Integrated cardiac mapping and piezoelectric micromachined ultrasound transducer (pMUT) ultrasound imaging catheter systems and methods

Abstract

An integrated cardiac mapping and piezoelectric micromachined ultrasound transducer (pMUT) ultrasound imaging system is disclosed. The system includes a pMUT imaging and mapping catheter having a longitudinal axis, a proximal end, and a distal end. A microelectromechanical (MEMS)-based pMUT or other transducer disposed within the distal end of a pMUT imaging and mapping catheter. A pMUT mapping array disposed within the distal end of the pMUT imaging and mapping catheter, where the mapping array includes an expandable basket structure, a grid, a hoop, or other configuration having an array of electronic sensors disposed on an electronic flexible circuit.

Description

Technical Field

[0001] The present disclosure relates generally to the fields of cardiac mapping and ultrasound imaging and mapping catheters. More particularly, embodiments relate to mapping catheters having a distal piezoelectric micromachined transducer for transmitting and receiving acoustic pulse information. Background Art

[0002] The use of catheter-based structural and electrophysiology procedures has recently expanded to more complex scenarios, where accurate definition of variable individual cardiac anatomy is key to achieving optimal outcomes. In electrophysiology procedures, piezoelectric micromachined ultrasonic transducer (pMUT) imaging allows the integration of real-time images with mapping to guide transcatheter cardiac procedures. Cardiac mapping utilizes electrodes that measure the electrical activity of cardiac tissue. This is transferred to the mapping system software, where a 3D model of the heart is created, with a color-coded overlay showing the electromagnetic waves generated during each heartbeat, the touch points where the tissue is mapped, and the position of the catheter inside the heart. Tissue identified as having unhealthy electrical activity that causes arrhythmias can then be directly ablated or isolated using an ablation catheter to cause small burns / scar tissue that block the electrical signals. The integration of pMUT imaging allows real-time assessment of cardiac anatomy during interventional procedures and guides catheter manipulation associated with different anatomical structures. Therefore, there is a need for improved mapping catheters that integrate ultrasonic pMUT imaging.

[0003] Atrial Fibrillation (AF) is one of the most common and persistent cardiac arrhythmias and it affects more than 30 million people worldwide. Although the prevalence in developed countries tends to be small, close to 1%-4%. AF is steadily increasing and is well known to be associated with an increased risk of all-cause mortality, heart failure, thromboembolism and dementia. Catheter mapping is an alternative treatment option that is more effective than antiarrhythmic drugs. Pulmonary vein isolation (PVI), which involves electrically isolating the pulmonary veins (PV) from the left atrium, remains the cornerstone of atrial fibrillation (AF) mapping. Catheter mapping is necessary to locate triggers and substrates so that ablation strategies can be optimized. The most commonly used cardiac mapping method is isochronous mapping or activation mapping, the purpose of which is to create a spatial model of the propagation of the electrical wavefront. Catheter mapping increases the ability to perform rapid and simultaneous contact mapping of the chambers. Typically, modern mapping techniques can improve the effectiveness, safety and efficiency of mapping of persistent AF. In addition, current technology requires the use of separate mapping, ablation catheters, and intracardiac echocardiography (ICE) pMUT imaging catheters. ICE has been applied to structural cardiac pMUT imaging of the left atrial appendage (LAA) to assist in septal defect closure and visualization of the fossa ovalis, and plays a role in transcatheter valve replacement. It is also used for ablation catheter guidance during EP procedures. ICE confirms the exact position of the catheter tip to assist in more accurate ablation. ICE can also help safely monitor the pericardial space for tamponade or pericardial effusion caused by transseptal puncture or ablation in rare cases. It is expected that ICE will become increasingly important to better guide the increasing number of transcatheter ablation procedures. Once transcatheter aortic and mitral heart valve replacement and LAA occlusion devices receive approval from the U.S. Food and Drug Administration (FDA), ICE is expected to be used more frequently for the accurate deployment of these devices.

[0004] Furthermore, AF refers to a type of cardiac arrhythmia in which there is disordered electrical conduction in the atria that causes rapid, uncoordinated contractions, which results in ineffective pumping of blood into the ventricles and a lack of synchrony. During AF, the atrioventricular node receives electrical impulses from many locations throughout the atria, rather than just from the sinus node. This overwhelms the atrioventricular node, producing an irregular and rapid heartbeat. As a result, blood pools in the atria, increasing the risk of blood clot formation. Major risk factors for atrial fibrillation include age, coronary artery disease, rheumatic heart disease, hypertension, diabetes, and thyrotoxicosis. AF affects 7% of the population over the age of 65.

