart.

FIG. 4B shows an example of electrical activation of the heart resulting from initial stimulation at the second stimulation location 18 ′ simultaneously with stimulation at the first stimulation location 10 . It should be understood that the generation of an initial stimulus at a second node of the mesh 6 (simultaneously with a stimulus at the first node associated with the first stimulus location 10) may be generated for each node of the mesh 6. view.

In the example shown in FIGS. 4C and 4D , specific electrical activation sequences of the entire heart are combined and shown as cardiac activation synchrony. In this example, the electrical activation sequence comprises stimulation at the second stimulation location 18 (simultaneously stimulation occurs at the first stimulation location 10). Cardiac activation synchrony again provides an indication of how the entire heart is activated synchronously. In some embodiments, cardiac activation synchrony may be determined separately for stimulation of each node (stimulation occurs simultaneously at first stimulation location 10 and second stimulation location 18). This provides a measure of cardiac activation synchrony for each node acting as a third stimulation site for the mesh 6 .

FIG. 4C shows an example of a cardiac synchrony map showing that if the first stimulation location 10 and the second stimulation location 18 are simultaneously stimulated, stimulating the heart at these locations results in good cardiac activation synchrony over the heart. location, and locations on the heart that lead to poor synchronicity of cardiac activation. In the example shown in Fig. 4C, the third most unfavorable stimulation location S- has the highest cardiac activation synchrony value of approximately 41 ms when the first stimulation location 10 and the second stimulation location 18 are stimulated simultaneously. In this example, when the first stimulation site 10 and the second stimulation site 18 are stimulated simultaneously, the most favorable third stimulation site S+ has the lowest cardiac activation synchrony value. In some cases, the most favorable stimulation position S+ can be best seen when looking at the synchrony plot 15 from the other direction, as shown in FIG. 4D.

FIG. 5 is a data flow representation of a system 100 for providing a synchronicity graph. FIG. 6 illustrates a method of determining cardiac synchrony using the system 100 shown in FIGS. 3 and 5 , according to one embodiment. Referring to Figures 3 and 5, the system 100 includes a processing unit 102 that receives data from hardware modules. Optionally, processing unit 102 may receive ECG data from electrocardiography system 106 . The processing unit may receive patient-specific anatomical data from the medical imaging system 108 .

The processing unit 102 may receive information from the positioning system 109 about the position of the ECG leads relative to the patient's anatomy, such as a 3D image of the patient's chest containing the electrodes. The 3D image and torso model can be aligned, and the positions of the electrodes in the model can be adjusted to match the positions of the electrodes in the 3D image. Knowledge of the location of the ECG electrodes relative to the heart, especially the V1-6 precordial electrodes, may be particularly important for accurate calculation of the onset location of PVCs.

In some embodiments, the offset of the electrodes relative to their assumed ideal position, particularly the offset of the V1-6 electrodes, may be determined based on a comparison of the detected ECG signal of a normal heart beat with the ideal ECG normal heart beat signal . For example, the offset may be determined based on how the detected ECG signal will be affected by changes in the position of the electrodes relative to the ideal electrode positions. In particular, the recorded ECG data can be used to determine the location of the stimulation onset of normal beating. Because the normal onset location in the SA node is known, the determined offset location can be compared to this known onset location, and their offset can be inferred based on the variation between electrodes. Thus, electrode offsets can be determined without generating a 3D map.

From the patient-specific anatomical data, the processing unit 102 can determine the synchrony map 15 . The processing unit 102 may include the following units, and may perform the operations of the method 200 shown in FIG. 6 and described below to generate a synchronization graph. In the method 200, the processing unit 102 may use a patient-specific 3D anatomical model of the patient's thoracic cavity and the size, orientation and location of the heart within the thoracic cavity. Such a model may be selected in block 201 for further use by the processing unit 102 . The processor may determine whether such a model is already available in decision block 202 . If a model is not yet available (ie determination block 202 =N), then in determination block 204 the retrieval unit 103 may check whether a suitable anatomical model for the patient exists in the database 117 .

If no suitable patient-specific anatomical model is available in the database 117 (ie determination block 202 =N), the retrieval unit 103 may generate a patient-specific anatomical model based on the received patient-specific anatomical 3D image data in block 208 .

If a suitable patient-specific anatomical model is available in the database 117 (ie determination block 202 =Y), then in block 206 the retrieval unit 103 retrieves a suitable anatomical model from the database 117 . Also in block 206, the retrieval unit 103 may adapt an anatomical model from the database to the 3D image of the patient in order to convert the selected anatomical model into a (quasi) patient-specific 3D anatomical model. Optionally, the patient-specific 3D model may also include the size, orientation and/or position of other structures within the patient's body, such as the lungs and/or other organs. The patient-specific 3D model may be a volume conductor model.

If the patient model is available (i.e., determine block 202=Y), either using the patient model created in block 208 or a stored model adapted to the patient in block 206, the location of the ECG leads, and the patient-specific model, then The lead locator module 105 may determine the corresponding locations of the ECG leads in the patient-specific 3D model to provide an enhanced patient-specific model in block 210 .

In determination block 212, when a patient-specific anatomical model and/or an enhanced patient-specific model is available, it is determined whether ECG data representative of intrinsic or stimulus activation is available. If intrinsic activation data or pacing stimuli from one or more pre-existing pacemaker leads are available (i.e., determination block 212=Y), in block 214 the activation unit 107 may base the patient-specific model and ECG The data generates a 3D electrical model showing the current activation of the patient's heart.

