Medical device and method for detecting electrical signal noise

Patent metadata

Field	Value
Publication number	US-2023233131-A1
Application number	US-202318193457-A
Country	US
Kind code	A1
Filing date	Mar 30, 2023
Priority date	Feb 14, 2020
Publication date	Jul 27, 2023
Grant date	—

Abstract

A medical device is configured to sense an electrical signal and determine that signal to noise criteria are met based on electrical signal segments stored in response to sensed electrophysiological events. The medical device is configured to determine an increased gain signal segment from one of the stored electrical signal segments in response to determining that the signal to noise criteria are met. The medical device determines a noise metric from the increased gain signal segment. The stored electrical signal segment associated with the increased gain signal segment may be classified as a noise segment in response to the noise metric meeting noise detection criteria.

First claim

What is claimed is:

1 . A medical device comprising:
a sensing circuit configured to:
sense at least one cardiac electrical signal; and
sense cardiac electrical event signals attendant to ventricular myocardial depolarizations from the at least one electrical signal;
a memory; and a control circuit in communication with the memory and the sensing circuit and configured to:
buffer in the memory, in response to a first cardiac electrical event signal sensed by the sensing circuit, a first signal segment from the at least one cardiac electrical signal sensed by the sensing circuit;
determine a pulse detection threshold amplitude from the first signal segment;
determine that the pulse detection threshold amplitude is less than a suspected noise threshold; and
in response to the pulse detection threshold amplitude being less than the suspected noise threshold, determine that the first signal segment is a non-noise segment.

2 . The medical device of claim 1 wherein the control circuit is further configured to:
determine a maximum peak amplitude of the first signal segment; and
determine the pulse detection threshold amplitude based on the maximum peak amplitude.

3 . The medical device of claim 1 wherein the control circuit is further configured to:
obtain, in response to a second cardiac electrical event signal sensed by the sensing circuit, a second signal segment from the at least one cardiac electrical signal sensed by the sensing circuit;
determine a second pulse detection threshold amplitude from the second signal segment;
determine that the second pulse detection threshold amplitude is not less than the suspected noise threshold; and
in response to the second pulse detection threshold amplitude not being less than the suspected noise threshold, determine a noise metric from the second signal segment.

4 . The medical device of claim 3 wherein the control circuit is further configured to:
compare the noise metric to a noise threshold; and
classify the second signal segment as one of a noise segment or a non-noise segment based on the comparison.

5 . The medical device of claim 3 wherein the control circuit is further configured to determine the noise metric by:
identifying signal pulses from the second signal segment; and
determining a count of the identified signal pulses.

6 . The medical device of claim 5 wherein the control circuit is further configured to identify signal pulses from the second signal segment by at least identifying signal pulses of the second signal segment having a peak amplitude that is greater than the second pulse detection threshold amplitude.

7 . The device of claim 1 wherein the control circuit is further configured to:
classify each of a plurality of signal segments comprising the first signal segment as one of a noise segment or a non-noise segment;
determine that less than a threshold number of the plurality of signal segments are classified as noise segments; and
detect a tachyarrhythmia based on the at least one cardiac electrical signal and less than the threshold number of the plurality of signal segments being classified as noise segments.

8 . The medical device of claim 7 further comprising a therapy delivery circuit configured to generate a tachyarrhythmia therapy in response to the control circuit detecting the tachyarrhythmia.

9 . The device of claim 1 wherein the control circuit is further configured to:
classify each of a plurality of signal segments comprising the first signal segment as one of a noise segment or a non-noise segment;
determine that at least a threshold number of the plurality of signal segments are classified as noise segments;
detect a required number of tachyarrhythmia intervals to detect a tachyarrhythmia based on the cardiac electrical event signals sensed by the sensing circuit; and
in response to determining that at least the threshold number of the plurality of signal segments are classified as noise segments, withhold detecting the tachyarrhythmia when the required number of tachyarrhythmia intervals are detected.

10 . The medical device of claim 1 further comprising a therapy delivery circuit configured to deliver an electrical stimulation therapy,
wherein the control circuit is further configured to control the delivery of the electrical stimulation therapy by the therapy delivery circuit based on at least the first cardiac electrical event signal in response to the first signal segment being a non-noise segment.

11 . A method comprising:
sensing at least one cardiac electrical signal by a sensing circuit; sensing cardiac electrical event signals attendant to ventricular myocardial depolarizations from the at least one electrical signal; buffering in a memory, in response to a first cardiac electrical event signal sensed by the sensing circuit, a first signal segment from the at least one cardiac electrical signal; determining a pulse detection threshold amplitude from the first signal segment; determining that the pulse detection threshold amplitude is less than a suspected noise threshold; and in response to the pulse detection threshold amplitude being less than the suspected noise threshold, determining that the first signal segment is a non-noise segment.

12 . The method of claim 11 further comprising:
determining a maximum peak amplitude of the first signal segment; and
determining the pulse detection threshold amplitude based on the maximum peak amplitude.

13 . The method of claim 11 further comprising:
obtaining, in response to a second cardiac electrical event signal sensed by the sensing circuit, a second signal segment from the at least one cardiac electrical signal sensed by the sensing circuit;
determining a second pulse detection threshold amplitude from the second signal segment;
determining that the second pulse detection threshold amplitude is not less than the suspected noise threshold; and
in response to the second pulse detection threshold amplitude not being less than the suspected noise threshold, determining a noise metric from the second signal segment.

14 . The method of claim 13 further comprising:
comparing the noise metric to a noise threshold; and
classifying the second signal segment as one of a noise segment or a non-noise segment based on the comparison.

15 . The method of claim 13 wherein determining the noise metric comprises:
identifying signal pulses from the second signal segment; and
determining a count of the identified signal pulses.

16 . The method of claim 15 wherein identifying signal pulses from the second signal segment comprises at least identifying signal pulses of the second signal segment having a peak amplitude that is greater than the second pulse detection threshold amplitude.

17 . The method of claim 11 further comprising:
classifying each of a plurality of signal segments comprising the first signal segment as one of a noise segment or a non-noise segment;
determining that less than a threshold number of the plurality of signal segments are classified as noise segments; and
detecting a tachyarrhythmia based on the at least one cardiac electrical signal and less than the threshold number of the plurality of signal segments being classified as noise segments.

18 . The method of claim 17 further comprising generating a tachyarrhythmia therapy in response to detecting the tachyarrhythmia.

19 . The method of claim 11 further comprising:
classifying each of a plurality of signal segments co

Assignees

• Medtronic Inc

Inventors

• Zhang Xusheng
• Greenhut Saul E
• Liu Yuanzhen

Classifications

• A61B5/363 Primary

  Detecting tachycardia or bradycardia · CPC title

• A61B5/7264

  Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems · CPC title

• A61B5/686

  Permanently implanted devices, e.g. pacemakers, other stimulators, biochips (A61B5/6861 takes precedence) · CPC title

• A61B5/4836

  Diagnosis combined with treatment in closed-loop systems or methods (A61B5/0036 takes precedence) · CPC title

• A61B5/29

  for permanent or long-term implantation · CPC title