[0005] Furthermore, AF treatment options are limited. Lifestyle changes only help individuals with lifestyle-related AF. Medication only helps manage AF symptoms, may have side effects that are more dangerous than atrial fibrillation, and does not cure AF. Cardioversion often restores sinus rhythm, but has a high recurrence rate. Furthermore, if a blood clot is present in the atria, cardioversion may cause the clot to escape the heart and travel to the brain or other parts of the body, which may lead to a stroke. Therefore, a need exists for improved cardiac mapping and pMUT ultrasound imaging catheter systems. Summary of the Invention

[0006] By way of introduction, the preferred embodiments described below include disclosing an easy-to-use integrated cardiac mapping and piezoelectric micromachined ultrasonic transducer (pMUT) ultrasound imaging catheter system. The integrated cardiac mapping and pMUT ultrasound imaging catheter system includes a pMUT imaging and mapping catheter having a longitudinal axis, a proximal end, and a distal end. In addition, an ultrasonic pMUT transducer array is disposed within the distal end of the pMUT imaging and mapping catheter. The ultrasonic pMUT transducer array includes a plurality of pMUT transducer array elements arranged on a substrate. It may be noted that the plurality of pMUT ultrasound transducer array elements correspond to microelectromechanical (MEMS)-based pMUTs. In addition, the integrated cardiac mapping and pMUT ultrasound imaging catheter system includes a catheter shaft connected at one end to a handle assembly and at the other end to the ultrasonic pMUT transducer array. The catheter shaft encloses an electronic flexible cable in communication with at least one signal trace and is configured to: guide each of the plurality of pMUT transducer array elements via the at least one signal trace to transmit and receive, relative to the heart, an ultrasound beam having a bandwidth that includes a predetermined fundamental mode vibration of each of the plurality of pMUT transducer array elements, such that a single array element can simultaneously transmit and receive multiple fundamental mode vibrations; receive at least one signal from the plurality of pMUT transducer array elements based on at least one of the transmitted and received ultrasound beams, and construct at least one image of at least a portion of the heart based on the at least one signal.

[0007] In one embodiment, an integrated cardiac mapping and pMUT ultrasound imaging catheter system includes a mapping catheter consisting of an open-lumen catheter shaft with a collapsible, basket-shaped distal end composed of multiple electrodes mounted on flexible, self-expanding, equidistant metal strut electrodes. The mapping catheter is constructed of a flexible material to allow passive deployment of the array catheter and optimize endocardial contact.

[0008] According to another aspect of the present invention, an integrated ultrasound imaging and mapping system is disclosed. The integrated ultrasound imaging and mapping system includes a mapping catheter having a longitudinal axis, a proximal end, and a distal end. In addition, the integrated ultrasound imaging and mapping system includes a MEMS-based piezoelectric micromachined ultrasonic transducer (pMUT) array disposed within the distal end of the mapping catheter. The MEMS-based pMUT array includes a substrate and a plurality of MEMS-based pMUT array elements disposed on the substrate. In addition, the integrated ultrasound imaging and mapping system includes a mapping array disposed within the distal end of the mapping catheter, wherein the mapping array includes an expandable basket structure, a grid, a hoop, or other configuration having an electronic sensor array disposed on an electronic flexible circuit.

[0009] According to another aspect of the present invention, a medical device is disclosed. The medical device includes a catheter shaft, a first carrier assembly, and a second carrier assembly. The first carrier assembly is coupled to the catheter shaft and includes a first radially expandable electrode array coupled to a plurality of first carrier arms. The second carrier assembly is rotatably coupled to the catheter shaft and includes a second radially expandable electrode array coupled to a plurality of second carrier arms, the second carrier assembly being rotatable about the first carrier assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] The accompanying drawings illustrate various embodiments of the systems, methods and embodiments of various aspects of the present disclosure. It will be understood by any person skilled in the art that the element boundaries (e.g., boxes, groups of boxes or other shapes) illustrated in the accompanying drawings represent an example of the various boundaries of the invention disclosed herein. In some examples, an element can be designed as multiple elements or multiple elements can be designed as one element. In other examples, an element shown as an internal component of an element can be implemented as an external component in another element, and vice versa. In addition, elements may not be drawn to scale. Non-restrictive and non-exhaustive descriptions of the present disclosure are described with reference to the following drawings. The components in the figure are not necessarily to scale, but emphasize the principles shown.

[0011] Various embodiments will be described below with reference to the accompanying drawings, which are provided to illustrate and not to limit the scope of the present disclosure in any way, wherein like numerals refer to like elements, and wherein:

[0012] Figure 1 and Figure 2 A prior art imaging system for acquiring two-dimensional image information is shown;

[0013] Figure 3 A schematic diagram of an integrated cardiac mapping and piezoelectric micromachined ultrasound transducer (pMUT) ultrasound imaging catheter system according to an embodiment of the present disclosure is shown;

[0014] Figure 4illustrates multi-channel electronic communication between a pMUT imaging and mapping device and a pMUT imaging and mapping catheter according to an embodiment of the present disclosure;

[0015] Figure 5 shows a cross-sectional view of the distal end of a pMUT imaging and mapping catheter having a plurality of pMUT transducer array elements according to an embodiment of the present disclosure;

[0016] Figure 6 shows a perspective view of a distal portion of a pMUT imaging and mapping catheter according to an embodiment of the present disclosure;

[0017] Figure 7 shows a plurality of circular mapping pMUT arrays arranged in a cylindrical manner according to an embodiment of the present disclosure;

[0018] Figure 8 shows a plurality of linear pMUT imaging arrays arranged in a linear manner according to an embodiment of the present disclosure;

[0019] Figure 9 shows a perspective view of a distal portion of a pMUT imaging and mapping catheter in a partially deployed state according to an embodiment of the present disclosure, wherein a plurality of circular pMUT imaging arrays are arranged in a linear fashion;