If no ECG data regarding intrinsic or stimulus activation is available (i.e., determination block 212=N), then in block 216, the virtual stimulation unit 111 may, based on previously determined and/or assumed transition velocities between nodes, Virtual stimuli added to the electrical model of the heart. For example, a hypothetical transition speed may be 0.8ms. As noted above, the electrical model may contain arteries, veins, and/or scar tissue. In block 218, a virtually activated 3D electrical model of the patient's heart may be generated.

As described above, in block 222 the synchrony determination unit 116 may generate a synchrony map 15 from the intrinsic, stimulated, or virtual activated 3D electrical model of the patient's heart. Based on the synchrony map, the processing unit 102 may determine whether the artificial stimulation location or the virtual stimulation location results in optimal activation and synchrony in determination block 230 . If yes (ie, determination block 230 =Y), the processing unit may calculate an optimal stimulation position for the patient's heart in block 234 .

If it is determined in block 230 that optimal synchronization has not been achieved (i.e., determination block 230=N), method 200 proceeds to determination block 232, where it is determined whether additional virtual stimulation locations are needed or should be added, or whether virtual stimulation locations should Move or change relative to a timing parameter. This determination may be made by the clinician, the processing unit, or the clinician based on information or advice presented by the processing unit on the display.

If it is determined that additional virtual leads are needed (ie, determination block 232 =Y), then in block 224, virtual pacing locations may be added based on the determined synchronicity. If it is determined that no additional virtual leads are needed and the virtual stimulation locations should be moved or changed (ie, determination block 232 =N), then the artificial or virtual stimulation locations may be adjusted accordingly in block 225 .

In block 226, a new activation may be generated. Synchronization may then be recalculated in block 222 and the process may repeat until it is determined in decision block 230 that the desired activation is achieved.

The system 100 can also virtually adjust the current artificial stimulation position, ie, the pacemaker lead position, relative to its current stimulation parameters to achieve optimal synchronization.

System 100 can also be used to evaluate multiple stimuli. For example, multiple stimulation can be a combination of intrinsic activation and stimulus activation (pacing). For example, multiple stimulation may be multiple stimulation activation (pacing). It is possible for the user or the processing unit 102 to determine 232 whether additional stimulation locations are required, such as additional pacemaker leads.

If additional stimulation sites are desired, they can be inserted via the insertion unit 114 . The activation of the case with the original stimulus position and the added virtual stimulus position can then be determined again in box 226 and the synchronicity can be recalculated in box 222 . Based on the synchrony map, the processing unit 102 may determine in determination block 230 whether the additional virtual stimulus locations result in optimal synchrony. If optimal synchronization has not been achieved, method 200 proceeds to block 232, where it is determined whether additional virtual stimulation locations should be added relative to the timing parameters, or whether virtual stimulation locations should be moved or removed. In this case, the process can be repeated one or more times.

Based on a patient-specific cardiac activation model, a cardiac synchrony model can be generated. The synchrony model may be a 3D heart surface model containing isosynchrony lines as described above, wherein the isosynchronous lines represent the activation synchrony of the heart. This synchronicity may be based on specific activation conditions, such as right ventricular activation at the lead location of a pacemaker.

As an example, a synchronicity model can be generated and the activation isochrones of the intrinsic LBBB modes can be determined in the following box.

1A) Patient-specific anatomical 3D models of the heart, lungs and thorax can be generated eg based on MRI or CT images of the patient, or derived from models taken from databases adapted to patient dimensions eg using a 3D camera. The anatomical 3D models may include a 3D surface model of the heart, a 3D surface model of the lungs, and a 3D surface model of the thorax. The 3D surface model may be a close approximation of the actual surface of the heart by a mesh of polygons, such as triangles, connected at their corners. The interconnected corners form the nodes of the mesh.

1B) An ECG, such as a 12-lead ECG, can be measured. The exact position of the electrodes of the ECG device on the chest can be recorded. The positions of the electrodes in the 3D anatomical model are used to estimate the distribution, fluctuations and/or movement of electrical activity through the heart tissue. The exact location of the recording leads or ECG equipment can be entered into an anatomical 3D representation of the chest cavity.

1C) Optionally, scar tissue can be incorporated into the anatomical 3D representation of the heart. The presence and location of scar tissue can be derived from delay-enhanced MRI images.

1D) ECG device measurements for each recorded lead may be related to heart and torso geometry. Using the reverse process, intrinsic activation can be determined. The distribution, fluctuations and/or movement of electrical activity through cardiac tissue may be based on a myocardial distance function, a fastest path algorithm, a shortest path algorithm, and/or a fast marching algorithm.

2) Once the activation isochrones of the intrinsic LBBB pattern are determined, the stimulation sites can be added to the intrinsic activation of each node on the heart, and the expected synchrony of the heart can be calculated from the results. "Nodes" refer to the intersections of the triangles on which the anatomical 3D heart model is based.

The method described above can also be used to determine the optimal placement of pacemaker electrodes. To determine the optimal pacing site, a synchrony map can be calculated. Intrinsic activation maps, combined with identified stimulus points, can be applied to new cardiac isochronal localization maps.

