Multilevel ERI for implantable medical devices

• US 6,016,448 A
• Filed: 10/27/1998
• Issued: 01/18/2000
• Est. Priority Date: 10/27/1998
• Status: Expired due to Term

• Current Assignee: Medtronic Incorporated (Medtronic Plc)
• Original Assignee: Medtronic Incorporated (Medtronic Plc)
• Inventors: Cinbis, Can, Busacker, James W.
• Primary Examiner(s): Getzow, Scott M.
• Application Number:
  US09/179,619
• Time in Patent Office: 448 Days
• Field of Search: 607/27, 607/28, 607/29, 607/30
• US Class Current: 607/29
• CPC Class Codes: A61N 1/3688 configured for switching the pacing mode, e.g. from AAI to DDD
• CPC Class Codes: A61N 1/3706 Pacemaker parameters stimulation threshold A61N1/371
• CPC Class Codes: A61N 1/3708 for power depletion

Abstract

An automatic, body-implantable medical device having at least two modes of operation is disclosed. The device is provided with circuitry for automatically detecting when the device has been implanted in a patient, so that the device can automatically switch from a first mode to a second mode of operation upon implantation. In one embodiment, the first mode is a power conserving mode in which one or more non-essential sub-systems of the device are disabled. Prior to detection of implant, at least two conditions of the device known to reflect whether the device has been implanted are monitored. After implant has been detected, situations in which power to the device is disrupted and then restored will cause the device to enter a predefined "power-on-reset" mode of operation. Prior to detection of implant, however, such conditions do not result in the device entering the power-on-reset mode, or this mode is reset. An Elective Replacement Indicator mode is also used which is based on measured impedance against a target battery impedance. When the measured battery impedance reaches the target level, the voltage of the battery that precipitates an ERI condition is modified.

Claims

1. An IMD having an automatically adjustable value for determining ERI condition of a battery power source such that said adjustable value is automatically adjusted by a value changing processor responsive to a measured level of a state of said battery power source, said measured level generated by a battery power source measuring circuit connected to said battery power source in said IMD.

2. An IMD as set forth in claim 1 wherein said measured level of battery power is battery impedance and said value for determining ERI condition is compared to measured battery voltage.

3. An IMD as set forth in claim 1 wherein said measured level of battery power is battery voltage and said value for determining ERI condition is compared to measured battery impedance.

4. An IMD as set forth in claim 1 further comprising discrimination means for determining the level of said adjustable value to be used for comparing to said measured level of said state of battery power, said discrimination means comprising;

a value for determining stored in a memory for comparison to said measured value of battery power for determining ERI condition.

5. An IMD as set forth in claim 1 further comprising discrimination means for determining the level of said adjustable value to be used for comparing to said measured level of said state of battery power, said discrimination means comprising;

a plurality of values for determining stored in a memory for comparison to said measured value of battery power for determining ERI condition.

6. An IMD as set forth in claim 1 further comprising discrimination means for determining the level of said adjustable value to be used for comparing to said measured level of said state of battery power, said discrimination means comprising;

a formula relating value for determining to time, for generating values to use at different times for comparison to said measured value of battery power for determining ERI condition.

7. An IMD as set forth in claim 1 further comprising discrimination means for determining the level of said adjustable value to be used for comparing to said measured level of said state of battery power, said discrimination means comprising;

a look-up table of values for determining stored in a memory for comparison to said measured value of battery power for determining ERI condition.

8. A method for determining whether to set an ERI condition for an IMD having a battery power source comprising:

storing a plurality of values to compare against a first measured battery depletion indicator value and storing a value for an alternative measure of battery depletion level,

measuring an alternative battery depletion level indicator,

comparing said alternative battery depletion level indicator to its stored value and selecting one of said plurality of values based on a predetermined formula for selection,

measuring said first battery depletion indicator value, and

if said first indicator value compares unfavorably against said selected one, generating an ERI signal.

9. A method for determining whether to set an ERI condition for an IMD having a battery power source comprising:

providing a first set of values to compare against a first measured battery depletion indicator value and providing a second set of values for an alternative measure of battery depletion level,

Measuring said alternative battery depletion level,

comparing said measured alternative battery depletion level indicator to said second set of values to find which of said second set of values is nearest to said measured alternative battery depletion level indicator and selecting one of said first set of values based on a predetermined formula for selection which depends on the selected value from said second set of values,

measuring said first battery depletion indicator value, and

if said first indicator value compares unfavorably against said selected one, generating an ERI signal.