An external medical device includes a battery that can support a plurality of charge-discharge cycles prior to a predetermined battery life threshold. The device also includes a battery circuit that is operative for monitoring a condition of the battery, determining a battery life status of the battery based on the monitored condition and the predetermined battery life threshold, and, responsive to the determined battery life status, causing the device to enter into a low power operating mode. The low power operating mode can include modifying device functions that are performed, or modifying the manner in which a capacitor of the device is charged, or changing the battery that charges the capacitor, or isolating the capacitor from charge drainage, or causing the device to operate from charge stored on the capacitor.

An implantable medical device (IMD) may include a sensor for providing a sensor output signal and a sense channel configured to receive the sensor output signal from the sensor. The sense channel may be configured to process the sensor output signal and output a sense channel output signal. The sense channel may have an adjustable performance level, wherein for a higher performance level the sense channel consumes more power than for a lower performance level. A controller may be configured to adjust the performance level of the sense channel to achieve more performance and more power consumption when a higher degree of sense channel performance is desired and to achieve less performance and less power consumption when a higher degree of performance is not desired.

According to some methods, for example, preprogrammed in a microprocessor element of an implantable cardiac pacing system, at least one of a number of periodic pacing threshold searches includes steps to reduce an evoked response amplitude threshold for evoked response signal detection. The reduction may be to a minimum value measurable above zero, for example, as determined by establishing a noise floor. Alternately, amplitudes of test pacing pulses and corresponding post pulse signals are collected and reviewed to search for a break, to determine a lower value to which the evoked response threshold may be adjusted without detecting noise. Subsequent to reducing the threshold, if no evoked response signal is detected for a test pulse applied at or above a predetermined maximum desirable pulse energy, an operational pacing pulse energy is set to greater than or equal to the maximum desirable in conjunction with a reduction in pacing rate.

A method of programming an implantable medical device (IMD) configured to provide electrical stimulation via a plurality of stimulation vectors during delivery of the electrical stimulation of a plurality of pulse widths to a neural target. The method may comprise comparing strength-duration curve data for the plurality of stimulation vectors to one another, the strength-duration curve data representing, for respective pulse widths and stimulation vectors, a corresponding stimulation strength that evokes a physiological response associated with the neural target. The method may comprise selecting at least one stimulation vector of the plurality of stimulation vectors based on the comparison of the strength-duration curve data for the plurality of stimulation vectors. The method may comprise programming, in response to the selection, the IMD to deliver the electrical stimulation to the neural target via the selected at least one stimulation vector.

A medical device system and method estimate a time from a first voltage of a power source of a medical device to a second voltage of the power source. The medical device includes a sensor coupled to the power source for generating a physiological signal. The medical device system determines a current drain from the power source required for generating the physiological signal and/or processing the physiological signal for detecting events from the physiological signal. A processor of the medical device system is configured to estimate the time from the first voltage of the power source until the second voltage based on at least the determined current drain.

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.

An implantable neural stimulator method for modulating excitable tissue in a patient including: implanting a neural stimulator within the body of the patient such that one or more electrodes of the neural stimulator are positioned at a target site adjacent to or near excitable tissue; generating an input signal with a controller module located outside of, and spaced away from, the patient's body; transmitting the input signal to the neural stimulator through electrical radiative coupling; converting the input signal to electrical pulses within the neural stimulator; and applying the electrical pulses to the excitable tissue sufficient to modulate said excitable tissue.

Implanted pulse generators with reduced power consumption via signal strength-duration characteristics, and associated systems and methods are disclosed. A representative method for treating a patient in accordance with the disclosed technology includes receiving an input corresponding to an available voltage for an implanted medical device and identifying a signal delivery parameter value of an electrical signal based on a correlation between values of the signal delivery parameter and signal deliver amplitudes. The signal deliver parameter can include at least one of pulse width or duty cycle. The method can further include delivering an electrical therapy signal to the patient at the identified signal delivery parameter value using a voltage within a margin of the available voltage.

A medical device system and method estimate a time from a first voltage of a power source of a medical device to a second voltage of the power source. The medical device includes a sensor coupled to the power source for generating a physiological signal. The medical device system determines a current drain from the power source required for generating the physiological signal and/or processing the physiological signal for detecting events from the physiological signal. A processor of the medical device system is configured to estimate the time from the first voltage of the power source until the second voltage based on at least the determined current drain.

Power saving communication techniques for communicating in a medical device system. One example medical device system may be for delivering electrical stimulation therapy to a heart of a patient, and may include a first implantable medical device implanted in a first chamber of the heart and configured to determine one or more parameters, a medical device physically spaced from and communicatively coupled to the first implantable medical device, the medical device configured to deliver electrical stimulation therapy to the heart of the patient, wherein the first implantable medical device is further configured to: compare a value of a first determined parameter to a first threshold; if the value of the first determined parameter passed the first threshold, communicate a first indication to the medical device; and if the value of the first determined parameter has not passed the first threshold, not communicating the first indication to the medical device.