Method and apparatus for identifying lead-related conditions using prediction and detection criteria

Patent metadata

Field	Value
Publication number	US-9561377-B2
Application number	US-5756208-A
Country	US
Kind code	B2
Filing date	Mar 28, 2008
Priority date	Dec 1, 2004
Publication date	Feb 7, 2017
Grant date	Feb 7, 2017

Abstract

A method for delivering therapy in a medical device includes a two-tiered approach of determining the presence of a lead-related condition, and determining, in response to a lead-related condition being present, the presence of oversensing. Delivery of therapy by the medical device is controlled in response to determining that both the lead-related condition and oversensing are present.

First claim

What is claimed is:

1. A method for delivering therapy in a medical device, comprising:
determining, prior to detection of a sustained tachyarrhythmia episode, whether a lead-related condition is present;
adjusting, in response to determining the lead-related condition is present, at least one parameter used to determine whether oversensing is present;
detecting the sustained tachyarrhythmia episode;
if the lead-related condition is present, determining, in response to the detection of the sustained tachyarrhythmia episode, whether oversensing is present using the at least one parameter that was adjusted in response to determining the lead-related condition is present;
withholding delivery of a shock therapy to treat the sustained tachyarrhythmia episode in response to both determining that the lead-related condition is present and determining that oversensing is present; and
delivering the shock therapy in response to determining that the lead-related condition is present and determining that oversensing is not present.

2. The method of claim 1 , further comprising generating an alert in response to determining that the lead-related condition is present.

3. The method of claim 1 , wherein determining whether the lead-related condition is present comprises:
determining whether a first oversensing criteria is satisfied;
determining whether a second oversensing criteria is satisfied;
determining whether an impedance criteria has been satisfied; and
determining the lead-related condition is present when more than one of the first oversensing criteria, the second oversensing criteria and the impedance criteria being satisfied at the same time.

4. The method of claim 3 , wherein determining whether a second oversensing criteria is satisfied comprises determining whether there are a predetermined number of non-sustained tachyarrhythmia events having average cycle lengths that are less than a predetermined threshold cycle length that occur within a predetermined time period.

5. The method of claim 3 , wherein determining whether an impedance criteria has been satisfied comprises:
measuring a plurality of lead impedances;
determining a short-term impedance trend of at least a portion of the measured lead impedances;
determining a long-term impedance trend of at least a portion of the measured lead impedances; and
applying a set of diagnostic criteria to the short-term and long-term impedance trends to determine whether an impedance criteria has been satisfied.

6. The method of claim 1 , wherein:
determining, prior to detection of a sustained tachyarrhythmia episode, whether a lead-related condition is present comprises determining, prior to detection of a ventricular fibrillation episode, whether a lead-related condition is present; and
determining, in response to detection of the sustained tachyarrhythmia episode, whether oversensing is present comprises determining, in response to detection of the ventricular fibrillation episode, whether oversensing is present.

7. The method of claim 1 , further comprising initiating the determining of whether oversensing is present when the lead-related condition is determined to be present.

8. The method of claim 1 , wherein determining whether the oversensing is present comprises:
obtaining a far-field signal; and
determining whether oversensing is present using at least the obtained far-field signal.

9. The method of claim 8 , wherein determining whether oversensing is present using at least the obtained far-field signal comprises:
obtaining amplitude values associated with a predetermined number of samples within a predetermined window of the far-field signal;
determining a variance of the obtained amplitude samples;
determining a central tendency of the obtained samples;
computing a baseline measure this is the product of the variance and the central tendency; and
determining oversensing is present when the baseline measure associated with the far-field signal is less than a baseline threshold.

10. The method of claim 8 , wherein determining whether oversensing is present using at least the obtained far-field signal comprises:
obtaining a maximum sample amplitude associated with a predetermined number of far-field sensed events;
obtaining a minimum sample amplitude associated with the predetermined number of far-field sensed events;
determining oversensing is present when the maximum sample amplitude is greater than a predetermined maximum sample amplitude threshold, the minimum sample amplitude is less than a predetermined minimum sample amplitude threshold, and the minimum sample amplitude is less than a predetermined percentage of the maximum sample amplitude.

11. The method of claim 1 wherein adjusting the at least one parameter used to determine whether oversensing is present comprises switching the electrodes used to obtain an electrogram to include a coil electrode of a lead connected to the medical device and a housing of the medical device.

12. A system comprising:
at least one lead; and
an implantable medical device coupled to the at least one lead and including at least one processor configured to:
determine, prior to detection of a sustained tachyarrhythmia episode, whether a lead-related condition is present;
adjusting, in response to determining the lead-related condition is present, at least one parameter used to determine whether oversensing is present;
detecting the sustained tachyarrhythmia episode;
if the lead-related condition is present, determine, in response to the detection of the sustained tachyarrhythmia episode, whether oversensing is present using the at least one parameter that was adjusted in response to determining that the lead-related condition is present;
withhold delivery of a shock therapy to treat the sustained tachyarrhythmia episode in response to both determining that the lead-related condition is present and determining that oversensing is present; and
deliver the shock therapy in response to determining that the lead-related condition is present and determining that oversensing is not present.

13. The system of claim 12 , wherein the processor determines whether the lead-related condition is present by:
determining whether a first oversensing criteria is satisfied;
determining whether a second oversensing criteria is satisfied;
determining whether an impedance criteria has been satisfied; and
determining the lead-related condition is present when more than one of the first oversensing criteria, the second oversensing criteria and the impedance criteria being satisfied at the same time.

14. The system of claim 13 , wherein the processor is configured to determine that the second oversensing criteria is satisfied when there are a predetermined number of non-sustained tachyarrhythmia events having average cycle lengths that are less than a predetermined threshold cycle length that occur within a predetermined time period.

15. The system of claim 13 , wherein the processor is configured to:
measure a plurality of lead impedances;
determine a short-term impedance trend of at least a portion of the measured lead impedances;
determine a long-term impedance trend of at least a portion of the measured lead impedances; and
apply a set of diagnostic criteria to the short-term and long-term impedance trends to determine whether an impedance criteria has been satisfied.

16. The system of claim 12 , wherein the processor is configured to:
determine, prior to detection of a ventricular fibrillation episode, whether a lead-related condition is present; and
determine, in

Assignees

• Gunderson Bruce D
• Medtronic Inc

Inventors

• Gunderson Bruce D

Classifications

• A61N1/3621

  for treating or preventing abnormally high heart rate · CPC title

• A61N1/3704 Primary

  Circuits specially adapted therefor, e.g. for sensitivity control · CPC title

• A61N1/3925

  Monitoring; Protecting · CPC title

• A61N1/3706

  Pacemaker parameters (stimulation threshold A61N1/371) · CPC title

• A61N2001/083

  Monitoring integrity of contacts, e.g. by impedance measurement · CPC title