Source: http://www.google.com/patents/US7949396?dq=5708422
Timestamp: 2016-10-23 10:16:34
Document Index: 492974992

Matched Legal Cases: ['Application No. 60', 'art 16', 'art 16', 'art 16', 'art 16', 'art 16', 'art 16', 'art 16', 'art 16', 'art 16', 'art 3', 'art 3', 'art 1', 'art 1', 'art 2', 'art 2']

Patent US7949396 - Ultrasonic transducer for a metallic cavity implated medical device - Google PatentsSearch Images Maps Play YouTube News Gmail Drive More »Sign inPatentsAn implantable medical device comprising a housing and an ultrasonic transducer having a communication frequency coupled to a portion of the housing. The housing resonates at the communication frequency, and a casing is coupled to the housing and disposed over the ultrasonic transducer. The casing is...http://www.google.com/patents/US7949396?utm_source=gb-gplus-sharePatent US7949396 - Ultrasonic transducer for a metallic cavity implated medical deviceAdvanced Patent SearchTry the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents.Publication numberUS7949396 B2Publication typeGrantApplication numberUS 11/780,992Publication dateMay 24, 2011Priority dateJul 21, 2006Fee statusPaidAlso published asEP2043740A2, US8548592, US20080021509, US20110190669, WO2008011577A2, WO2008011577A3Publication number11780992, 780992, US 7949396 B2, US 7949396B2, US-B2-7949396, US7949396 B2, US7949396B2InventorsBin Mi, Abhijeet V. Chavan, Keith R. MaileOriginal AssigneeCardiac Pacemakers, Inc.Export CitationBiBTeX, EndNote, RefManPatent Citations (179), Non-Patent Citations (21), Referenced by (7), Classifications (8), Legal Events (2) External Links: USPTO, USPTO Assignment, EspacenetUltrasonic transducer for a metallic cavity implated medical device
US 7949396 B2Abstract
An implantable medical device comprising a housing and an ultrasonic transducer having a communication frequency coupled to a portion of the housing. The housing resonates at the communication frequency, and a casing is coupled to the housing and disposed over the ultrasonic transducer. The casing is adapted to amplify the deformation of the ultrasonic transducer in a bending mode and transfer the bending moment to the housing. An implantable medical device comprising a housing having an upper portion and a lower portion. A first ultrasonic transducer is coupled to a first connection rod and is coaxial with the first connection rod. The first ultrasonic transducer and first connection rod are interposed between the upper and lower portions such that the first ultrasonic transducer is adapted to vibrate the upper and lower portions simultaneously. A method of optimizing an ultrasonic transducer and a housing of an implantable medical device.
an ultrasonic transducer coupled to a portion of the housing and disposed inside the housing, the transducer having a communication frequency, wherein the housing resonates at the communication frequency; and
a casing coupled to the housing and disposed over the ultrasonic transducer, wherein the casing is adapted to amplify the deformation of the ultrasonic transducer in a bending mode and transfer the bending moment to the housing.
2. The implantable medical device of claim 1 wherein the implantable medical device comprises a pulse generator.
3. The implantable medical device of claim 1 wherein the ultrasonic transducer comprises a piezoelectric material.
4. The implantable medical device of claim 3 wherein the piezoelectric material comprises polyvinylidine diflouride (PVDF) material.
5. The implantable medical device of claim 3 wherein the ultrasonic transducer comprises lead magnesium niobate—lead titanate (PMN-PT).
6. The implantable medical device of claim 3 wherein the piezoelectric material comprises a lead zirconate titanate (PZT) material.
7. The implantable medical device of claim 6 wherein the ultrasonic transducer has a circular shape, a diameter of approximately 25.4 millimeters or less, and a thickness of approximately 3 millimeters or less.
8. The implantable medical device of claim 1 wherein the casing has a diameter of greater than approximately 25.4 millimeters, a height of less than approximately 4 millimeters, a top thickness of between approximately 0.2 and 1 millimeter, and a wall thickness of between 3 and 6 millimeters.
9. The implantable medical device of claim 1 wherein the ultrasonic transducer has a mechanical resonance of greater than approximately 20 kiloHertz.
10. The implantable medical device of claim 1 wherein the ultrasonic transducer has a mechanical resonance of approximately 40 kiloHertz.
11. The implantable medical device of claim 1 wherein the housing includes thinned regions having a thinner cross-section than a substantial portion of the housing and the ultrasonic transducer is located adjacent to the thinned regions.
12. The implantable medical device of claim 11 wherein the thinned regions have an annular shape.
13. The implantable medical device of claim 11 wherein the thinned regions have a wavy or corrugated shape.
a housing having an upper portion and a lower portion;
a first ultrasonic transducer coupled to a first connection rod and coaxial with the first connection rod;
wherein the first ultrasonic transducer and first connection rod are interposed between the upper and lower portions, such that the first ultrasonic transducer is configured to propagate acoustic waves in a first direction towards the upper portion of the housing and a second direction towards the lower portion of the housing, the first ultrasonic transducer configured to vibrate the upper and lower portions simultaneously.
15. The implantable medical device of claim 14 wherein the implantable medical device further comprises a second ultrasonic transducer coaxial with the first ultrasonic transducer and the first connection rod and interposed between the upper and lower portions.
16. The implantable medical device of claim 14 wherein the implantable medical device further comprises a second connection rod coaxial with the first ultrasonic transducer and the first connection rod and interposed between the upper and lower portions.
17. The implantable medical device of claim 14 wherein the implantable medical device further comprises a second connection rod and a second ultrasonic transducer coaxial with the first ultrasonic transducer and the first connection rod and interposed between the upper and lower portions.
18. The implantable medical device of claim 14 wherein the combined thickness of the first connection rod and the first ultrasonic transducer is between approximately 6 and 7 millimeters.
19. The implantable medical device of claim 14 wherein the first ultrasonic transducer comprises a lead zirconate titanate (PZT) material having a diameter of approximately 1 centimeter and a height of approximately 1 millimeter, the connection rod has a height of approximately 6 millimeters, a minimum diameter of approximately 1 centimeter, a maximum diameter of approximately 2.5 centimeters, and a taper beginning at a height of approximately 3 millimeters, and the thickness of the housing is between 0.3 to 2 millimeters and the width of the housing is between about 2.5 to 5 centimeters. Description
This application claims priority to Provisional Application No. 60/820,055, filed Jul. 21, 2006, which is herein incorporated by reference in its entirety.
The present invention relates to transducers used in combination with an implantable medical device for wireless communication between the implantable medical device and remote devices implanted in the body. The present invention more particularly relates to ultrasonic transducers used in combination with a metallic cavity implantable medical device.
Implantable medical devices are often used to treat a variety of medical conditions. Examples of implantable medical devices include drug delivery devices, pain management devices, and devices that treat heart arrhythmias. One example of an implantable medical device used to treat heart arrhythmias is a cardiac pacemaker, which is commonly implanted in a patient to treat bradycardia (i.e., abnormally slow heart rate). A pacemaker includes a pulse generator and leads, which form the electrical connection between the pulse generator and the heart. An implantable cardioverter defibrillator (ICD) is used to treat tachycardia (i.e., abnormally rapid heart rate). An ICD also includes a pulse generator and leads that deliver electrical energy to the heart. Pulse generators typically include a metallic housing for a battery and electrical circuitry and a header for connecting the leads to the pulse generator.