[0020] Figure 10 shows a perspective view of a distal portion of a pMUT imaging and mapping catheter in a partially deployed state according to an embodiment of the present disclosure, wherein a plurality of linear pMUT imaging arrays are arranged in a linear manner;

[0021] Figure 11 shows a grid mapping view of a pMUT imaging and mapping catheter according to an embodiment of the present disclosure, wherein a plurality of circular pMUT imaging arrays are arranged in a linear manner; and

[0022] Figure 12 A grid mapping view of a pMUT imaging and mapping catheter according to an embodiment of the present disclosure is shown, in which a plurality of linear pMUT imaging arrays are arranged in a linear manner. DETAILED DESCRIPTION

[0023] The components of the embodiments as generally described and illustrated in the drawings herein may be arranged and designed in a wide variety of different configurations. Therefore, the following more detailed description of the various embodiments, as represented in the drawings, is not intended to limit the scope of the present disclosure but is merely representative of the various embodiments. Although various aspects of the embodiments are presented in the drawings, the drawings are not necessarily drawn to scale unless otherwise indicated.

[0024] Some embodiments of the present disclosure will now be discussed in detail, which illustrate all of the features of the present disclosure. The words "include," "have," "include," and "contain" and other forms thereof are intended to be equivalent and open ended, in that one or more items following any of these words are not intended to be an exhaustive list of the one or more items, nor are they intended to be limited to the listed one or more items.

[0025] It must also be noted that, as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context dictates otherwise. Although any systems and methods similar or equivalent to the systems and methods described herein can be used in the practice or testing of embodiments of the present disclosure, the preferred systems and methods are now described. The terms "proximal" and "distal" are opposite directional terms. For example, the distal end of a device or component is the end of the component farthest from a practitioner during ordinary use. The proximal end refers to the opposite end, or the end that is closest to the practitioner during ordinary use.

[0026] Embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings, in which like numerals represent like elements throughout the several figures, and in which example embodiments are shown. However, embodiments of the present disclosure may be embodied in alternative forms and should not be construed as limited to the embodiments set forth herein. The examples set forth herein are non-limiting examples and are merely examples among other possible examples.

[0027] Figure 1 and 2 A prior art imaging system 100 is shown. The imaging system 100 provides an ultrasound transmit pulse 102 and an ultrasound receive path 104 for connecting to an ultrasound transducer (not shown). The ultrasound transmit pulse 102 can transmit an ultrasound signal from the imaging system 100 toward an object, such as a patient's heart. In addition, the ultrasound receive path 104 can create a waveform based on at least the ultrasound signal. Thereafter, the imaging system 100 can convert the received ultrasound signal or ultrasound information into a two-dimensional (2D) image of the object or a portion of the object.

[0028] Figure 3 A schematic diagram of an integrated cardiac mapping and piezoelectric micromachined ultrasound transducer (pMUT) ultrasound imaging catheter system 300 is shown, in accordance with an embodiment of the present disclosure.

[0029] In one embodiment, the integrated cardiac mapping and pMUT ultrasound imaging catheter system 300 can utilize an array of microelectromechanical (MEMS) pMUT transducers, defined as pMUTs or other types of MEMS transducers, interconnected using matching flex circuits. It is noted that the use of high-density flex circuits can achieve highly repeatable and stable transmit and return signals. Furthermore, the high-density flex circuit transmission lines can transmit power from one end of the integrated cardiac mapping and pMUT ultrasound imaging catheter system 300 to the other distal end.

[0030] The integrated cardiac mapping and pMUT ultrasound imaging catheter system 300 may include a pMUT imaging and mapping device 302 linked to a pMUT imaging and mapping catheter 304 via a communication channel 306. The pMUT imaging and mapping device 302 may include a display 308, an image processor 310, a receive beamformer 312, a transmit beamformer 314, and a dongle 316. The pMUT imaging and mapping catheter 304 may be positioned within a chamber of the patient's heart and the pMUT imaging and mapping device 302 may receive at least one signal from the pMUT imaging and mapping catheter 304. The at least one signal may be transmitted from the pMUT imaging and mapping catheter 304 to the pMUT imaging and mapping device 302 via an electronic flexible cable (not shown) connected to the dongle 316.

[0031] The image processor 310 can be configured to generate a two-dimensional (2D) image based on data received from the pMUT imaging and mapping catheter 304. In one embodiment, the image processor 310 can be configured to receive a focus signal from a receive beamformer 312. The image processor 310 can present the data to construct an image or a sequence of images. In one embodiment, the image can be a three-dimensional (3D) representation, such as a two-dimensional image presented from a viewing direction selected by a user or a processor. In one embodiment, the image processor 310 can be a detector, a filter, a processor, an application specific integrated circuit, a field programmable gate array, a digital signal processor, a control processor, a scan converter, a three-dimensional image processor, a graphics processing unit, an analog circuit, a digital circuit, or a combination thereof. The image processor 310 can receive beamforming data and can generate an image for display on the display 308. It can be noted that the generated image is associated with a two-dimensional (2D) scan. Alternatively, the generated image can be a three-dimensional (3D) representation.