Figure 7A shows an example of a 3D synchrony map of the LBBB activation pattern of the heart. On the left, Figure 7A shows a left oblique (LOA) view. On the right, Figure 7A shows a posterior anterior (PA) view. Figure 7B shows a synchrony map of the heart of Figure 7A. On the left, Figure 7B shows the LAO view, and on the right, Figure 7B shows the PA view.

The synchrony plot of Figure 7B shows the standard deviation of the heart's depolarization time due to one additional stimulus location combined with the heart's intrinsic activation. As can be seen from Figure 7B, the choice of additional stimulation locations on the basal left free wall 20 minimized the standard deviation of the depolarization times of the heart. Therefore, in this example, an area on the left free wall of the base can be selected as the optimal location for the pacemaker electrode.

An updated 3D model of the electrical activation of the heart can be generated, including intrinsic activation (while stimulation occurs in the region on the basal left free wall). This updated 3D map can then be used to generate a new synchrony map to examine lead locations in the RV. By doing this, the clinician can determine whether the lead should also stimulate, rather than just sense. The clinician can also determine if the leads should be moved. Clinicians can also determine if additional stimulation leads should be added.

Clinicians can also determine whether intrinsic AV conduction is beneficial. Intrinsic AV conduction will usually be conducted to the right tract, after which activation of the LV is required by stimulation of the LV. This can also be reversed, whereby the RBBB waits for LV activation and stimulates the RV free wall in the optimal position. By repeating this process for the left and right ventricles, the exact location and timing of cardiac pacing can be fine-tuned.

When intrinsic activation signals are not available due to severe damage to the heart, the entire procedure can be performed using only simulated (pacemaker) stimulation instead of intrinsic activation. In this case, Box 1B and Box 1D above can be omitted. Then the whole process will be based on manual activation.

Figure 8A shows an example of left stimulus activation of the LBBB pattern. On the left, Figure 8A shows the LAO view, and on the right the PA view. FIG. 8B shows an example of the synchrony graph 15 for the heart shown in FIG. 8A. On the left, Figure 8B shows the LAO view, and on the right the PA view. The synchrony plot of Figure 8B shows the standard deviation of the heart's depolarization time due to one additional stimulation location combined with the left stimulation activation of the heart. As can be seen from Fig. 8B, the choice of additional stimulation locations in the region on the basal left free wall 20 minimized the standard deviation of the depolarization times of the heart. Therefore, in this example, an area on the left free wall of the base can be selected as the optimal location for the pacemaker electrode. An updated 3D model of the electrical activation of the heart can be generated, including intrinsic activation (while stimulation occurs in the region on the basal left free wall).

The above-mentioned whole process can be carried out during the implantation process to find the best pacing site.

Figure 9 is a block diagram of a cardiac imaging system according to various embodiments. FIG. 10 is a flowchart illustrating a method 300 of implanting electrodes using the system of FIG. 9 , according to various embodiments. Referring to FIGS. 9 and 10 , in block 301 a 3D activation map of the patient's heart may be generated by the processing unit 400 of the system. In particular, a 3D model of the patient's chest and/or heart may be generated by a CT or MRI device 108 , the patient's ECG data may be recorded by an ECG recorder 106 , and a 3D image of the patient's torso may be generated by a 3D camera 109 . This data may be provided to the activation map generator 320 of the processing unit 400 . ECG data may contain extrinsic and/or intrinsic stimulus signals received from the patient.

In block 302, the location of one or more predicted optimal pacing locations may be identified. For example, the activation map may be provided to the synchrony determination unit 322 to determine cardiac synchrony. This data may then be used by virtual stimulation point generator 324 to identify one or more suggested pacing locations.

In CRT patients, the pacing site may be located where cardiac asynchrony occurs, thereby predicting its stimulation to generate the greatest amount of cardiac activation and/or synchronization. Pacing location may be based on, for example, the difference between LV and RV activation times, earliest and/or latest activation of LV and/or RV, detected blockage of depolarizing waves, and the like.

In block 304, one or more virtual pacing locations may be displayed. For example, one or more pacing locations may be added to the activation map as virtual pacing locations. Optionally, activation maps and images generated by real-time imaging equipment 328 (such as fluoroscopy, radiographic equipment, x-ray computed tomography (CT) equipment, etc.) may be provided to image integrator 326 . Image integrator 326 may compare and/or align the activation map and real-time images. Based on the comparison and/or alignment, an activation map containing stimulus points can be overlaid on the live image. In other embodiments, virtual stimulus points may be added to the real-time image to generate a modified real-time image, which may be provided to display 330 for rendering.

In some embodiments, in addition to displaying the activation map, block 304 may involve providing to display 330 a reference image showing the internal structure of the heart. The additional image may be based on a 2D cardiac image, such as one of the MRI or CT images used to generate the activation map. Such 2D images can be modified to show additional features. For example, a 2D cardiac image can be modified to identify structures contained in the earliest activated regions and/or pacing sites contained in the activation map. Thus, reference images can be referred to when positioning electrodes using the real-time imaging device 328 . Reference images are discussed in detail below with reference to FIG. 11B .

In block 306, one or more pacing electrodes may be located at the identified virtual stimulation points. The physician may use the reference image and/or activation map shown in display 330 to align the pacing electrodes with the virtual stimulation points. The heart can then be paced and the resulting ECG data can be collected.

