Ultrasound imaging ablation catheter system and method

Abstract

An integrated ultrasound imaging and ablation system is disclosed. The system comprises an ablation catheter having a longitudinal axis, a proximal end, and a distal end. A microelectromechanical (MEMS)-based piezoelectric microfabricated ultrasonic transducer (pMUT) or other ultrasonic transducer is located at the distal end of the ablation catheter. One end of the catheter shaft is connected to a handle assembly, and the other end is connected to a MEMS-based pMUT array. A first carrier assembly is connected to the catheter shaft and has an array of first electrodes connected to a plurality of first carrier arms. A second carrier assembly is connected to the catheter shaft and has an array of second electrodes connected to a plurality of second carrier arms.

Description

Technical Field

[0001] The present disclosure generally relates to the field of ablation and ablation catheters. More specifically, embodiments relate to an ablation catheter incorporating an ultrasonic transducer for imaging utilizing a distal piezoelectric micromachined transducer for transmitting and receiving acoustic pulse information.

Background Art

[0002] The use of catheter-based structural and electrophysiological procedures has recently expanded to more complex cases, and an accurate definition of the individual cardiac anatomy with variations is key to obtaining optimal results. In electrophysiological procedures, imaging enables the integration of real-time images and ablation. The integration of imaging allows for real-time evaluation of the cardiac anatomy during an interventional procedure and guides catheter manipulation in relation to distinct anatomical structures.

[0003] Catheter ablation is a more effective alternative treatment option than antiarrhythmic drugs. Pulmonary vein isolation (PVI), which involves electrically isolating the pulmonary veins (PV) from the left atrium, remains the basis for atrial fibrillation (AF) ablation. Modern ablation techniques can generally improve the efficacy, safety, and efficiency of ablation for persistent AF. These techniques include high-power short-duration (HPSD) radiofrequency (RF) delivery, single-shot RF balloons, advances in cryoablation, and electroporation. Furthermore, current techniques require the use of ablation catheters and intracardiac echocardiography (ICE) imaging catheters. ICE has applications for structural cardiac imaging of the left atrial appendage (LAA), assists in septal defect closure and visualization of the fossa ovale, and plays a role in transcatheter valve replacement. ICE is also used in EP procedures for guiding the ablation catheter. ICE confirms the precise positioning of the catheter tip to aid in more accurate ablation. ICE can also be useful for safe monitoring of the pericardial chambers for cardiac tamponade or pericardial effusion, which can rarely be caused by either transseptal puncture or ablation. ICE is expected to become increasingly important for better guiding the growing number of transcatheter ablation procedures. As transcatheter aortic and mitral valve replacements and LAA occlusion devices receive approval from the U.S. Food and Drug Administration (FDA), the use of ICE is expected to increase for the precise deployment of these devices.

[0004] Furthermore, atrial fibrillation (AF) is one of the most widespread and persistent cardiac arrhythmias, affecting more than 30 million people worldwide. While its prevalence in developed countries tends to be low, around 1% to 4%, AF is steadily increasing, and it is widely known to be associated with an increased risk of all-cause mortality, heart failure, thromboembolism, and dementia. Moreover, AF is a type of cardiac arrhythmia in which uncontrolled electrical conduction in the atria results in rapid, uncoordinated contractions, leading to inefficient pumping of blood into the ventricles and a lack of synchronicity. During AF, the atrioventricular node receives electrical impulses not only from the sinoatrial node but from multiple locations throughout the atria. This overloads the atrioventricular node, causing irregular and rapid heartbeats. As a result, blood pools in the atria, increasing the risk of thrombus formation. Major risk factors for atrial fibrillation include aging, coronary artery disease, rheumatic heart disease, hypertension, diabetes, and hyperthyroidism. AF affects 7% of the population aged 65 and over.

[0005] Furthermore, treatment options for atrial fibrillation (AF) are limited. Lifestyle modifications are only effective for patients with AF caused by lifestyle factors. While drug therapy helps manage the symptoms of AF, it can have more dangerous side effects than atrial fibrillation and does not cure AF. Electrical cardioversion is often successful in restoring sinus rhythm, but has a high recurrence rate. Moreover, if a thrombus is present in the atrium, electrical cardioversion can cause the thrombus to detach from the heart and travel to the brain or other parts of the body, which can lead to a stroke. Therefore, improved ultrasound imaging and ablation systems are needed. [Overview of the project]

