FR3129242A3 - Method for assigning identification information to a signal from a cardiac electrode - Google Patents

Abstract

A method of assigning identifying information to a cardiac electrode signal A computer-implemented method of assigning identifying information to a first sensing signal (SD), characterized by comprising: Acquisition of a sensing signal (SD) in response to receiving a cardiac electrical current, said sensing signal (SD) comprising a signal portion corresponding to an electrical pattern over a first interval (i); a comparison algorithm comprising:Comparing the first interval with a first threshold;Comparing a second interval associated with a portion of a second detection signal (SD-1) prior to the first detection signal (SD) with a second threshold;Assignment of identification information to the first detection signal (SD), said identification information being determined according to the result of the comparisons carried out by the comparison algorithm. Figure for abstract: Fig.6

Description

Method for assigning identification information to a signal from a cardiac electrode

Field of invention

The field of the invention relates to the field of methods and devices for detecting, analyzing and processing cardiac signals. In particular, the field of the invention relates to the field of methods for identifying characteristics of cardiac signals from one or more detection probe(s), such as one or more cardiac electrode(s). s), and to assign information to said signals.

State of the art

There are in the prior art processes applied to pacemakers also known in the literature under the name of "pacemaker" or "cardiac battery", and to defibrillators such as implantable automatic defibrillators, also designated in the literature by the acronym "DAI", to deliver therapeutic shocks to patients.

Such devices comprise electrodes, also called probes, which make it possible to detect the heart rate, or even to deliver stimulation and/or so-called “therapeutic” electric shocks to patients. When a rhythm change is detected, such as a rhythm characteristic of bradycardia, ventricular fibrillation, or ventricular tachycardia, a therapeutic pacing or electric shock can be delivered by the device to restore a natural heartbeat.

However, a problem exists when a lead of a pacemaker or defibrillator is damaged. When a probe is damaged on a "pacemaker", there is a risk that the patient's heart will stop and therefore a risk of death. A damaged probe can come, for example, from the rupture of the internal cable of the probe or from the fact that its insulator is open.

In both cases, this is manifested by the appearance of noise, intermittently or continuously, on a detection channel of the probe. However, the noise appearing on the detection channel can be misinterpreted as a signal of cardiac origin. This signal will have the effect of inhibiting stimulation on a pacemaker with a risk of cardiac arrest and/or of causing the delivery of an electric shock, or even repeated electric shocks, by a defibrillator. These electrical shocks delivered inappropriately can have dramatic consequences on patients. Consequently, it is advisable to set up a process to distinguish the pathological signals from the signals due to a defective electrode.

There are, in the prior art, methods making it possible to overcome this problem of electric shocks delivered inappropriately. By way of example, patent US7369893 describes a method for evaluating whether the detection of a signal by a probe of a pacemaker is indeed linked to a cardiac arrhythmia phenomenon and not to an oversensing phenomenon, by detecting a probe-related condition. Indeed, it is possible that an electrode is defective due to the breakage of a conductor and results in the appearance of noise on the detection channel. However, such a method has the disadvantage of lacking precision in the detection of noise, the appearance of which may be due to multiple factors.

The invention aims to exploit another way of determining the presence of noise, in particular by directly interpreting the signals on a detection channel of a probe. Indeed, starting from the proven principle that the heart of a human being cannot contract several times in too short a time interval, it is possible to observe on the detection channel of an electrode that a signal cannot not be physiological; by comparing the time intervals separating several cardiac cycles. Therefore, the appearance of a non-physiological signal on the detection channel can be attributed to noise, and therefore, to a high probability that an electrode is defective.

An object of the invention is to solve the drawbacks due to the appearance of noise on a detection channel of an electrode by proposing a computer-implemented method for assigning identification information to a signal resulting from the detection of a cardiac electrical current. The method is based on the time intervals separating several detected signals, such as the time intervals between several successive signals, and advantageously makes it possible to accurately detect the appearance of noise on a detection channel. Another advantage is to reduce the number of alerts issued by defibrillators and “pacemakers” in response to the detection of false positive ventricular arrhythmias.

According to a first aspect, the invention relates to a computer-implemented method for assigning identification information to a detection signal, characterized in that it comprises:

• acquiring a first sense signal in response to receiving a cardiac electrical current, said first sense signal including a signal portion corresponding to an electrical pattern over a first interval;
• the implementation of a comparison algorithm comprising:
  • comparing the first interval with a first threshold;
  • comparing a second interval associated with a portion of a second detection signal prior to the first detection signal with a second threshold;

• the assignment of identification information to the first detection signal, said identification information being determined according to the result of the comparisons carried out by the comparison algorithm, said identification information making it possible to discriminate a detection signal having a physiological cause of a detection signal caused by a malfunction of electronic equipment.