In block 308, the collected ECG data may be used to generate an updated activation map showing the effect of the stimulation. In some embodiments, ECG data can be used to identify pacing locations, which can be displayed on the activation map. Since the pacing electrode is disposed at the pacing location, the pacing location may represent the current location of the pacing electrode. Thus, pacing electrode locations can be displayed while navigating to a pacing location. Accordingly, additional mapping applications may not be required to determine the location of the pacing electrodes, thereby significantly reducing the cost of the pacing procedure.

In determination block 310, it may be determined whether a pacing electrode is placed in a proper cardiac location. For example, in a CRT patient, it can be determined whether the stimulation was a sufficient amount of synchrony and/or restored a desired amount of cardiac function. If so (ie, determination block 310 =Yes), the electrodes may be stitched into place in block 312 . If not (ie, determination block 310 =No), new cardiac stimulation points may be generated in block 302 based on the updated activation map generated in block 308 . For example, one or more virtual stimulus points can be moved to a new location, and/or additional virtual stimulus points can be added. Then, in block 304, virtual stimulation points may be added to the real-time cardiac image. In some embodiments, the pacing interval to stimulate the LV and RV may also be adjusted.

For a PVC and/or VT patient, determination block 310 may involve using the updated activation map to determine whether the stimulus replicated the patient's PVC. In other words, determination block 310 may involve determining whether a stimulation point is a suitable ablation point. If so (ie, determination block 310 =Yes), then in block 312 the heart may be ablated at the stimulation point. If not (ie, determination block 310 =No), then in block 302 new stimulation points may be generated based on ECG data collected during previous stimulation.

In some embodiments, an activation map can be used to determine whether CRT is appropriate for a patient. For example, if a patient's cardiac output is not predicted to be at an acceptable level following optimal placement of a pacemaker or pacing leads, it may be determined that CRT is not appropriate for the patient.

In various embodiments, a workstation that may be used includes a processing unit 400, a display 330, and wired or wireless connections to other hardware, such as a CT/MRI device 108, a 3D camera 109, an ECG recorder 106, and/or real-time imaging device328. The workstation may also contain interfaces for controlling surgical equipment, such as catheter implantation equipment or other robotic surgical equipment.

FIG. 11A is a flowchart illustrating a cardiac imaging method 500 using the system of FIG. 9 , according to various embodiments. 11B and 11C illustrate activation maps that may be generated during the method of FIG. 11A.

Ablation is an effective treatment for PVC and/or VT. However, some patients may experience paroxysmal VT and/or PVC, in which case when the patient is tested in a hospital during a catheterization procedure or at an electrophysiology facility during an electrophysiology test, Events or symptoms may not occur. To ensure that sufficient ECG data is obtained for patients exhibiting symptoms of paroxysmal VT and/or PVC, a portable ECG recording device 106, such as a Holter-type device, may be used to record ECG data.

Referring to FIGS. 9 and 11A , the processing unit 400 may generate a PVC activation map showing electrical activation during a PVC in block 501 . For example, PVC activation maps can identify the earliest activated regions in the PVC process. The PVC activation map can be based on ECG data collected during PVC, as well as CT and/or MRI data from the patient as described above. In particular, the data may be provided to the activation map generator 320 of the processing unit 400 . In some embodiments, ECG data from a single PVC beat may be sufficient to generate a PVC activation map. The PVC activation map identifies the earliest regions of the heart that are activated during PVC heartbeats.

In some embodiments, the method may optionally include block 502 . In block 502, the processor 400 may be used to generate a reference image showing the internal structure of the heart. The activation map and the reference image can be displayed on the same display or on different displays simultaneously or at different times. In other words, blocks 501 and 502 may involve providing the generated activation map and reference image to display 330 .

The reference image may be based on a cardiac image, such as one of the 2D MRI or CT images used to generate the activation map. In addition to the internal cardiac structures shown in the cardiac image, the reference image may contain additional features. For example, to form a reference image, the heart image may be modified to show structures contained in the earliest activation regions and/or virtual pacing locations contained in the activation map.

In some embodiments, the processing unit 400 may be configured to select the cardiac image closest to the image provided by the real-time imaging device 328 , as discussed in block 503 . In other embodiments, the reference image may be based on a manually selected cardiac image. Thus, reference heart images can be referenced when positioning electrodes using the real-time imaging device 328 .

FIG. 11B shows an example of a reference image of a PVC/VT patient. Referring to FIG. 11B , the reference image can identify the earliest activation region 340 (eg, cardiac structures contained in the 2D image in the earliest activation region can be identified). The reference image may also contain pacing locations 342 . Pacing location 342 may be a virtual pacing location generated by stimulation point generator 324 . In some embodiments, pacing site 342 may be an actual pacing/catheter site. For example, when the heart is paced, the processing unit 400 may analyze the resulting ECG data to identify the corresponding pacing location 342, thereby identifying the current location of the pacing catheter, pacing electrodes, and the like.

In some embodiments, if the pacing location 342 does not provide the desired cardiac response (such as a simulated PVC or desired cardiac synchrony), the guidance information generator 332 may provide guidance information (such as a vector showing the direction the electrodes should move 344).

In block 503, the method includes performing an electrophysiological (EP) procedure that includes catheterizing the heart to analyze electrical activity and determine where the arrhythmia is located. In PVC patients, the goal of the EP procedure may be to pace the heart at a location that produces a PVC that closely approximates the patient's symptomatic PVC. For example, an EP procedure may involve pacing the heart with a catheter at the location of the earliest activated region. During EP, additional electrodes can also be inserted to internally detect ECG data. For example, pacing data can be recorded by recording ECG data during pacing.

