Annotation of a wavefront

Patent metadata

Field	Value
Publication number	US-10383534-B2
Application number	US-201715646373-A
Country	US
Kind code	B2
Filing date	Jul 11, 2017
Priority date	Aug 11, 2016
Publication date	Aug 20, 2019
Grant date	Aug 20, 2019

Abstract

A method, including receiving a bipolar signal from a pair of electrodes in proximity to a myocardium of a human subject and receiving a unipolar signal from a selected one of the pair of electrodes. The method further includes computing a local unipolar minimum derivative of the unipolar signal, and a time of occurrence of the unipolar minimum derivative. The method also includes computing a bipolar derivative of the bipolar signal, evaluating a ratio of the bipolar derivative to the local unipolar minimum derivative, and when the ratio is greater than a preset threshold ratio value, identifying the time of occurrence as a time of activation of the myocardium.

First claim

The invention claimed is:

1. A computer implemented method, comprising:
inserting a probe into the heart of a living patient, the probe having a distal end portion and a pair of electrodes along the distal end portion;
receiving a bipolar ECG signal from a location in the heart with the pair of electrodes;
receiving a unipolar ECG signal from the location in the heart with a selected one of the pair of electrodes;
analyzing the received unipolar and bipolar ECG signals by a processor, comprising:
computing a local unipolar minimum derivative of the unipolar signal;
computing a time of occurrence of the local unipolar minimum derivative;
computing a bipolar derivative of the bipolar signal;
evaluating a ratio of the bipolar derivative to the local unipolar minimum derivative at the time of occurrence of the unipolar minimum derivative;
computing a confidence level value to the time of occurrence;

assigning the time of occurrence as a time of activation of the myocardium at the location in the heart when the ratio is greater than a preset threshold ratio value and the confidence level value of the time of occurrence is greater than a preset confidence value; and
generating a local activation time map using the assigned time of activation of the myocardium at the location in the heart.

2. The method according to claim 1 , and further comprising, when the bipolar derivative is less than a preset bipolar derivative threshold, assigning the time of occurrence as the time of activation of the myocardium.

3. The method according to claim 1 , and further comprising, when the local unipolar minimum derivative is less than a preset unipolar derivative threshold, assigning the time of occurrence as the time of activation of the myocardium.

4. The method according to claim 1 , and comprising assigning the time of occurrence as the time of activation of the myocardium when an amplitude of the bipolar signal is greater than a preset bipolar signal threshold.

5. The method according to claim 1 , wherein computing a confidence level value to the time of occurrence, comprises:
computing a time duration of a downward segment of the unipolar minimum derivative;
computing an amplitude of a unipolar slope segment within the time duration;
computing a ratio between the amplitude and the time duration; and
computing an amplitude of the bipolar derivative within the time duration.

6. Apparatus, comprising:
a probe having a distal end portion and being adapted for insertion into a heart of a living subject;
a pair of electrodes located along the distal end portion configured to be placed in proximity to a myocardium of a human subject; and
a processor configured to:
receive a bipolar ECG signal from a location in the heart with the pair of electrodes,
receive a unipolar ECG signal from the location in the heart with a selected one of the pair of electrodes;
compute a local unipolar minimum derivative of the unipolar signal, and a time of occurrence of the unipolar minimum derivative;
compute a bipolar derivative of the bipolar signal;
evaluate a ratio of the bipolar derivative to the local unipolar minimum derivative at the time of occurrence;
compute a confidence level value to the time of occurrence;
assign the time of occurrence as a time of activation of the myocardium at the location in the heart when the ratio is greater than a preset threshold ratio value and the confidence level value of the time of occurrence is greater than a preset confidence value; and
generate a local activation time map using the assigned time of activation of the myocardium at the location in the heart.

7. The apparatus according to claim 6 , and further comprising, when the bipolar derivative is less than a preset bipolar derivative threshold, the processor being configured to assign the time of occurrence as the time of activation of the myocardium.

8. The apparatus according to claim 6 , and further comprising, when the local unipolar minimum derivative is less than a preset unipolar derivative threshold, the processor being configured to assign the time of occurrence as the time of activation of the myocardium.

9. The apparatus according to claim 6 , further comprising the processor being configured to assign the time of occurrence as the time of activation of the myocardium when an amplitude of the bipolar signal is greater than a preset bipolar signal threshold.

10. The apparatus according to claim 6 , wherein the processor is further configured to:
compute a time duration of a downward segment of the unipolar minimum derivative;
compute an amplitude of a unipolar slope segment within the time duration;
compute a ratio between the amplitude and the time duration; and
compute an amplitude of the bipolar derivative within the time duration.

Assignees

• Biosense Webster Israel Ltd

Inventors

• Botzer Lior
• Bar-Tal Meir
• Nakar Elad

Classifications

• A61B5/7235

  Details of waveform analysis (detecting specific parameters of the electrocardiograph cycle A61B5/349) · CPC title

• A61B2505/05

  Surgical care · CPC title

• A61B5/743

  Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots · CPC title

• A61B5/6869

  Heart · CPC title

• A61B5/7239

  using differentiation including higher order derivatives · CPC title