[0006] As an introduction, a user-friendly integrated ultrasound imaging and ablation system is disclosed in the preferred embodiments described below. The integrated ultrasound imaging and ablation system comprises an ablation catheter having a longitudinal axis, a proximal end, and a distal end. Furthermore, an ultrasound transducer array is located at the distal end of the ablation catheter. The ultrasound transducer array comprises a plurality of transducer array elements arranged on a substrate. Note that the plurality of transducer array elements correspond to micro-electromechanical (MEMS) based piezoelectric micromachined ultrasonic transducers (pMUTs) or other types of transducers. Furthermore, the integrated ultrasound imaging and ablation system comprises a catheter shaft with one end connected to a handle assembly and the other end connected to the ultrasound transducer array. Furthermore, the integrated ultrasound imaging and ablation system comprises a first carrier assembly connected to the catheter shaft, the first carrier assembly having a first electrode array connected to a plurality of first carrier arms. Furthermore, the integrated ultrasound imaging and ablation system comprises a second carrier assembly connected to a catheter shaft, the second carrier assembly having a second electrode array connected to a plurality of second carrier arms.

[0007] In another aspect of the present invention, an integrated ultrasound imaging and ablation system is disclosed. The integrated ultrasound imaging and ablation system comprises an ablation catheter having a longitudinal axis, a proximal end, and a distal end. Furthermore, the integrated ultrasound imaging and ablation system comprises a MEMS-based pMUT array located at the distal end of the ablation catheter. The MEMS-based pMUT array comprises a substrate and a plurality of MEMS-based pMUT array elements disposed on the substrate. Furthermore, the integrated ultrasound imaging and ablation system includes an electronic flexible cable, one end of which is connected to a handle assembly and the other end of which is connected to the MEMS-based pMUT array. The electronic flexible cable is configured to communicate with at least one signal trace and, via the at least one signal trace, direct each of the plurality of MEMS-based pMUT array elements to transmit and receive a plurality of ultrasound beams to and from the heart, receive at least one signal from the plurality of MEMS-based pMUT array elements based on transmitting and receiving at least one of the plurality of ultrasound beams, and construct at least one image of at least a portion of the heart based on at least one signal.

[0008] According to another aspect of the present invention, an ablation catheter for an operator to treat a patient with arrhythmia is disclosed. The catheter includes an elongated, flexible tubular body member having a proximal end, a distal end, and a lumen between them. The catheter further includes a control shaft that is coaxial with the lumen of the tubular body member and slidably received. A flexible carrier assembly is attached to the end of the control shaft and includes at least one imaging, ablation, and / or mapping element. As the control shaft retracts, the carrier assembly transitions from a compact, substantially linear form to a helical or partially helical form.

[0009] In a preferred embodiment, the catheter comprises an ultrasonic array for directing ultrasonic energy into tissue in a circular pattern. In a preferred embodiment, the catheter comprises an ultrasonic array for directing ultrasonic energy into tissue in a controlled direction.

[0010] According to another aspect of the present invention, a medical device is disclosed. The medical device comprises a catheter shaft, a first carrier assembly, and a second carrier assembly. The first carrier assembly is connected to the catheter shaft and has a first radially expandable electrode array connected to a plurality of first carrier arms. The second carrier assembly is rotatably connected to the catheter shaft and has a second radially expandable electrode array connected to a plurality of second carrier arms, and the second carrier assembly is rotatable around the first carrier assembly.

[0011] In a preferred embodiment, the first and second carrier assemblies can be retracted to a position within a tubular body member. In another preferred embodiment, the ablation catheter includes at least two carrier assemblies that can transition between a compact, substantially linear form and a helical or partially helical form. In yet another preferred embodiment, the ablation catheter may be positioned on a guidewire or include an integrated guidewire tip.

[0012] According to yet another aspect of the present invention, an ablation catheter is disclosed for an operator to treat a patient with arrhythmia. The ablation catheter comprises an elongated, flexible tubular body member having a proximal end, a distal end, and a lumen between them. The ablation catheter further comprises a flexible carrier assembly, the carrier assembly comprising an inflatable balloon with attached or imaging elements, an embedded ablation element, and / or a mapping element.

[0013] One example of such minimally invasive treatment is the treatment of cardiac arrhythmias or irregular heartbeats, in which physicians use specialized cardiac evaluation and treatment devices such as mapping catheters and ablation catheters to access internal areas of the patient's body for diagnosis and treatment.

