Method and apparatus for detecting cardiac event oversensing

Patent metadata

Field	Value
Publication number	US-12589248-B2
Application number	US-202418444625-A
Country	US
Kind code	B2
Filing date	Feb 16, 2024
Priority date	Dec 9, 2019
Publication date	Mar 31, 2026
Grant date	Mar 31, 2026

Abstract

A medical device is configured to detect an alternating pattern of signal features determined from consecutive segments of a cardiac electrical signal and determine a gross morphology metric from at least one segment of the cardiac electrical signal. The device is configured to detect cardiac event oversensing in response to detecting the alternating pattern and the gross morphology metric not meeting tachyarrhythmia morphology criteria. The medical device may withhold detecting an arrhythmia in response to detecting the cardiac event oversensing.

First claim

What is claimed is:

1 . A medical device comprising:
a cardiac electrical signal sensing circuit configured to sense a plurality of cardiac electrical signals; a control circuit configured to:
determine signal features from the plurality of cardiac electrical signals;
detect an alternating pattern of the signal features;
identify, based on the alternating pattern of the signal features, at least one segment of the plurality of cardiac electrical signals that is a suspected R-wave;
from the at least one segment identified as a suspected R-wave, determine at least one of:
a maximum signal pulse width; or
an amplitude metric;

based on at least one of the maximum signal pulse width or the amplitude metric, determine that the suspected R-wave is one of:
a tachyarrhythmia morphology; or
a true sensed R-wave;

detect a tachyarrhythmia in response to at least determining the suspected R-wave is the tachyarrhythmia morphology; and
withhold detecting the tachyarrhythmia in response to at least determining that the suspected R-wave is the true sensed R-wave; and
a therapy delivery circuit configured to deliver a tachyarrhythmia therapy in response to the control circuit detecting the tachyarrhythmia.

2 . The medical device of claim 1 wherein:
the sensing circuit is further configured to:
sense a first cardiac electrical signal of the plurality of cardiac electrical signals;
sense a second cardiac electrical signal of the plurality of cardiac electrical signals; and
sense cardiac event signals from the first cardiac electrical signal:

the control circuit is further configured to detect the alternating pattern of signal features from the second cardiac electrical signal.

3 . The medical device of claim 2 further comprising:
a memory configured to store segments of the second cardiac electrical signal, each stored segment corresponding in time to one of the sensed cardiac event signals; and
wherein the control circuit is further configured to detect the alternating pattern of signal features from the stored segments of the second cardiac electrical signal.

4 . The medical device of claim 3 wherein the control circuit is further configured to:
determine the signal features from a first group of three consecutively sensed segments of the stored segments;
detect one of a high-low-high pattern or a low-high-low pattern of the signal features of the first group of three consecutively sensed segments; and
identify the suspected R-wave based on the alternating pattern of signal features as at least one of the first group of the three consecutively sensed segments determined to be a high signal feature of the high-low-high or the low-high-low pattern.

5 . The medical device of claim 4 wherein the control circuit is further configured to:
determine the signal features from a plurality of groups of three consecutively sensed segments of the stored segments including the first group of three consecutively sensed segments;
for each of the plurality of groups of three consecutively sensed segments:
determine if the signal features are an alternating pattern; and
if the signal features are an alternating pattern, identify at least one segment of the three consecutively sensed segments that is a suspected R-wave;
determine that the suspected R-wave is one of:
a tachyarrhythmia morphology; or
a true sensed R-wave; and

increase a P-wave oversensing count when the signal features are an alternating pattern and the suspected R-wave is determined to be a true sensed R-wave and not the tachyarrhythmia morphology;

determine if the P-wave oversensing count meets a tachyarrhythmia rejection threshold; and
detect the tachyarrhythmia in response to at least determining the suspected R-wave is the tachyarrhythmia morphology by determining that the P-wave oversensing count does not meet the tachyarrhythmia rejection threshold; and
withhold detecting the tachyarrhythmia in response to at least determining that the suspected R-wave is the true sensed R-wave by determining that the P-wave oversensing count meets the tachyarrhythmia rejection threshold.

6 . The medical device of claim 5 wherein the control circuit is further configured to, for each of the plurality of groups of three consecutively sensed segments:
when the signal features are not determined to be an alternating pattern or the suspected R-wave is determined to be a tachyarrhythmia morphology, do not increase the P-wave oversensing count; and
advance to a next group of the plurality of groups of three consecutively sensed segments for determining if the signal features are an alternating pattern, wherein the groups of three consecutively sensed segments are overlapping groups of three consecutively sensed segments.

7 . The medical device of claim 2 wherein the control circuit is further configured to:
determine from the sensed cardiac event signals that a detection threshold number of tachyarrhythmia intervals is met;
detect the tachyarrhythmia in response to determining that the detection threshold number of tachyarrhythmia intervals is met and at least determining that the suspected R-wave is the tachyarrhythmia morphology; and
withhold detecting the tachyarrhythmia in response to determining that the detection threshold number of tachyarrhythmia intervals is met and at least determining that the suspected R-wave is the true sensed R-wave.

8 . The medical device of claim 2 wherein the control circuit is further configured to:
detect a first threshold number of tachyarrhythmia intervals from the sensed cardiac event signals; and
responsive to detecting the first threshold number of tachyarrhythmia intervals determine the signal features for detecting the alternating pattern of the signal features.

9 . The medical device of claim 1 wherein the control circuit is further configured to determine the signal features as peak to peak amplitudes.

10 . The medical device of claim 1 wherein the control circuit is further configured to determine the at least one of the maximum signal pulse width or the amplitude metric of the at least one segment identified as a suspected R-wave by:
determining the maximum signal pulse width by:
identifying a plurality of signal pulses of the segment;
determining a signal pulse width of each of the plurality of signal pulses; and
determining a maximum signal pulse width out of the determined signal pulse widths; or

determining the amplitude metric by:
determining a maximum amplitude of the segment;
determining a summation of a plurality of sample point amplitudes of the segment; and
dividing the summation by the maximum amplitude.

11 . A method comprising:
sensing a plurality of cardiac electrical signals; determining signal features from the plurality of cardiac electrical signals; detecting an alternating pattern of the signal features; identifying, based on the alternating pattern of the signal features, at least one segment of the plurality of cardiac electrical signals that is a suspected R-wave; from the at least one segment identified as a suspected R-wave, determining at least one of:
a maximum signal pulse width; or
an amplitude metric;
based on at least one of the maximum signal pulse width or the amplitude metric, determining that the suspected R-wave is one of:
a tachyarrhythmia morphology; or
a true sensed R-wave;
detecting a tachyarrhythmia in response to at least determining the suspected R-wave is the tachyarrhythmia morphology; withholding detecting the tachyarrhythmia in response to at least determining that the suspected R-wave is the true sensed R-wave; and delivering a tachyarrhythmia therapy i

Assignees

• Medtronic Inc

Inventors

• Mischler Gavin M
• Liu Yuanzhen
• Greenhut Saul E
• Zhang Xusheng

Classifications

• A61N1/3704

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

• A61B5/363

  Detecting tachycardia or bradycardia · CPC title

• A61N1/3706

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

• A61B5/352

  Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval · CPC title

• A61N1/365

  controlled by a physiological parameter, e.g. heart potential {(evoked response A61N1/371)} · CPC title