Implantable medical devices are also useful in the treatment of heart failure. For example, cardiac resynchronization therapy (CRT) (also commonly referred to as biventricular pacing) is an emerging treatment for heart failure, which involves stimulation of both the right and left ventricles to increase hemodynamic efficiency and cardiac output. The treatment of heart failure and heart arrhythmias can be enhanced through the use of remote implanted devices. One example of such a remote device is a pressure sensor located in the vasculature. Communication between the implantable medical device and the remote device can allow the sensor data to be downloaded by a clinician used to modify the therapy delivered by the implantable medical device, or both. There is therefore a need for an implantable medical device that includes a transducer for communication with a remote implanted device.
The present invention, according to one embodiment is an implantable medical device comprising a housing and an ultrasonic transducer having a communication frequency coupled to a portion of the housing. The housing resonates at the communication frequency, and a casing is coupled to the housing and disposed over the ultrasonic transducer. The casing is adapted to amplify the deformation of the ultrasonic transducer in a bending mode and transfer the bending moment to the housing.
The present invention, according to another embodiment, is an implantable medical device comprising a housing having an upper portion and a lower portion. A first ultrasonic transducer is coupled to a first connection rod and is coaxial with the first connection rod. The first ultrasonic transducer and first connection rod are interposed between the upper and lower portions such that the first ultrasonic transducer is adapted to vibrate the upper and lower portions simultaneously.
The present invention, according to yet another embodiment, is a method of optimizing an ultrasonic transducer and a housing of an implantable medical device. The method comprises determining system level requirements for the ultrasonic transducer and selecting an initial ultrasonic transducer based on the system level requirements. A first finite element methods analysis is conducted to verify the feasibility of the initial ultrasonic transducer, and a second finite element methods analysis and water tank experiments are conducted to determine whether the housing and ultrasonic transducer have a desired vibration mode at a targeted ultrasonic communication frequency. The ultrasonic transducer or the design of the housing are optimized based on the results of the first and second finite element methods analysis and water tank experiments. The resonance frequency and amplitude of the optimized ultrasonic transducer are verified using finite element method analysis and water tank experiment. A final ultrasonic transducer and housing design are selected based upon the results of the verifying step.
FIG. 1 is a combined cutaway and perspective view of an implantable medical device in accordance with one embodiment of the present invention.
FIG. 2 is a front view of the inside of the implantable medical device of FIG. 1 in accordance with one embodiment of the present invention.
FIGS. 3A-3B depict various views of the implantable medical device of FIG. 2.
FIGS. 4A-4B are various views of an implantable medical device in accordance with another embodiment of the present invention.
FIGS. 5A-5B are various views of an implantable medical device in accordance with yet another embodiment of the present invention.
FIG. 6 is a cross-sectional view of an implantable medical device in accordance with another embodiment of the present invention.
FIGS. 7A-7B are various views of an implantable medical device in accordance with another embodiment of the present invention.
FIG. 8 is a cross-sectional view of an implantable medical device in accordance with yet another embodiment of the present invention.
FIGS. 9A-9B are various views of an implantable medical device in accordance with another embodiment of the present invention.
FIGS. 10A-10B are various views of an implantable medical device in accordance with another embodiment of the present invention.
FIGS. 11A-11B are various views of an implantable medical device in accordance with another embodiment of the present invention.
FIG. 12 is a cross-sectional view of an implantable medical device in accordance with yet another embodiment of the present invention.
FIG. 13 is a cross-sectional view of an implantable medical device in accordance with yet another embodiment of the present invention.
FIG. 14 is a flowchart depicting an exemplary method of optimizing an implantable medical device having an acoustic transducer in accordance with the present invention.
FIG. 1 is a perspective view of an implantable medical device (IMD) 10. The IMD 10 includes a pulse generator 12 and a cardiac lead 14. The lead 14 operates to convey electrical signals between the heart 16 and the pulse generator 12. A proximal end 18 of the lead 14 is coupled to the pulse generator 12 and a distal end 20 is coupled to the heart 16. The lead 14 includes a lead body 17 extending from the lead proximal end 18 to the lead distal end 20.
The heart 16 includes a right atrium 22, a right ventricle 24, and a pulmonary artery 26. A tricuspid valve 28 is located between and controls the flow of blood from the right atrium 22 and the right ventricle 24. A pulmonic valve 30 is located between and controls the flow of blood from the right ventricle 24 to the pulmonary artery 26. The heart 16 also includes a left atrium 32, a left ventricle 34, and an aorta 36. A mitral valve 38 is located between and controls the flow of blood from the left atrium 32 to the left ventricle 34. An aortic valve 40 is located between and controls the flow of blood from the left ventricle 34 to the aorta 36. In one embodiment, the IMD 10 includes a plurality of leads 14. For example, it may include a first lead 14 adapted to convey electrical signals between the pulse generator 12 and the left ventricle 34 and a second lead 14 adapted to convey electrical signals between the pulse generator 12 and the right ventricle 24.
In the embodiment shown in FIG. 1, a helical electrode 42 penetrates the endocardium 43 of the right ventricle 24 and is embedded in the myocardium 44 of the heart 16. When positioned as above, the electrode 42 can be used to sense the electrical activity of the heart 16 or to apply a stimulating pulse to the right ventricle 24. In other embodiments, the cardiac lead 14 of the present invention can also be implanted in any other portion of the heart 16 as known in the art. For example, it may be implanted in the right atrium 22, the right ventricle 24, the pulmonary artery 26, the left ventricle 34, or in the coronary veins. In one embodiment, the IMD 10 includes multiple electrodes 42 disposed to sense electrical activity and/or deliver therapy to both the left and right sides of the heart 16. In one embodiment, the lead 14 can be an epicardial lead where the electrode 42 penetrates the epicardium 45.
As shown in FIG. 1, a remote device 46 is located in the pulmonary artery 26. Alternatively, the remote device 46 could be located in the right ventricle 24, the aorta 36, or any other location in or near the heart 16 or vasculature. The remote device 46 shown in FIG. 1 comprises a pressure sensor. The remote device 46 shown in FIG. 1 can be used to measure pressure in the pulmonary artery 26. In one embodiment, the remote device 46 measures end-diastolic pressure in the pulmonary artery 26. The sensed pressure can be used to predict decompensation of a heart failure patient or to optimize pacing or defibrillation therapy. One example of a pressure sensor 46 adapted to measure pressure is disclosed in U.S. Pat. No. 6,764,446 to Wolinsky et al.
While the IMD 10 shown in FIG. 1 comprises a cardiac pacemaker, in other embodiments, the IMD 10 could comprise any other medical device suitable for implantation in the body. For example, the IMD 10 could comprise a drug delivery device or a pain management device. The remote device 46 can comprise any type of chronically implanted device or remote sensor adapted to deliver therapy or monitor biological functions. The remote device 46 can be located anywhere in the body adapted for sensing a desired biological parameter or delivering therapy. For example, the remote device 46 could comprise a volume sensor or sense any other cardiac parameter, such as maximum or minimum pressure, or calculate a cardiac parameter derivative, such as the slope of the pressure. In other embodiments, the remote device 46 could comprise a glucose level monitor, a pulmonary sound sensor, a satellite pacing device, or any other remote sensing or therapy-delivering device. A plurality of remote devices 46 could be implanted throughout the body and in wireless communication with each other and with an IMD 10.
FIG. 2 depicts a front view of the inside of the pulse generator 12. The pulse generator 12 includes a housing 48 and a header 50. An acoustic transducer 52 is attached to the inside of the housing 48 and is electrically connected to control circuitry (not shown). The acoustic transducer 52 can be used as a sensor, an actuator, or as both a sensor and an actuator. FIGS. 3A-3B depict cross-sectional views of the housing 48. The acoustic transducer 52 includes electrodes 54 and can be coupled to the inside of the housing 48 by an insulating bonding layer 55. In the embodiment shown in FIG. 2, the acoustic transducer 52 has a circular shape, but the acoustic transducer could take any other shape, such as rectangular, beam-shaped, circular, annular, or triangular.
