WO2009156894A1

WO2009156894A1 - Method and system for cardiac resynchronization therapy

Info

Publication number: WO2009156894A1
Application number: PCT/IB2009/052525
Authority: WO
Inventors: Robert Manzke; Raymond Chan; Luis Felips Gutierrez; Guy Shechter
Original assignee: Koninklijke Philips Electronics, N.V.
Priority date: 2008-06-25
Filing date: 2009-06-12
Publication date: 2009-12-30

Abstract

A cardiac resynchronization therapy system (10) can include a cardiac pacer (30) having a lead, a tracking system (100), a guide wire (110) that is trackable using the tracking system where the guide wire has a size and shape for advancing the cardiac pacer lead to a target cardiac region, an ultrasound imaging system (150), and a processor (75) in communication with the tracking system and the ultrasound imaging system. The processor can register the tracking system with the ultrasound imaging system. The processor can display ultrasound images of the target cardiac region where the ultrasound images show a position of the guide wire.

Description

METHOD AND SYSTEM FOR CARDIAC RE SYNCHR ONIZA TION THERAPY [0001] The present application relates to the therapeutic arts, in particular in conjunction with cardiac resynchronization therapy and will be described with particular reference thereto. However, it is to be appreciated that the exemplary embodiments can also find application in conjunction with other therapeutic treatments, positioning other treatment sources, and the like.

[0002] The heart is an electro-mechanical system which controls blood flow through an individual's circulatory system. The heart includes four chambers: the right atrium (RA), the right ventricle (RV), the left atrium (LA), and the left ventricle (LV). The left portions of the heart, including the LA and the LV, draw oxygenated blood from the lungs and pump it to tissues throughout the body, while the right portions of the heart, including the RA and the RV, draw deoxygenated blood from a body's tissues and pump it to the lungs where the blood gets re-oxygenated. The efficiency of the pumping functions, which is indicative of whether the heart is normal and healthy, can be measured by the hemodynamic performance of the heart, including parameters that relate to intracardiac blood pressures and cardiac output. [0003] In a normal heart, the sinoatrial node generates electrical impulses that propagate through an electrical conduction system to various regions of the heart to excite the myocardial tissues of these regions. Coordinated delays in the propagations of the impulses in a normal electrical conduction system cause the various portions of the heart to contract in a synchronized fashion resulting in efficient pumping functions or normal hemodynamic performance. An abnormal electrical conduction and/or deteriorated myocardial tissue can cause non-synchronous contraction of the heart, resulting in poor hemodynamic performance, including a diminished blood supply to the heart or the rest of the body. Congestive heart failure can occur when the heart fails to pump enough blood to meet the body's metabolic needs.

[0004] There are numerous patient conditions that may require the use of a cardiac management device. For example, a bradyarrhythmia patient is a person whose intrinsic heart beat can fall below a level necessary to meet hemodynamic needs. If a bradyarrhythmia patient's intrinsic heart beat is constantly below the level needed to sustain hemodynamic functions, then a pacer must constantly supply pacing pulses or other therapy to the patient's heart. If a patient experiences sporadic episodes of brady arrhythmia, then the pacer may supply the therapy on an as needed basis.

[0005] A tachyarrhythmia patient is a person whose heart rate can be accelerated, which may also diminish hemodynamic function. For a tachyarrhythmia patient, a pacer can deliver anti-tachyarrhythmia pacing or counter-shock therapy to interrupt a tachyarrhythmia event. In other patients, the atria or ventricles may contract out of synchronization. For example, when a left ventricle becomes enlarged, it may not contract synchronously with the right ventricle, reducing cardiac output. Cardiac resynchronization therapy pulses may be delivered to such a patient, such as to bring the ventricles back into synchronization.

[0006] However, delivery of the pulses is dependent on the positioning of the lead of the pacer in proximity to dyssynchronous LV segments. Proper positioning of the lead can be a time consuming and difficult process.

[0007] The Summary is provided to comply with 37 CF. R. § 1.73, requiring a summary of the invention briefly indicating the nature and substance of the invention. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

[0008] In accordance with one aspect of the exemplary embodiments, a method can include providing a guide wire that is trackable using a tracking system; registering the tracking system with an ultrasound imaging system; acquiring x-ray imaging of a cardiac vessel; positioning the guide wire in the cardiac vessel using the x-ray imaging; acquiring ultrasound imaging of a cardiac region using the ultrasound imaging system; presenting the ultrasound imaging of the cardiac region with the guide wire displayed therein; and positioning a lead of a cardiac pacer in the cardiac region using the guide wire and based on the presentation of the ultrasound imaging with the guide wire.

