Abstract: Provided herein are implantable systems that include an implantable photoplethysmography (PPG) sensor, which can be used to obtain an arterial PPG waveform. In an embodiment, a metric of a terminal portion of an arterial PPG waveform is determined, and a metric of an initial portion of the arterial PPG waveform is determined, and a surrogate of mean arterial pressure is determined based on the metric of the terminal portion and the metric of the initial portion. In another embodiment, a surrogate of diastolic pressure is determined based on a metric of a terminal portion of an arterial PPG waveform. In a further embodiment, a surrogate of cardiac afterload is determined based on a metric of a terminal portion of an arterial PPG waveform.

Abstract: An exemplary method for treating obesity includes calling for delivery of electrical energy to a vagal nerve, detecting pre-prandial activity and, in response to the detection of pre-prandial activity, calling for delivery of electrical energy to the stomach for a pre-determined amount of time to induce satiety. Various other technologies are also disclosed.

Abstract: An implantable medical device system that senses physiologic processes via multiple sensor signal configurations. The device can further process the sensor configurations to obtain additional processed signal configurations. The device can utilize the processed configurations for ongoing sensing of the physiologic process. The device can also automatically evaluate the multiple sensor configurations as well as the processed configurations and select the configuration offering the best signal discrimination to reduce oversensing or erroneously interpreting secondary characteristics of the physiologic process as corresponding to primary characteristics of the process as in double-counting. The signal discrimination can be evaluated as an absolute margin and/or a ratio between amplitudes of the primary and secondary characteristics. The signal discrimination can also be evaluated based at least in part on a calculated mean and standard deviation according to each configuration.

Abstract: Disclosed herein is an implantable medical lead. In one embodiment, the lead includes a ring electrode, a tip electrode, first and second helically wound coaxial conductor coils, and a distal coil transition. The coils extend between the proximal and distal ends of the lead. The distal coil transition is proximal to the ring electrode and near the distal end and is where the first coil transitions from being outside the second coil proximal of the distal coil transition to being inside the second coil distal of the distal coil transition.

Abstract: A universal cable connector for detachably connecting a stimulation lead to a system analyzer includes a nonconductive connector block for releasably receiving and holding fixed a proximate contact electrically in continuity with a distal electrode, a cable for selectively electrically interconnecting the proximate contact and the system analyzer, and a switch mechanism for selectively connecting electrically the system analyzer cable with the proximate contact thereby enabling the system analyzer to determine the efficacy of the chosen body tissue site. The connector block includes a nest region for receiving the proximal end of the lead and the switch mechanism includes a switch contact electrically engaged with the cable and movable between a first position disengaged from an associated and selected exposed proximate contact and a second position engaged with the proximate contact for electrically connecting the distal electrode to the system analyzer.

Abstract: A system and method for increasing the speed of individualizing amplifier gain optimization in implantable medical devices. A variable amplifier gain is initially set at a relatively high level such that the amplifier experiences at least intervals of saturation. A saturation indicator is determined which is indicative of the relative degree of saturation. The gain is then adjusted as a function of the saturation indicator. Relative larger degrees of saturation result in more aggressive gain adjustment. This increases the speed of adjustment with reduced likelihood of loss of sensing. In one implementation, one or more discrete amplifier gain adjustment steps are made in a single adjustment to effectively skip over intermediate adjustments. In another implementation, an estimate is made of a signal peak during a saturating interval. The gain is adjusted directly based on the estimated peak with appropriate sensing safety margins.

Abstract: A device, such as an implantable cardiac device, and methods for determining exercise diagnostic parameters of a patient are disclosed. Specifically, a maximum observed heart rate of a patient during exercise can be identified when an activity level and a heart rate measurement of the patient exceed predetermined thresholds. Included are methods for filtering out premature heartbeats or noise from the maximum heart rate determination. Methods of determining other exercise parameters, such as workload are also disclosed. The device includes hardware and/or software for performing the described methods.

Abstract: An exemplary method for multi-tier pacing includes delivering single site, left ventricular pacing, sensing patient activity; comparing the sensed patient activity to a patient activity threshold and, if the sensed patient activity exceeds the patient activity threshold, then delivering multi-site, left ventricular pacing for a predetermined period of time and, after the predetermined period of time, delivering single, site left ventricular pacing. In such a method, the period of time may be determined based on cardio-pulmonary demand. Other exemplary technologies are also disclosed.

Abstract: A cardiac capture threshold may be determined using a test pulse and a backup pulse. Here, delivery of a test pulse is followed almost immediately by a non-conditional backup pulse of sufficient energy such that the backup pulse should always capture in the event the test pulse does not capture. The timing of the evoked response that follows the backup pulse may then be used to determine whether the test pulse or the backup pulse captured the cardiac tissue. In some embodiments morphology discrimination may be employed to determine whether an evoked response was triggered by the test pulse or the backup pulse. In some embodiments timing information associated with one or more features of the evoked response may be analyzed to determine whether an evoked response was triggered by the test pulse or the backup pulse.

Abstract: A lead construction includes a lead body, an electrically conductive element disposed therein, and a shield layer disposed over the conductive element formed from a composite material comprising a polymer material and a non-ferrous particulate material. The non-ferrous material can include gold, platinum, iridium, nickel, cobalt, chromium, molybdenum, carbon/graphite powders, and alloys thereof. The composite material has a non-ferrous particulate content of from about 40 to 90 volume percent, and the shield layer has a thickness of from about 0.1 to 1 mm. The composite material forms an electrically conductive layer when exposed to RF having a frequency of greater than about 64 MHz. A layer of insulating material may be interposed between the shield layer and the conductive element. The shield layer can be part of the lead body, can be an intermediate layer within the lead body, or can be an outer surface of the lead body.