[0032] The image processor 310 can be programmed for hardware-accelerated two-dimensional reconstruction. The image processor 310 can store processed data of at least one signal and image sequence in a memory. In one embodiment, the memory can be a non-transitory computer-readable storage medium. Instructions for implementing the processes, methods, and / or techniques discussed herein are provided on the computer-readable storage medium or memory, such as a cache, buffer, RAM, removable media, hard drive, or other computer-readable storage medium. Non-transitory computer-readable storage media include various types of volatile and non-volatile storage media. The functions, actions, or tasks shown in the figures or described herein are performed in response to one or more instruction sets stored in or on the computer-readable storage medium. The functions, actions, or tasks are independent of the specific type of instruction set, storage medium, processor, or processing strategy, and can be performed by software, hardware, integrated circuits, firmware, microcode, and the like, operating alone or in combination.

[0033] The pMUT imaging and mapping catheter 304 can be in electronic communication with the pMUT imaging and mapping device 302 for transmitting and receiving ultrasonic signals to and from the arterial walls of the vascular system. In one embodiment, the pMUT imaging and mapping catheter 304 can be configured to visualize standard echocardiographic views of the heart, such as in a standard version, the right atrium can be visualized. The pMUT imaging and mapping catheter 304 can be employed in transseptal catheterization for several percutaneous interventions, including left heart catheter mapping, atrial septal defect closure, to effectively replace surgical intervention. In one embodiment, the pMUT imaging and mapping catheter 304 can include a body having a longitudinal axis, a proximal end, a distal end, a handle assembly, a catheter shaft, an electronic flexible cable, and a distal tip, such as Figure 6 shown.

[0034] Reference Figure 4 , discloses multi-channel electronic communication between a pMUT imaging and mapping device 302 and a pMUT imaging and mapping catheter 304 according to an embodiment of the present disclosure.

[0035] The pMUT imaging and mapping catheter 304 may include a MEMS-based pMUT array 402 coupled to the pMUT imaging and mapping device 302 via a catheter shaft (not shown) and an adapter 316. The adapter 316 may be referred to as a communication channel to the catheter shaft.

[0036] The MEMS-based pMUT array 402 may include a plurality of pMUT array elements 404 arranged on a substrate 406. In addition, each of the plurality of pMUT array elements 404 may provide a wide bandwidth of an individually focused beam. The MEMS-based pMUT array 402 may be coupled to the pMUT imaging and mapping device 302 using an adapter 316, as previously described. The MEMS-based pMUT array 402 disposed within the distal end of the pMUT imaging and mapping catheter 304 may transmit at least one signal to the pMUT imaging and mapping device 302 via an electronic flexible cable inside the catheter shaft. The at least one signal may be an acoustic echo emitted from the MEMS-based pMUT array 402. It may be noted that the acoustic echo of the acoustic energy may be received from the face of the MEMS-based pMUT array 402 and received at the image processor 310.

[0037] The ultrasound beam can have a bandwidth that includes a predetermined fundamental mode vibration of each of the plurality of pMUT array elements 404, such that a single array element can transmit and receive multiple fundamental mode vibrations simultaneously. It can be noted that the plurality of pMUT array elements 404 can transmit and receive ultrasound beams relative to the heart or at least a portion of the heart. In addition, the electronic flexible cable inside the catheter shaft can be configured to receive at least one signal from the plurality of pMUT array elements 404 based on at least one of the transmitted and received ultrasound beams. The pMUT imaging and mapping device 302 can be further configured to construct at least one image of at least a portion of the heart based on the at least one signal. It can be noted that the electronic flexible cable can be configured as a transmit beamformer 314 and a receive beamformer 312 to display two-dimensional (2D) image information of the heart or at least a portion of the heart.

[0038] In one embodiment, the plurality of pMUT array elements 404 may correspond to MEMS-based pMUTs. The catheter shaft may be connected to the handle assembly 324 at one end and to the MEMS-based pMUT array 402 at the other end. An electronic flex cable within the catheter shaft may communicate with at least one signal trace. It may be noted that the electronic flex cable may further communicate to the transmit beamformer 314 and the receive beamformer 312 via the adapter 316 to display two-dimensional (2D) image information of the heart to be scanned.

[0039] Reference Figure 5 , discloses a cross-sectional view of the distal end of a pMUT imaging and mapping catheter 304 having a plurality of pMUT transducer array elements 402 according to an embodiment of the present disclosure.

[0040] The MEMS-based pMUT array 402 can include a plurality of pMUT array elements 404 arranged toward the distal end of the pMUT imaging and mapping catheter 304. The distal end of the pMUT imaging and mapping catheter 304 can be provided with a MEMS-based pMUT array 402 having a plurality of pMUT array elements 404. Furthermore, each of the plurality of pMUT array elements 404 can have a plurality of individual transducer cells 502 arranged in a manner to provide a wide bandwidth of an individual focused beam. In one embodiment, the MEMS-based pMUT array 402 can be constructed from a pMUT array comprising individual elements of varying diameters. In one embodiment, to achieve a wider bandwidth with the pMUT array, pMUT cells of multiple diameters can be integrated into a single element. It can be noted that by arranging pre-formed pMUTs having varying diameters, a wider bandwidth can be achieved through complex interactions between the individual pMUT elements. In one embodiment, pMUT cells of multiple diameters can achieve a bandwidth greater than 55%. For example in 3 elements there are 5 different dome diameters and each array has a different size, such as 300 μm.

