# US 11,992,323 B1 · Method and system for measuring cardiac tissue health based on DV/DTMIN of a depolarization wave within a cardiac electrogram

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- Number: US 11,992,323 B1
- Document ID: US11992323B1
- Status: Granted
- Kind: B1
- Application number: 17/821,791
- Filed: 2022-08-23
- Granted: 2024-05-28
- Earliest claimed: 2020-10-16
- Assignees: Neutrace Inc.
- Applicants: Neucures Inc.
- Inventors: Robert L. Lux
- Web page: https://patentgrep.com/patent/US11992323B1

## CPC

- A61B 5/349: Detecting specific parameters of the electrocardiograph cycle
- A61B 5/367: Electrophysiological study [EPS], e.g. electrical activation mapping or electro-anatomical mapping
- A61B 5/346: Analysis of electrocardiograms
- A61B 5/062: {using magnetic field}
- A61B 5/283: Invasive
- A61B 5/7203: {for noise prevention, reduction or removal}
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)

## Abstract

A method for determining cardiac tissue health based on a depolarization wave within an EGM is disclosed. The method includes computing a first derivative with respect to time (DV/DT) of the EGM, determining extrema for the first derivative, establishing a value DV/DTMIN based on the extrema and mapping the value DV/DTMIN to cardiac tissue.

## Claims

### Claim 1

A method for determining cardiac tissue health based on a depolarization wave within an electrogram (EGM), comprising:
measuring the EGM as a voltage signal using one or more catheters;
computing a derivative signal as a first derivative of the EGM with respect to time (DV/DT);
determining extrema for the derivative signal;
establishing a value DV/DTMIN as a minimum value of the derivative signal, based on the extrema; and
mapping the value DV/DTMIN to cardiac tissue.

### Claim 2 (depends on 1)

The method of claim 1, when the electrogram comprises a unipolar electrogram, then establishing the value DV/DTMIN comprises selecting a minima from the extrema as the value for DV/DTMIN.

### Claim 3 (depends on 1)

The method of claim 1, when the electrogram comprises a bipolar electrogram, then establishing the value DV/DTMIN comprises selecting as one of a maxima and a minima from the extrema as the value for DV/DTMIN N based on a ratio.

### Claim 4 (depends on 3)

The method of claim 3, wherein the value for DV/DTMIN is selected as Min dV/dt when the ratio |Min dV/dt|/|Max dV/dt| is greater than or equal to one.

### Claim 5 (depends on 3)

The method of claim 3, wherein the value for DV/DTMIN is selected as the—Max dV/dt when the ratio |Min dV/dt|/|Max dV/dt| is less than one.

### Claim 6

A system for determining cardiac tissue health based on a depolarization wave within an electrogram (EGM), comprising:
a signal acquisition module to measure the EGM as a voltage signal;
one or more processors coupled to a memory programmed with executable instructions to:
compute a derivative signal as a first derivative of the EGM with respect to time (DV/DT);
determine extrema for the derivative signal;
establish a value DV/DTMIN as a minimum value of the derivative signal, based on the extrema;
map the value DV/DTMIN to cardiac tissue.

### Claim 7 (depends on 6)

The system of claim 6, when the electrogram comprises a unipolar electrogram, then the value of DV/DTMIN is established by selecting a minima from the extrema as the value for DV/DTMIN.

### Claim 8 (depends on 6)

The system of claim 6, when the electrogram comprises a bipolar electrogram, then the value DV/DTMIN is established by selecting as one of a maxima and a minima from the extrema as the value for DV/DTMIN based on a ratio.

### Claim 9 (depends on 8)

The system of claim 8, wherein the value for DV/DTMIN is selected as Min dV/dt when the ratio |Min dV/dt|/|Max dV/dt| is greater than or equal to one.

### Claim 10 (depends on 8)

The system of claim 8, wherein the value for DV/DTMIN is selected as the—Max dV/dt when the ratio |Min dV/dt|/|Max dV/dt| is less than one.

### Claim 11

A non-transitory computer readable storage medium, having stored thereon, a set of computer-executable instructions that causes a computer to perform the method comprising:
measuring an electrogram (EGM) as a voltage signal using one or more catheters;
computing a derivative signal as a first derivative of the EGM with respect to time (DV/DT);
determining extrema for the derivative signal;
establishing a value DV/DTMIN as a minimum value of the derivative signal, based on the extrema; and
mapping the value DV/DTMIN to cardiac tissue.

### Claim 12 (depends on 11)

The non-transitory computer readable storage medium of claim 11, when the electrogram comprises a unipolar electrogram, then establishing the value DV/DTMIN comprises selecting a minima from the extrema as the value for DV/DTMIN.

### Claim 13 (depends on 11)

The non-transitory computer readable storage medium of claim 11, when the electrogram comprises a bipolar electrogram, then establishing the value DV/DTMIN comprises selecting as one of a maxima and a minima from the extrema as the value for DV/DTMIN based on a ratio.

### Claim 14 (depends on 13)

The non-transitory computer readable storage medium of claim 13, wherein the value for DV/DTMIN is selected as Min dV/dt when the ratio |Min dV/dt|/|Max dV/dt| is greater than or equal to one.

### Claim 15 (depends on 13)

The non-transitory computer readable storage medium of claim 13, wherein the value for DV/DTMIN is selected as the—Max dV/dt when the ratio |Min dV/dt|/|Max dV/dt| is less than one.