# US 10,863,948 B2 · Heart failure stratification based on respiratory pattern

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- Number: US 10,863,948 B2
- Document ID: US10863948B2
- Status: Granted
- Kind: B2
- Application number: 16/182,353
- Filed: 2018-11-06
- Published: 2019-06-06
- Granted: 2020-12-15
- Earliest claimed: 2017-12-06
- Assignees: Cardiac Pacemakers, Inc.
- Applicants: Cardiac Pacemakers, Inc.
- Inventors: Qi An; Jianjun Yuan; Pramodsingh Hirasingh Thakur; Yi Zhang; Rezwan Ahmed; Viktoria A. Averina
- Web page: https://patentgrep.com/patent/US10863948B2

## CPC

- A61B 5/7275: {Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor}
- A61B 5/0205: Simultaneously evaluating both cardiovascular conditions and different types of body conditions, e.g. heart and respiratory condition
- A61B 5/0816: {Measuring devices for examining respiratory frequency (measuring frequency of electric signals G01R23/00)}
- A61B 5/086: {by impedance pneumography}
- A61B 5/4836: {Diagnosis combined with treatment in closed-loop systems or methods (A61B5/0036 takes precedence)}
- A61B 5/686: {Permanently implanted devices, e.g. pacemakers, other stimulators, biochips (A61B5/6861 takes precedence)}
- A61B 7/04: Electric stethoscopes
- G16H 20/40: relating to mechanical, radiation or invasive therapies, e.g. surgery, laser therapy, dialysis or acupuncture
- G16H 40/63: for local operation
- G16H 50/30: for calculating health indices; for individual health risk assessment
- A61B 5/0538: invasively, e.g. using a catheter
- A61B 5/091: Measuring volume of inspired or expired gases, e.g. to determine lung capacity
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G16H: HEALTHCARE INFORMATICS, i.e. INFORMATION AND COMMUNICATION TECHNOLOGY [ICT] SPECIALLY ADAPTED FOR THE HANDLING OR PROCESSING OF MEDICAL OR HEALTHCARE DATA

## Abstract

Systems and methods for monitoring patients for risk of worsening heart failure (WHF) are discussed. A patient management system includes a receiver to receive patient respiration measurement. A respiratory pattern analyzer circuit measures respiratory pattern indicative of rapid-shallow breathing pattern from the received respiration measurement, and determine a respiratory pattern variability indicator. A risk analyzer circuit determines patient WHF risk using the respiratory pattern variability indicator. The system may use the WHF risk to guide WHF event detection, or to deliver or adjust a heart failure therapy.

## Claims

### Claim 1

A system for assessing a patient risk for a future worsening heart failure (WHF) event, comprising:
a signal receiver circuit configured to receive a respiratory signal from the patient;
a processor circuit, including:
a respiratory pattern analyzer circuit configured to measure a rapid-shallow breathing index (RSBI) parameter using the received respiratory signal, and to determine an RSBI variability indicator indicative of temporal variation of the measured RSBI parameter; and
a risk analyzer circuit configured to generate a WHF risk indicator using the determined RSBI variability indicator.

### Claim 2 (depends on 1)

The system of claim 1, comprising a sensor circuit coupled to an impedance sensor configured to sense a thoracic impedance correlated to respiration,
wherein the respiratory patter analyzer circuit is configured to detect a respiratory rate and a tidal volume using the sensed thoracic impedance, and to generate the RSBI based on a ratio of the detected respiratory rate to the detected tidal volume.

### Claim 3 (depends on 1)

The system of claim 1, wherein the RSBI parameter includes a daily representative RSBI, and
wherein the respiratory pattern analyzer circuit is configured to determine the RSBI variability indicator using measurements of daily representative RSBI over multiple days.

### Claim 4 (depends on 3)

The system of claim 3, wherein the daily representative RSBI includes a daily minimum RSBI.

### Claim 5 (depends on 3)

The system of claim 3, wherein the daily representative RSBI includes a specific percentile of measurements of daily RSBI parameters, the specific percentile being lower than 50-th percentile.

### Claim 6 (depends on 1)

The system of claim 1, comprising an activity detection circuit configured to detect patient physical activity, wherein the signal receiver circuit configured to receive a respiratory signal when the detected patient physical activity satisfies a specific condition.