[0014] Such devices may include energizing electrodes or other ablation assemblies for generating a cauterized lesion or other anatomical effect that interrupts or blocks an electrical pathway through the target tissue. [Brief explanation of the drawing]

[0015] [Figure 1] This figure shows a conventional imaging system for acquiring two-dimensional image information. [Figure 2] This figure shows a conventional imaging system for acquiring two-dimensional image information. [Figure 3] This is a schematic diagram of an ultrasonic imaging system according to an embodiment of the present disclosure. [Figure 4] This figure shows multichannel electronic communication between an imaging device and an ablation catheter according to an embodiment of the present disclosure. [Figure 5] This is a cross-sectional view of the distal end of an ablation catheter having multiple transducer array elements according to an embodiment of the present disclosure. [Figure 6] This is a perspective view of the distal end of an ablation catheter according to an embodiment of the present disclosure. [Figure 7] This figure shows a plurality of cylindrically arranged circular arrays according to an embodiment of the present disclosure. [Figure 8] This figure shows a plurality of linear arrays arranged in a cylindrical shape according to an embodiment of the present disclosure. [Figure 9] This is a perspective view of the distal portion of an ablation catheter in a partially deployed state according to an embodiment of the present disclosure. [Modes for carrying out the invention]

[0016] The accompanying drawings illustrate embodiments of systems, methods, and various aspects of the present disclosure. Those skilled in the art will understand that the boundaries of the illustrated elements in the drawings (e.g., boxes, groups of boxes, or other shapes) represent examples of various boundaries that represent the disclosed invention. In some examples, one element may be designed as multiple elements, or multiple elements may be designed as one element. In other examples, an element shown as an internal component of one element may be implemented as an external component of another element, and vice versa. Furthermore, elements may not be drawn to a fixed scale. A non-limiting and non-exclusive description of the present disclosure is given with reference to the following drawings. The elements in the drawings are not necessarily to a fixed scale, but rather the emphasis is on the illustrated principle.

[0017] Various embodiments are described below with reference to the accompanying drawings, which are provided to illustrate the scope of the disclosure and not to limit the scope of the disclosure in any way, and similar symbols indicate similar elements.

[0018] The components of the embodiments described herein and shown in the figures can be arranged and designed in a wide variety of different configurations. Therefore, the following more detailed description of the various embodiments shown in the figures is not intended to limit the scope of this disclosure, but merely to represent the various embodiments. While various aspects of the embodiments are presented in the drawings, the drawings are not necessarily drawn to a fixed scale unless specifically indicated.

[0019] Next, some embodiments of the present disclosure that show all features of the present disclosure will be described in detail. The words "comprising", "having", "containing", and "including", and their derivatives are equivalent in meaning and are intended to be open-ended in that one or more items following any one of these words do not mean an exhaustive listing of such one or more items or are not meant to be limited to only the one or more items listed.

[0020] It should also be noted that, as used in this specification and the appended claims, the singular forms "a", "an", and "the" include plural references unless the context dictates otherwise. Any system and method similar or equivalent to those described herein can be used in the implementation or testing of embodiments of the present disclosure, but the preferred systems and methods are described herein. The terms "proximal" and "distal" are terms indicating opposite directions. For example, the distal end of a device or component is the end of the component that is farthest from the operator during normal use. The proximal end refers to the opposite end or the end that is closest to the operator during normal use.

[0021] Embodiments of the present disclosure are represented by like numbers for like components throughout several figures and will be described more fully hereinafter with reference to the accompanying drawings, which illustrate exemplary embodiments. However, embodiments of the present disclosure may be embodied in alternative forms and should not be construed as limited to the embodiments described herein. The examples described herein are non-limiting examples and are merely examples among other possible examples.

[0022] Figures 1 and 2 show a prior art imaging system 100. The imaging system 100 provides an ultrasonic transmission pulse 102 and an ultrasonic reception path 104 for connection with an ultrasonic transducer (not shown). The ultrasonic transmission pulse 102 can transmit an ultrasonic signal from the imaging system 100 towards an object such as a patient's heart. Further, the ultrasonic reception path 104 can generate a waveform based at least on the ultrasonic signal. Thereafter, the imaging system 100 can convert the received ultrasonic signal or ultrasonic information into a two-dimensional (2D) image of the object or a part of the object.

[0023] Figure 3 shows a schematic diagram of an ultrasonic imaging system 300 according to an embodiment of the present disclosure. In one embodiment, the ultrasonic imaging system 300 can utilize a MEMS transducer array defined as piezoelectric microfabricated ultrasonic transducers (pMUTs) or other types of microelectromechanical (MEMS) transducers interconnected using a conformable flexible circuit. Note that the use of a high-density flexible circuit can enable high reproducibility and stable transmission and return signals. Further, the transmission lines of the high-density flexible circuit can transmit electrical energy from one end of the ultrasonic imaging system 300 to the other distal end.

[0024] The ultrasonic imaging system 300 can include an imaging device 302 connected to an ablation catheter 304 via a communication channel 306. The imaging device 302 can include a display 308, an image processor 310, a receive beamformer 312, a transmit beamformer 314, and a dongle 316. The ablation catheter 34 can be disposed within a chamber of a patient's heart, and the imaging device 302 can receive at least one signal from the ablation catheter 304. The at least one signal can be transmitted from the ablation catheter 304 to the imaging device 302 via an electronic flex cable (not shown) connected to the dongle 316.

