Abstract: Devices, systems, and techniques for managing heat generated in coils for wireless energy transmission are disclosed. Inductive coupling between two coils may be used to recharge the power source of an implantable medical device. A phase change material may be thermally coupled to a flexible coil to absorb heat generated during the inductive coupling and reduce temperature increases of the flexible coil. The flexible coil may be configured to at least one of transmit energy to or receive energy from a second coil, and the phase change material may be configured to deform with the flexible coil and absorb heat from the flexible coil. The phase change material may be contained within thermally conductive tubes or channels configured in shapes that promote flexibility of the flexible coil.

Abstract: A recharging system and method for an implantable medical device includes: a secondary coil associated with the implantable medical device; an external power source including a primary coil and a modulation circuit operatively coupled to the primary coil, the modulation circuit being capable of driving the primary coil at a carrier frequency when the primary coil is in proximity to the secondary coil and of varying the carrier frequency in response to sensor data received from the implantable medical device; a first sensor associated with the implantable medical device and in communication with the modulation circuit, the first sensor capable of sensing a first condition indicating a need to adjust the carrier frequency during a charging process; and a second sensor associated with the implantable medical device and in communication with the modulation circuit, the second sensor capable of sensing a second condition which is affected by the carrier frequency.

Abstract: Techniques for recharging a rechargeable power source coupled to a secondary coil implanted within a living body are described. In one embodiment, a recharging device external to the living body induces a sequence of pulses in a primary coil that is coupled to the secondary coil. The sequence includes high-amplitude pulses alternating with low-amplitude pulses, each high-amplitude pulse having an amplitude selected to transfer charge to the rechargeable power source during times of poor coupling between the primary coil and the secondary coil, each low-amplitude pulse having an amplitude selected to transfer charge to the rechargeable power source during times of good coupling between the primary coil and the secondary coil, and wherein the sequence of pulses is selected to prevent a violation of a limiting condition such as heating that is associated with recharging the rechargeable power source when recharging occurs in an open-loop manner.

Abstract: Techniques are disclosed for recharging an Implantable Medical Device (IMD). In one embodiment, a first external coil is positioned on one side of a patient's body, such as on a front side of the torso in proximity to the IMD. A second external coil is positioned on an opposite side of the patient's body, such as on the back of the torso. A recharging device generates a current in each of the coils, inductively coupling the first and the second coils to the secondary recharge coil of the IMD. According to another aspect, each of the two external coils may wrap around a portion of the patient's body, such as the torso or head, and are positioned such that the IMD lies between the coils. According to this aspect, current generated in the coils inductively couples to a second recharge coil that is angled within the patient's body.

Abstract: A charging system is disclosed. In one embodiment, the system includes a charging unit having a primary coil, and an implantable medical device comprising a secondary coil to receive charge from the primary coil. The implantable medical device further includes a half-wave voltage-doubling rectifier coupled to the secondary coil, a full-wave rectifier coupled to the secondary coil, and a rechargeable power source. Control logic is provided to periodically configure the rechargeable power source to receive charge from a selected one of the voltage-doubling circuit and the full-wave rectifier in a manner that increases rate at which charge is transferred from the secondary coil to the rechargeable power source. The control logic may configure the rechargeable power source to receive charge based on one or more monitored conditions which may include, for example, an indication of a current, a voltage, a coupling coefficient, back-scatter, and temperature.

Abstract: A charging system for an implantable medical device having a secondary coil. The charging system includes an external power source having at least one primary coil, a modulation, circuit operatively coupled to the primary coil and capable of driving it in a manner characterized by a charging parameter, and a sensor in communication with the modulation circuit and capable of sensing a condition indicating a need to adjust the charging parameter during a charging process. The parameter may be varied so that data sensed by the sensor meets a threshold requirement, which may be based on a patient preference, a government regulation, a recommendation promulgated by a health authority and/or a requirement associated with another device carried by the patient. In one embodiment, the regulation dictates maximum magnetic field exposure, and a field limiting circuit is employed to adjust the charging process.

Abstract: Techniques are disclosed for recharging an Implantable Medical Device (IMD). In one embodiment, a first external coil is positioned on one side of a patient's body, such as on a front side of the torso in proximity to the IMD. A second external coil is positioned on an opposite side of the patient's body, such as on the back of the torso. A recharging device generates a current in each of the coils, inductively coupling the first and the second coils to the secondary recharge coil of the IMD. According to another aspect, each of the two external coils may wrap around a portion of the patient's body, such as the torso or head, and are positioned such that the IMD lies between the coils. According to this aspect, current generated in the coils inductively couples to a second recharge coil that is angled within the patient's body.

Abstract: Systems and methods for orienting a medical instrument relative to at least a portion of a medical device include a first tilt detector associated with the medical instrument and a second tilt detector associated with the medical device. The first tilt detector may be within an orientation device that is coupled to or separate from the medical instrument. The tilt detectors generate signals that may be used to determine the relative orientation between at least a portion of the medical device and medical instrument. For example, in some embodiments, the signals may be used to determine whether the orientations of the portion of the medical device and the medical instrument substantially match.

Abstract: A medical system includes a sensor location module, a first module, and a second module. The sensor location module determines a location of a magnetic field sensor within a magnetic field. The first module determines an acceleration of the magnetic field sensor. The second module indicates a modified location of the magnetic field sensor in an image of a medical patient based on the acceleration and one or more previously determined locations.