[0041] In addition, the MEMS-based pMUT array 402 can correspond to a pMUT and the plurality of pMUT array elements 404 can correspond to a plurality of pMUT elements. In one embodiment, the plurality of pMUT elements can be directed to transmit and receive an ultrasonic beam having a bandwidth that includes a predetermined fundamental mode vibration of each of the plurality of pMUT elements, such that a single pMUT element can simultaneously transmit and receive multiple fundamental mode vibrations. In addition, the electronic flexible cable inside the catheter shaft receives at least one signal from the plurality of pMUT elements. It may be noted that the at least one signal may correspond to at least one ultrasonic beam. The at least one signal may be transmitted to the pMUT imaging and mapping device 302 for further processing in the image processor 310. The image processor 310 may construct at least one image of the heart. It may be noted that the plurality of pMUT elements may be used to create separate focused beams. In one embodiment, the pMUT elements are arranged in a linear manner. In a second embodiment, the pMUTs are arranged in a cylindrical manner, such as Figures 7 and 8 As shown in .

[0042] Reference Figure 6 , discloses a perspective view of a distal portion of a pMUT imaging and mapping catheter 304 according to an embodiment of the present disclosure, wherein the device includes an electronic connection assembly and a distal mapping carrier assembly.

[0043] The pMUT imaging and mapping catheter 304 can include a plurality of expandable basket structures 602, wherein a plurality of flexible struts 604 are optionally disposed along the length of each of the plurality of expandable basket structures 602. The plurality of expandable basket structures 602 can be disposed serially along a single axis in an umbrella-shaped tip configuration. In addition, the pMUT imaging and mapping catheter 304 includes an elongated tube serving as a catheter shaft 606, preferably constructed of Pebax material and having a diameter of approximately 6-8 French. Alternatively, in place of the expandable basket structure, the mapping catheter can include a grid, hoop, or other configuration. The catheter shaft 606 slidably receives a first control shaft 608. The first control shaft 608 is attached to the plurality of expandable basket structures 602, grid, hoop, or another configuration toward the distal portion.

[0044] Additionally, a plurality of flexible prongs 604 are configured with electronic sensors 610. The plurality of flexible prongs 604 can have a first end 612 and a second end 614. The first ends 612 of the plurality of flexible prongs 604 are attached to a control on the proximal end of the pMUT imaging and mapping catheter 304 that is configured to allow an operator to precisely advance and retract the plurality of expandable basket structures 602, mesh, hoop, or another configuration.

[0045] In addition, the pMUT imaging and mapping catheter 304 may include a first carrier assembly (not shown) and a second carrier assembly coupled to the catheter shaft 606. The first carrier assembly and the second carrier assembly may have a first radially expandable electrode array and a second radially expandable electrode array coupled to a plurality of first carrier arms and a plurality of second carrier arms (not shown). It may be noted that the first radially expandable electrode array and the second radially expandable electrode array may correspond to the electronic sensors 610. It may also be noted that the plurality of first carrier arms and the plurality of second carrier arms may correspond to the plurality of branch splines 604. The second carrier assembly can rotate around the first carrier assembly. In one embodiment, the first radially expandable electrode array and the second radially expandable electrode array may have a series of longitudinally spaced electrodes or electronic sensors 610 longitudinally spaced along a plurality of expandable basket structures 602. Alternatively, in place of the expandable basket structure, the mapping catheter may include a mesh, a hoop, or other construction.

[0046] In addition, the pMUT imaging and mapping catheter 304 can include a first ring 616 on the first end 612. The first ring 616 fixedly attaches one end of the plurality of flexible struts 604. The plurality of flexible struts 604 can be made of Nitinol. It can be noted that the Nitinol is elastically biased in a straight or umbrella-shaped tip configuration. In addition, advancement and retraction of the first control shaft 608 changes the diameter of the plurality of expandable basket structures 602, including a fully compacted (minimum diameter) radial state when the first control shaft is fully advanced, and a maximum diameter state when the first control shaft is fully retracted.

[0047] In addition, the pMUT imaging and mapping catheter 304 can include a mapping element 618 fixedly mounted to each of the plurality of flexible legs 604. The mapping element 618 is configured to map a pathway in tissue. In addition, the mapping element 618 can include an electronic sensor 610 configured to perform the mapping. In another embodiment, the mapping element 618 is attached to a guide wire (not shown) that travels proximally to the proximal end of the pMUT imaging and mapping catheter 304 for attachment to an energy delivery unit, a mapping unit, and / or another electronic device for sending or receiving signals and / or power.

[0048] In addition, the mapping element 618 is configured to map electrical activity present in the tissue to a target area for creating a lesion and / or otherwise assessing the patient's condition. In one embodiment, the mapping element 618 is constructed from an electronic sensor, a conductive material such as platinum or a combination of platinum and iridium. In addition, the mapping element 618 can include an integral temperature sensor, such as a thermocouple welded to an internal portion of the mapping element 618. In another embodiment, the mapping element 618 and the integral temperature or other sensor are attached to a wire (not shown) that travels proximally to a proximal portion of the pMUT imaging and mapping catheter 304 for attachment to a pMUT imaging engine, a mapping unit, an energy delivery unit, and / or another electronic device for sending or receiving signals and / or power.