In one embodiment, the acoustic transducer 52 comprises a piezoelectric material. Piezoelectric materials adapted for use in the acoustic transducer 52 include piezo polymer, piezo crystal, or piezo ceramic materials. In one embodiment, the acoustic transducer 52 can comprise a polyvinylidine difluoride (PVDF) material. In another embodiment, the acoustic transducer 52 can comprise a lead zirconate titanate (PZT) material. In yet another embodiment, the acoustic transducer can comprise a piezo single crystal material, such as lead magnesium niobate-lead titanate (PMN-PT). In other embodiments, the acoustic transducer 52 can comprise a cMUT transducer. In one embodiment where a PZT material is used, the thickness of the PZT material is approximately equivalent to the thickness of the housing 48. In one embodiment, the acoustic transducer 52 comprises PZT5A material, has a diameter of 25.4 millimeters or less, and has a thickness of 3 millimeters or less.
As shown in FIGS. 3A-3B, one electrode 54 is connected to an AC voltage source and the other electrode 54 is connected to ground. (The thickness of the electrodes 54 in the Figures is not shown to scale.) The AC voltage can be applied to the acoustic transducer 52 to cause it to vibrate at a desired frequency. Alternatively, both electrodes 54 could be driven simultaneously by an H-bridge, as is known to one of skill in the art. In one embodiment, the acoustic transducer 52 has a mechanical resonance of greater than approximately 20 kiloHertz. In another embodiment, the acoustic transducer 52 has a mechanical resonance at a frequency of approximately 40 kiloHertz. In yet another embodiment, the acoustic transducer 52 can operate in an electrically resonant mode.
In one embodiment, the acoustic transducer 52 is adapted to generate and receive acoustic waves having a frequency greater than approximately 20 kiloHertz, has a transmit sensitivity greater than approximately 100 Pascals per Volt at 0.25 meters of water or transmitting voltage response (TVR) greater than approximately 148 decibels (dB) referenced to (re) 1 microPascal per Volt at 1 meter of water, has a receive sensitivity greater than approximately 0.5 milliVolt per Pascal or free-field voltage sensitivity (FFVS) greater than −186 dB re 1 Volt per microPascal, and has a total static capacitance less than or equal to approximately 20 nanoFarads. In another embodiment, the acoustic transducer 52 is adapted to generate and receive acoustic waves having a frequency of approximately 40 kiloHertz, has a transmit sensitivity greater than approximately 200 Pascals per Volt at 0.25 meters of water or TVR greater than approximately 154 decibels re 1 microPascal per Volt at 1 meter of water, has a receive sensitivity greater than approximately 0.5 milliVolts per Pascal or FFVS greater than −186 dB re re 1 Volt per microPascal, and a total static capacitance less than or equal to approximately 8 nanoFarads.
The acoustic transducer 52 can be used for wireless communication between the IMD 10 and the remote device 46. As shown in FIG. 3B, acoustic signals are transmitted from the IMD 10 to the remote device 46 by applying an AC voltage or a charge change to the acoustic transducer 52 so that the acoustic transducer 52 deforms and the pulse generator housing 48 vibrates in response to the deformation. Acoustic signals sent from the remote device 46 are received by the acoustic transducer 52 when an impinging acoustic wave results in mechanical vibration of the housing 48, thus causing a voltage change or a charge density change in the acoustic transducer 52, which is detected by control circuitry (not shown).
FIGS. 4A-4B depict an embodiment of the present invention where a casing 62 encloses the acoustic transducer 52. The casing 62 serves two functions. First, it bends when the acoustic transducer 52 deforms, thereby applying a bending moment to the housing 48. Second, it mechanically amplifies the deformation of the acoustic transducer 52, particularly when the housing 48 has a resonant mode at the desired frequency. In one embodiment, the casing 62 has a diameter of greater than 25 millimeters, a height of less than 4 millimeters, a top thickness of between 0.2 and 1 millimeter, and a wall thickness of between 3 to 6 millimeters. In one embodiment, the acoustic transducer 52 is attached to the casing 62 and there may be a gap or space between the acoustic transducer 52 and the housing 48. In another embodiment, the acoustic transducer 52 is attached to the housing 48 and there may be a gap between the acoustic transducer 52 and the casing 62.
FIGS. 5A-5B and 6 depict alternative embodiments of an IMD 10 having an acoustic transducer 52. As shown in FIGS. 5A-5B, the housing 48 includes annular regions 64 having a thinner cross-section than a substantial portion of the housing 48. The regions 64 shown in FIG. 5A comprise a “bull's eye” but alternatively could have any other shape, including a plurality of rectangles or circles. As shown in FIG. 5B, the acoustic transducer 52 is adjacent to the regions 64, thereby allowing for increased vibration, movement, and/or deformation of the housing 48. In one embodiment, the thickness of the regions 64 is approximately 0.12 millimeter. FIG. 6 depicts an alternative housing 48 where the region 64 takes the form of a corrugated or wavy region of the housing 48 located underneath the acoustic transducer 52. The gaps 66 shown in FIGS. 5A-5B and 6 can contain air, nitrogen, some other gas, or vacuum. As shown, FIGS. 5A-5B and 6 include the casing 62 described with respect to FIGS. 4A-4B, but in alternative embodiments, the casing 62 need not be present.
FIGS. 7A-7B depict an alternative embodiment of an IMD 10 having an acoustic transducer 52. In this embodiment, the acoustic transducer 52 has an annular shape. The acoustic transducer 52 acts as a limiting structure and defines the resonance characteristics of the region 56 by establishing boundary conditions for the region 56. The resonance characteristics of the region 56 enhance the performance of the acoustic transducer 52. When acoustic waves having the same frequency as the resonant frequency of the region 56 impact the region 56, the region 56 vibrates, resulting in deformation of the acoustic transducer 52. This deformation results in a voltage or a charge change in the acoustic transducer 52, which is detected by the control circuitry. Driving the acoustic transducer 52 using an AC voltage or an H-bridge at the resonant frequency results in periodic deformation of the acoustic transducer 52. This deformation causes the region 56 to vibrate at the resonant frequency, thereby transmitting an acoustic wave from the region 56 at the desired frequency.
The dimensions of the acoustic transducer 52 can be determined using the following formula from Blevins, “Formulas for Natural Frequencies and Mode Shapes”, ISBN 1-57524-184-6, herein incorporated by reference in its entirety:
As used in the above equation, a is the plate radius, h is the plate thickness, E is Young's modulus, ν is Poisson's ratio, ρ is the density, γ is the mass per unit area or ρ*h, and λ is a dimensionless frequency parameter dependent on the mode shape that can be found in Blevins.
In one embodiment, the acoustic transducer 52 comprises a PZT material and defines a region 56 having a mechanical resonance of greater than approximately 20 kiloHertz. In one embodiment where the housing 48 comprises titanium and λ=3.19 for mode 00, E=116 GigaPascals, ν=0.3, h=0.3 millimeters, and ρ=4500 kg/m3, and a=4.2 millimeters, for an annular piezoelectric transducer 52 with an inner radius of 4.2 millimeters, an outer radius of 8.4 millimeters, and a thickness of 2 millimeters, the natural frequency f of the first mode of the region 56 is at 40 kHz. The acoustic transducer 52 can be bonded to the housing 48 using epoxy or medical adhesive. Blevins provides additional mode resonant frequency formulas for additional shapes and boundary conditions.