[0009] In accordance with another aspect of the exemplary embodiments, a computer- readable storage medium can include computer-executable code stored therein, where the computer-executable code is configured to cause a computing device in which the computer- readable storage medium is loaded to execute the steps of registering an electromagnetic tracking system with an ultrasound imaging system where the electromagnetic tracking system is capable of tracking a guide wire; and displaying ultrasound images of a left ventricle region of a heart where the ultrasound images show the guide wire positioned therein. The ultrasound images can show functional changes to the left ventricle region caused by a cardiac pacer.

[0010] In accordance with another aspect of the exemplary embodiments, a cardiac resynchronization therapy (CRT) system can include a cardiac pacer with a lead, a tracking system, a guide wire that is trackable using the tracking system where the guide wire has a size and shape for advancing the cardiac pacer lead to a target cardiac region, an ultrasound imaging system, and a processor in communication with the tracking system and the ultrasound imaging system. The processor can register the tracking system with the ultrasound imaging system. The processor can display ultrasound images of the target cardiac region where the ultrasound images show a position of the guide wire. [0011] In accordance with another aspect of the exemplary embodiment, an ultrasound imaging system and an electromagnetic tracking system can be registered with each other. This can be achieved in calibration steps and may only require that the tracking system remains in the same position during the intervention. During the intervention, the clinician can use the tracked guide wire to access the desired cardiac vein for lead placement using fluoroscopic X-ray imaging. Once the guide wire is within the desired cardiac vein, ultrasound image acquisition can be performed. Since the ultrasound and tracking systems are registered, they can be displayed in spatial relation of each other. In the ultrasound image, direct functional changes due to the pacing can be observed. The lead, which can be fed over the tracked guide wire can be repositioned to optimize the LV functional response. Either real-time ultrasound imaging or quantitative ultrasound analysis tools with more latency can be used for such purpose.

[0012] The exemplary embodiments described herein have a number of advantages over contemporary systems and processes, including accuracy of lead placement, time savings and reducing radiation exposure. [0013] The above-described and other features and advantages of the present disclosure will be appreciated and understood by those skilled in the art from the following detailed description, drawings, and appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 is a schematic illustration of an exemplary embodiment of a system for use in cardiac resynchronization therapy;

[0015] Figure 2 depicts an image generated by the system of FIG. 1 when the biventricular pacing is not being utilized;

[0016] Figure 3 depicts an image generated by the system of FIG. 1 when the biventricular pacing is being utilized;

[0017] Figure 4 depicts an image generated by the system of FIG. 1 including 3D realtime ultrasound imaging;

[0018] Figure 5 depicts an image generated by the system of FIG. 1 including LV functional feedback; and

[0019] Figure 6 is a method that can be used by the system of FIG. 1 for cardiac resynchronization therapy.

DETAILED DESCRIPTION OF THE INVENTION

[0020] Referring to the drawings, and in particular to FIGS. 1-5, a CRT system 10 can have an x-ray imaging system 50, a tracking system 100 and an ultrasound imaging system 150 that can be utilized for placement of a cardiac pacer 30 in a target cardiac region of a patient 20. Each of these systems 50, 100 and 150 can be in communication with a processor 75 having a display device (e.g., a monitor) connected thereto. However, while the exemplary embodiment describes each of the systems 50, 100 and 150 being connected to the processor 75, it would be understood by one of ordinary skill in the art that certain techniques that are described with respect to system 10 can be performed independently of other techniques. For example, the x-ray imaging system 50 can be an independent system that is utilized for positioning of the guide wire 110 in a cardiac vein, where the tracking system 100 and ultrasound imaging systems are then employed for the further techniques that are utilized by system 10 for the CRT procedure.

