Abstract: An acoustic energy delivery system for delivering acoustic energy to an implantable medical device (“IMD”). The system includes an IMD having a power source and an energy delivery device. The energy delivery device includes a controller and an array of ultrasonic elements electrically coupled to the controller and configured to deliver acoustic energy to the IMD. Methods of delivering acoustic energy to an IMD are also disclosed.

Abstract: This document discusses, among other things, systems and methods to determine amplitude and morphology variations of a first heart sound over a first number of cardiac cycles, and to calculate an atrial fibrillation metric indicative of an atrial fibrillation episode of the heart using the determined amplitude and morphology variations. The systems and methods can determine a variability score using the determined amplitude and morphology variations, and can calculate the atrial fibrillation metric using the variability score.

Abstract: Systems and methods for detecting atrial tachyarrhythmias (AT) such as atrial fibrillation (AF) are disclosed. A medical system can include a cardiac signal sensor circuit to sense a cardiac electrical signal and a heart sound (HS) sensor to sense heart a HS signal. A cardiac electrical signal metric, including a cycle length variability or a detection of atrial electrical activity, can be generated from the cardiac electrical signal. A HS metric can be generated from the HS signal, including a status of detection of S4 heart sound or a S4 heart sound intensity indicator. The system can include an AT detector circuit that can detect an AT event, such as an AF event, using the cardiac electrical signal metric and the HS metric. The system can additionally classify the detected AT event as an AF or an atrial flutter event.

Abstract: Methods and devices for configuring the use of a motion sensor in an implantable cardiac device. The electrical signals of the patient's heart are observed and may be correlated to the physical motion of the heart as detected by the motion sensor of the implantable cardiac device in order to facilitate temporal configuration of motion sensor data collection that avoids detecting cardiac motion in favor of overall motion of the patient.

Abstract: Implantable devices having motion sensors. In some examples the a configuration is generated for the implantable device to use the motion sensor in an energy preserving mode in which one or more axis of detection of the motion sensor is disabled or ignored. In some examples the motion sensor outputs along multiple axes are analyzed to determine which axes best correspond to certain patient parameters including patient motion/activity and/or cardiac contractility. In other examples the output of the motion sensor is observed across patient movements or postures to develop conversion parameters to determine a patient standard frame of reference relative to outputs of the motion sensor of an implanted device.

Abstract: Various implantable medical device embodiments stimulate an autonomic neural target from within a pulmonary artery, and comprise at least one electrode, a power supply, a neural stimulator connected to the power supply, and an anchor structure. The neural stimulator is configured to generate a neural stimulation signal for delivery to the neural stimulation target through the at least one electrode. The anchor structure is configured to chronically and securely implant the neural stimulator, the power supply and the at least one electrode within the pulmonary artery. The anchor structure, the neural stimulator, the power supply and the at least one electrode are configured to be implanted through a pulmonary valve into the pulmonary artery. In various embodiments, the neural stimulator is configured to be operational to implement a neural stimulation protocol when chronically implanted within the pulmonary artery without a wired connection through the pulmonary valve.

Abstract: Methods, systems, and apparatus for recharging medical devices implanted within the body are disclosed. An illustrative rechargeable system includes a charging device that includes an elongate shaft having a proximal section and a distal section. The distal section is configured to be delivered to a location within the body adjacent to the implanted medical device. The charging device includes a charging element configured to transmit charging energy to a receiver of the implanted medical device.

Abstract: An implantable medical device includes a housing defining a hermetically sealed chamber and includes a diaphragm portion having a first resonance frequency, an acoustic communication circuit within the chamber, and an acoustic transducer within the chamber. The transducer includes a substantially rigid pin member attached to an inner surface of the diaphragm portion, and an active portion coupled to the pin member. The active portion has a second resonant frequency and includes a piezoelectric element electrically coupled to the acoustic communication circuit. The diaphragm portion and the active transducer portion may be configured such that the first and second resonance frequencies are substantially equal.

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 recharging medical devices implanted within the body are disclosed. An illustrative rechargeable system includes a charging device that includes an elongate shaft having a proximal section and a distal section. The distal section is configured to be delivered to a location within the body adjacent to the implanted medical device. The charging device includes a charging element configured to transmit charging energy to a receiver of the implanted medical device.

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: Various implantable medical device embodiments stimulate an autonomic neural target from within a pulmonary artery, and comprise at least one electrode, a power supply, a neural stimulator connected to the power supply, and an anchor structure. The neural stimulator is configured to generate a neural stimulation signal for delivery to the neural stimulation target through the at least one electrode. The anchor structure is configured to chronically and securely implant the neural stimulator, the power supply and the at least one electrode within the pulmonary artery. The anchor structure, the neural stimulator, the power supply and the at least one electrode are configured to be implanted through a pulmonary valve into the pulmonary artery. In various embodiments, the neural stimulator is configured to be operational to implement a neural stimulation protocol when chronically implanted within the pulmonary artery without a wired connection through the pulmonary valve.

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: 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: Various implantable medical device embodiments stimulate an autonomic neural target from within a pulmonary artery, and comprise at least one electrode, a power supply, a neural stimulator connected to the power supply, and an anchor structure. The neural stimulator is configured to generate a neural stimulation signal for delivery to the neural stimulation target through the at least one electrode. The anchor structure is configured to chronically and securely implant the neural stimulator, the power supply and the at least one electrode within the pulmonary artery. The anchor structure, the neural stimulator, the power supply and the at least one electrode are configured to be implanted through a pulmonary valve into the pulmonary artery. In various embodiments, the neural stimulator is configured to be operational to implement a neural stimulation protocol when chronically implanted within the pulmonary artery without a wired connection through the pulmonary valve.

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: Methods and systems for implantably determining a patient's anemia status and treating anemia are described. Blood viscosity is compared one or more thresholds to determine a patient's anemia status. Therapy, in the form of electrical stimulation therapy or administration of a pharmaceutical delivered to the patient's kidneys or hypothalamus is controlled based on the anemia status.

Abstract: An implantable system for ambulatory monitoring of a high-risk heart failure patient includes a first pressure sensor implantable within an abdomen of the patient for sensing and generating an output representative of a baseline intra-abdominal pressure value of the patient and for chronically sensing and generating an output representative of an intra-abdominal pressure value of the patient at periodic intervals. At least one second implantable sensor is provided for sensing and generating an output representative of a second physiological parameter of the patient. Additionally, the system includes a processor for correlating the output of the first pressure sensor and the second physiologic sensor, and for comparing differences between the baseline intra-abdominal pressure value and subsequent intra-abdominal pressure values. The processor can reside in another implantable device or in an external device/system.

Abstract: An acoustic energy delivery system for delivering acoustic energy to an implantable medical device (“IMD”). The system includes an IMD having a power source and an energy delivery device. The energy delivery device includes a controller and an array of ultrasonic elements electrically coupled to the controller and configured to deliver acoustic energy to the IMD. Methods of delivering acoustic energy to an IMD are also disclosed.

Abstract: Systems and methods for wireless signal transfers between ultrasound-enabled medical devices are disclosed. An illustrative system includes a source device equipped with multiple transducer elements configured to transmit an acoustic wave, a target device including an acoustic transducer for receiving the acoustic wave from the source device, and a controller configured to determine adjustments to one or more transmission parameters of the source device for increasing the signal coherence of the acoustic wave at the target device.