# US 7,610,084 B2 · System and method for classifying cardiac depolarization complexes with multi-dimensional correlation

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- Number: US 7,610,084 B2
- Document ID: US7610084B2
- Status: Granted
- Kind: B2
- Application number: 11/422,772
- Filed: 2006-06-07
- Published: 2006-09-21
- Granted: 2009-10-27
- Earliest claimed: 2001-06-05
- Assignees: Cardiac Pacemakers, Inc.
- Inventors: Robert J. Sweeney; William Hsu
- Web page: https://patentgrep.com/patent/US7610084B2

## CPC

- A61B 5/7264: {Classification of physiological signals or data, e.g. using neural networks, statistical classifiers, expert systems or fuzzy systems}
- A61B 5/35: by template matching
- A61N 1/39622: {Pacing therapy}
- G16H 50/20: for computer-aided diagnosis, e.g. based on medical expert systems
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- A61N: ELECTROTHERAPY; MAGNETOTHERAPY; RADIATION THERAPY; ULTRASOUND THERAPY (measurement of bioelectric currents A61B; surgical instruments, devices or methods for transferring non-mechanical forms of energy to or from the body A61B18/00; anaesthetic apparatus in general A61M; incandescent lamps H01K; infrared radiators for heating H05B)
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA

## Abstract

A system and method for classifying cardiac depolarization complexes in which waveforms of a depolarization complex are sensed by separate electrodes and correlated with template waveforms of a template depolarization complex. The system is particularly suitable for incorporation into a cardiac rhythm management device such as an implantable cardioverter/defibrillator or pacemaker in order to facilitate arrhythmia prediction and/or prevention.

## Claims

### Claim 1

A method for classifying a sensed cardiac depolarization complex, comprising:
sensing a plurality of depolarization waveforms resulting from a cardiac depolarization complex, wherein each of the plurality of sensed waveforms is sensed with a sensing channel having a different electrode configuration, and generating digital samples of the sensed waveforms over a defined period of time to result in a sample set for each sensed waveform;
storing the sample set of each sensed waveform in a sensed sample array and a sample set of each corresponding waveform of a template depolarization complex in a template sample array;
computing a multi-dimensional correlation between the sensed sample arrays and the corresponding template sample arrays;
classifying the sensed depolarization complex is as being equivalent to the template complex if the multi-dimensional correlation indicates a specified degree of similarity;
grouping samples of the sensed and template waveforms at a particular sampling time into a sensed complex vector and template complex vector, respectively; and,
adding one or more parameter features to the sensed and template complex vectors, wherein a parameter feature is defined as the deviation from a mean value of a measurable parameter related to a cardiac depolarization complex.

### Claim 2 (depends on 1)

The method of claim 1 further comprising subtracting a mean waveform value from each array member of the sensed sample and template arrays.

### Claim 3 (depends on 2)

The method of claim 2 further comprising averaging samples of a sensed waveform to compute a mean value for that waveform.

### Claim 4 (depends on 1)

The method of claim 1 wherein a parameter feature added to the sensed complex vector and the template complex vector is a signal amplitude associated with a depolarization complex.

### Claim 5 (depends on 1)

The method of claim 1 wherein a parameter feature added to the sensed complex vector and the template complex vector is a time interval associated with a depolarization complex.

### Claim 6 (depends on 5)

The method of claim 5 wherein a parameter feature added to the sensed complex vector and the template complex vector is a QRS duration.

### Claim 7 (depends on 5)

The method of claim 5 wherein a parameter feature added to the sensed complex vector and the template complex vector is a QT interval.

### Claim 8 (depends on 5)

The method of claim 5 wherein a parameter feature added to the sensed complex vector and the template complex vector is an ST segment duration.

### Claim 9

A cardiac rhythm management device having incorporated therein a system for classifying sensed cardiac depolarization complexes, comprising:
a plurality of sensing channels for sensing waveforms of a cardiac depolarization complex and for converting the sensed waveforms into digitized samples, wherein each of the plurality of sensing channels has a different electrode configuration;
a processor and associated memory interfaced to the sensing channels; and,
wherein the processor is programmed to:
store digital samples of the sensed waveforms from each of the plurality of sensed channels over a defined period of time to result in a sample set of each sensed waveform;
store the sample set of each sensed waveform in a sensed sample array;
store a sample set of each corresponding waveform of a template depolarization complex in a template sample array;
compute a multi-dimensional correlation between the sensed sample arrays and the corresponding template sample arrays;
classify the sensed depolarization complex is as being equivalent to the template complex if the multi-dimensional correlation indicates a specified degree of similarity;
group samples of the sensed and template waveforms at a particular sampling time into a sensed complex vector and template complex vector, respectively; and,
add one or more parameter features to the sensed and template complex vectors, wherein a parameter feature is defined as the deviation from a mean value of a measurable parameter related to a cardiac depolarization complex.

### Claim 10 (depends on 9)

The device of claim 9 wherein the processor is programmed to subtract a mean waveform value from each array member of the sensed sample and template arrays.

### Claim 11 (depends on 10)

The device of claim 10 wherein the processor is programmed to average samples of the sensed waveforms to compute a mean value.

### Claim 12 (depends on 9)

The device of claim 9 wherein a parameter feature added to the sensed complex vector and the template complex vector is a signal amplitude associated with a depolarization complex.

### Claim 13 (depends on 9)

The device of claim 9 wherein a parameter feature added to the sensed complex vector and the template complex vector is a time interval associated with a depolarization complex.

### Claim 14 (depends on 13)

The device of claim 13 wherein a parameter feature added to the sensed complex vector and the template complex vector is a QRS duration.

### Claim 15 (depends on 13)

The device of claim 13 wherein a parameter feature added to the sensed complex vector and the template complex vector is a QT interval.

### Claim 16 (depends on 13)

The device of claim 13 wherein a parameter feature added to the sensed complex vector and the template complex vector is an ST segment duration.