[0021] X-ray imaging system 50 can utilize fluoroscopic x-ray imaging, such as the system depicted in FIG. 1 using a C-arm having an x-ray emitter and detector connected thereto. System 50 can provide the clinician with x-ray images in order to position the guide wire 110 in the cardiac vessel which will allow for access to the target cardiac region (e.g., the LV region of the heart). In one embodiment, the system 50 can acquire the fluoroscopic x-ray images of the cardiac vein, which are then displayed on monitor 80 by the processor 75. [0022] The tracking system 100 can be in communication with the processor 75 and can include a field generator 120, such as positioned under a bed 25 or other support for the patient 20. However, the particular positioning of the field generator 120 can vary depending on a number of factors, including the type of field generator or the structure of the other components of system 10 (e.g., use of a C-arm x-ray device). In one embodiment, the tracking system 100 can be an electromagnetic tracking system that utilizes an electromagnetic field generator 120 and one or more electromagnetic sensors coupled to, or incorporated in, the guide wire 110. Other components can be utilized by the system 100, such as fiducial markers.

[0023] In one embodiment, the tracking system 100 can use various tracking components, such as those available from Traxtal Inc. or Northern Digital Inc. As another example, the tracking system 100 can utilize optical tracking techniques and components, such as available in the Northern Digital Optotrak Certus Motion Capture System. Other techniques and components can be used as a location sensor or transmitter and a location monitor or receiver for tracking the position of the guide wire 110, including ultrasound techniques and components.

[0024] The ultrasound imaging system 150 can be in communication with the processor 75 and can include an ultrasound controller 160 and an ultrasound probe 170. The particular type of ultrasound controller 160, probe 170 and other ultrasound components that are utilized by system 10 can vary, and the particular imaging techniques, such as with respect to data capture, analysis and presentation, can also vary. For example, the controller 160 can include a beamformer for processing received echo signals, a Doppler processor for processing Doppler-related information, and an image processor for forming 2D and/or 3D images. The controller 160 can also include a memory device, such as a CINELOOP ® memory, and a video processor. In one embodiment, the controller 160 can include components and/or utilize techniques associated with steering and electronic focusing of the ultrasound waves of the probe 170. Other components and/or techniques can also be used with the controller 160, such as an automatic border detection processor that can define and graphically overlay anatomical borders with respect to the images presented. The present disclosure also contemplates the use of other components and/or techniques in addition to, or in place of, the components of controller 160 described above. It should further be understood by one of ordinary skill in the art that controller 160 or one or more of its components can be incorporated into, or shared with, processor 75, such as for data processing and presentation techniques.

[0025] Probe 170 can include an array of transducer or acoustic elements for the transmission of ultrasonic waves and for the receipt of ultrasonic echo signals. In one embodiment, probe 170 can provide for steering and electronic focusing of the ultrasound waves with respect to the target cardiac region under examination. For example, probe 170 can include a transmit/receive (T/R) switch coupled to the transducer array, such as a two- dimensional array of transducer elements for performing three-dimensional scanning. The transducer array can transmit ultrasound energy into a region being imaged and receive reflected ultrasound energy or echoes, from the vessel and other structures and organs within the patient's body. By appropriately delaying the pulses applied to each transducer element, the probe 120 can transmit a focused ultrasound beam along a desired transmit scan line. According to one embodiment, the array transducer of the probe 170 can include a two dimensional array such as disclosed in U.S. Pat. No. 6,428,477, assigned to the assignee of the present disclosure and incorporated herein by reference. U.S. Pat. No. 6,428,477 discloses delivery of therapeutic ultrasound and performing ultrasound diagnostic imaging with the use of a two dimensional ultrasound array. The two dimensional ultrasound array can include a matrix or grid of transducer elements that allows three-dimensional (3D) images to be acquired, although 2D imaging is also contemplated by the present disclosure. The matrix of transducer elements makes possible the steering and electronic focusing of ultrasound energy in any arbitrary direction. The present disclosure also contemplates the use of other components and/or techniques in addition to, or in place of, the components of probe 170 described above.