In the embodiment shown in FIG. 8, the acoustic transducer 52 is mechanically bonded to a non-active limiting structure 58. As shown, the limiting structure 58 has an annular shape and defines the resonant region 56. Use of the non-active limiting structure 58 improves both the transmit and receive sensitivity of the acoustic transducer 52 when the resonant region 56 which has the same resonant frequency as the acoustic transducer 52. The non-active limiting structure 58 transfers deformation between the acoustic transducer 52 and the housing 48. For example, when the acoustic transducer 52 is in a receive mode, an impinging acoustic wave causes the resonant region 56 to vibrate, and the resulting deformation is transferred to the acoustic transducer 52 through the non-active limiting structure 58. When the acoustic transducer 52 is in a transmit mode, actuation of the acoustic transducer 52 causes it to vibrate at the resonant frequency, which is then transferred to the housing 48 by the non-active limiting structure 58, thus causing the resonant region 56 to vibrate at the resonant frequency. The non-active limiting structure 58 can be comprised of titanium, aluminum, stainless steel, ceramic material, or any other rigid material. The gap 60 between the acoustic transducer 52 and the resonant region 56 can be filled with air, nitrogen, some other gas, or vacuum.
FIGS. 9A-9B depict an alternative embodiment of the IMD 10. As shown in FIG. 9A, the limiting structure 58 is located in a corner 70 of the housing 48, has an approximately semicircular shape, and defines a resonant region 56. The acoustic transducer 52 is bonded to the housing 48 and extends from the limiting structure 58 into the resonant region 56. In one embodiment, the length of the acoustic transducer 52 is determined by the strain/stress profile of the resonant region 56. In one embodiment, the deformation of the acoustic transducer 52 is constrained by the limiting structure 58 and the acoustic transducer 52 has a length of no more than half of the radius of the resonant region 56. As shown in the cross-sectional view of FIG. 9B, the limiting structure 58 does not extend to the rear wall 72 of the housing, but in an alternative embodiment, the limiting structure 58 could extend to the rear wall 72. In yet another alternative embodiment, the limiting structure 58 could be located on the outside of the housing 48. In one embodiment, the limiting structure 58 could take the shape of an annular ring located on the outside of the housing 48.
FIGS. 10A-10B depict yet another alternative embodiment of the present invention. In this embodiment, the acoustic transducer 52 is located in the corner 70 of the housing 48. The checkerboard pattern shown in FIG. 10A represents the mode shape of the housing 48 at approximately 40 kiloHertz. The regions 73 represent regions of the housing 48 that are moving in the Z-axis. These regions 73 can be moving either in a positive or negative direction along the Z-axis. The dotted regions 73 can be moving in a positive direction along the Z-axis while the undotted regions can be moving in a negative direction along the Z-axis. The lines 74 of the checkerboard pattern represent the nodal regions, or lines where the housing is motionless with respect to the Z-axis. In the embodiment shown, the corner 70 acts as a limiting structure and defines a resonant region 56, but in other embodiments, the transducer 52 could be located in a region 73 where the nodal lines 74 create a resonant region 56. As shown, the acoustic transducer 52 is bonded to the top face 76 and is located in the resonant region 56. In one embodiment, the acoustic transducer 52 is located in a region of maximum stress and strain. In other embodiments, the shape of the housing 48 itself can be changed to obtain a desired frequency characteristic. In other embodiments, the housing 48 could be embossed or include a “dimple” to obtain a desired frequency characteristic.
FIGS. 11A-11B show another alternative embodiment of the IMD 10 of the present invention. In this embodiment, the header 50 acts as a limiting structure on the acoustic transducer 52. An aperture 78 is located in the header 50 and defines a resonant region 56. The acoustic transducer 52 extends into the resonant region 56 and is bonded to the inside of the housing 48.
FIG. 12 shows a cross-sectional view of an alternative embodiment of the IMD 10 of the present invention. The IMD 10 includes a housing 48 having an upper portion 48 a and lower portion 48 b. A connection rod 84 is coupled to the upper portion 48 a and a second connection rod 84 is coupled to the lower portion 48 b. An acoustic transducer 52 is interposed between the two connection rods 84. The connection rods 84 have a bell shape in FIG. 12, but could have any other shape. When the acoustic transducer 52 of FIG. 12 is actuated, the portions 48 a, 48 b will vibrate, propagating acoustic waves in two directions. The thickness of the acoustic transducer 52 can be adjusted according to the desirable actuation displacement of the housing 48 for generation of acoustic waves.
FIG. 13 shows a cross-sectional view of an alternative embodiment where an acoustic transducer 52 is coupled to each portion 48 a, 48 b and two connection rods 84 are interposed between the acoustic transducers 52. The structure depicted in FIG. 13 also allows acoustic waves to propagate in two directions simultaneously. The symmetrical design of FIG. 13 allows for easier design and manufacture of the acoustic transducers 52 and connection rods 84.
The embodiments shown in FIGS. 12 and 13 increase the sensitivity of the acoustic transducer or transducers 52. The acoustic transducer or transducers 52 can comprise a piezoelectric material such as PZT or PVDF. In FIGS. 12 and 13, the portions 48 a, 48 b can apply a pre-stress to the acoustic transducer or transducers 52. In one embodiment, the acoustic transducer or transducers 52 and connection rods 84 are resonant in the thickness mode. In another embodiment, the acoustic transducer or transducers 52 and connection rods 84 are resonant in a radial mode. In one embodiment, the combined thickness of the connection rod 84 and the acoustic transducer 52 is approximately half of the wavelength of the communication frequency. In one embodiment, the combined thickness of the connection rod 84 and the acoustic transducer 52 is between 6 and 7 millimeters. In an alternative embodiment, a single connection rod 84 and a single acoustic transducer 52 are interposed between the portions 48 a, 48 b. In one embodiment, the single acoustic transducer 52 comprises a PZT material 1 centimeter in diameter and 1 millimeter thick. The connection rod 84 has a height of about 6 millimeters, a minimum diameter of 1 centimeter, a maximum diameter of 2.5 centimeters, and a taper beginning at a height of approximately 3 millimeters. In one embodiment, the thickness of the housing 48 is between 0.3 to 2 millimeters and the width of the housing 48 is between about 2.5 to 5 centimeters.
FIG. 14 depicts an exemplary method 200 for optimizing an acoustic transducer 52 and an IMD 10 for wireless communication with a remote device 46. System level requirements such as the power budget, transducer sensitivity, mechanical size, material selection, and the vibration mode of the metallic housing 48 are determined (block 210). An initial acoustic transducer 52 is selected based on the system level requirements (block 220). A Finite Element Methods (FEM) analysis, as is known to those of skill in the art, is performed to verify the feasibility of the initial transducer in simplified geometries (block 230). In this embodiment, verifying the feasibility includes determining whether the acoustic transducer 52 system level attributes fall within an acceptable range for the system level requirements. FEM and water tank experiments are used to determine whether the metallic housing 48 and acoustic transducer 52 have the desired vibration mode at the targeted ultrasonic communication frequency (block 240). The design can be optimized by varying the design of the housing 48, incorporating a casing 62, modifying the design 62 of the casing, modifying the characteristics of the acoustic transducer 52, including the dimensions, or any combination thereof (block 250).
Once the design is further refined, the underwater resonance frequency and amplitude of the acoustic transducer 52 can be verified through Finite Element Method models and water tank experiments (block 260). The experiments can be conducted in a water tank using a hydrophone and can utilize a scanning laser vibrometer (SLV). One such SLV can be obtained from Polytec GmbH, Polytec-Platz 1-7, D-76337 Waldbronn, Germany. The design can again be optimized by varying the parameters such as housing 48 design, acoustic transducer 52 design, etc. (block 250). This optimization is repeated until the desired resonance characteristics are obtained and a final acoustic transducer design is reached (block 270).