Abstract: An exemplary method includes detecting ventricular fibrillation, delivering a low voltage cardiac stimulus, determining whether the low voltage cardiac stimulus terminated the ventricular fibrillation, and delivering a higher voltage cardiac stimulus if the low voltage cardiac stimulus did not terminate the ventricular fibrillation. In one example, the delivering the low voltage cardiac stimulus occurs within approximately 10 event intervals from the detected onset of ventricular fibrillation; otherwise, delivery of an appropriate higher voltage cardiac stimulus occurs. Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: Implantable multi-wavelength oximetry sensors, which can be used to monitor a patient's blood oxygen saturation level, are described. The sensor includes an implantable sensor housing within which are located a plurality of light sources that each transmits light of a different wavelength. Also within the sensor housing are one or more surfaces that are configured to combine the light from the plurality of light sources into a beam of light for transmission through a portion of the housing (e.g., a window) through which light can exit and enter the housing. Additionally, a light detector is located within the sensor housing, to detect light scattered by blood back into the housing. This description is not intended to be a complete description of, or limit the scope of, the invention. Other features, aspects, and objects of the invention can be obtained from a review of the specification, the figures, and the claims.

Abstract: Disclosed herein is an implantable pulse generator feedthru configured to make generally planar electrical contact with an electrical component housed within a can of an implantable pulse generator. The feedthru may include a feedthru housing including a header side and a can side, a core within the feedthru housing, a generally planar electrically conductive interface adjacent the can side, and a feedthru wire extending through the core. The feedthru wire may include an interface end and a header end, wherein the header end extends from the header side and the interface end is at least one of generally flush with the generally planar interface and generally recessed relative to the generally planar interface.

Abstract: In one embodiment an implantable cardiac device is provided that includes an implantable cardiac stimulation device with an implantable satellite device coupled to it. The implantable satellite device has a charge storage device. The implantable stimulation device having a refresh generator configured to generate a charge and voltage balanced multi-phasic refresh signal with a duration less than a capacitive time constant of an electro-electrolyte interface of the implantable cardiac device and transmit the charge and voltage balanced multi-phasic refresh signal to the implantable satellite device for charging the charge storage device. In various embodiments, the charge and voltage balanced multi-phasic refresh signal having alternating phase signs and null durations between the alternating phases. In some embodiments, the refresh generator is configured to modulate the multi-phasic waveform refresh signal.

Abstract: Techniques are provided for use with a pacemaker or other implantable medical device for detecting arterial blood pressure. Briefly, the pacemaker detects aortic electrical resistance using sensing/pacing leads. Aortic electrical resistance pertains to the resistance to an electrical current passing through the aorta. The pacemaker then determines the arterial blood pressure of the patient based on the aortic resistance and a predetermined calibration value that relates aortic resistance to arterial pressure. The calibration value is updated monthly based on blood pressure values detected using an external blood pressure sensor employing a blood pressure cuff. Other techniques described herein pertain to the determination of other physiologic parameters such as stroke volume and cardiac output and to the detection of changes in hematocrit. Any of the various physiological parameters may then be used to trigger or control warning signals and responsive therapy.

Abstract: A wireless communication threshold for an implantable medical device is automatically adapted in an attempt to maintain optimum signal detection sensitivity. In some aspects, a threshold level may be adapted to account for current environmental conditions, implant conditions, device conditions, or other conditions that may affect the reception of wireless signals at the device. In some aspects, the determination of an optimum level for the threshold involves a tradeoff relating to effectively detecting target signals while avoiding detection of noise and/or interference. In some aspects, adaptation of a threshold may be based on maximum energy levels associated with one or more sets of RF energy sample data. In some aspects, adaptation of a threshold may be based on the number of false wakeups that occur during a period of time.

Abstract: Disclosed herein is an EMI filtered feedthru for an implantable pulse generator. The EMI filtered feedthru may include a filter assembly, which has a chip capacitor and a body. The body may include a cavity in which the chip capacitor resides.

Abstract: During a period of time comprising a plurality of cardiac cycles, a time relationship between ventricular events and atrial detections is established. Based on the relationship, a post-ventricular atrial refractory period is defined. The period includes an absolute atrial refractory period and a segmented relative atrial refractory period, wherein the segmented relative atrial refractory period includes at least one blanking window during which atrial detections of ventricular events have or are likely to occur.

Abstract: A method for producing battery cathodes comprises mixing a cathode active material and a conductive polymer such as polyaniline or poly(ethylenedioxythiophene). The conductive polymers are used in lieu of or in addition to conventional conductive additives and binder materials and significantly reduces or even eliminates the need for such conductive additives or binder materials. The resulting cathodes have a greater weight percentage of the active material and a larger volumetric energy density.

Abstract: Embodiments of the present invention relate to implantable sensors for obtaining hemodynamic data and/or physiologic data. More specifically, embodiments of the present invention enable additional sensing hardware to be added into implantable devices more quickly and less expensively. Additionally, embodiments of the present invention enable such adding of additional sensing hardware with little or no effect on the conventional functions of the implantable device to which the sensor hardware is being added.