[0025] The image processor 310 may be configured to generate a two-dimensional (2D) image according to data received from the ablation catheter 304. In one embodiment, the image processor 310 may be configured to receive a focused signal from the receiving beamformer 312. The image processor 310 may render the data to construct an image or a series of images. In one embodiment, the image may be a three-dimensional (3D) representation, such as a two-dimensional image rendered from a viewpoint direction selected by the user or processor. In one embodiment, the image processor 310 may be a detector, filter, processor, application-specific integrated circuit, field-programmable gate array, digital signal processor, control processor, scan converter, 3D image processor, graphics processing unit, analog circuitry, digital circuitry, or a combination thereof. The image processor 310 may receive beamformed data and generate an image for display on the display 308. Note that the generated image may be associated with a two-dimensional (2D) scan, or it may be a three-dimensional (3D) representation.

[0026] The image processor 310 may be programmed to support hardware-accelerated two-dimensional reconstruction. The image processor 310 may store processed data of at least one signal and a sequence of images in memory. In one embodiment, the memory may be a non-temporary computer-readable storage medium. Instructions for performing the processes, methods, and / or techniques described herein are provided on a computer-readable storage medium such as a cache, buffer, RAM, removable media, hard drive, or memory or other computer-readable storage medium. Non-temporary computer-readable storage mediums include various types of volatile and non-volatile storage media. The functions, operations, or tasks shown in the figures or described herein are performed in response to one or more instruction sets stored on a computer-readable storage medium. The functions, operations, or tasks may be performed by software, hardware, integrated circuits, firmware, microcode, etc., which are independent of any particular type of instruction set, storage medium, processor, or processing strategy and operate alone or in combination.

[0027] The ablation catheter 304 can electronically communicate with an imaging device 302 for transmitting ultrasound signals to and receiving ultrasound signals from the arterial walls of the vascular system. In one embodiment, the ablation catheter 304 may be configured to visualize a standard echocardiographic image of the heart, for example, in a standard version the right atrium may be visualized. The ablation catheter 304 may be employed in transseptal catheterization for several percutaneous interventions, including left cardiac catheter ablation and atrial septal defect closure, as an effective alternative to surgical intervention. In one embodiment, the ablation catheter 304 may comprise a body having a longitudinal axis, a proximal end, a distal end, a handle assembly, a catheter shaft, an electronic flex cable, and a distal tip, as shown in Figure 6.

[0028] Referring to Figure 4, one embodiment of the present disclosure is disclosed, which involves multi-channel electronic communication between an ultrasound imaging device 302 and an ablation catheter 304. The ablation catheter 304 may comprise a MEMS-based pMUT array 402 coupled to an imaging device 302 via a catheter shaft (not shown) and a dongle 316. The dongle 316 may be referred to as a communication channel connected to the catheter shaft.

[0029] The MEMS-based pMUT array 402 may comprise a plurality of pMUT array elements 404 arranged on a substrate 406. Furthermore, each of the plurality of pMUT array elements 404 may provide a wide bandwidth for individual focused beams. The MEMS-based pMUT array 402 may be connected to the ultrasound imaging device 302 using a dongle 316, as described above. The MEMS-based pMUT array 402, located at the distal end of the ablation catheter 304, may transmit at least one signal to the imaging device 302 via an electronic flexible cable in the catheter shaft. At least one signal may be an acoustic echo transmitted from the MEMS-based pMUT array 402. Note that the acoustic echo of acoustic energy may be received from the front of the MEMS-based pMUT array 402 and received in the image processor 310.

[0030] Furthermore, the ablation catheter 304 may include a plurality of steering cables (not shown) configured to direct each of a plurality of pMUT array elements 404 via at least one signal trace for transmitting and receiving an ultrasound beam. The ultrasound beam may 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 a plurality of fundamental mode vibrations simultaneously. Note that the plurality of pMUT array elements 404 can transmit and receive ultrasound beams to and from the heart or at least a portion of the heart. Furthermore, the electronic flex cable in the catheter shaft may be configured to receive at least one signal from the plurality of pMUT array elements 404 based on transmitting and receiving at least one ultrasound beam from the plurality of ultrasound beams. The imaging device 302 may be further configured to construct at least one image of at least a portion of the heart based on at least one signal. Note that the electronic flex cable may be configured for a transmitting beamformer 314 and a receiving beamformer 312 to display two-dimensional (2D) image information of the heart or at least a portion of the heart.