Patent CitationsCited PatentFiling datePublication dateApplicantTitleUS2967957Sep 17, 1957Jan 10, 1961Frank MassaElectroacoustic transducerUS3568661Oct 2, 1968Mar 9, 1971Us Health Education & WelfareFrequency modulated ultrasound technique for measurement of fluid velocityUS3676720Jan 26, 1971Jul 11, 1972Univ OhioMethod and apparatus for controlling frequency of piezoelectric transducersUS3757770Feb 22, 1971Sep 11, 1973Bio Tel WesternPhysiological pressure sensing and telemetry means employing a diode connected transistor transducerUS3792204Dec 3, 1971Feb 12, 1974Kureha Chemical Ind Co LtdAcoustic transducer using a piezoelectric polyvinylidene fluoride resin film as the oscillatorUS3798473Nov 6, 1972Mar 19, 1974Kureha Chemical Ind Co LtdPolymer type electroacoustic transducer elementUS3832580Jan 4, 1973Aug 27, 1974Pioneer Electronic CorpHigh molecular weight, thin film piezoelectric transducersUS3894198Nov 6, 1972Jul 8, 1975Kureha Chemical Ind Co LtdElectrostatic-piezoelectric transducerUS3940637Apr 24, 1974Feb 24, 1976Toray Industries, Inc.Polymeric piezoelectric key actuated deviceUS3978353May 6, 1975Aug 31, 1976Pioneer Electronic CorporationPiezoelectric acoustic speaker systemUS4008408Feb 24, 1975Feb 15, 1977Pioneer Electronic CorporationPiezoelectric electro-acoustic transducerUS4051455Nov 20, 1975Sep 27, 1977Westinghouse Electric CorporationDouble flexure disc electro-acoustic transducerUS4056742Apr 30, 1976Nov 1, 1977Tibbetts Industries, Inc.Transducer having piezoelectric film arranged with alternating curvaturesUS4064375Aug 11, 1976Dec 20, 1977The Rank Organisation LimitedVacuum stressed polymer film piezoelectric transducerUS4096756Jul 5, 1977Jun 27, 1978Rca CorporationVariable acoustic wave energy transfer-characteristic control deviceUS4127110May 24, 1976Nov 28, 1978Huntington Institute Of Applied Medical ResearchImplantable pressure transducerUS4170742Aug 5, 1977Oct 9, 1979Pioneer Electronic CorporationPiezoelectric transducer with multiple electrode areasUS4181864Jun 22, 1978Jan 1, 1980Rca CorporationMatching network for switchable segmented ultrasonic transducersUS4227407Nov 30, 1978Oct 14, 1980Cornell Research Foundation, Inc.Volume flow measurement systemUS4281484Feb 11, 1980Aug 4, 1981The Stoneleigh TrustSystem for precisely and economically adjusting the resonance frequence of electroacoustic transducersUS4431873Dec 8, 1981Feb 14, 1984Her Majesty The Queen In Right Of Canada, As Represented By The Minister Of National DefenceDiaphragm design for a bender type acoustic sensorUS4433400Nov 24, 1980Feb 21, 1984The United States Of America As Represented By The Department Of Health And Human ServicesAcoustically transparent hydrophone probeUS4440983Jan 5, 1981Apr 3, 1984Thomson-CsfElectro-acoustic transducer with active domeUS4456850Feb 9, 1983Jun 26, 1984Nippon Electric Co., Ltd.Piezoelectric composite thin film resonatorUS4481950Apr 3, 1981Nov 13, 1984Medtronic, Inc.Acoustic signalling apparatus for implantable devicesUS4517665Nov 17, 1983May 14, 1985The United States Of America As Represented By The Department Of Health And Human ServicesAcoustically transparent hydrophone probeUS4519401Sep 20, 1983May 28, 1985Case Western Reserve UniversityPressure telemetry implantUS4541431Sep 20, 1984Sep 17, 1985Telectronics Pty. Ltd.Use of telemetry coil to replace magnetically activated reed switch in implantable devicesUS4558249Mar 12, 1984Dec 10, 1985Reinhard LerchStretched piezopolymer transducer with unsupported areasUS4577132Oct 19, 1984Mar 18, 1986Toray Industries, Inc.Ultrasonic transducer employing piezoelectric polymeric materialUS4580074Nov 26, 1984Apr 1, 1986General Motors CorporationPiezoelectric transducer with coded output signalUS4593703May 17, 1984Jun 10, 1986Cosman Eric RTelemetric differential pressure sensor with the improvement of a conductive shorted loop tuning element and a resonant circuitUS4600855May 30, 1985Jul 15, 1986Medex, Inc.Piezoelectric apparatus for measuring bodily fluid pressure within a conduitUS4642508Mar 8, 1985Feb 10, 1987Kabushiki Kaisha ToshibaPiezoelectric resonating deviceUS4653036Oct 23, 1984Mar 24, 1987The United States Of America As Represented By The Department Of Health And Human ServicesTransducer hydrophone with filled reservoirUS4653508Jan 23, 1981Mar 31, 1987Cosman Eric RPressure-balanced telemetric pressure sensing system and method thereforeUS4660568Jan 23, 1981Apr 28, 1987Cosman Eric RTelemetric differential pressure sensing system and method thereforeUS4672976Jun 10, 1986Jun 16, 1987Cherne Industries, Inc.Heart sound sensorUS4676255Jul 3, 1985Jun 30, 1987Cosman Eric RTelemetric in-vivo calibration method and apparatus using a negative pressure applicatorUS4677337Oct 29, 1986Jun 30, 1987Siemens AktiengesellschaftBroadband piezoelectric ultrasonic transducer for radiating in airUS4781715Apr 30, 1986Nov 1, 1988Temple University Of The Commonwealth System Of Higher EducationCardiac prosthesis having integral blood pressure sensorUS4793825Sep 11, 1985Dec 27, 1988The Secretary Of State For Defence In Her Britannic Majesty's Government Of The United Kingdom And Northern IrelandActive silicon implant devicesUS4835435Jan 19, 1988May 30, 1989Hewlett-Packard CompanySimple, sensitive, frequency-tuned drop detectorUS4846191May 27, 1988Jul 11, 1989Data Sciences, Inc.Device for chronic measurement of internal body pressureUS4911172Mar 28, 1988Mar 27, 1990Telectronics Pacing Systems, Inc.Probe tip ultrasonic transducers and method of manufactureUS4958100Feb 22, 1989Sep 18, 1990Massachusetts Institute Of TechnologyActuated truss systemUS4992692May 16, 1989Feb 12, 1991Hewlett-Packard CompanyAnnular array sensorsUS5012815Jun 5, 1990May 7, 1991Yale UniversityDynamic spectral phonocardiographUS5024224Sep 1, 1988Jun 18, 1991Storz Instrument CompanyMethod of readout of implanted hearing aid device and apparatus thereforUS5088576Jul 12, 1989Feb 18, 1992E.A.P. Akustik GmbhMass and spring systems for soundproofingUS5113859Jun 25, 1990May 19, 1992Medtronic, Inc.Acoustic body bus medical device communication systemUS5160870Jun 25, 1990Nov 3, 1992Carson Paul LUltrasonic image sensing array and methodUS5178153Feb 25, 1985Jan 12, 1993Einzig Robert EFluid flow sensing apparatus for in vivo and industrial applications employing novel differential optical fiber pressure sensorsUS5283397Sep 25, 1992Feb 1, 1994Akg Akustische U. Kino-Gerate Gesellschaft M.B.H.Diaphragm for electrodynamic transducerUS5289821Jun 30, 1993Mar 1, 1994Swartz William MMethod of ultrasonic Doppler monitoring of blood flow in a blood