Abstract: Techniques adapted for use with recharging a rechargeable power source of an implantable device. One aspect relates to providing a flexible primary coil that can be transcutaneously coupled to a secondary coil of the implantable device. Multiple adjacent turns of the coil are grouped via lacing to form bundles. The bundles have at least one dimension that is selected to be a same size as a predetermined thickness of the coil. In one embodiment, the dimension is a diameter of the bundle. In another embodiment, the dimension is at least one of a length or width of the bundle. Insulating overmolding may be provided over the coil. In one embodiment, the resulting antenna structure is bidirectional such that substantially the same performance characteristics are obtained during recharge regardless of which of two major surfaces of the antenna is placed in proximity to the patient.

Abstract: Techniques are described in this disclosure for delivering electrical stimulation therapy to a patient over multiple channels, with independent rate control for each channel, using a single stimulation generator. In one example, the disclosure describes a method for delivering electrical stimulation therapy to a patient that includes delivering first electrical stimulation pulses at a first programmed rate on a first channel using a stimulation generator, and delivering second electrical stimulation pulses at a second programmed rate on a second channel using the stimulation generator, the second programmed rate being different than the first programmed rate, and the second programmed rate being independent of the first programmed rate.

Abstract: A bus system is provided for implantable medical devices. The bus system provides for flexible and reliable communication between subsystems in an implantable medical device. The bus system facilitates a wide variety of communications between various subsystems. These various subsystems can include one or more sensing devices, processors, data storage devices, patient alert devices, power management devices, signal processing and other devices implemented to perform a variety of different functions.

Abstract: Techniques for recharging a rechargeable power source coupled to a secondary coil implanted within a living body are described. In one embodiment, a recharging device external to the living body induces a sequence of pulses in a primary coil that is coupled to the secondary coil. The sequence includes high-amplitude pulses alternating with low-amplitude pulses, each high-amplitude pulse having an amplitude selected to transfer charge to the rechargeable power source during times of poor coupling between the primary coil and the secondary coil, each low-amplitude pulse having an amplitude selected to transfer charge to the rechargeable power source during times of good coupling between the primary coil and the secondary coil, and wherein the sequence of pulses is selected to prevent a violation of a limiting condition such as heating that is associated with recharging the rechargeable power source when recharging occurs in an open-loop manner.

Abstract: A charging system is disclosed. In one embodiment, the system includes a charging unit having a primary coil, and an implantable medical device comprising a secondary coil to receive charge from the primary coil. The implantable medical device further includes a half-wave voltage-doubling rectifier coupled to the secondary coil, a full-wave rectifier coupled to the secondary coil, and a rechargeable power source. Control logic is provided to periodically configure the rechargeable power source to receive charge from a selected one of the voltage-doubling circuit and the full-wave rectifier in a manner that increases rate at which charge is transferred from the secondary coil to the rechargeable power source. The control logic may configure the rechargeable power source to receive charge based on one or more monitored conditions which may include, for example, an indication of a current, a voltage, a coupling coefficient, back-scatter, and temperature.

Abstract: A recharging system and method for an implantable medical device includes: a secondary coil associated with the implantable medical device; an external power source including a primary coil and a modulation circuit operatively coupled to the primary coil, the modulation circuit being capable of driving the primary coil at a carrier frequency when the primary coil is in proximity to the secondary coil and of varying the carrier frequency in response to sensor data received from the implantable medical device; a first sensor associated with the implantable medical device and in communication with the modulation circuit, the first sensor capable of sensing a first condition indicating a need to adjust the carrier frequency during a charging process; and a second sensor associated with the implantable medical device and in communication with the modulation circuit, the second sensor capable of sensing a second condition which is affected by the carrier frequency.

Abstract: Techniques associated with a universal recharging device for recharging a power source of implantable medical devices (IMDs). The recharging device includes an interface to allow an antenna assembly to be removably coupled. The antenna assembly has a primary coil and a corresponding sense coil. The sense coil has a configuration that is selected based on the configuration of the primary coil. The sense coil is adapted to prevent voltage across the primary coil from exceeding a maximum voltage amplitude allowable with the recharging device. The maximum voltage amplitude may be selected based on a maximum magnetic field strength to which a patient is to be exposed. In one embodiment, the maximum voltage amplitude is programmable.

Abstract: A method and system which includes a minimally invasive, implantable device with a sensor configured for collecting electrical data associated with cardiac performance, a sensor configured for collecting mechanical data associated with cardiac performance, a sensor for collecting optical data associated with cardiac performance, a sensor for collecting biochemical data associated with cardiac performance, and a processor for deriving cardiac conditions and actuating an alarm upon identifying a cardiac event.

Abstract: Techniques are disclosed for recharging an Implantable Medical Device (IMD). In one embodiment, a first external coil is positioned on one side of a patient's body, such as on a front side of the torso in proximity to the IMD. A second external coil is positioned on an opposite side of the patient's body, such as on the back of the torso. A recharging device generates a current in each of the coils, inductively coupling the first and the second coils to the secondary recharge coil of the IMD. According to another aspect, each of the two external coils may wrap around a portion of the patient's body, such as the torso or head, and are positioned such that the IMD lies between the coils. According to this aspect, current generated in the coils inductively couples to a second recharge coil that is angled within the patient's body.

Abstract: Systems and methods for orienting a medical instrument relative to at least a portion of a medical device include a first tilt detector associated with the medical instrument and a second tilt detector associated with the medical device. The first tilt detector may be within an orientation device that is coupled to or separate from the medical instrument. The tilt detectors generate signals that may be used to determine the relative orientation between at least a portion of the medical device and medical instrument. For example, in some embodiments, the signals may be used to determine whether the orientations of the portion of the medical device and the medical instrument substantially match.

Abstract: A bus system is provided for implantable medical devices. The bus system provides for flexible and reliable communication between subsystems in an implantable medical device. The bus system facilitates a wide variety of communications between various subsystems. These various subsystems can include one or more sensing devices, processors, data storage devices, patient alert devices, power management devices, signal processing and other devices implemented to perform a variety of different functions.