Abstract: Devices and systems for transmitting information within a body are disclosed. An example system includes a signal generator configured for transmitting an acoustic interrogation signal, a sensor for sensing at least one parameter within the body and generating an electrical sensor signal, an acoustic transducer configured to convert a received acoustic interrogation signal into an electrical signal, and a switching element adapted to modulate a reflected acoustic wave from the acoustic transducer. The switching element is configured to controllably change the mechanical impedance of the acoustic transducer.

Abstract: Systems and methods provide intrabody communication using acoustic telemetry. The system includes a first or control implant including a first acoustic transducer, and a second implant including a switch and a second acoustic transducer coupled to the switch. The second acoustic transducer receives acoustic signals from the first acoustic transducer for closing the switch to activate the second implant. The second implant may include a therapeutic device for providing therapy to the patient. For example, the second implant may provide pacing therapy, defibrillation therapy, pain control stimulation, or neuro-stimulation.

Abstract: A piezoelectric element within an external ultrasonic transducer assembly can be used for wireless communication of data between an implantable device and the external ultrasonic transducer assembly such as using ultrasonic energy coupled to a flexible portion of a housing of the transducer assembly. The flexible portion can be configured to contact skin of a body containing the implantable device. The transducer assembly can be configured to respectively transmit or receive ultrasonic energy using at least partially overlapping respective ranges of resonant frequencies.

Abstract: Systems and methods for determining cardiac output are disclosed. An illustrative method of determining cardiac output includes sensing an arterial pressure waveform using a pressure sensor located within a pulmonary artery, identifying a valve closure time associated with the pulmonary valve using the sensed arterial pressure waveform, estimating stroke volume using the systolic portion of the arterial pressure waveform and the valve closure time, and obtaining a measure of cardiac output based on the estimated stroke volume.

Abstract: Methods, systems, and apparatus for recharging medical devices implanted within the body are disclosed. An illustrative method of recharging an implanted medical device includes delivering a charging device to a location adjacent to the implanted medical device, activating a charging element coupled to the charging device and transmitting charging energy to a receiver of the implanted medical device, and charging the implanted medical device using the transmitted charging energy from the charging device.

Abstract: Systems and methods provide intrabody communication using acoustic telemetry. The system includes a first or control implant including a first acoustic transducer, and a second implant including a switch and a second acoustic transducer coupled to the switch. The second acoustic transducer receives acoustic signals from the first acoustic transducer for closing the switch to activate the second implant. The second implant may include a sensor for measuring a physiological parameter that is transmitted using acoustic signals including the physiological data to the first implant. For example, the second implant may measure pressure in the patient's heart that may be used by the first implant to control a pacemaker. Alternatively, the second implant may blood sugar concentration that may be used by the first implant to control an insulin pump. Alternatively, the first implant may store and transfer the data to an external device for monitoring the patient.

Abstract: Devices and systems for transmitting information within a body are disclosed. An example system includes a signal generator configured for transmitting an acoustic interrogation signal, a sensor for sensing at least one parameter within the body and generating an electrical sensor signal, an acoustic transducer configured to convert a received acoustic interrogation signal into an electrical signal, and a switching element adapted to modulate a reflected acoustic wave from the acoustic transducer. The switching element is configured to controllably change the mechanical impedance of the acoustic transducer.

Abstract: Devices, systems, and methods for selectively activating medical devices are disclosed. A medical device in accordance with an illustrative embodiment includes an energy storage device, an acoustic transducer configured to convert an acoustic signal into an electrical signal, a signal detector configured to generate a trigger signal when the electrical signal exceeds a specific threshold established by a biasing element, a control circuit, and an activation/deactivation switch configured to switch the medical device between an inactive state and an active state in response to the trigger signal.

Abstract: Devices and systems for transmitting information within a body are disclosed. An example system includes a signal generator configured for transmitting an acoustic interrogation signal, a sensor for sensing at least one parameter within the body and generating an electrical sensor signal, an acoustic transducer coupled to the sensor and configured to convert a received acoustic interrogation signal into an electrical signal, and a switching element adapted to modulate a reflected acoustic wave from the acoustic transducer based on the electrical sensor signal. The switching element is configured to controllably change the mechanical impedance of the acoustic transducer based a parameter of the electrical sensor signal, such as frequency.

Abstract: A piezoelectric element within an external ultrasonic transducer assembly can be used for wireless communication of data between an implantable device and the external ultrasonic transducer assembly such as using ultrasonic energy coupled to a flexible portion of a housing of the transducer assembly. The flexible portion can be configured to contact skin of a body containing the implantable device. The transducer assembly can be configured to respectively transmit or receive ultrasonic energy using at least partially overlapping respective ranges of resonant frequencies.