vesselUS5300875Jun 8, 1992Apr 5, 1994Micron Technology, Inc.Passive (non-contact) recharging of secondary battery cell(s) powering RFID transponder tagsUS5314457Apr 8, 1993May 24, 1994Jeutter Dean CRegenerative electricalUS5339290Apr 16, 1993Aug 16, 1994Hewlett-Packard CompanyMembrane hydrophone having inner and outer membranesUS5367500Sep 30, 1992Nov 22, 1994The United States Of America As Represented By The Secretary Of The NavyTransducer structureUS5381067Mar 10, 1993Jan 10, 1995Hewlett-Packard CompanyElectrical impedance normalization for an ultrasonic transducer arrayUS5381386May 19, 1993Jan 10, 1995Hewlett-Packard CompanyMembrane hydrophoneUS5410587Mar 1, 1993Apr 25, 1995Matsushita Communication Industrial Corp. Of AmericaUltrasonic radiotelephone for an automobileUS5411551Sep 28, 1993May 2, 1995Ultrasonic Sensing And Monitoring Systems, Inc.Stent assembly with sensorUS5423334Feb 1, 1993Jun 13, 1995C. R. Bard, Inc.Implantable medical device characterization systemUS5438553Aug 22, 1983Aug 1, 1995Raytheon CompanyTransducerUS5476488Dec 15, 1993Dec 19, 1995Pacesetter, Inc.Telemetry system power control for implantable medical devicesUS5483501Apr 29, 1994Jan 9, 1996The Whitaker CorporationShort distance ultrasonic distance meterUS5488954Sep 9, 1994Feb 6, 1996Georgia Tech Research Corp.Ultrasonic transducer and method for using sameUS5495137Aug 31, 1994Feb 27, 1996The Whitaker CorporationProximity sensor utilizing polymer piezoelectric film with protective metal layerUS5554177Mar 27, 1995Sep 10, 1996Medtronic, Inc.Method and apparatus to optimize pacing based on intensity of acoustic signalUS5562714Feb 3, 1995Oct 8, 1996Medtronic, Inc.Magnetic field strength regulator for implantUS5571152May 26, 1995Nov 5, 1996Light Sciences Limited PartnershipMicrominiature illuminator for administering photodynamic therapyUS5628782Aug 17, 1993May 13, 1997W. L. Gore & Associates, Inc.Method of making a prosthetic vascular graftUS5679026Dec 21, 1995Oct 21, 1997Ventritex, Inc.Header adapter for an implantable cardiac stimulation deviceUS5704352Nov 22, 1995Jan 6, 1998Tremblay; Gerald F.Implantable passive bio-sensorUS5733313Aug 1, 1996Mar 31, 1998Exonix CorporationRF coupled, implantable medical device with rechargeable back-up power sourceUS5735887Dec 10, 1996Apr 7, 1998Exonix CorporationClosed-loop, RF-coupled implanted medical deviceUS5741316Dec 2, 1996Apr 21, 1998Light Sciences Limited PartnershipElectromagnetic coil configurations for power transmission through tissueUS5749909Nov 7, 1996May 12, 1998Sulzer Intermedics Inc.Transcutaneous energy coupling using piezoelectric deviceUS5757104Aug 5, 1997May 26, 1998Endress + Hauser Gmbh + Co.Method of operating an ultransonic piezoelectric transducer and circuit arrangement for performing the methodUS5792195Dec 16, 1996Aug 11, 1998Cardiac Pacemakers, Inc.Acceleration sensed safe upper rate envelope for calculating the hemodynamic upper rate limit for a rate adaptive cardiac rhythm management deviceUS5807258Oct 14, 1997Sep 15, 1998Cimochowski; George E.Ultrasonic sensors for monitoring the condition of a vascular graftUS5825117Mar 26, 1996Oct 20, 1998Hewlett-Packard CompanySecond harmonic imaging transducersUS5832924Feb 16, 1995Nov 10, 1998Medwave, Inc.Method of positioning a sensor for determining blood pressure of an arteryUS5833603Mar 13, 1996Nov 10, 1998Lipomatrix, Inc.Implantable biosensing transponderUS5843135Oct 20, 1997Dec 1, 1998Medtronic, Inc.Pacing system with lead having a single conductor for connecting to pressure sensor and electrodeUS5870351Oct 29, 1996Feb 9, 1999The Board Of Trustees Of The Leland Stanford Junior UniversityBroadband microfabriated ultrasonic transducer and method of fabricationUS5873835Sep 13, 1995Feb 23, 1999Scimed Life Systems, Inc.Intravascular pressure and flow sensorUS5879283Aug 7, 1997Mar 9, 1999St. Croix Medical, Inc.Implantable hearing system having multiple transducersUS5935081Jan 20, 1998Aug 10, 1999Cardiac Pacemakers, Inc.Long term monitoring of acceleration signals for optimization of pacing therapyUS5956292Sep 16, 1997Sep 21, 1999The Charles Stark Draper Laboratory, Inc.Monolithic micromachined piezoelectric acoustic transducer and transducer array and method of making sameUS5957950Jun 13, 1997Sep 28, 1999Northwestern University Medical SchoolVascular acoustic emission analysis in a balloon angioplasty systemUS5967986Nov 25, 1997Oct 19, 1999Vascusense, Inc.Endoluminal implant with fluid flow sensing capabilityUS6044298Oct 13, 1998Mar 28, 2000Cardiac Pacemakers, Inc.Optimization of pacing parameters based on measurement of integrated acoustic noiseUS6053873Apr 9, 1998Apr 25, 2000Biosense, Inc.Pressure-sensing stentUS6058329May 7, 1999May 2, 2000Cardiac Pacemakers, Inc.Optimization of pacing parameters based on measurement of acoustic noiseUS6068589Feb 14, 1997May 30, 2000Neukermans; Armand P.Biocompatible fully implantable hearing aid transducersUS6082367Apr 29, 1998Jul 4, 2000Medtronic, Inc.Audible sound communication from an implantable medical deviceUS6140740Dec 30, 1997Oct 31, 2000Remon Medical Technologies, Ltd.Piezoelectric transducerUS6141588Jul 24, 1998Oct 31, 2000Intermedics Inc.Cardiac simulation system having multiple stimulators for anti-arrhythmia therapyUS6185452Feb 25, 1998Feb 6, 2001Joseph H. SchulmanBattery-powered patient implantable deviceUS6223081Mar 28, 1996Apr 24, 2001Medtronic, Inc.Implantable stimulus system having stimulus generator with pressure sensor and common lead for transmitting stimulus pulses to a body location and pressure signals from the body location to the stimulus generatorUS6409675Nov 10, 1999Jun 25, 2002Pacesetter, Inc.Extravascular hemodynamic monitorUS6475170Mar 10, 2000Nov 5, 2002Remon Medical Technologies LtdAcoustic biosensor for monitoring physiological conditions in a body implantation siteUS6477406Apr 5, 2000Nov 5, 2002Pacesetter, Inc.Extravascular hemodynamic acoustic sensorUS6480733Dec 17, 1999Nov 12, 2002Pacesetter, Inc.Method for monitoring heart failureUS6486588Jun 1, 2001Nov 26, 2002Remon Medical Technologies LtdAcoustic biosensor for monitoring physiological conditions in a body implantation siteUS6504286Oct 20, 2000Jan 7, 2003Remon Medical Technologies Ltd.Piezoelectric transducerUS6527729Oct 11, 2000Mar 4, 2003Pacesetter, Inc.Method for monitoring patient using acoustic sensorUS6537200Mar 28, 2001Mar 25, 2003Cochlear LimitedPartially or fully implantable hearing systemUS6554761Oct 29, 1999Apr 29, 2003Soundport CorporationFlextensional microphones for implantable hearing devicesUS6575894Apr 13, 2001Jun 10, 