Implantable wireless accoustic stimulators with high energy conversion efficiencies
Inventors
Moore, David F. • Mohr, Paul • Willis, N. Parker • Brisken, Axel F.
Assignees
Interested in licensing this patent?
MTEC can help explore whether this patent might be available for licensing for your application.
Publication Number
US-10512785-B2
Publication Date
2019-12-24
Expiration Date
Abstract
A controller-transmitter transmits acoustic energy through the body to an implanted acoustic receiver-stimulator. The receiver-stimulator converts the acoustic energy into electrical energy and delivers the electrical energy to tissue using an electrode assembly. The receiver-stimulator limits the output voltage delivered to the tissue to a predetermined maximum output voltage. In the presence of interfering acoustic energy sources output voltages are thereby limited prior to being delivered to the tissue.Furthermore, the controller-transmitter estimates the output voltage that is delivered to the tissue by the implanted receiver-stimulator. The controller-transmitter measures a query spike voltage resulting from the electrical energy delivered to the tissue by the receiver-stimulator, and computes a ratio of the predetermined maximum output voltage and a maximum query spike voltage. The maximum query spike voltage is computed by detecting a query spike voltage plateau. Based on this ratio, the controller-transmitter uses a measured query spike voltage to estimate the output voltage delivered by the receiver-stimulator to tissue.
Core Innovation
The invention provides an implantable medical device system that delivers electrical stimulation pulses to a patient by using acoustic energy to drive cardiac pacing/stimulation. A controller-transmitter defines a first implantable device with an output transducer assembly and control circuitry that transmits first acoustic energy at an electrical pulse rate configured to electrically pace/stimulate cardiac tissue. A receiver-stimulator defines a second implantable device with a piezoelectric receiving transducer that receives the first acoustic energy from the controller-transmitter and converts it into an electrical output that is delivered to tissue stimulation electrodes for pacing/stimulation.
The core receiver-stimulator concept conditions the electrical output using circuit behavior tied to the origin of the acoustic energy. The piezoelectric receiving transducer also receives second acoustic energy from a diagnostic ultrasound source, and converts it into an electrical output coupled to the circuit. The circuit is configured to produce output energy by delivering a first portion of the electrical output to the electrodes in response to the first acoustic energy transmitted by the controller-transmitter, while filtering out or preventing delivery of a second portion of the electrical output associated with the second acoustic energy produced by the diagnostic ultrasound source.
The disclosed receiver-stimulator processing uses a voltage limiting concept and associated filtering to address undesired stimulation from diagnostic ultrasound interference. A voltage limiter limits output voltage, and a low pass filter is configured to remove or prevent voltage components associated with the diagnostic ultrasound source. The document also discloses output-voltage inference using sensing electrodes and a short query spike voltage to estimate delivered output voltage across drive levels, including determining a maximum query spike voltage via a query spike plateau and using a ratio relative to a predetermined maximum output voltage.
Claims Coverage
Two independent claims are identified, each sharing the same core architecture (controller-transmitter sending first acoustic energy and receiver-stimulator converting acoustic energy to electrode-deliverable electrical output) while differing in whether the diagnostic-ultrasound-associated electrical output is described as filtered out versus prevented from being delivered. Across the independent claims, the coverage includes additional inventive features such as phased-array steering/focusing of the first acoustic energy and low-pass filtering that passes a first acoustic frequency range while filtering out a second acoustic frequency range.
Acoustic-to-electrical pacing with ultrasound-component filtering
A receiver-stimulator includes a piezoelectric receiving transducer configured to receive first acoustic energy and second acoustic energy from a diagnostic ultrasound source and convert them to an electrical output, and electrodes deliver output energy to pace/stimulate cardiac tissue, wherein the circuit delivers a first portion of electrical output produced in response to the first acoustic energy and filters out the second portion produced in response to the diagnostic ultrasound source.
Acoustic-to-electrical pacing with ultrasound-component prevention
A receiver-stimulator includes a piezoelectric receiving transducer configured to receive first acoustic energy and second acoustic energy from a diagnostic ultrasound source and convert them to an electrical output, and electrodes deliver output energy to pace/stimulate cardiac tissue, wherein the circuit delivers a first portion of electrical output produced in response to the first acoustic energy and prevents a second portion produced in response to the diagnostic ultrasound source from being delivered to the electrodes.
Phased-array steering and focusing for first acoustic energy
The output transducer assembly includes multiple phased array transducers configured to steer and focus the first acoustic energy transmitted by the controller-transmitter.
Low pass filtering to remove diagnostic-ultrasound-associated voltage
The receiver-stimulator circuit includes a low pass filter configured to remove voltage associated with the second acoustic energy produced by the diagnostic ultrasound source from being delivered to the electrodes.
Frequency-band low-pass conditioning for electrode delivery
The receiver-stimulator low pass filter supplies electrical energy to the electrodes for first acoustic energy in an 800 kHz to 1.3 MHz range while filtering out electrical energy for second acoustic energy in a 2 MHz to 10 MHz range.
The claim set covers an implantable acoustic wireless pacing/stimulation system in which a receiver-stimulator converts received acoustic energy to electrical output and conditions that output so that an ultrasound-derived component is either filtered out or prevented from electrode delivery. Dependent features further narrow the transmitted first acoustic energy using phased-array steering/focusing and narrow the receiver conditioning using low-pass filtering, including explicit frequency ranges.
Stated Advantages
Reduces undesired pacing/stimulation from diagnostic ultrasound interference by filtering out or preventing delivery of a diagnostic-ultrasound-associated portion of the receiver electrical output.
Documented Applications
Delivering electrical pacing/stimulation to cardiac tissue using an implantable wireless acoustic stimulation system.
Operating in the presence of diagnostic ultrasound sources such as diagnostic echocardiography by preventing ultrasound-associated electrical output from being delivered to pacing/stimulation electrodes.
Interested in licensing this patent?