[0026] Referring additionally to FIG. 6, a method that may be utilized for performing CRT with system 10 is shown and generally represented by reference numeral 600. It should be understood by one of ordinary skill in the art that the steps described with respect to method 600 are intended to be exemplary of the use of system 10 and more or less steps can be employed. Additionally, other components or devices that are not specifically described with respect to system 10 can also be employed in the performance of method 600. Method 600 can commence with step 602 where the electromagnetic tracking system 100 is registered with the ultrasound imaging system 150. The registration technique can include one or more calibration steps as are known in the art, such as through acquiring position data while maintaining the tracking system components in a stationary position. The registration technique can include each point acquired by the tracking system 100 corresponding to a respective point in the image data acquired by the ultrasound imaging system 150. Projection and other imaging techniques can then be utilized for displaying the target cardiac region and the guide wire 110 as will be described again later.

[0027] In step 604, the guide wire 110 can be introduced into the patient 20 and positioned into a cardiac vessel which will provide the cardiac pacer 30 with the necessary access to the target cardiac region. The positioning of the guide wire 110 in the cardiac vessel can be performed with the assistance of x-ray imaging, such as fluoroscopic x-ray imaging from x-ray imaging system 50.

[0028] In step 606, the processor 75 can utilize the data from the ultrasound imaging system 100 to display ultrasound images of the target cardiac region and can use the registered tracking system 100 to display the guide wire 100 as in step 608. For instance, the processor 75 can display the ultrasound images on the monitor 80 such as in FIGS. 2 and 3 where the guide wire 110 is displayed in spatial relation to a functional ultrasound mesh 115. Depending on whether the bi-ventricular pacing of the cardiac pacer 30 is turned on or off, the mesh can change color or provide some other indicia.

[0029] In step 610, the physician can relocate the guide wire 110 and/or the lead or electrode of the cardiac pacer 30 to adjust (e.g., optimize) the pacing locus, iteratively. As shown in FIG 4, the tracked guide wire 110 can be displayed in spatial relation to the anatomic 3D real-time ultrasound image. In FIG. 5, a TDI acquisition can be utilized which directly presents LV functional feedback. In one embodiment, the tracked guide wire 110 can be forward projected in the 2D TDI plane.

[0030] In the ultrasound image, direct functional changes due to the pacing can be observed. The lead of the cardiac pacer 30, which can be fed over the tracked guide wire 100 or otherwise guided to the target cardiac region by the guide wire can be repositioned to adjust or optimize the LV functional response. Either real-time ultrasound imaging or quantitative ultrasound analysis tools with more latency can be used by method 500. [0031] The exemplary embodiments of the present disclosure are described with respect to guidance for CRT of a human. It should be understood by one of ordinary skill in the art that the exemplary embodiments of the present disclosure can be applied to other types of medical intervention and other portions of the body, whether human or animal. The use of the method and system of the exemplary embodiments of the present disclosure can be adapted for application to other types of implantable devices.

[0032] The invention, including the steps of the methodologies described above, can be realized in hardware, software, or a combination of hardware and software. The invention can be realized in a centralized fashion in one computer system, or in a distributed fashion where different elements are spread across several interconnected computer systems. Any kind of computer system or other apparatus adapted for carrying out the methods described herein is suited. A typical combination of hardware and software can be a general purpose computer system with a computer program that, when being loaded and executed, controls the computer system such that it carries out the methods described herein. [0033] The invention, including the steps of the methodologies described above, can be embedded in a computer program product. The computer program product can comprise a computer-readable storage medium in which is embedded a computer program comprising computer-executable code for directing a computing device or computer-based system to perform the various procedures, processes and methods described herein. Computer program in the present context means any expression, in any language, code or notation, of a set of instructions intended to cause a system having an information processing capability to perform a particular function either directly or after either or both of the following: a) conversion to another language, code or notation; b) reproduction in a different material form. [0034] The illustrations of embodiments described herein are intended to provide a general understanding of the structure of various embodiments, and they are not intended to serve as a complete description of all the elements and features of apparatus and systems that might make use of the structures described herein. Many other embodiments will be apparent to those of skill in the art upon reviewing the above description. Other embodiments may be utilized and derived therefrom, such that structural and logical substitutions and changes may be made without departing from the scope of this disclosure. Figures are also merely representational and may not be drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized. Accordingly, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense.

[0035] Thus, although specific embodiments have been illustrated and described herein, it should be appreciated that any arrangement calculated to achieve the same purpose may be substituted for the specific embodiments shown. This disclosure is intended to cover any and all adaptations or variations of various embodiments. Combinations of the above embodiments, and other embodiments not specifically described herein, will be apparent to those of skill in the art upon reviewing the above description. Therefore, it is intended that the disclosure not be limited to the particular embodiment(s) disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope of the appended claims. [0036] The Abstract of the Disclosure is provided to comply with 37 C.F.R. § 1.72(b), requiring an abstract that will allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims.