2003Cochlear LimitedAt least partially implantable system for rehabilitation of a hearing disorderUS6600949May 5, 2000Jul 29, 2003Pacesetter, Inc.Method for monitoring heart failure via respiratory patternsUS6628989Oct 16, 2000Sep 30, 2003Remon Medical Technologies, Ltd.Acoustic switch and apparatus and methods for using acoustic switches within a bodyUS6629922Oct 29, 1999Oct 7, 2003Soundport CorporationFlextensional output actuators for surgically implantable hearing aidsUS6629951 *Jul 18, 2001Oct 7, 2003Broncus Technologies, Inc.Devices for creating collateral in the lungsUS6643548Apr 6, 2000Nov 4, 2003Pacesetter, Inc.Implantable cardiac stimulation device for monitoring heart sounds to detect progression and regression of heart disease and method thereofUS6645145Sep 24, 2001Nov 11, 2003Siemens Medical Solutions Usa, Inc.Diagnostic medical ultrasound systems and transducers utilizing micro-mechanical componentsUS6654638Apr 6, 2000Nov 25, 2003Cardiac Pacemakers, Inc.Ultrasonically activated electrodesUS6671550Sep 14, 2001Dec 30, 2003Medtronic, Inc.System and method for determining location and tissue contact of an implantable medical device within a bodyUS6697674Apr 13, 2001Feb 24, 2004Cochlear LimitedAt least partially implantable system for rehabilitation of a hearing disorderUS6720709Sep 6, 2002Apr 13, 2004Remon Medical Technologies Ltd.Piezoelectric transducerUS6740076Apr 26, 2002May 25, 2004Medtronic, Inc.Ultrasonic septum monitoring for implantable medical devicesUS6741714Jun 25, 2001May 25, 2004Widex A/SHearing aid with adaptive matching of input transducersUS6763722Jul 13, 2001Jul 20, 2004Transurgical, Inc.Ultrasonic transducersUS6764446Jun 21, 2001Jul 20, 2004Remon Medical Technologies LtdImplantable pressure sensors and methods for making and using themUS7016739Aug 27, 2003Mar 21, 2006Cardiac Pacemakers, Inc.System and method for removing narrowband noiseUS7024248Nov 19, 2001Apr 4, 2006Remon Medical Technologies LtdSystems and methods for communicating with implantable devicesUS7035684Feb 26, 2003Apr 25, 2006Medtronic, Inc.Method and apparatus for monitoring heart function in a subcutaneously implanted deviceUS7107103Oct 16, 2002Sep 12, 2006Alfred E. Mann Foundation For Scientific ResearchFull-body charger for battery-powered patient implantable deviceUS7220232Jul 24, 2002May 22, 2007Timi 3 Systems, Inc.Method for delivering ultrasonic energyUS7228175May 15, 2002Jun 5, 2007Cardiac Pacemakers, Inc.Cardiac rhythm management systems and methods using acoustic contractility indicatorUS7236821Feb 19, 2002Jun 26, 2007Cardiac Pacemakers, Inc.Chronically-implanted device for sensing and therapyUS7283874Jul 31, 2003Oct 16, 2007Remon Medical Technologies Ltd.Acoustically powered implantable stimulating deviceUS7335169Jul 24, 2002Feb 26, 2008Timi 3 Systems, Inc.Systems and methods for delivering ultrasound energy at an output power level that remains essentially constant despite variations in transducer impedanceUS7522962Dec 2, 2005Apr 21, 2009Remon Medical Technologies, LtdImplantable medical device with integrated acoustic transducerUS7634318Dec 15, 2009Cardiac Pacemakers, Inc.Multi-element acoustic recharging systemUS20020027400Aug 3, 2001Mar 7, 2002Minoru TodaUltrasonic transducer having impedance matching layerUS20020036446Sep 17, 2001Mar 28, 2002Minoru TodaPiezeoelectric transducer having protuberances for transmitting acoustic energy and method of making the sameUS20020151938Nov 15, 2001Oct 17, 2002Giorgio CorbucciMyocardial performance assessmentUS20020177782May 20, 2002Nov 28, 2002Remon Medical Technologies, Ltd.Barometric pressure correction based on remote sources of informationUS20030055461Aug 6, 2002Mar 20, 2003Girouard Steven D.Cardiac rhythm management systems and methods predicting congestive heart failure statusUS20040103906Nov 21, 2003Jun 3, 2004Schulman Joseph H.Battery-powered patient implantable deviceUS20040106954Nov 14, 2003Jun 3, 2004Whitehurst Todd K.Treatment of congestive heart failureUS20040106960Dec 2, 2002Jun 3, 2004Siejko Krzysztof Z.Phonocardiographic image-based atrioventricular delay optimizationUS20040106961Dec 2, 2002Jun 3, 2004Siejko Krzysztof Z.Method and apparatus for phonocardiographic image acquisition and presentationUS20040122315Sep 24, 2003Jun 24, 2004Krill Jerry A.Ingestible medical payload carrying capsule with wireless communicationUS20040122484Dec 18, 2002Jun 24, 2004John HatlestadAdvanced patient management for defining, identifying and using predetermined health-related eventsUS20040127792Dec 30, 2002Jul 1, 2004Siejko Krzysztof Z.Method and apparatus for monitoring of diastolic hemodynamicsUS20040138572May 28, 2002Jul 15, 2004Arvind ThiagarajanHeart diagnosis systemUS20040167416Feb 26, 2003Aug 26, 2004Medtronic, Inc.Method and apparatus for monitoring heart function in a subcutaneously implanted deviceUS20040204744Apr 14, 2003Oct 14, 2004Remon Medicaltechnologies Ltd.Apparatus and methods using acoustic telemetry for intrabody communicationsUS20040230249Mar 15, 2004Nov 18, 2004Paul HaefnerImplantable device with cardiac event audio playbackUS20040260214Jun 15, 2004Dec 23, 2004Ebr Systems, Inc.Methods and systems for vibrational treatment of cardiac arrhythmiasUS20050102001Nov 6, 2003May 12, 2005Maile Keith R.Dual-use sensor for rate responsive pacing and heart sound monitoringUS20050131472Feb 2, 2005Jun 16, 2005Cardiac Pacemakers, Inc.Cardiac pacing using adjustable atrio-ventricular delaysUS20050137490Jan 18, 2005Jun 23, 2005Cardiac Pacemakers, Inc.Apparatus and method for outputting heart soundsUS20050148896Dec 24, 2003Jul 7, 2005Siejko Krzysztof Z.Method and apparatus for third heart sound detectionUS20050149136Dec 24, 2003Jul 7, 2005Siejko Krzysztof Z.Third heart sound activity index for heart failure monitoringUS20050149138Dec 24, 2003Jul 7, 2005Xiaoyi MinSystem and method for determining optimal pacing sites based on myocardial activation timesUS20060009818 *Jul 9, 2004Jan 12, 2006Von Arx Jeffrey AMethod and apparatus of acoustic communication for implantable medical deviceUS20060082259Oct 18, 2004Apr 20, 2006Ssi Technologies, Inc.Method and device for ensuring transducer bond line thicknessUS20060136004Dec 21, 2005Jun 22, 2006Ebr Systems, Inc.Leadless tissue stimulation systems and methodsUS20060142819Mar 6, 2006Jun 29, 2006Avi PennerAcoustic switch and apparatus and methods for using acoustic switchesUS20060149329 *Nov 23, 2005Jul 6, 2006Abraham PennerImplantable medical device with integrated acousticUS20070049977Aug 26, 2005Mar 1, 2007Cardiac Pacemakers, Inc.Broadband acoustic