[0049] In addition, the first control shaft 608 includes a distal tip 620 facing the distal end. In one embodiment, the distal tip 620 can be preferably constructed of a soft or flexible material, such as, a soft plastic or elastomer, which is non-traumatic to tissue and preferably non-radiopaque, such as Pebax material doped with barium sulfate. It can be noted that the distal tip 620 is configured to facilitate navigation into and stabilization within the pulmonary vein. In addition, the first control shaft 608 can include a cylindrical section 622 between the first ring 616 and the distal tip 620. In addition, the cylindrical section 622 is configured to move on the first control shaft 608. In addition, the cylindrical section 622 is configured to move the first ring 616 in a forward and backward direction to expand or retract a plurality of expandable basket structures 602, grids, hoops or other structures for mapping the heart wall. In addition, the first ring 616 can be mounted with a MEMS-based pMUT transducer, which is configured to image the heart wall, such as Figure 7-Figure 8 shown.

[0050] In addition, the pMUT imaging and mapping catheter 304 may include a second ring 624 between the first end 612 and the second end 614 proximal to the cylindrical section 622. In one embodiment, the cylindrical section 622 may correspond to a cylinder that moves radially between the first end 612 and the second end 614. The second ring 624 may be positioned above the first control axis 608. In addition, the first ring 616 and the second ring 624 may be mounted with the MEMS-based pMUT array 402 in a circular or cylindrical manner, such as Figure 7-Figure 8 shown.

[0051] Figure 7 A plurality of circular mapping pMUT arrays 702 are shown arranged in a cylindrical manner according to an embodiment of the present disclosure.

[0052] In one embodiment, the first ring 616, distal tip 620, and second ring 624 may be mounted with a plurality of circular mapping pMUT arrays 702 arranged in a cylindrical manner. In one embodiment, the plurality of circular mapping pMUT arrays 702 correspond to pMUT circular arrays or pMUT elements.

[0053] Figure 8 A plurality of linear pMUT imaging arrays 802 are shown arranged in a linear manner according to an embodiment of the present disclosure.

[0054] In one embodiment, the first ring 616, the distal tip 620, and the second ring 624 may be mounted with a plurality of linear pMUT imaging arrays 802 arranged in a linear manner.

[0055] In one embodiment, the plurality of circular mapping pMUT arrays 702 and the plurality of linear pMUT imaging arrays 802 can be arrays of mapping elements, preferably geometrically adjustable electrode arrays, and can be configured in a variety of ways and patterns. In another embodiment, the plurality of circular mapping pMUT arrays 702 and the plurality of linear pMUT imaging arrays 802 provide electrical energy (such as radiofrequency (RF) energy) in a unipolar, bipolar, or combined unipolar-bipolar manner and methods for treating conditions (e.g., atrial fibrillation, supraventricular tachycardia, atrial tachycardia, ventricular tachycardia, ventricular fibrillation, and the like). Additionally, multiple types of mapping catheters can be used for different minimally invasive procedures, such as: atrioventricular (AV) node ablation, which is a treatment for the irregular, rapid and chaotic heartbeat known as atrial fibrillation; cryoablation, in which extremely cold fluid or an instrument called a cryoprobe is used to freeze and eliminate abnormal tissue; and epicardial ablation, in which tiny scars are created on the outside of the heart to block the erroneous electrical signals that cause the heart to beat too fast, thereby restoring normal heart rhythm.

[0056] Reference Figure 9 , discloses a perspective view of a distal portion of an alternative pMUT imaging and mapping catheter 304 in a partially deployed state according to one embodiment, wherein a plurality of circular pMUT imaging arrays 702 are arranged in a linear manner.

[0057] The first control shaft 608 of the pMUT imaging and mapping catheter 304 is in a linear configuration for advancing the pMUT imaging and mapping catheter 304 through a guidewire 902. The guidewire 902 can be advanced for intraluminal advancement when inserted into the femoral vein and traveled to the heart, through the septum separating the right and left atria (e.g., via a transseptal sheath), and into a pulmonary vein such as the left superior pulmonary vein. The first control shaft 608 is placed in this linear, maximally compact configuration by advancing the first control shaft 608 (such as by a control on a joystick). A plurality of expandable basket structures 602, grids, hoop or other configurations include a mapping element 618. The plurality of expandable basket structures 602 or alternative configurations have a proximal end fixedly attached to the catheter shaft 606 via a first ring 616. It may be noted that the first ring 616 may also be referred to as a crimp ring. A plurality of circular pMUT imaging arrays 702 are arranged in a linear manner above the first ring. The first ends 612 of the plurality of flexible prongs 604 are fixedly attached to the first control shaft 608 at a radial position offset 90° from the proximal attachment, such that the plurality of flexible prongs 604 radially expand as the first control shaft 608 is retracted. The distal end of the first control shaft 608 is covered with a distal tip 620. A cylindrical section 622 is slidably positioned upwardly against the distal tip 620. In one embodiment, the distal tip 620 can be an atraumatic tip having an exit hole (not shown) that communicates with an internal guidewire lumen through which a guidewire passes.

[0058] In one embodiment, the distal portion of the pMUT imaging and mapping catheter 304 is in a partially deployed state, wherein a plurality of linear pMUT imaging arrays 802 are arranged in a linear manner, such as Figure 10 As shown, a plurality of linear pMUT imaging arrays 802 may be arranged in a linear manner above the first ring 616 .