The EP procedure may also involve mapping internal features of the patient's heart, such as features in and around the earliest activated PVC regions. In some embodiments, the EP procedure may involve generating a 3D triangulated inner surface model on a point-by-point basis by contacting different points of the heart with the catheter. Suitable systems for performing the EP process include the EnSite Precision Mapping System and the Carto 3 Mapping System. The system tracks the catheter's 3D position in the body and records the position of the inner surface of the heart each time the catheter makes contact with cardiac tissue. The collection of these 3D positions is synchronized with the heart beat, ensuring that each point is collected when the heart is in the same state as the other recorded points (ie, full volume as opposed to systolic). In addition to modeling, relative ECG activation times can be recorded and mapped onto the cardiac phantom.

Block 503 may also involve generating a real-time image of the heart using the real-time imaging device 328, as described above. In some embodiments, block 502 may be performed after the real-time image is generated, such that the reference image may be based on a cardiac image that approximates the real-time image.

The EP procedure may also involve positioning the catheter in contact with a location in the earliest activation region. In block 504, the catheter may then be used to pace the heart through electrical stimulation. The goal of pacing may be to pace the heart at a location that produces a PVC very close to the patient's symptomatic PVC. During EP, additional electrodes can also be inserted to internally detect ECG data. For example, pacing data can be recorded by recording ECG data during pacing.

Although EP procedures and pacing are shown as separate boxes in FIG. 11A , the present disclosure is not so limited. For example, both EP procedures and pacing can occur in a single procedure.

In some embodiments, block 504 may involve using the collected ECG data to generate an updated activation map to show the effect of the stimulation. In some embodiments, ECG data can be used to identify pacing locations, which can be displayed on the activation map. Since the pacing electrode is disposed at the pacing location, the pacing location may represent the current location of the pacing electrode. Thus, pacing electrode locations can be displayed while navigating to a pacing location. Accordingly, additional mapping applications may not be required to determine the location of the pacing electrodes, thereby significantly reducing the cost of the pacing procedure.

In determination block 506, the pacing data may be analyzed to determine whether the pacing electrodes are placed in the proper cardiac location for achieving a desired cardiac response. For example, pacing data can be compared to ECG data used to generate an activation map. In a PVC, the pacing may be analyzed to determine whether the pacing data adequately matches the PVC ECG data recorded during the presentation of the patient's PVC. In other words, the pacing data is analyzed to determine whether the catheter has identified a location that can be ablated to relieve the patient's PVC and/or VT. In CRT patients, pacing data can be analyzed to determine whether sufficient cardiac synchronization and/or activation has been achieved.

If it is determined that the desired cardiac response has been achieved (ie, determination block 506 = Yes), then in block 510 the catheter may be used to ablate the heart at the PVC patient's ablation site. In a CRT patient, at block 510, pacing electrodes and/or a micropacemaker may be sewn into place.

If it is determined that the desired cardiac response has not been achieved (i.e., determination block 506=No), then in block 508, the processing unit 400 may use the pacing data, PVC ECG data, and/or catheter position data to identify the direction in which the catheter should be moved, In order to better simulate the patient's PVC. For example, pacing data and catheter position data may be provided to guidance information generator 332 of processing unit 400 . Guidance information generator 332 may contain an algorithm configured to compare pacing data and/or position data with PVC ECG data in order to determine the direction and/or distance that the catheter should be moved to correctly simulate the patient's PVC. This information can be presented using icons and/or text. In CRT patients, pacing data may be analyzed to determine whether one or more pacing electrodes should be moved to achieve a desired cardiac response.

Guidance information generator 332 may provide guidance information to activation map generator 320 . The activation map generator 320 may update the activation map based on the guidance information provided by the guidance information generator 332, as discussed below with reference to FIGS. 11B and 11C. In other embodiments, guidance information generator 332 may provide guidance information to image integrator 326 for integration with images provided by real-time imaging device 328 . In other embodiments, guidance information may be provided to the EP system and displayed on the resulting EP map.

After the guidance information is displayed in block 508, the method returns to block 504 to pace the heart again. However, in some embodiments, the method may return to block 503 to perform the EP process. Thus, in PVC/VT patients, multiple sites can be stimulated until pacing produces a PVC that accurately replicates the patient's PVC, and the corresponding ablation sites are identified. In CRT patients, the stimulation position can be adjusted until the desired cardiac response is achieved. In addition, guidance information can be provided to the doctor to help identify the point of irritation.

In some embodiments, block 503 may involve externally recording ECG data during cardiac pacing using the mapping system of FIG. 9 . Further, block 504 may also include using a mapping system to determine a pacing location within the heart based on the recorded ECG data. For example, pacing locations can be determined by identifying the earliest activated regions during cardiac pacing. Further, block 508 may also include adding pacing locations to the PVC activation map. In this way, at least the location of the catheter's pacing electrode can be identified on the PVC activation map because the pacing electrode is placed at the pacing site during pacing.

Referring to Figure 11C, the updated activation map may contain a first point 700 showing the pacing/stimulation location corresponding to the most recent pacing location and/or catheter location. The updated activation map may also contain the earliest activated region 710, which may be the target region for ablation. In some embodiments, the activation map may contain a vector 712 showing direction and distance recommendations for moving the catheter to a new stimulation location in the earliest activation region 710 .