[0031] In one embodiment, multiple pMUT array elements 404 may correspond to MEMS-based pMUTs. The catheter shaft may be connected at one end to a handle assembly 324 and at the other end to a MEMS-based pMUT array 402. An electronic flex cable within the catheter shaft may communicate with at least one signal trace. Note that the electronic flex cable may also communicate with a transmitting beamformer 314 and a receiving beamformer 312 via a dongle 316 to display two-dimensional (2D) image information of the heart being scanned.

[0032] Referring to Figure 5, a cross-sectional view of the distal end of an ablation catheter 304 having a plurality of transducer array elements 402 according to one embodiment of the present disclosure is disclosed. A MEMS-based pMUT array 402 may comprise a plurality of pMUT array elements 404 arranged toward the distal end of an ablation catheter 304. The distal end of the ablation catheter may comprise a MEMS-based pMUT array 402 having a plurality of pMUT array elements 404. Furthermore, each of the plurality of pMUT array elements 404 may have a plurality of individual transducer cells 502 arranged to provide a broadband for individual focused beams. In one embodiment, a MEMS-based pMUT array 402 may be constructed from a pMUT array containing individual elements of different diameters. In one embodiment, to achieve a broadband using a pMUT array, a plurality of pMUT cells having multiple diameters may be integrated into a single element. It should be noted that by arranging pre-formed pMUTs having different diameters, a broadband can be achieved through complex interactions between individual pMUT elements. In one embodiment, a plurality of diameter pMUT cells may achieve a bandwidth greater than 55%. For example, with three elements, there are five different dome diameters, and each array has a different size, such as 300 μm.

[0033] Furthermore, a MEMS-based pMUT array 402 may correspond to a pMUT, and multiple pMUT array elements 404 may correspond to multiple pMUT elements. In one embodiment, multiple pMUT elements may be directed to transmit and receive multiple ultrasound beams having a bandwidth including a predetermined fundamental mode vibration of each of the multiple pMUT elements, so that a single pMUT element can transmit and receive multiple fundamental mode vibrations simultaneously. Furthermore, an electronic flexible cable in the catheter shaft receives at least one signal from the multiple pMUT elements. Note that at least one signal may correspond to at least one ultrasound beam. At least one signal may be transmitted to an ultrasound imaging device 302 for further processing in an image processor 310. The image processor 310 may construct at least one image of the heart. Note that multiple pMUT elements may be used to generate individual focused beams. In one embodiment, the multiple pMUT elements are arranged linearly. In a second embodiment, the pMUTs are arranged cylindrically, as shown in Figures 7-8.

[0034] Referring to Figure 6, a perspective view of the distal end of the ablation catheter 304 is disclosed. The ablation catheter 304 may comprise a proximal energy delivery carrier assembly 602 and a distal mapping carrier assembly 604.

[0035] The proximal energy delivery carrier assembly 602 and the distal mapping carrier assembly 604 may be arranged in series along a single axis, with each having an umbrella-shaped tip configuration. Furthermore, the ablation catheter 304 preferably includes an elongated tube as an outer shaft 606, constructed from Pebax® material and having a diameter of about 6 to 8 French. The outer shaft 606 slidably receives a first control shaft 608. The first control shaft 608 is attached to the proximal energy delivery carrier assembly 602 on its distal portion. It should be noted that the proximal energy delivery carrier assembly 602 comprises a plurality of carrier arms and ablation elements configured to deliver energy. The proximal energy delivery carrier assembly 602 may have a first end 610 and a second end 612. The first end 610 of the proximal energy delivery carrier assembly 602 is attached to a control unit at the proximal end of the ablation catheter 304, which is configured to allow the operator to precisely advance and retract the proximal energy delivery carrier assembly 602.

[0036] The proximal energy delivery carrier assembly 602 may include a first ring 614 located at a second end 612. The first ring 614 securely attaches one end of each distal carrier arm segment 616 to the proximal energy delivery carrier assembly 602. Each distal carrier arm segment 616 is pivotally attached at the opposite end to one end of a proximal carrier arm segment 618. Furthermore, the opposite end of each proximal carrier arm segment 618 is securely attached to the first end 610 of the proximal energy delivery carrier assembly 602 toward the outer shaft 606 via a second ring 620.

[0037] In one embodiment, the distal carrier arm segment 616 and the proximal carrier arm segment 618 are constructed of a flexible material. In another embodiment, the distal carrier arm segment 616 and the proximal carrier arm segment 618 may be made from nitinol. Note that nitinol is elastically biased to either a linear or umbrella-shaped tip configuration. Furthermore, the advance and retraction of the first control shaft 608 changes the diameter of the proximal energy delivery carrier assembly 602, including a fully compressed (minimum diameter) radial state when the first control shaft is fully advanced and a maximum diameter state when the first control shaft 608 is fully retracted.