One advantage is to determine, on the basis of the results of the comparisons implemented by the algorithm, whether a detected signal indeed corresponds to a physiological signal; or if it is a measurement artifact possibly due to a faulty cardiac probe. Another advantage is to detect the presence of noise by implementing an algorithm that is not very complex, and can therefore be implemented on devices with little computing power.

According to one embodiment, the comparison algorithm comprises a step of comparing a third interval associated with a portion of a third detection signal with a third threshold, said third detection signal being prior to the second detection signal.

An advantage is to improve the noise identification on the detected signals by adding a comparison step in the algorithm. Another advantage is to allow the distinction between signals characteristic of oversensing phenomena and signals characteristic of a broken probe.

According to one embodiment, the method comprises the implementation of a second comparison algorithm comprising:

• A step of comparing the first interval with a fourth threshold;
• A step of comparing the second interval with a fifth threshold;
• A step of comparing the third interval with a sixth threshold.

One advantage is to improve the detection of noise on a detection channel of a probe; by the implementation of another algorithm comprising additional comparison steps. Another advantage is to allow the distinction between signals characteristic of oversensing phenomena and signals characteristic of a broken probe.

According to one embodiment, the method comprises the implementation, by the first or the second comparison algorithm, of the comparison with a seventh threshold of a fourth time interval associated with a portion of a fourth prior detection signal at the third detection signal

One advantage is to allow the distinction between signals characteristic of oversensing phenomena and signals characteristic of a broken probe.

According to one embodiment, one or more thresholds among the first, second, third, fourth, fifth, sixth or seventh threshold are defined by:

• A predefined threshold value or;
• A median value or an average of several values between them or;
• A mathematical function defined with respect to one or more time intervals or;
• A mathematical function independent of the values of the acquired intervals or;
• A combination of several mathematical functions.

An advantage is to define the criteria for assigning the type of identification information from more complex thresholds to obtain additional precision on the detection of noise on the detection channel.

According to one embodiment, the identification information is assigned to the first detection signal according to the result of the comparisons of at least one of the two comparison algorithms. An advantage is to exploit the results of the comparisons of at least one of the algorithms to precisely identify the signal on the detection channel of the electrode.

According to one embodiment, the identification information attributed to the first detection signal comprises either:

• physiological information defining a natural heartbeat rhythm or a cardiac arrhythmia;
• anomaly information characterizing data from a non-physiological signal.

An advantage is to characterize the identification information assigned to the detection signal to determine whether said detection signal corresponds to the detection of a heart rhythm or if the detection signal corresponds to a measurement artifact, for example due to the malfunction of an electrode.

According to one embodiment, the method comprises:

• Generating a notification or an alert when the identification information assigned to the first detection signal includes anomaly information;
• Recording of said alert/notification in a memory space,
• The transmission of said generated alert/notification to equipment on a remote data network.

One advantage is to alert the competent personnel when a defect on a patient's electrode is observed.

According to one embodiment, the identification information assigned to the first detection signal comprises anomaly information:

• Either when the first time interval is less than the first threshold, the second time interval is less than the second threshold and the third time interval is greater than the third threshold;
• Either when the first time interval is less than the first threshold, the second time interval is less than the second threshold, the third time interval is greater than the third threshold and the fourth time interval is greater than the seventh threshold.

An advantage is to deduce the presence of a non-physiological signal on the detection channel, based on the results of comparisons between characteristic threshold temporal values and the intervals associated with the detection signals.

According to one embodiment, the method comprises:

• generating an electrogram, said electrogram comprising a graphical representation of at least one detection signal among the signals and at least one interval;
• acquiring at least one image of the electrogram;
• the recording of the image of the electrogram acquired within a memory space;
• the transmission of the image of the electrogram acquired to at least one device of a data network.

An advantage is to be able to record and transmit to remote equipment a graphic representation of the detected signals, which can subsequently be examined by competent personnel to confirm or invalidate the presence of noise on the detection channel.

According to one embodiment, the method includes generating a visual, sound and/or vibration alert when the identification information includes anomaly information.

One advantage is to alert the patient to the presence of an anomaly potentially due to equipment malfunction.