Claims

What is claimed is:

1. A method comprising: providing a guide wire (110) that is trackable using a tracking system (100); registering the tracking system with an ultrasound imaging system (150); acquiring x-ray imaging of a cardiac vessel; positioning the guide wire in the cardiac vessel using the x-ray imaging; acquiring ultrasound imaging of a cardiac region using the ultrasound imaging system; presenting the ultrasound imaging of the cardiac region with the guide wire displayed therein; and positioning a lead of a cardiac pacer (30) in the cardiac region using the guide wire and based on the presentation of the ultrasound imaging with the guide wire.

2. The method of claim 1, wherein the tracking system (100) is an electromagnetic tracking system, and wherein the guide wire (110) comprises one or more electromagnetic sensors.

3. The method of claim 1, further comprising displaying functional changes in the ultrasound imaging, the functional changes being to the cardiac region caused by the cardiac pacer (30).

4. The method of claim 3, wherein the positioning of the lead is an iterative process based on the functional changes displayed.

5. The method of claim 1, further comprising acquiring and presenting the ultrasound imaging in real-time.

6. The method of claim 1, wherein the x-ray imaging comprises fluoroscopic x-ray imaging.

7. The method of claim 1, further comprising forward projecting the guide wire (110) for presenting the ultrasound imaging of the cardiac region with the guide wire displayed therein.

8. The method of claim 1, wherein the registering of the tracking system (100) with the ultrasound imaging system (150) is performed while a tracking field generator (120) remains stationary.

9. A computer- readable storage medium in which computer-executable code is stored, the computer-executable code configured to cause a computing device in which the computer- readable storage medium is loaded to execute the steps of: registering an electromagnetic tracking system ( 100) with an ultrasound imaging system (150), the electromagnetic tracking system being capable of tracking a guide wire (110); and displaying ultrasound images of a left ventricle region of a heart, the ultrasound images showing the guide wire positioned therein, wherein the ultrasound images show functional changes to the left ventricle region caused by a cardiac pacer (30).

10. The computer-readable storage medium of claim 9, further comprising computer- executable code for causing the computing device to forward project the guide wire (110) for displaying within the ultrasound images.

11. The computer-readable storage medium of claim 9, further comprising computer- executable code for causing the computing device to display the ultrasound images while the cardiac pacer (30) is active and inactive.

12. The computer-readable storage medium of claim 9, further comprising computer- executable code for causing the computing device to register the electromagnetic tracking system (100) with the ultrasound imaging system (150) while an electromagnetic field generator (120) remains stationary.

13. The computer-readable storage medium of claim 9, further comprising computer- executable code for causing the computing device to display the ultrasound images in real time.

14. The computer-readable storage medium of claim 10, further comprising computer- executable code for causing the computing device to display the ultrasound images in two dimensional imaging and in three dimensional imaging.

15. A cardiac resynchronization therapy system comprising: a cardiac pacer (30) having a lead; a tracking system (100); a guide wire (110) that is trackable using the tracking system, the guide wire being a size and shape for advancing the cardiac pacer lead to a target cardiac region; an ultrasound imaging system (150); and a processor (75) in communication with the tracking system and the ultrasound imaging system, wherein the processor registers the tracking system with the ultrasound imaging system, and wherein the processor displays ultrasound images of the target cardiac region, the ultrasound images showing a position of the guide wire.

16. The system of claim 15, wherein the tracking system (100) is an electromagnetic tracking system, and wherein the guide wire (110) comprises one or more electromagnetic sensors.

17. The system of claim 16, wherein the ultrasound images show functional changes to the target cardiac region caused by the cardiac pacer (30).

18. The system of claim 15, wherein the ultrasound images are displayed in real-time.

19. The system of claim 15, wherein the processor forward projects the guide wire (110) to display the guide wire in the ultrasound images.

20. The system of claim 19, wherein the ultrasound images are displayed while the cardiac pacer (30) is active and inactive, and wherein the ultrasound images are displayed in two dimensional imaging and in three dimensional imaging.