[0038] Furthermore, the ablation catheter 304 may include ablation and mapping elements 622 fixedly attached to each of the distal carrier arm segments 616. The ablation and mapping elements 622 are configured to deliver energy to tissue to create ablation lesions for blocking abnormal electrical pathways within the tissue. Furthermore, the ablation and mapping elements 622 may include fins 624 configured to be present in the blood flow during energy delivery and to provide heat dissipation to the circulating blood. In one embodiment, the ablation and mapping elements 622 are configured to deliver unipolar, bipolar, or a combination of unipolar and bipolar RF energy as described above. The ablation and mapping elements 622 include an integrated temperature sensor, such as a thermocouple, welded to the internal portion of each ablation and mapping element 622. In another embodiment, the ablation and mapping element 622 and an integrated temperature sensor or other sensor are connected to a wire (not shown) that extends proximal to the proximal end of the ablation catheter 304 for connection to an energy delivery unit, a mapping unit, and / or other electronic device for transmitting or receiving signals and / or power.

[0039] Furthermore, the first control shaft 608 slidably receives the second control shaft 626. The second control shaft 626 is attached to the distal mapping carrier assembly 604 on its distal portion. The distal mapping carrier assembly 604 may comprise a plurality of carrier arms and ablation elements configured to map electrical activity. The proximal end of the second control shaft 626 is attached to a control unit at the proximal end of the ablation catheter 304 and is configured to allow the operator to precisely advance and retract the second control shaft 626. Furthermore, the second control shaft 626 includes a distal tip 628 on the distal end side. The distal tip 628 can be fixedly attached to the second control shaft 626, with one end of each distal carrier arm segment 616 being attached to the second control shaft 626.

[0040] In one embodiment, the distal tip 628 may be constructed from a soft or flexible material such as a soft plastic or elastomer that is non-traumatic to tissue, and preferably radiopaque, such as barium sulfate-doped Pebax® material. Note that the distal tip 628 is constructed to assist in navigation into and stabilization within the pulmonary veins.

[0041] The distal tip 628 may include a guidewire lumen 630 that is in fluid communication with an internal lumen (not shown) of the second control shaft 626. The guidewire lumen 630 extends to the proximal portion of the ablation catheter 304 and opens, so that the ablation at the proximal end of the ablation catheter 304 is connected to an imaging engine, a mapping unit, an energy delivery unit, and / or another electronic device for transmitting and receiving signals and / or power. It should be noted that the ablation catheter 304 can be percutaneously inserted into the patient's vascular system on the guidewire.

[0042] Furthermore, each distal carrier arm segment 616 is pivotably attached to one end of the proximal carrier arm segment 618 at its opposite end. Additionally, each opposite end of the proximal carrier arm segment 618 is fixedly attached to the distal end of the first control shaft 608 via a first ring 614. In one embodiment, the distal carrier arm segments 616 and proximal carrier arm segments 618 are constructed of a flexible material. Furthermore, the advance and retraction of the second control shaft 626 changes the diameter of the distal mapping carrier assembly 604, including a fully compressed (minimum diameter) radial state when the second control shaft 626 is fully advanced and a maximum diameter state when the second control shaft 626 is fully retracted.

[0043] Furthermore, the distal mapping carrier assembly 604 may comprise an ablation element and a mapping electrode 632 fixedly attached to the distal carrier arm segment 616. The ablation element and mapping electrode 632 are further configured to map electrical activity present within the tissue to identify target areas for creating ablation lesions and / or to assess the patient's condition in other ways. In one embodiment, the mapping electrode 632 is made of a conductive material such as platinum or a platinum-iridium alloy. The mapping electrode 632 may further comprise an integrated temperature sensor, such as a thermocouple, welded to the inner portion of the mapping electrode 632. In another embodiment, the mapping electrode 632 and the integrated temperature sensor or other sensor are connected to a wire (not shown) extending proximal to the proximal portion of the ablation catheter 304 for connection to an imaging engine, a mapping unit, an energy delivery unit, and / or other electronic devices for transmitting or receiving signals and / or power.

[0044] Furthermore, the electronic flex cable 634 may be mounted between the first end 610 and the second end 612 of the proximal energy delivery carrier assembly 602. One end of the electronic flex cable 634 is inserted into the second ring 620 on the second end 612 side of the proximal energy delivery carrier assembly 602. The other end of the electronic flex cable 634 enters into the first ring 614 on the first end 610 side of the proximal energy delivery carrier assembly 602. The electronic flex cable 634 may have the same length as the proximal carrier arm segment 618. Furthermore, the first ring 614 may mount a MEMS-based pMUT transducer configured to image the cardiac wall, as shown in Figures 7-8.

[0045] As shown in Figure 7, in one embodiment, the first ring 614 has a cylindrically arranged circular array 702. The electronic flex cable 634 may be connected to the circular array 702. In one embodiment, the circular array 702 corresponds to the pMUT element.

