An electrical stimulation system includes a lead having electrodes disposed along a distal portion of the lead; and an implantable control module coupled, or coupleable, to the lead and configured for implantation in a patient. The implantable control module includes a power source, and a processor coupled to the power source and configured for directing electrical stimulation through the electrodes of the lead using the power source and for calculating an estimate of a capacity or energy of the power source that has been used based, at least in part, on the directed electrical stimulation.

A rechargeable-battery Implantable Medical Device (IMD) is disclosed including a primary battery which can be used as a back up to power critical loads in the IMD when the rechargeable battery is undervoltage and other non-critical loads are thus decoupled from the rechargeable battery. A rechargeable battery undervoltage detector provides at least one rechargeable battery undervoltage control signal to a power supply selector, which is used to set the power supply for the critical loads either to the rechargeable battery voltage when the rechargeable battery is not undervoltage, or to the primary battery voltage when the rechargeable battery is undervoltage. Circuitry for detecting the rechargeable battery undervoltage condition may be included as part of the critical loads, and so the undervoltage control signal(s) is reliably generated in a manner to additionally decouple the rechargeable battery from the load to prevent further rechargeable battery depletion.

Disclosed herein are implantable medical devices (IMDs) including a receiver and a battery, and methods for use therewith. The receiver includes first and second differential amplifiers, each of which monitors for a predetermined signal within a frequency range and drains power from the battery while enabled, and while not enabled drains substantially no power from the battery. To remove undesirable input offset voltages, each of the differential amplifiers, while enabled, is selectively put into an offset correction phase during which time the predetermined signal is not detectable by the differential amplifier. At any given time at least one of the first and second differential amplifiers is enabled without being in the offset correction phase so that at least one of the differential amplifiers is always monitoring for the predetermined signal. In this manner, the receiver is never blind to signals, including the predetermined signals, sent by another IMD.

Described herein are methods, devices, and systems that estimate a total amount of time it takes to discharge a battery of an IMD from initial to subsequent capacity levels, which total amount of time is indicative of a longevity of the IMD. In certain embodiments, a range of capacity levels for the battery is separated into N separate intervals. For each of the N intervals, an estimate of an amount of time it takes for the battery to discharge from a beginning to an end of the interval is determined, to thereby determine N amounts of time that are summed to estimate the total amount of time that it takes to discharge the battery from the initial to subsequent capacity levels. In other embodiments, an iterative equation is used to estimate the total amount of time takes it takes to discharge the battery from the initial to subsequent capacity levels.

An algorithm programmed into the control circuitry of a rechargeable-battery Implantable Medical Device (IMD) is disclosed that can adjust the charging current (Ibat) provided to the rechargeable battery over time (e.g., the life of the IMD) in accordance with one or more of the parameters having an effect on rechargeable battery capacity, such as number of charging cycles, charging current, discharge depth, load current, and battery calendar age. The algorithm consults such parameters as stored over the history of the operation of the IMD in a parameter log, and in conjunction with a battery capacity database reflective of the effect of these parameters on battery capacity, estimates a change in the capacity of the battery, and adjust the charging current in one or both of trickle and active charging paths to slow the loss of battery capacity and extend the life of the IMD.

A medical device and method conserve electrical power used in monitoring cardiac arrhythmias. The device includes a sensing circuit configured to sense a cardiac signal, a power source and a control circuit having a processor powered by the power source. The control circuit is configured to operate in a normal state by waking up the processor to analyze the cardiac electrical signal for determining a state of an arrhythmia. The control circuit switches from the normal state to a power saving state that includes waking up the processor at a lower rate than during the normal state.

A medical device system includes an IMD configured to deliver a plurality of stimulation vectors and processing circuitry. The processing circuitry is configured to determine strength-duration curve data for the plurality of stimulation vectors, the strength-duration curve data representing, for respective pulse widths and stimulation vectors, a corresponding strength of electrical stimulation that evokes a physiological response, compare respective slopes of the strength-duration curve data for the plurality of stimulation vectors to one another, select at least one stimulation vector of the plurality of stimulation vectors based on the comparison of the respective slopes of the strength-duration curve data for the plurality of stimulation vectors, and cause the IMD to deliver the electrical stimulation to a neural target via the selected at least one stimulation vector.

A Medical Device Application (MDA) is disclosed for an external device (e.g., a cell phone) that can communicate with an Implantable Medical Device (IMD). The MDA receives data logged in the IMD, processes that data in manners reviewable by an IMD patient, and that can control the IMD based on such processed data. The MDA can use the logged data to adjust IMD therapy based on patient activity or posture, and allows a patient to learn optimal therapy settings for particular activities. The MDA can also use the logged data to allow a patient to review details about IMD battery performance, whether such battery is primary or rechargeable, and to control stimulation parameters based on that performance. The MDA also allows a patient to enter medicine dose information, to review the relationship between medicinal therapy and IMD therapy, and to adjust IMD therapy based on the dosing information.

Provided herein are methods of treating a patient comprising providing a medical apparatus comprising an external system and an implantable system, implanting the implantable system, and delivering at least one of power or data to the implantable system with the external system. The external system comprises: at least one external antenna configured to transmit a first transmission signal to the implantable system; an external transmitter configured to drive the at least one external antenna; an external power supply; and an external controller. The implantable system comprises: at least one implantable antenna configured to receive the first transmission signal from the first external device; an implantable receiver; at least one implantable functional element configured to interface with the patient; an implantable controller; an implantable energy storage assembly; and an implantable housing surrounding at least the implantable controller and the implantable receiver. Medical apparatus are also provided.

Described herein are methods, systems, and devices for estimating remaining longevity of an IMD powered by a battery that at any given time has a battery voltage (BV) and a remaining battery capacity (RBC). Such a method can include estimating the RBC using a first technique when the battery is operating within a t least one of one or more plateau regions, estimating the RBC using a second technique, that differs from the first technique when the battery is operating within a decline region, and estimating the remaining longevity of the IMD based on at least one of the estimates of the RBC. Additionally, historical battery data can be stored and used to estimate the RBC, e.g., when the battery is operating within a heavy usage and recovery period. RBC estimation can also depend on whether the IMD is close to its recommended replacement time (RRT).