### Claim 7 (depends on 1)

The system of claim 1, wherein:
the signal receiver circuit is further configured to receive a heart sounds signal;
the processor circuit includes a heart sound analyzer circuit configured to generate a heart sound metric using the received heart sounds signal; and
the risk analyzer circuit is configured to:
generate the WHF risk indicator using the RSBI variability indicator if the received heart sounds signal fails to satisfy a signal quality condition; and
generate the WHF risk indicator using the heart sound metric if the received heart sounds signal satisfies the signal quality condition.

### Claim 8 (depends on 1)

The system of claim 1, wherein:
the respiratory pattern analyzer circuit is further configured to generate, from the sensed respiratory signal, one or more respiratory metrics including a respiratory rate trend, a respiratory rate variability over time, a tidal volume trend, or a tidal volume variability over time; and
the risk analyzer circuit is configured to generate the WHF risk indicator further using the generated one or more respiratory metrics.

### Claim 9 (depends on 8)

The system of claim 8, wherein the respiratory pattern analyzer circuit is configured to generate a tidal volume trend and a respiratory rate trend from the sensed respiratory signal, and the risk analyzer circuit is configured to:
generate the WHF risk indicator using the RSBI variability indicator if the tidal volume trend satisfies a quality condition; and
generate the WHF risk indicator using the respiratory rate trend if the tidal volume trend fails to satisfy the quality condition.

### Claim 10 (depends on 1)

The system of claim 1, comprising a detector circuit configured to detect a WHF event based on the generated WHF risk indicator.

### Claim 11 (depends on 1)

The system of claim 1, comprising a therapy circuit configured to generate a heart failure therapy when the WHF risk indicator satisfies a specific condition.

### Claim 12 (depends on 1)

The system of claim 1, wherein the respiratory pattern analyzer circuit is configured to determine the RSBI variability indicator using a range between two percentiles of measurements of RSBI parameters over one or more days.

### Claim 13

A method for assessing a patient risk for a future worsening heart failure (WHF) event using a medical system, the method comprising:
receiving a respiratory signal from the patient via a signal receiver circuit;
measuring, via a respiratory pattern analyzer circuit, a rapid-shallow breathing index (RSBI) parameter from the received respiratory signal;
determining an RSBI variability indicator indicative of temporal variation of the measured RSBI parameter; and
generating a WHF risk indicator using the determined RSBI variability indicator via a risk analyzer circuit.

### Claim 14 (depends on 13)

The method of claim 13, wherein the RSBI parameter includes a daily representative RSBI, and
wherein the RSBI variability indicator is determined using measurements of daily representative RSBI over multiple days.

### Claim 15 (depends on 14)

The method of claim 14, further comprising determining a baseline RSBI using the measurements of daily representative RSBI over multiple days, wherein generating the WHF risk indicator is further based on the baseline RSBI.

### Claim 16 (depends on 13)

The method of claim 13, further comprising generating a heart sound metric using a heart sounds signal, wherein generating the WHF risk indicator includes:
generating the WHF risk indicator using the RSBI variability indicator if the received heart sounds signal satisfies a signal quality condition; and
generating the WHF risk indicator using the heart sound metric if the received heart sounds signal fails to satisfy the signal quality condition.

### Claim 17 (depends on 13)

The method of claim 13, further comprising generating one or more respiratory metrics from the sensed respiratory signal, the one or more respiratory metrics including a respiratory rate trend, a respiratory rate variability over time, a tidal volume trend, or a tidal volume variability over time, wherein generating the WHF risk indicator is further based on the one or more respiratory metrics.

### Claim 18 (depends on 17)

The method of claim 17, wherein the one or more respiratory metrics include a tidal volume trend and a respiratory rate trend from the sensed respiratory signal, wherein generating the WHF risk indicator includes:
generating the WHF risk indicator using the RSBI variability indicator if the tidal volume trend satisfies a quality condition; and
generating the WHF risk indicator using the respiratory rate trend if the tidal volume trend fails to satisfy the quality condition.

### Claim 19 (depends on 13)

The method of claim 13, further comprising delivering a heart failure therapy when the WHF risk indicator satisfies a specific condition.

### Claim 20 (depends on 13)

The method of claim 13, wherein the RSBI variability indicator includes a range between two percentiles of measurements of RSBI parameters over one or more days.