In some embodiments, as shown in Figure 1 ID, the updated activation map may contain one or more third points 704 showing previous pacing locations. For example, an updated activation map may contain a first point 700 representing a first stimulus location, a second point 702 representing a second stimulus location, a third point 704 representing a third (e.g., current) stimulus location, and a proposed stimulus location The fourth point 706. In some embodiments, earliest activation region 710 may be recalculated based on ECG data from each pacemaker.

Dots 700-706 may be of different colors, shades and/or shapes to provide timing information. For example, points 700-706 may be shaded to indicate the order in which the points were created to identify the path of the catheter. For example, points 700-706 may gradually become brighter or darker. In some embodiments, the fourth dot 706 may be brighter than the others. Once pacing occurs at the location represented by the fourth dot 706, each of the dots 700-706 may be dimmed, or otherwise modified to indicate that the dots represent a previous pacing location.

In other embodiments, the points may be connected by a line 708 to represent the path of the catheter during EP. In some embodiments, the vector 712 of FIG. 11B may also be applied to the activation map of FIG. 11C in addition to or instead of the fourth point 706 .

FIG. 12 is a block diagram illustrating an image integration method 800 according to various embodiments. Method 800 may be performed using the system of FIG. 9 . Referring to Figures 9 and 12, in block 801, a PVC activation map of a patient's heart may be generated using processor 400, as described above.

In block 802, a 3D inner surface model of the heart may be generated on a point-by-point basis by 3D triangulation. In particular, inner surface features of the patient's heart, such as ventricular surface features, may be mapped on a point-by-point basis through point contact between the inner surface of the heart and the EP catheter. Suitable systems for performing the EP process include the EnSite Precision Mapping System and the Carto 3 Mapping System. The system tracks the catheter's 3D position in the body and records the location of the heart's surface each time the catheter makes contact with cardiac tissue. The collection of this point-by-point contact data is synchronized with the beating of the heart, ensuring that each point is collected when the heart is in the same state as the other recorded contact points (ie, the volume of the heart is substantially the same). For example, the heart may be at full volume or fully contracted when point contact is made.

In conventional EP systems, an inner surface model is merged with an acquired MRI or CT data set to form a heart model. In particular, merging may involve adjusting the inner surface model data to more accurately represent the true geometry of the heart, as well as revealing additional cardiac features that were not mapped during EP. This process involves calculating which point size represents tissue versus blood in CT or MR. Adjustments can then be made to better represent the heart geometry.

The EP procedure may also involve recording relative ECG data (eg, activation time) during point-by-point contact. In some embodiments, this ECG data can be mapped onto the inner surface model. This may involve mapping the normal ECG signal, as this allows rapid collection of points when heart/catheter contact occurs.

To determine the ablation point, a PVC activation map can be generated, since a PVC activation map contains the earliest activated regions during PVC. However, when generating PVC activation maps using conventional EP systems, the catheter must be in contact with the heart during the PVC. Since PVCs may appear only intermittently, it may take significantly longer to generate PVC activation maps using conventional methods compared to using asymptomatic ECG data. This increases patient stress and usage of surgical resources.

Thus, in block 804, the interior surface model generated in block 802 may be merged with the PVC activation map generated in block 801 to form a PVC activation surface model. In particular, the PVC activation data contained in the PVC activation map can be applied to the interior surface model. Further, the surface features contained in the PVC activation map (which already contain MRI or CT data) can be merged with the triangulated pointwise data contained in the inner surface model. In this way, the PVC inner surface model can be generated without performing the conventional process of merging triangulated point-wise data with MRI or CT data, which further simplifies the process.

In block 806, the catheter may be located in the area of earliest PVC activation shown on the EP PVC activation phantom, and the heart may be paced. Pacing ECG data can be recorded during pacing.

In block 808, the pacing data may be analyzed to determine whether an ablation site has been identified. In particular, the pacing data may be analyzed to determine whether the pacing data adequately matches ECG data recorded during the patient's PVC episode. In other words, the pacing data is analyzed to determine if the catheter has been paced out of position where it can be ablated to relieve the patient's PVC and/or VT.

In determination block 810, it is determined whether an ablation location has been identified. If an ablation location has been identified (ie, determination block 810 = Yes), then in block 814 the catheter is used to ablate the heart at the identified ablation location.

If an ablation location is not identified (ie, determination block 810 =No), guidance information may be provided in block 812, as discussed above with respect to the method of FIG. 11A. The method may then proceed to block 806 . However, in some embodiments, when an ablation location is not identified (ie, determination block 810 =No), block 812 may be omitted, and the method may proceed directly from determination block 810 to block 806 . Method 800 may then repeat until an ablation location is identified and ablated in block 814 .

In some embodiments, the method can include displaying pacing locations on the PVC activation map. For example, a PVC activation surface model can be registered with the PVC activation map, and pacing locations can be added to the PVC activation map. The pacing site can also represent the position of the EP catheter during pacing. In other embodiments, processor 400 may analyze ECG data recorded during pacing to determine pacing and/or pacing catheter location, which is then added to the PVC activation map.

In some embodiments, method 800 may include generating and displaying a reference image with a PVC activation map and/or displaying guidance information, as discussed above with reference to FIGS. 11A-11D .