[0046] As shown in Figure 8, in another embodiment, the first ring 614 has a plurality of linear arrays 802 arranged in a straight line. In one embodiment, the circular array 702 and the plurality of linear arrays 802 may be arrays of ablation elements, preferably geometrically adjustable electrode arrays, and may be composed of a wide variety of shapes and patterns. In another embodiment, the circular array 702 and the plurality of linear arrays 802 may supply electrical energy such as radio frequency (RF) energy in a unipolar, bipolar, or composite unipolar-bipolar manner, and also provide a method for treating symptoms (e.g., atrial fibrillation, supraventricular tachycardia, atrial tachycardia, ventricular tachycardia, ventricular fibrillation, etc.). Furthermore, multiple types of ablation catheters may be used for different minimally invasive procedures. Minimally invasive procedures include atrioventricular (AV) node ablation, a treatment for atrial fibrillation, an irregular, rapid, and disordered heartbeat; cryoablation, which uses cryogenic liquid or a device called a cryoprobe to freeze and remove abnormal tissue; and epicardial ablation, which restores a regular heart rhythm by creating small scars on the outside of the heart to block the defective electrical signals that cause the heart to beat too fast.

[0047] Referring to Figure 9, a perspective view of the distal portion of an ablation catheter 304 in a partially deployed state according to one embodiment is disclosed. The second control shaft 626 of the ablation catheter 304 is linear in shape to advance the ablation catheter 304 on the guidewire 902. Once inserted into the femoral vein, the guidewire 902 is advanced for intraluminal advancement, proceeding to the heart, passing through the septum separating the right and left atria (e.g., through the transseptal sheath) and entering a pulmonary vein such as the left superior pulmonary vein. The second control shaft 626 is positioned in this linear and maximally compact shape by advancing it, for example by operating the control unit on the handle. The electronic flex cable 634 contains the ablation and mapping elements 622. The proximal end of the electronic flex cable 634 is fixedly attached to the outer shaft 606 via a second ring 620. Note that the second ring 620 may also be called a crimp ring. The distal end of the electronic flex cable 634 is fixedly attached to the second control shaft 626 at a radial position offset by 90° from the mounting position of the proximal end, such that the electronic flex cable 634 expands radially as the second control shaft 626 is retracted. The distal end of the second control shaft 626 is covered by the distal tip portion 628. The first ring 614 is positioned to contact the distal tip portion 628. In one embodiment, the distal tip portion 628 may be a non-traumatic tip portion having an exit hole (not shown) that communicates with an internal guidewire lumen through which the guidewire passes.

[0048] The present invention provides an ablation catheter 304 for performing targeted tissue ablation on target tissues such as atrial fibrillation, supraventricular tachycardia, atrial tachycardia, ventricular tachycardia, and ventricular fibrillation. In one alternative embodiment, the ablation catheter 304 may comprise a tubular body member (not shown) having a proximal end and a distal end, and preferably a lumen extending between them. The ablation catheter 304 is preferably of a type used for intracardiac procedures and is typically introduced subcutaneously and advanced through the femoral vein in the patient's leg. Alternative methods include percutaneous introduction into the jugular vein in the patient's neck, or other anatomical introduction points that may be used to access a target site within the patient. The ablation catheter 304 is preferably introduceable through a sheath and preferably advanceable along a guidewire. The ablation catheter 304 preferably has a steerable tip that allows for precise positioning of the distal portion.

[0049] The ablation catheter 304 allows for the creation of ablation foci of appropriate size and shape to treat conditions involving disordered electrical conduction (e.g., atrial fibrillation). The created ablation foci are segmented and localized. The ablation foci can be linear or curved, annular, and partially annular, and / or continuous or discontinuous. The ablation catheter 304 is also practical in that it is easy to operate, reduces risks to the patient, and significantly shortens the procedure time. The ablation foci formed by the ablation catheter 304 are suitable for suppressing the propagation of inappropriate electrical impulses in the heart to prevent reentrant arrhythmias.

[0050] In one embodiment, energy to the ablation catheter 304 may be delivered using a pulse-width modulated drive signal, which is well known to those skilled in the art. Furthermore, energy may also be delivered in a closed-loop manner. In a system using temperature feedback, the type, frequency, and / or magnitude of the delivered energy is altered by temperature.

[0051] In one embodiment, the electrodes or ablation elements may have one or more different shapes. As used herein, the terms “proximal energy delivery carrier assembly and distal energy delivery carrier assembly” refer to a flexible carrier on which one or more ablation elements are arranged. The carrier assembly includes one or more carrier arms as the arm segments described above. The carrier assembly is not limited in size or shape and can be configured in an expanded, unexpanded, or compact state. As used herein, the terms “proximal carrier arm and distal carrier arm” refer to wire-like shafts capable of interface with the electrodes and control shafts. Furthermore, the distal and proximal carrier arms are not limited in size or measurement.

