Abstract: Methods, systems, and apparatus for powering and/or recharging medical devices implanted within the body are described. An illustrative power generation module disposable within the interior space of an implantable medical device includes a module body that defines an interior cavity as well as a flexible diaphragm that spans the interior cavity. The flexible diaphragm includes a first electrical conductor, a piezoelectric layer disposed adjacent to the first electrical conductor, and a second electrical conductor disposed adjacent to the piezoelectric layer. The piezoelectric layer is configured to displace within the interior cavity and generate a voltage differential between the first electrical conductor and the second electrical conductor.

Abstract: An implantable medical device includes an acoustic transducer for intra-body communication with another medical device via an acoustic couple. The acoustic transducer includes one or more piezoelectric transducers. In one embodiment, an implantable medical device housing contains a cardiac rhythm management (CRM) device and an acoustic communication circuit. The acoustic communication circuit includes an error detection circuit configured for detecting an error rate associated with demodulated incoming acoustic signals and a frequency selection circuit configured for adjusting a carrier frequency of outbound acoustic signals. The acoustic transducer is electrically connected to the acoustic communication circuit to function as an acoustic coupler and physically fastened to a wall of the implantable housing, directly or via a supporting structure.

Abstract: Implantable medical devices including an ultrasonic transducer and methods of optimizing an ultrasonic transducer of an implantable medical device are disclosed. The implantable medical device can include a housing, an ultrasonic transducer disposed within an interior of the housing, and a limiting structure configured to constrain deformation of the ultrasonic transducer. The limiting structure can include a separate structure coupled to the housing, or can comprise a resonant portion of the housing itself. During operation, the ultrasonic transducer is configured to communicate at a frequency at or near a resonant frequency of the housing.

Abstract: Methods, systems, and apparatus for powering and/or recharging medical devices implanted within the body are described. An illustrative implantable medical device includes a housing having an internal cavity and a flexible anchor assembly that is coupled to the housing. The flexible anchor assembly includes a first electrical conductor, a second electrical conductor, and a piezoelectric layer that is disposed between the first and second electrical conductors and that is configured to displace in response to a physiologic force applied to the flexible anchor assembly and generate a voltage differential between the first and second electrical conductors. The implantable medical device includes power circuitry that converts the voltage differential between the first and second electrical conductors into an operating current for powering one or more components within the implantable medical device and/or for recharging a rechargeable power supply within the device.

Abstract: A method carried out by an implantable medical device (IMD) for coordinating performance of one or more designated functions includes waiting in a low-power state for a predetermined event, detecting the predetermined event, and, responsive to detecting the predetermined event, searching for a wake-up command from a coordinating device implanted in the human body. The method further includes, receiving the wake-up command, and responsive to receiving the wake-up command, performing the one or more designated functions, and returning to the low-power state. A system includes a network of one or more implantable medical devices (IMDs) implanted in a human body. The system includes a satellite IMD operable to change between a plurality of power states, search for a wake-up command, and transmit an identification signal. The system may include a primary unit operable to receive the signal and coordinate a wake-up time based on the signal.

Abstract: Systems and methods for communicating with or powering implantable medical devices using a direct inductive/acoustic telemetry link are disclosed. An illustrative system includes an interrogator device located outside of the patient's body, an implantable medical device including an energy translator circuit adapted to convert inductive or RF signals received from the interrogator device into an acoustic signal for driving an acoustic transducer, and a remote device adapted to sense one or more parameters within the body.

Abstract: Implantable medical devices including an ultrasonic transducer and methods of optimizing an ultrasonic transducer of an implantable medical device are disclosed. The implantable medical device can include a housing, an ultrasonic transducer disposed within an interior of the housing, and a limiting structure configured to constrain deformation of the ultrasonic transducer. The limiting structure can include a separate structure coupled to the housing, or can comprise a resonant portion of the housing itself. During operation, the ultrasonic transducer is configured to communicate at a frequency at or near a resonant frequency of the housing.

Abstract: 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.

Abstract: A system and method for administering a therapeutic treatment to the heart includes a pressure sensor positioned in the pulmonary artery, an implantable medical device located remotely from the sensor, and communication means for communicating pressure data from the pressure sensor to the implantable medical device. The system includes a control module operatively coupled to the implantable medical device. The control module is adapted for comparing the pulmonary arterial pressure data to a pre-programmed value, adjusting an operating parameter of the implantable medical device based on the relationship of the pulmonary arterial pressure to the pre-programmed value, and repeating this process until the relationship between the pulmonary arterial pressure data and the pre-programmed value is such that no adjustment is necessary.

Abstract: An implantable medical device comprising a housing and a limiting structure defining a resonant region in the housing. An acoustic transducer is connected to the limiting structure and extends into the resonant region so that the resonant region mechanically amplifies the deformation of the acoustic transducer at a resonant frequency. An implantable medical device comprising a housing and a limiting structure defining a resonant region in the housing. An acoustic transducer having the shape of a beam is mechanically coupled to the limiting structure and partially extends into the resonant region so that the resonant region mechanically amplifies the deformation of the acoustic transducer at a resonant frequency. An implantable medical device comprising a housing, an acoustic transducer coupled to the housing, and a means for mechanically amplifying the deformation of the acoustic transducer at a resonant frequency. The means defines a resonant region in the housing.