Some embodiments comprise a hardware system comprising a processing unit configured with software to receive patient-specific data, generate and display a 3D model of the heart's electrical activity in the form of a synchrony map of the patient's heart based on the ECG imaging data, and use Identifiable markers on the body that serve as fiducial reference points (referred to herein as "fiducial markers") associate or register the 3D model/map with the patient's body. An external imaging system, such as a 3D camera, can be used to obtain 3D image data of the patient's body (e.g., torso or chest) with key anatomical reference points (e.g., clavicle, shoulder, ribs, etc.) by the clinician as part of the CRT procedure setup indicated by markers applied to the patient). Patient-specific 3D anatomical model The image data can be merged with the 3D anatomical model of the patient's chest by registering the identified anatomical locations with the corresponding anatomical locations in the imaging obtained from the CT or MRI scan.

FIG. 13 is a system block diagram of a cardiac imaging system 1000 according to various embodiments. Referring to FIG. 13 , system 1000 includes processing unit 102 which may be electrically connected to hardware modules such as electrocardiography system 106 , internal imaging system 1080 , external imaging system 1090 and output unit 1200 .

The processing unit 1020 receives patient-specific data from the hardware modules. From the patient-specific anatomical data, the processing unit 1020 may generate a synchrony map of the patient's heart, which may be output to the output unit 1200 . The output unit 1200 may be configured to output a synchronization map and/or substitute data to a user. The output unit may be a display unit, a printer, a message unit, and the like.

For example, processing unit 1020 may receive electrocardiogram (ECG) imaging data from electrocardiogram system 1060 , such as a 12-lead ECG device. The processing unit 1020 may use the ECG data to determine a 3D model 4 of the electrical activation of the heart. In particular, the ECG signal may be combined with a patient-specific 3D anatomical model of the heart, lungs and/or torso in order to calculate the position of the isochrone of the heart.

A patient-specific 3D anatomical model may be obtained from an internal imaging system 1080, such as an MRI device or a CT device. Alternatively or additionally, the 3D anatomical model exhibiting the closest conformity to the patient may be selected from a database containing a plurality of 3D anatomical models and optionally modified. The selected and optionally modified 3D anatomical model can be used as the patient-specific 3D anatomical model.

Further, the processing unit 1020 may receive patient image data from an external imaging system 1090 . For example, the external imaging system 1090 may be a 3D camera, and the processing unit 1020 may receive 3D image data of the patient's chest surface, as shown in Figure 14A or Figure 14B.

Referring to FIG. 14A , the 3D image data may contain the location of ECG leads relative to the patient's anatomy, such as the V1-6 precordial electrodes shown in FIG. 14A . Knowledge of the location of the ECG electrodes relative to the heart, especially the V1-6 precordial electrodes, may be particularly important for accurate calculation of the onset location of PVCs.

In some embodiments, the offset of the electrodes relative to their assumed ideal position, particularly the offset of the V1-6 electrodes, may be determined based on a comparison of the detected ECG signal of a normal heart beat with the ideal ECG normal heart beat signal . For example, the offset may be determined based on how the detected ECG signal will be affected by changes in the position of the electrodes relative to the ideal electrode positions. In particular, the recorded ECG data can be used to determine the location of the stimulation onset of normal beating. Because the normal onset location in the SA node is known, the determined offset location can be compared to this known onset location, and their offset can be inferred based on the variation between electrodes. Thus, electrode offsets can be determined without generating a 3D map.

The processing unit 1020 may be configured to align and/or merge the 3D image data generated by the external imaging system 1090 with the anatomical torso and/or heart model generated by the internal imaging system 1080, and electrode positions in the torso model may be adjusted to match The electrode positions in the 3D image data are consistent. However, if the external imaging system 1090 is not properly aligned with the torso, it may be difficult to properly align the 3D image data and anatomical model.

To facilitate alignment of the 3D image data and the anatomical torso model, the system 100 may include fiducial markers captured in the 3D image data generated by the external imaging system 109 that were previously placed on (eg, adhered to) the patient's torso. Clinicians can place fiducial markers on the patient at set anatomical locations identified in the torso model to facilitate alignment of the 3D image of the patient with the anatomical torso model. In some embodiments, the fiducial marker may be a sticker with an adhesive backing configured to adhere to the skin, having a shape, color, and/or shape, color, and/or Surface materials (eg, reflective or retroreflective materials).

For example, first fiducial markers 900 may be placed at set anatomical locations on the patient's shoulder, such as the distal ends of each clavicle. The second fiducial markers 902 may be placed between the first fiducial markers 902 at a set anatomical location, such as on the patient's sternum.

The processing unit 1020 may be configured to identify the two fiducial markers and their corresponding anatomical locations based on one or more identifying features of the fiducial markers 900, 902 contained in the 3D image data collected by the external imaging device. In some embodiments, the processing unit 1020 may be configured to identify the anatomical locations corresponding to the fiducial markers 900, 902 based on the color, shape and/or reflectivity of the corresponding anatomical markers contained in the image data.

In some embodiments, fiducial markers 900, 902 may be configured to reflect specific wavelengths of light. For example, first fiducial marker 900 may have a first color and second fiducial marker 902 may have a second color. In some embodiments, each indicium 900, 902 may have a different color.