According to another aspect, the invention relates to a system for generating information identifying a cardiac detection signal comprising:

• An electrical device comprising at least one probe for acquiring a first sensing signal in response to receiving a cardiac electrical current, said sensing signal comprising a signal portion corresponding to an electrical pattern over a first interval;
• A computer configured to implement:
  • on the one hand a comparison algorithm comprising:
    1. Comparing the first interval with a first threshold;
    2. comparing a second interval associated with a portion of a second detection signal prior to the first detection signal with a second threshold;

• on the other hand, a function for assigning identification information to the first detection signal, said identification information being determined according to the result of the comparisons carried out by the comparison algorithm, said identification information making it possible to discriminating a detection signal having a physiological cause from a detection signal having as its cause a malfunction of an electronic device.

• A display for generating a graphic marker superimposed on an electrogram comprising the first detection signal in order to temporally locate the information identifying the first detection signal.

According to another aspect, the invention relates to a system configured to implement any one of the steps of the method according to the invention, said system comprising:

• the electrical device comprising at least one probe for receiving cardiac electrical current;
• a signal generator for generating the sensing signal in response to receiving the cardiac electrical current;
• a memory for storing data;
• a communication interface for exchanging data with equipment of a remote data network;

According to another aspect, the invention relates to a computer program product comprising instructions which, when the program is executed by a computer, lead the latter to implement the steps of the method according to the invention.

Brief description of figures

Other characteristics and advantages of the invention will become apparent on reading the following detailed description, with reference to the appended figures, which illustrate:

• : An electrical device comprising a lead implanted in a patient's heart.
• : A flowchart of the implementation of the comparison algorithm by a computer to obtain the identification information.
• : A flowchart of the comparison algorithm implemented by a computer when it includes two comparison steps.
• : A flowchart of the comparison algorithm implemented by a computer when it includes three comparison steps.
• : A flowchart of the implementation of two comparison algorithms comprising a plurality of comparison steps.
• : A visual of an electrogram including a graphical representation of three detection signals and associated intervals.
• : A flowchart of the transmission of an alert to equipment in a data network.
• : An example of a threshold defined by a function of two successive time intervals.
• : A flowchart of the implementation of two comparison algorithms comprising a plurality of comparison steps.
• : A visual of an electrogram including a graphical representation of four detection signals and associated intervals.

Claims (13)

A computer-implemented process for assigning identification information (I_id) to a detection signal (S_D), characterized in that it comprises:

• Acquisition of a first detection signal (S_D) in response to receiving a cardiac electrical current, said detection signal (S_D) comprising a signal portion corresponding to an electrical pattern over a first time interval (i), said time interval being defined between two events defined from at least one electrical pattern;
• Implementation of a comparison algorithm (A _COMP1 ) comprising:
  • Comparison (COMP ₁ ) of the first time interval (i) with a first threshold (V _threshold1 );
  • Comparison (COMP ₂ ) of a second time interval (i-1) associated with a portion of a second detection signal (S _{D- 1)} prior to the first detection signal (S _D ) with a second threshold (V _threshold2 );
• Allocation of identification information (I _id ) to the first detection signal (S _D ), said identification information (I _id ) being determined according to the result of the comparisons carried out by the comparison algorithm (A _comp1 ) , said identification information (I _id ) making it possible to discriminate between a detection signal (S _D ) having a physiological cause and a detection signal (S _D ) having as its cause a malfunction of an electronic device.

Computer-implemented method according to claim 1 characterized in that the comparison algorithm (A_COMP1) understand :

• Comparison (COMP ₃ ) of a third time interval (i-2) associated with a portion of a third detection signal (S _D-2 ) with a third threshold (V _threshold3 ), said third detection signal (S _D-2 ) being prior to the second detection signal (S _D-1 ).

Computer-implemented method according to any one of claims 1 and 2 characterized in that it comprises:

• Implementation of a second comparison algorithm (A _COMP2 ) comprising:
  • Comparison (COMP ₄ ) of the first time interval (i) with a fourth threshold (V _{threshold 4} );
  • Comparison (COMP ₅ ) of the second time interval (i-1) with a fifth threshold (V _{threshold 5} );
  • Comparison (COMP ₆ ) of the third time interval (i-2) with a sixth threshold (V _{threshold 6} ).