Abstract: Methods, systems, and apparatus for powering and/or recharging medical devices implanted within the body are described. An illustrative implantable sensor for sensing one or more physiologic parameters within a body lumen includes a housing having an exterior wall that has an inner surface and an outer surface and that defines an internal cavity. A portion of the housing includes an electrically conductive material that functions as a first electrical conductor. A flexible piezoelectric layer is disposed adjacent to a portion of the exterior wall and a second electrical conductor is disposed adjacent to the piezoelectric layer. The piezoelectric layer is configured to displace in response to periodic pressure pulses within the body lumen and generate a voltage differential between the first and second electrical conductors.

Abstract: Methods, systems, and apparatus for powering and/or recharging medical devices implanted within the body are described. An illustrative power generation module disposable within the interior space of an implantable medical device includes a module body that defines an interior cavity as well as a flexible diaphragm that spans the interior cavity. The flexible diaphragm includes a first electrical conductor, a piezoelectric layer disposed adjacent to the first electrical conductor, and a second electrical conductor disposed adjacent to the piezoelectric layer. The piezoelectric layer is configured to displace within the interior cavity and generate a voltage differential between the first electrical conductor and the second electrical conductor.

Abstract: Methods, systems, and apparatus for powering and/or recharging medical devices implanted within the body are described. An illustrative implantable medical device includes a housing having an internal cavity and a flexible anchor assembly that is coupled to the housing. The flexible anchor assembly includes a first electrical conductor, a second electrical conductor, and a piezoelectric layer that is disposed between the first and second electrical conductors and that is configured to displace in response to a physiologic force applied to the flexible anchor assembly and generate a voltage differential between the first and second electrical conductors. The implantable medical device includes power circuitry that converts the voltage differential between the first and second electrical conductors into an operating current for powering one or more components within the implantable medical device and/or for recharging a rechargeable power supply within the device.

Abstract: A system and method for waking up an implantable medical device (“IMD”) from a sleep state in which power consumption by the IMD is essentially zero. The IMD may be adapted to perform one or more designated measurement and/or therapeutic functions. In one embodiment, the IMD includes a wake-up sensor that is adapted to sense the presence or absence of a wake-up field generated by another IMD or an external device. The wake-up field may, in some embodiments, be an electromagnetic field, a magnetic field, or a physiologically sub-threshold excitation current (i.e., E-field). Upon sensing by the wake-up sensor of the wake-up field, other components of the IMD, which may include a controller, a sensing and/or therapy module, and/or a communications module, are awakened to perform one or more designated functions.

Abstract: Methods for activating implantable medical devices within a patient's body are disclosed. An illustrative method includes activating an implantable medical device from a low-power state to an awake state in response to a scheduled time event, sensing one or more pressure measurements within the body, computing an average pressure measurement based on the sensed pressure measurements, storing the average pressure measurement within a memory of the implantable medical device, and then returning the device to the low-power state. A triggering event such as the detection of patient activity or motion can also be used to activate the implantable medical device between the low-power state and an active state.

Abstract: Systems and methods for communicating with or powering implantable medical devices using a direct inductive/acoustic telemetry link are disclosed. An illustrative system includes an interrogator device located outside of the patient's body, an implantable medical device including an energy translator circuit adapted to convert inductive or RF signals received from the interrogator device into an acoustic signal for driving an acoustic transducer, and a remote device adapted to sense one or more parameters within the body.

Abstract: An implantable medical device is adapted for implantation into body tissue. The implantable medical device comprises a housing and a header coupled to the housing. A cavity is located in the header. An ultrasonic transducer adapted to transmit acoustic waves at a communication frequency is located in the cavity, and a coupling surface is interposed between the ultrasonic transducer and the body tissue and is acoustically coupled with the body tissue.

Abstract: 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.

Abstract: A method and apparatus for evaluating the functionality and sensitivity of an infrared sensor to infrared radiation. The method and apparatus are adapted for testing an infrared sensor having a diaphragm containing a heating element and a transducer that generates an output responsive to temperature. The method entails placing the infrared sensor in a controlled environment, and then exposing the diaphragm of the sensor to different levels of thermal radiation so as to obtain outputs of the transducer at different output levels. In the absence of exposure of the diaphragm to thermal radiation, flowing current through the heating element at different input levels so that the output of the transducer returns to the different output levels obtained using thermal radiation, the input difference between the input levels can be computed and used to assess the functionality and the sensitivity of the sensor.

Abstract: A method of flip-chip mounting a circuit device to a substrate in a manner that avoids damage and impairment of a fragile or otherwise sensitive element on the device facing the substrate, and a circuit assembly produced thereby. The assembly includes a substrate having at least two sets of bonding sites spaced apart from each other to define an intermediate surface region therebetween. The device is attached to the bonding sites with solder connections, with the solder connections being present on a surface of the device that faces the substrate and on which the element is present so that the element overlies the intermediate surface region of the substrate. An underfill material is present between the device and the substrate and encapsulates the solder connections. The underfill material is separated from the intermediate surface region of the substrate so that the underfill material does not contact the element.