In some embodiments, the fiducial markers 900, 902 may comprise a reflective material, which may be in the form of a reflective coating. In some embodiments, a reflective material may be configured to reflect one or more particular wavelengths or ranges of wavelengths of light. For example, in some embodiments, fiducial markers 900, 902 may be formed from a material configured to reflect visible light, infrared light, ultraviolet light, or combinations thereof. In some embodiments, external imaging system 1090 may contain a light source, and the reflective material may be configured to reflect all or a portion of light emitted from the light source. For example, fiducial markers 900, 902 may be configured to selectively reflect emitted light at a particular wavelength or range of wavelengths. The processing unit 1020 may be configured to identify the fiducial markers 900, 902 based on the light reflected thereby.

In some embodiments, fiducial markers 300, 302 may comprise retroreflective material. In particular, the retroreflective material may be configured to reflect incident light, or a portion thereof, at an angle substantially equal to the angle of incidence of the incident light (ie, directly back to the source of the incident light). For example, retroreflective materials are known to be used in safety vests and traffic signs. In such an embodiment, the processing unit 102 may be configured to detect light as peaks in brightness in image data received from an external imaging system.

In some embodiments, fiducial markers may have one or more different shapes. For example, as shown in FIG. 14B , system 1000 may include triangular-shaped fiducial markers 904 , cross-shaped fiducial markers 906 , and/or trapezoidal-shaped fiducial markers 908 . The processing unit 1020 may be configured to identify an anatomical location corresponding to the fiducial marker based on the shape of the fiducial marker.

However, the various embodiments are not limited to any particular fiducial marker for identifying properties, so long as the fiducial marker comprises a property that is identifiable by the processing unit 1020 and detectable by the external imaging system 1090 . Further, although three fiducial markers are shown in FIGS. 14A and 14B , any suitable number of fiducial markers may be used.

The foregoing method descriptions and process flow diagrams are provided as illustrative examples only, and are not intended to require or imply that the steps of the various embodiments must be performed in the order presented. As will be appreciated by those skilled in the art, the sequence of steps in the foregoing embodiments may be performed in any order. Words such as "then," "then," "next," etc. are not intended to limit the order of the steps; these words are simply used to guide the reader through the description of the method. Further, any singular reference to claim elements, eg, use of the articles "a," "an," or "the," should not be construed as limiting the element to the singular.

The various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints placed on the overall system. Skilled artisans may implement the described functionality in varying ways for a particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.

Hardware for implementing the various illustrative logics, logic blocks, modules, and circuits described in connection with aspects disclosed herein can be implemented using general purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field programmable gates, FPGAs (FPGAs) or other programmable logic devices, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general-purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices (eg, a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors in combination with a DSP core, or any other such configuration). Alternatively, some steps or methods may be performed by circuitry specific to a given function.

In one or more exemplary aspects, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented in software, the functions may be stored as one or more instructions or code on a non-transitory computer-readable medium or a non-transitory processor-readable medium. The steps of a method or algorithm disclosed herein may be embodied in processor-executable software modules and/or processor-executable instructions, which may reside on a non-transitory computer-readable or non-transitory processor-readable storage medium. A non-transitory server-readable, computer-readable, or processor-readable storage medium may be any storage medium that can be accessed by a computer or a processor. By way of example and not limitation, such non-transitory server-readable, computer-readable, or processor-readable media may comprise RAM, ROM, EEPROM, flash memory devices, CD-ROM or other optical disk storage, magnetic disk storage, or other magnetic storage device, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer. Disc and disc, as used herein, includes compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disc, and blu-ray disc where discs usually reproduce data magnetically, while discs reproduce data optically using lasers . Combinations of the above are also included within the scope of non-transitory server-readable, computer-readable and processor-readable media. Additionally, the operations of a method or algorithm may reside on a non-transitory server-readable, processor-readable, and/or computer-readable medium as one or any combination or set of codes and/or instructions, which may be embodied in in computer program products.

The above description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit and scope of the claims. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the following claims and the principles and novel features disclosed herein.

Claims (3)

1. A method for cardiac mapping, comprising: attaching the 12 electrodes of an electrocardiogram (ECG) device to the patient's chest; applying at least three fiducial markers to the patient's body with two of the fiducial markers positioned on the patient's shoulders and one of the fiducial markers positioned on on the patient's sternum, wherein the fiducial markers reflect different wavelengths of light, have different shapes, or reflect different wavelengths of light and have different shapes, such that the fiducial markers are distinguishable using image processing; generating external image data of the patient's body comprising imaging the fiducial markers and the electrodes; by analyzing the image data to detect the light reflected from the fiducial marker, the different shape of the marker or the light reflected from the fiducial marker and the Both different shapes to identify anatomical locations corresponding to the fiducial markers; and By registering the identified anatomical locations with corresponding anatomical locations in imaging obtained from CT or MRI scans and by combining the image data with three-dimensional (3D) images of the patient's chest generated using two-dimensional (2D) images, ) anatomical models are merged to generate a 3D chest model; Use an electrocardiogram (ECG) device to record ECG data; generating a premature ventricular systole (PVC) activation map of the patient's heart based on the ECG data of the heart, the 3D chest model, and 2D images, the PVC activation map including regions of earliest activation; determining the relationship between the actual location of each electrode included in the 3D chest model and the ideal location of each electrode based on a comparison of the earliest activated region in the PVC activation map to the earliest activated known normal region offset by ; and The PVC activation map is adjusted based on the determined offset. 2. The method of claim 1, wherein the ECG data is recorded during a PVC of the heart. 3. The method of claim 1, wherein: two of the fiducial markers are positioned on the patient's shoulders; and One of the fiducial markers is disposed on the patient's sternum.

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