Computer-implemented method according to any one of Claims 2 to 3, characterized in that it comprises the implementation by the first or the second comparison algorithm (A _COMP1, A _COMP2 ) of the comparison (COMP ₇ ) with a seventh threshold (V _threshold7 ) of a fourth time interval (i-3) associated with a portion of a fourth detection signal (S _D-3 ) prior to the third detection signal (S _{D -2} ) . Computer-implemented method according to any one of Claims 3 to 4, characterized in that the identification information (I _id ) is assigned to the first detection signal S _D according to the result of the comparisons of at least one of the two comparison algorithms (A _COMP1 , A _COMP2 ) or of a joint implementation of the two comparison algorithms (A _COMP1 , A _COMP2 ). Computer-implemented method according to any one of Claims 4 to 5, characterized in that one or more of the first, second, third, fourth, fifth, sixth and seventh thresholds (V_threshold1, V_threshold2, V_threshold3, V_threshold4, V_threshold5, V_{threshold6 ,}V_threshold7) are defined by:

• A predefined threshold value or;
• A median value or an average of several values between them or;
• A mathematical function defined with respect to one or more time intervals (i, i-1, i-2) or;
• A mathematical function independent of the values of the acquired intervals or;
• A combination of several mathematical functions.

Computer-implemented method according to any one of Claims 1 to 6, characterized in that the identification information (I_id) assigned to the first detection signal (S_D) includes either:

• Physiological information characterizing heart rate data;
• Anomaly information characterizing a datum of a non-physiological signal.

Computer-implemented method according to claim 7 characterized in that the identification information (I_id) assigned to the first detection signal (S_D) includes anomaly information characteristic of a ruptured probe:

• Either when the first time interval (i) is less than the first threshold (V _threshold1 ), the second time interval (i-1) is less than the second threshold (V _threshold2 ) and the third time interval is greater than the third threshold (V _threshold3 );
• Either when the first time interval (i) is lower than the first threshold (V _threshold1 ), the second time interval (i-1) is lower than the second threshold (V _threshold2 ), the third time interval (i-2) is greater than the third threshold (V _threshold3 ) and the fourth time interval (i-3) is greater than the seventh threshold (V _{threshold 7} ).

Computer-implemented method according to any one of Claims 7 to 8, characterized in that it comprises:

• Generating a notification or an alert (A ₁ ) when the identification information (I _id ) attributed to the first detection signal (S _D ) comprises anomaly information;
• Recording of said alert/notification (A ₁ ) within a memory space,
• Transmission of said alert/notification (A ₁ ) generated to equipment of a remote data network (NET).

Computer-implemented method according to any one of Claims 4 to 9, characterized in that it comprises:

• Generation of an electrogram (E _G ), said electrogram (E _G ) comprising a graphic representation of at least one detection signal among the first, second, third and fourth detection signal (S _D , S _D-1 , S _{D-2 ,} S _D-3 ) and at least one time interval (i, i-1, i-2, i-3);
• Acquisition, recording and transmission of the image of the electrogram (E _G ) acquired to at least one device of a data network (NET).

A system for generating cardiac sensing signal identification information comprising:

• An electrical device (1) comprising at least one probe (2) for acquiring a first detection signal (S_D) in response to receiving cardiac electrical current, said electrical device (1), said detection signal (S_D) comprising a signal portion corresponding to an electrical pattern over a first time interval (i);
• A computer (K) configured to implement:
  • on the one hand a comparison algorithm (A _COMP1 ) comprising:
    1. Comparison (COMP ₁ ) of the first time interval (i) with a first threshold (V _threshold1 );
    2. Comparison (COMP ₂ ) of a second time interval (i-1) associated with a portion of a second detection signal (S _D-1 ) prior to the first detection signal (S _D ) with a second threshold (V _threshold2 );
• on the other hand, a function for assigning identification information (I _id ) to the first detection signal (S _D ), said identification information (I _id ) being determined according to the result of the comparisons carried out by the comparison algorithm (A _comp1 ), said identification information (I _id ) making it possible to discriminate between a detection signal (S _D ) having a physiological cause and a detection signal (S _D ) having as its cause a malfunction of electronic equipment.
• A display for generating a graphic marker superimposed on an electrogram comprising the first detection signal (S _D ) in order to temporally locate the identification information (I _id ) of the first detection signal (S _D ).

A system configured to implement the steps of the method according to any one of claims 1 to 10, said system comprising:

• An electrical device (1) comprising at least one probe (2) for receiving an electrical current;
• A signal generator for generating the first detection signal (S _D ) in response to receipt of electric current by the probe (2);
• A memory (M) for storing data;
• A communication interface for exchanging data with equipment of a remote data network (NET);

Computer program product comprising instructions which, when the program is executed by a computer, lead the latter to implement the steps of the method according to any one of Claims 1 to 10.