Abstract: Devices and systems for transmitting information within a body are disclosed. An example system includes a signal generator configured for transmitting an acoustic interrogation signal, a sensor for sensing at least one parameter within the body and generating an electrical sensor signal, an acoustic transducer coupled to the sensor and configured to convert a received acoustic interrogation signal into an electrical signal, and a switching element adapted to modulate a reflected acoustic wave from the acoustic transducer based on the electrical sensor signal. The switching element is configured to controllably change the mechanical impedance of the acoustic transducer based a parameter of the electrical sensor signal, such as frequency.

Abstract: A miniature piezoelectric transducer element is provided, comprising; (a) a cell element having a cavity; (b) a flexible piezoelectric layer attached to the cell member, the piezoelectric layer having an external surface and an internal surface, the piezoelectric layer featuring such dimensions so as to enable fluctuations thereof at its resonance frequency upon impinging of an external acoustic wave; and (c) a first electrode attached to the external surface and a second electrode attached to the internal surface of the piezoelectric layer. At least one of the electrodes may be specifically shaped so as to provide a maximal electrical output, wherein the electrical output may be current, voltage or power. A preferred shape of the electrodes includes two cores interconnected by a connecting member. The transducer element may function as a transmitter.

Abstract: A medical system includes an implantable sensor; and a medical device having a communication link with the sensor. The medical device further including a controller, wherein operating parameters for controlling sampling of a physiological characteristic or other parameter by the implantable sensor are calculated by the controller and communicated to the sensor dynamically.

Abstract: Systems and methods for communicating with an implant within a patient's body using acoustic telemetry includes an external communications device attachable to the patient's skin. The device includes an acoustic transducer for transmitting acoustic signals into the patient's body and/or for receiving acoustic signals from the implant. The device includes a battery for providing electrical energy to operate the device, a processor for extracting data from acoustic signals received from the implant, and memory for storing the data. The device may include an interface for communicating with a recorder or computer, e.g., to transfer data from the implant and/or to receive instructions for controlling the implant. The device is secured to the patient's skin for controlling, monitoring, or otherwise communicating with the implant, while allowing the patient to remain mobile.

Abstract: Methods, systems, and apparatus for recharging medical devices implanted within the body are disclosed. An illustrative method of recharging an implanted medical device includes delivering a charging device to a location adjacent to the implanted medical device, activating a charging element coupled to the charging device and transmitting charging energy to a receiver of the implanted medical device, and charging the implanted medical device using the transmitted charging energy from the charging device.

Abstract: Systems and methods for determining cardiac output are disclosed. An illustrative method of determining cardiac output includes sensing an arterial pressure waveform using a pressure sensor located within a pulmonary artery, identifying a valve closure time associated with the pulmonary valve using the sensed arterial pressure waveform, estimating stroke volume using the systolic portion of the arterial pressure waveform and the valve closure time, and obtaining a measure of cardiac output based on the estimated stroke volume.

Abstract: A miniature piezoelectric transducer element is provided, comprising; (a) a cell element having a cavity; (b) a flexible piezoelectric layer attached to the cell member, the piezoelectric layer having an external surface and an internal surface, the piezoelectric layer featuring such dimensions so as to enable fluctuations thereof at its resonance frequency upon impinging of an external acoustic wave; and (c) a first electrode attached to the external surface and a second electrode attached to the internal surface of the piezoelectric layer. At least one of the electrodes may be specifically shaped so as to provide a maximal electrical output, wherein the electrical output may be current, voltage or power. A preferred shape of the electrodes includes two cores interconnected by a connecting member. The transducer element may function as a transmitter.

Abstract: An implantable medical device comprises a hermetically sealed housing having a housing wall with an interior surface, and an ultrasonic acoustic transducer, the transducer comprising one or more piezoelectric discs fixed to the interior surface of the housing wall, such that the housing wall acts as a diaphragm in response to induced movement by the one or more piezoelectric material discs.

Abstract: Systems and methods for monitoring the acoustic coupling of medical devices is disclosed. An illustrative system for monitoring the acoustic coupling of an acoustic transducer attached to a patient's body includes a signal generator adapted to supply an electrical signal to the transducer, a circuit configured to measure at least one electrical parameter of the transducer, and a processor adapted to evaluate the degree of acoustic coupling of the transducer to the body based on the measured electrical signal. The processor can measure the frequency response of the acoustic transducer to the electrical signal, a time domain response of the acoustic transducer to the electrical signal, or a combination of both.

Abstract: An implant includes a pressure sensor, a controller for acquiring pressure data from the sensor, and an acoustic transducer for converting energy between electrical energy and acoustic energy. A capacitor is coupled to the acoustic transducer for storing electrical energy converted by the transducer and/or for providing electrical energy to operate the implant. The acoustic transducer may operate alternatively or simultaneously as an energy exchanger or an acoustic transmitter. During use, the implant is implanted within a patient's body, and an external transducer transmits a first acoustic signal into the patient's body, to energize the capacitor. The implant then obtains pressure data, and transmits a second acoustic signal to the external transducer, the second acoustic signal including the pressure data.