# US 2013/0158619 A1 · Multi-ventricular site timing optimization using cardiogenic impedance

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- Number: US 2013/0158619 A1
- Document ID: US20130158619A1
- Status: Published application
- Kind: A1
- Application number: 13/329,091
- Filed: 2011-12-16
- Published: 2013-06-20
- Earliest claimed: 2011-12-16
- Assignees: Pacesetter, Inc.
- Inventors: Kwangdeok Lee; Jong Gill; Kyungmoo Ryu
- Web page: https://patentgrep.com/patent/US20130158619A1

## CPC

- A61B 5/0538: invasively, e.g. using a catheter
- A61B 5/686: {Permanently implanted devices, e.g. pacemakers, other stimulators, biochips (A61B5/6861 takes precedence)}
- A61B 5/6869: {Heart}
- A61N 1/36521: {the parameter being derived from measurement of an electrical impedance}
- A61N 1/3682: {with a variable atrioventricular delay}
- A61N 1/36843: {Bi-ventricular stimulation}
- A61N 1/3684: {for stimulating the heart at multiple sites of the ventricle or the atrium}
- A61N 1/36842: {Multi-site stimulation in the same chamber}
- 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)

## Abstract

A method of calculating a timing delay for an implantable medical device based on cardiogenic impedance estimates cardiogenic impedance from a signal between a first electrode and a second electrode positioned in at least one chamber of a heart. The method also determines the timing delay based on the estimated cardiogenic impedance.

## Claims

### Claim 1

A method of calculating a timing delay for an implantable medical device based on cardiogenic impedance, comprising:
estimating cardiogenic impedance from a signal between a first electrode and a second electrode positioned in at least one chamber of a heart; and
determining the timing delay based on the estimated cardiogenic impedance.

### Claim 2 (depends on 1)

The method of claim 1, in which the timing delay comprises an atrio-ventricular (AV) delay.

### Claim 3 (depends on 2)

The method of claim 2, in which estimating comprises calculating a maximum negative slope based on a derivative of a systolic portion of the signal.

### Claim 4 (depends on 2)

The method of claim 2, in which estimating is based on a time interval between a bi-ventricular pacing spike and a maximum cardiogenic impedance.

### Claim 5 (depends on 2)

The method of claim 2, further comprising evaluating a bi-ventricular pacing percentage associated with the timing delay to determine whether the bi-ventricular pacing percentage meets a threshold value.

### Claim 6 (depends on 1)

The method of claim 1, in which the signal comprises a vector that encompasses a mitral valve region of the heart, the vector capturing information related to blood flow across the mitral valve region and information related to left ventricular contraction.

### Claim 7 (depends on 1)

The method of claim 1, further comprising selecting the second electrode such that the signals acquired correlate to an echo-based E/A waveform.

### Claim 8 (depends on 7)

The method of claim 7, in which the selection of the electrodes is based on at least one of timing, morphology of E and A peaks, consistency of a cardiogenic impedance pattern, signal to noise ratio and random noise level.

### Claim 9 (depends on 1)

The method of claim 1, in which the timing delay comprises an interventricular timing delay.

### Claim 10 (depends on 9)

The method of claim 9, in which the estimating comprises measuring peak to peak cardiogenic impedance.

### Claim 11

An apparatus for calculating a timing delay for an implantable medical device based on cardiogenic impedance, comprising:
a memory; and
at least one processor coupled to the memory and configured:
to estimate cardiogenic impedance from a signal between a first electrode and a second electrode positioned in at least one chamber of a heart; and
to determine the timing delay based on the estimated cardiogenic impedance.

### Claim 12 (depends on 11)

The apparatus of claim 11, in which the timing delay comprises an atrio-ventricular (AV) delay.

### Claim 13 (depends on 12)

The apparatus of claim 12, in which the at least one processor is configured to estimate by calculating a maximum negative slope based on a derivative of a systolic portion of the signal.

### Claim 14 (depends on 12)

The apparatus of claim 12, in which the at least one processor is configured to estimate based on a time interval between a bi-ventricular pacing spike and a maximum cardiogenic impedance.

### Claim 15 (depends on 12)

The apparatus of claim 12, in which the at least one processor is further configured to evaluate a bi-ventricular pacing percentage associated with the timing delay to determine whether the bi-ventricular pacing percentage meets a threshold value.

### Claim 16 (depends on 11)

The apparatus of claim 11, in which the signal comprises a vector that encompasses a mitral valve region of the heart, the vector capturing information related to blood flow across the mitral valve region and information related to left ventricular contraction.

### Claim 17 (depends on 11)

The apparatus of claim 11, in which the at least one processor is further configured to select the second electrode such that the signals acquired correlate to an echo-based E/A waveform.

### Claim 18 (depends on 17)

The apparatus of claim 17, in which the at least one processor is configured to select the electrodes based on at least one of timing, morphology of E and A peaks, consistency of a cardiogenic impedance pattern, signal to noise ratio and random noise level.

### Claim 19 (depends on 11)

The apparatus of claim 11, in which the timing delay comprises an interventricular timing delay.

### Claim 20 (depends on 19)

The apparatus of claim 19, in which the at least one processor is configured to estimate by measuring peak to peak cardiogenic impedance.

### Claim 21

An apparatus for calculating a timing delay for an implantable medical device based on cardiogenic impedance, comprising:
means for estimating cardiogenic impedance from a signal between a first electrode and a second electrode positioned in at least one chamber of a heart; and
means for determining the timing delay based on the estimated cardiogenic impedance.

### Claim 22

A computer program product for calculating a timing delay for an implantable medical device based on cardiogenic impedance, comprising:
a computer-readable medium having non-transitory program code recorded thereon, the program code comprising:
program code to estimate cardiogenic impedance from a signal between a first electrode and a second electrode positioned in at least one chamber of a heart; and
program code to determine the timing delay based on the estimated cardiogenic impedance.