[0059] The present invention provides a pMUT imaging and mapping catheter 304 for performing mapping of a target tissue in a subject, such as atrial fibrillation, supraventricular tachycardia, atrial tachycardia, ventricular tachycardia, ventricular fibrillation, and the like. In an alternative embodiment, the pMUT imaging and mapping catheter 304 may include a tubular body member (not shown) having a proximal end and a distal end and preferably a lumen extending therebetween. The pMUT imaging and mapping catheter 304 is preferably of the type used to perform intracardiac procedures and is typically introduced and advanced subcutaneously from a femoral vein in the patient's leg. Alternative methods involve percutaneous introduction into the jugular vein in the patient's neck, or other anatomical entry points that may be used to access a target location within the patient. The pMUT imaging and mapping catheter 304 is preferably introduceable through a sheath and preferably advanceable over a guidewire. The pMUT imaging and mapping catheter 304 preferably has a steerable tip that allows precise positioning of the distal portion.

[0060] The pMUT imaging and mapping catheter 304 allows for the generation of lesions of appropriate size and shape to treat conditions involving disordered electrical conduction (e.g., atrial fibrillation). The lesions created are segmented and localized. The lesions can be linear or curvilinear, circumferential and partially circumferential, and / or continuous or discontinuous. The pMUT imaging and mapping catheter 304 is also practical in terms of ease of use and limiting risk to the patient and significantly reducing surgical time. The lesions created by the pMUT imaging and mapping catheter 304 are suitable for inhibiting the propagation of inappropriate electrical impulses in the heart for the prevention of reentrant arrhythmias.

[0061] In one embodiment, energy to the pMUT imaging and mapping catheter 304 can be delivered using a pulse width modulated drive signal, as is well known to those skilled in the art. Furthermore, energy can also be delivered in a closed loop manner, such as a system with temperature feedback, where the temperature modifies the type, frequency, and / or magnitude of the energy delivered.

[0062] Reference Figure 11 , discloses a grid mapping view of a pMUT imaging and mapping catheter 304 according to an embodiment of the present disclosure, wherein a plurality of circular pMUT imaging arrays 702 are arranged in a linear manner.

[0063] In addition, the pMUT imaging and mapping catheter 304 can include a mapping element 1002 fixedly mounted to each of the plurality of flexible branches 1004. The mapping element 1002 is configured to map pathways in the tissue. In addition, the mapping element 1002 is configured to map electrical activity present in the tissue to a target area for creating lesions and / or otherwise assessing the patient's condition. In one embodiment, the mapping element 1002 is comprised of an electronic sensor, a conductive material such as platinum or a combination of platinum and iridium. Additionally, the mapping element 1002 can include an integral temperature sensor, such as a thermocouple welded to an internal portion of the mapping element 1002. In another embodiment, the mapping element 1002 and the integral temperature or other sensor are attached to a wire (not shown) that travels proximally to a proximal portion of the mapping catheter 304 for attachment to a pMUT imaging engine, a mapping unit, an energy delivery unit, and / or another electronic device for sending or receiving signals and / or power.

[0064] In addition, the pMUT imaging and mapping catheter 304 may include a first ring 1006 having a plurality of circular mapping pMUT arrays 702 arranged in a cylindrical manner. In one embodiment, the first ring 1006 has a plurality of linear pMUT imaging arrays 802 arranged in a linear manner, such as Figure 12 shown.

[0065] In one embodiment, the plurality of circular mapping pMUT arrays 702 and the plurality of linear pMUT imaging arrays 802 can be arrays of mapping elements, preferably geometrically adjustable electrode arrays, and can be configured in a variety of ways and patterns. In another embodiment, the plurality of circular mapping pMUT arrays 702 and the plurality of linear pMUT imaging arrays 802 provide electrical energy (such as radiofrequency (RF) energy) in a unipolar, bipolar, or combined unipolar-bipolar manner and methods for treating conditions (e.g., atrial fibrillation, supraventricular tachycardia, atrial tachycardia, ventricular tachycardia, ventricular fibrillation, and the like). Additionally, multiple types of mapping catheters can be used for different minimally invasive procedures, such as: atrioventricular (AV) node ablation, which is a treatment for the irregular, rapid and chaotic heartbeat known as atrial fibrillation; cryoablation, in which extremely cold liquid or an instrument called a cryoprobe is used to freeze and eliminate abnormal tissue; and epicardial ablation, in which normal heart rhythm is restored by creating tiny scars on the outside of the heart to block the erroneous electrical signals that cause the heart to beat too fast.

[0066] In one embodiment, the electrode or mapping element can have one or more different shapes. As used herein, the term "proximal and distal energy delivery carrier assembly" refers to a flexible carrier on which one or more mapping elements are disposed. The carrier assembly includes one or more carrier arms, such as arm segments as described above. The carrier assembly is not limited to size or shape and can be configured to be in expanded and unexpanded or compact states. As used herein, the term "proximal and distal carrier arms" refers to a linear shaft that can be connected to an electrode or control shaft interface. In addition, the proximal and distal carrier arms are not limited to any size or measurement.

[0067] Other embodiments of the present invention will be apparent to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the description and examples be considered exemplary only, with the true scope and spirit of the invention being indicated by the following claims. Furthermore, if the application has listed the steps of a method or process in a particular order, the order of performing certain steps may be changed or even advantageous in certain circumstances, and it is intended that the specific steps of the method or process claims set forth below are not to be construed as being sequence-specific unless such sequence-specificity is explicitly stated in the claims.