sensor for an implantable medical deviceUS20070055184Aug 29, 2006Mar 8, 2007Ebr Systems, Inc.Methods and systems for heart failure prevention and treatments using ultrasound and leadless implantable devicesUS20070093875Oct 24, 2005Apr 26, 2007Cardiac Pacemakers, Inc.Implantable and rechargeable neural stimulatorUS20070142728Feb 28, 2007Jun 21, 2007Avi PennerApparatus and methods using acoustic telemetry for intrabody communicationsUS20080021289Jul 20, 2007Jan 24, 2008Cardiac Pacemakers, Inc.Acoustic communication transducer in implantable medical device headerUS20080021509Jul 20, 2007Jan 24, 2008Cardiac Pacemakers, Inc.Ultrasonic transducer for a metallic cavity implated medical deviceUS20080021510Jul 20, 2007Jan 24, 2008Cardiac Pacemakers, Inc.Resonant structures for implantable devicesUS20100004718Jan 7, 2010Remon Medical Technologies, Ltd.Implantable medical device with integrated acoustic transducerUS20100049269Feb 25, 2010Tran Binh CMulti-element acoustic recharging systemUS20100094105Oct 13, 2009Apr 15, 2010Yariv PoratPiezoelectric transducerDE3222349A1Jun 14, 1982Jan 5, 1984Helga BertholdElectronic clockEP0798016B1Feb 26, 1997Dec 17, 2003Vitatron Medical B.V.Implantable stimulus system having stimulus generator with pressure sensor and common lead for transmitting stimulus pulses to a body location and pressure signals from the body location to the stimulus generatorEP0897690B1Aug 15, 1997Apr 24, 2013Academisch Ziekenhuis Leiden h.o.d.n. LUMCPressure sensor for use in an aneurysmal sacEP1151719B1Apr 30, 2001Sep 12, 2007Pacesetter, Inc.Apparatus for monitoring heart failure via respiratory patterns* Cited by examinerNon-Patent CitationsReference1Blevins, "Formulas for Natural Frequencies and Mode Shapes", ISBN 1-57524-184-6.2C. Hierold et al (Germany, 1998) "Implantable Low Power Integrated Pressure Sensor System for Minimal Invasive Telemetric Patient Monitoring" IEEE, pp. 568-573.3Cassereau et al., "Time Reversal of Ultrasonic Fields-Part 3: Theory of the Closed Time-Reversal Cavity," IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 39, No. 5, Sep. 1992, pp. 579-592.4Cassereau et al., "Time Reversal of Ultrasonic Fields—Part 3: Theory of the Closed Time-Reversal Cavity," IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 39, No. 5, Sep. 1992, pp. 579-592.5ER. Cosman et al (Massachussetts, Apr. 1979) "A Telemetric Pressure Sensor for Ventricular Shunt Systems" Surgical Neurology, vol. 11, No. 4, pp. 287-294.6Fink et al., "Time Reversal Acoustics," 2004 IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control Joint 50th Anniversary Conference, Ultrasonics Symposium, pp. 850-859.7Fink, "Time Reversal of Ultrasonic Fields-Part 1: Basic Principles," IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 39, No. 5, Sep. 1992, pp. 555-566.8Fink, "Time Reversal of Ultrasonic Fields—Part 1: Basic Principles," IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 39, No. 5, Sep. 1992, pp. 555-566.9G. W. H. Schurink et al (1998) "Late Endoleak after Endovascular Therapy for Abdominal Aortic Aneurysm" Eur. J. Vasc. Endovasc. Surg. vol. 17, pp. 448-450.10GH White et al (1997) "Endoleak Following Endoluminal Repair of AAA: Management Options and Patient Outcomes", J. Endovasc Surg. p. I-45.11International Search Report and Written Opinion of International No. PCT/US2006/033273, filed Aug. 25, 2006,both mailed Jan. 19, 2007.12Karl E. Richard et al (Germany, Jan. 1999) "First clinical results with a telemetric shunt-integrated ICP-sensor" Neurological Research vol. 21, pp. 117-120.13Prof. Dr. Johannes Zacheja et al (Germany, Sep. 1996) "An Implantable Microsystem for Biomedical Applications" Micro System Technologies 96, pp. 717-722.14S. K. Gupta et al (1999) "Use of a Piezoelectric Film Sensor for Monitoring Vascular Grafts" The American Journal of Surgery vol. 160, pp. 182-186.15Search Report and Written Opinion of PCT/US2007/073989, filed Jul. 20, 2007, both mailed Dec. 20, 2007.16Search Report and Written Opinion of PCT/US2007/073998, filed Jul. 20, 2007, both mailed Mar. 6, 2008.17T. Chuter et al (Sweden, Jan. 1997) "Aneurysm Pressure following Endovascular Exclusion" Eur. J. Vasc. Endovasc. Surg. vol. 13, pp. 85-87.18T.A. Cochran et al (1990) "Aortic Aneurysm Abdominal", Current Therapy in Adult Medicine, Fourth Edition.19Wu et al., "Time Reversal of Ultrasonic Fields-Part 2: Experimental Results," IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 39, No. 5, Sep. 1992, pp. 567-578.20Wu et al., "Time Reversal of Ultrasonic Fields—Part 2: Experimental Results," IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control, vol. 39, No. 5, Sep. 1992, pp. 567-578.21Z. Tang et al (May 1995) "Data Transmission from an Implantable Biotelemeter by Load-Shift Keying Using Circuit Configuration Modulator" IEEE Transactions on Biomedical Engineering, vol. 42, No. 5, pp. 524-528.Referenced byCiting PatentFiling datePublication dateApplicantTitleUS8275459 *Sep 25, 2012Biotronik Crm Patent AgWireless feedthrough for medical implantsUS8277441Oct 2, 2012Remon Medical Technologies, Ltd.Piezoelectric transducerUS8548592Apr 8, 2011Oct 1, 2013Cardiac Pacemakers, Inc.Ultrasonic transducer for a metallic cavity implanted medical deviceUS8647328Sep 5, 2012Feb 11, 2014Remon Medical Technologies, Ltd.Reflected acoustic wave modulationUS20100298909 *May 20, 2009Nov 25, 2010Ingo WeissWireless feedthrough for medical implantsUS20110190669 *Aug 4, 2011Bin MiUltrasonic transducer for a metallic cavity implanted medical deviceWO2014179886A1 *May 8, 2014Nov 13, 2014Dalhousie UniversityAcoustic transmitter and implantable receiver* Cited by examinerClassifications U.S. Classification607/36International ClassificationA61N1/375Cooperative ClassificationA61B5/0028, A61N1/37288, A61N1/37217European ClassificationA61N1/372D2, A61N1/372D8S, A61B5/00B7BLegal EventsDateCodeEventDescriptionJan 10, 2008ASAssignmentOwner name: CARDIAC PACEMAKERS, INC., MINNESOTAFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MI, BIN;CHAVAN, ABHIJEET V.;MAILE, KEITH R.;REEL/FRAME:020347/0349;SIGNING DATES FROM 20070621 TO 20070706Owner name: CARDIAC PACEMAKERS, INC., MINNESOTAFree format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:MI, BIN;CHAVAN, ABHIJEET V.;MAILE, KEITH R.;SIGNING DATES FROM 20070621 TO 20070706;REEL/FRAME:020347/0349Oct 29, 2014FPAYFee paymentYear of fee payment: 4RotateOriginal ImageGoogle Home - Sitemap - USPTO Bulk Downloads - Privacy Policy - Terms of Service - About Google Patents - Send FeedbackData provided by IFI CLAIMS Patent Services