[0052] Other embodiments of the present invention will be apparent to those skilled in the art by considering this specification and practicing the invention disclosed herein. This specification and examples are intended to be considered illustrative only, and the true scope and spirit of the invention are shown by the following claims. In addition, where this application lists steps of a method or procedure in a particular order, it is possible or may be advantageous in certain circumstances to change the order in which some steps are performed, and it is intended that any particular step in the claims of a method or procedure described herein shall not be construed as order-specific unless such order specificity is expressly stated in the claims.

Claims

1. An integrated ultrasound imaging and ablation system, An ablation catheter having a longitudinal axis, a proximal end, and a distal end, A microelectromechanical (MEMS)-based piezoelectric microfabrication ultrasonic transducer (pMUT) or other transducer disposed at the distal end of the ablation catheter, wherein the MEMS-based pMUT array comprises a substrate and a plurality of pMUT array elements disposed on the substrate, A catheter shaft, one end of which is connected to the handle assembly and the other end of which is connected to the pMUT array on the MEMS base, A first carrier assembly connected to the catheter shaft, the first carrier assembly having an array of first electrodes connected to a plurality of first carrier arms, An integrated ultrasound imaging and ablation system comprising: a second carrier assembly connected to the catheter shaft, the second carrier assembly having an array of second electrodes connected to a plurality of second carrier arms.

2. The integrated ultrasound imaging and ablation system according to claim 1, wherein the ablation catheter comprises a steering control unit located within the handle assembly for articulating the distal tip of the ablation catheter to adjust the plane of the MEMS-based pMUT array toward an internal view including anterior or posterior and right or left positions of the tissue.

3. The integrated ultrasound imaging and ablation system according to claim 2, wherein the distal tip of the ablation catheter is coated with a material that provides electrical insulation and transmission of ultrasound signals.

4. The integrated ultrasound imaging and ablation system according to claim 1, wherein the ablation catheter is coupled to an imaging device using a dongle, and the dongle is configured to transmit ultrasound transmission pulses and ultrasound reception waveforms between the imaging device and the ablation catheter.

5. The integrated ultrasound imaging and ablation system according to claim 1, wherein each of the plurality of pMUT array elements has a plurality of transducer cells of different diameters to achieve a wide bandwidth.

6. The integrated ultrasound imaging and ablation system according to claim 1, wherein each of the plurality of pMUT array elements is a linear phased array.

7. The integrated ultrasound imaging and ablation system according to claim 1, wherein each of the plurality of pMUT array elements is a circular array.

8. An integrated ultrasound imaging and ablation system, An ablation catheter having a longitudinal axis, a proximal end, and a distal end, A microelectromechanical (MEMS)-based piezoelectric microfabrication ultrasonic transducer (pMUT) array disposed at the distal end of the ablation catheter, comprising a substrate and a plurality of MEMS-based pMUT array elements disposed on the substrate, An electronic flexible cable, one end of which is connected to a handle assembly and the other end of which is connected to the MEMS-based pMUT array, which is capable of communicating with at least one signal trace, Through the aforementioned at least one signal trace, each of the plurality of MEMS-based pMUT array elements is directed to transmit and receive a plurality of ultrasound beams to and from the heart. Based on transmitting and receiving at least one of the plurality of ultrasonic beams, at least one signal is received from the plurality of MEMS-based pMUT array elements. An integrated ultrasound imaging and ablation system comprising: an electronic flexible cable configured to construct at least one image of at least a portion of the heart based on the at least one signal.

9. The integrated ultrasonic imaging and ablation system according to claim 8, 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 transmits and receives a plurality of fundamental mode vibrations simultaneously.

10. It is a medical device, Catheter shaft and A first carrier assembly connected to the catheter shaft, the first carrier assembly having a first radially expandable electrode array connected to a plurality of first carrier arms, A medical device comprising: a second carrier assembly rotatably connected to the catheter shaft, the second carrier assembly having a second radially expandable electrode array connected to a plurality of second carrier arms, wherein the second carrier assembly is rotatable around the first carrier assembly.

11. The medical device according to claim 10, wherein the first radially expandable electrode array has a series of electrodes spaced apart in the longitudinal direction.

12. The medical device according to claim 10, further comprising a mapping element connected to the first carrier assembly.

13. The medical device according to claim 12, wherein the mapping element is located distal to the first radially expandable electrode array.

14. The medical device according to claim 10, wherein the catheter shaft defines a guidewire lumen.

Images