Operation and estimation of output voltage of wireless stimulators

• US 8,364,276 B2
• Filed: 03/10/2010
• Issued: 01/29/2013
• Est. Priority Date: 03/25/2008
• Status: Active Grant

• Current Assignee: EBR Systems, Inc.
• Original Assignee: EBR Systems, Inc.
• Inventors: Willis, N. Parker
• Primary Examiner(s): Schaetzle, Kennedy
• Application Number:
  US12/721,483
• Publication Number:
  US 20100234924A1
• Time in Patent Office: 1,056 Days
• Field of Search: None
• US Class Current: 607/61
• CPC Class Codes: A61N 1/362 Heart stimulators heart defibrillators A61N1/39
• CPC Class Codes: A61N 1/37205 Microstimulators, e.g. implantable through a cannula
• CPC Class Codes: A61N 1/3756 Casings with electrodes thereon, e.g. leadless stimulators
• CPC Class Codes: A61N 1/3787 from an external energy source

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.

Claims

1. An acoustic controller-transmitter device for transmitting acoustic energy into a body, comprising:

an output transducer assembly configured to transmit acoustic energy into the body, wherein the acoustic energy is received by an implantable acoustic receiver-stimulator configured to convert the acoustic energy into electrical energy and deliver the electrical energy to tissue, wherein the receiver-stimulator comprises a voltage limiter, and wherein the voltage limiter is configured to limit the output voltage delivered to the tissue to a predetermined maximum output voltage;

a control circuitry configured to estimate an output voltage delivered to the tissue by the receiver-stimulator; and

a sensing electrode assembly, wherein the sensing electrode assembly is in contact with the body and is configured to detect and measure a query spike voltage as a result of the electrical energy delivered to the tissue by the receiver-stimulator.

2. The device of claim 1, wherein the controller-transmitter is configured to determine a maximum query spike voltage.

3. The device of claim 2, wherein the controller-transmitter determines the maximum query spike voltage by detecting and measuring a query spike voltage plateau.

4. The device of claim 2, wherein the controller-transmitter is configured to compute a ratio of the predetermined maximum output voltage and the maximum query spike voltage, and is further configured to estimate the output voltage of the receiver-stimulator based on the ratio and on the query spike voltage.

5. The device of claim 1, wherein the controller-transmitter is configured to transmit sufficient acoustic energy to the receiver-stimulator to pace the tissue.

6. The device of claim 1, wherein the controller-transmitter is implantable in the body.

7. A method for estimating output voltage of an implantable acoustic receiver-stimulator, comprising:

transmitting acoustic energy from an acoustic controller-transmitter to an acoustic receiver-stimulator;

converting the acoustic energy into electrical energy using the acoustic receiver-stimulator;

delivering the electrical energy to tissue using an electrode assembly, wherein the delivering comprises limiting the electrical output voltage delivered to the tissue to a predetermined maximum output voltage;

measuring a query spike voltage using the controller-transmitter, wherein the query spike voltage is a result of the electrical energy delivered to the tissue by the receiver-stimulator;

determining a maximum query spike voltage and computing a ratio of the predetermined maximum output voltage and the maximum query spike voltage; and

comparing the query spike voltage to the computed ratio to estimate the output voltage delivered to the tissue by the receiver-stimulator.

8. The method of claim 7, wherein the determining the maximum query spike voltage comprises detecting and measuring a query spike voltage plateau.

9. The method of claim 7, comprising transmitting sufficient acoustic energy from the controller-transmitter to the receiver-stimulator to pace the tissue.