Claims

1. An integrated cardiac mapping and piezoelectric micromachined ultrasound transducer (pMUT) ultrasound imaging system comprising: a pMUT imaging and mapping catheter having a longitudinal axis, a proximal end, and a distal end; a microelectromechanical (MEMS)-based pMUT or other transducer disposed within the distal end of the mapping catheter, wherein the MEMS-based pMUT array includes a substrate and a plurality of pMUT array elements disposed on the substrate; and A mapping array is disposed within the distal end of the pMUT imaging and mapping catheter, wherein the mapping array comprises an expandable basket structure, grid, hoop, or other configuration having an electronic sensor array disposed on an electronic flex circuit or micro-coaxial cable.

2. The integrated cardiac mapping and pMUT ultrasound imaging system of claim 1 , further comprising a catheter shaft connected at one end to the handle assembly and at another end to the MEMS-based pMUT array and further to the mapping array.

3. The integrated cardiac mapping and pMUT ultrasound imaging system according to claim 2, wherein: The mapping catheter includes a steering control unit positioned within the handle assembly for articulating the distal tip of the pMUT imaging and mapping catheter and aligning the surface of the MEMS-based pMUT array toward an internal view, wherein the internal view includes a front position or a rear position and a left position or a right position of the tissue.

4. The integrated cardiac mapping and pMUT ultrasound imaging system according to claim 3, wherein: The distal tip of the mapping catheter is coated with a material for providing electrical isolation and transmission of ultrasound signals.

5. The integrated cardiac mapping and pMUT ultrasound imaging system according to claim 1, wherein: The pMUT imaging and mapping catheter is coupled to an adapter, and the adapter is configured to communicate ultrasound transmit pulses and ultrasound receive waveforms between the pMUT array and a combined ultrasound and mapping computer system.

6. The integrated cardiac mapping and pMUT ultrasound imaging system according to claim 1, wherein: The pMUT imaging and mapping catheter is coupled to an adapter, and the adapter is configured to transmit electronic mapping data between the mapping basket, grid, hoop, or other construct and a combined ultrasound and mapping computer system.

7. The integrated cardiac mapping and pMUT ultrasound imaging system according to claim 1, wherein: Each of the plurality of pMUT array elements has transducer units of multiple diameters to achieve wide bandwidth.

8. The integrated cardiac mapping and pMUT ultrasound imaging system according to claim 1, wherein: Each of the plurality of pMUT array elements is a linear phased array.

9. The integrated cardiac mapping and pMUT ultrasound imaging system according to claim 1, wherein: Each of the plurality of pMUT array elements is a pMUT circular array.

10. The integrated cardiac mapping and pMUT ultrasound imaging system according to claim 1, wherein: The electronic sensor array corresponds to a mapping element.

11. The integrated cardiac mapping and pMUT ultrasound imaging system according to claim 1, wherein: The expandable basket, mesh, hoop or other construct is placed against the inner wall of the heart.

12. An integrated ultrasound imaging and mapping system comprising: A piezoelectric micromachined ultrasound transducer (pMUT) imaging and mapping catheter having a longitudinal axis, a proximal end, and a distal end; a microelectromechanical (MEMS)-based pMUT array disposed within a distal end of the pMUT imaging and mapping catheter, wherein the MEMS-based pMUT array comprises a substrate and a plurality of MEMS-based pMUT array elements disposed on the substrate; and an electronic flex cable connected at one end to the handle assembly and at another end to the MEMS-based pMUT array, wherein the electronic flex cable is in communication with at least one signal trace and is configured to: directing each of the plurality of MEMS-based pMUT array elements via the at least one signal trace to transmit and receive ultrasound beams relative to the heart; receiving at least one signal from the plurality of MEMS-based pMUT array elements based on transmitting and receiving at least one of the ultrasonic beams; and At least one image of at least a portion of the heart is constructed based on the at least one signal.

13. The integrated ultrasound imaging and mapping system of claim 11, wherein: The ultrasonic beam has a bandwidth that includes a predetermined fundamental mode vibration of each of the plurality of pMUT array elements, such that a single array element simultaneously transmits and receives multiple fundamental mode vibrations.

14. A medical device comprising: catheter shaft; as well as A first carrier assembly is coupled to the catheter shaft and has a first radially expandable electrode array coupled to a first plurality of carrier arms.

15. The medical device according to claim 14, wherein The first radially expandable electrode array has a series of longitudinally spaced electrodes.

16. The medical device of claim 14, further comprising a mapping element coupled to the electronic flex circuit.

17. The medical device according to claim 14, wherein The catheter shaft defines a guidewire lumen.

18. The medical device according to claim 14, wherein The catheter shaft slidingly receives a first control shaft disposed toward a distal portion of the plurality of first carrier arms.

19. The medical device according to claim 18, wherein The first control shaft is coupled at one end to a first ring fixedly attached to one end of the plurality of first carrier arms, and at the other end to a second ring capable of being slidably positioned on the first control shaft to move the first ring in a forward direction and a backward direction and to expand or retract a first radially expandable electrode array and a second radially expandable electrode array for mapping the heart wall.

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