MULTI-VECTOR SENSING IN CARDIAC DEVICES USING A HYBRID APPROACH

• US 20170112399A1
• Filed: 10/19/2016
• Published: 04/27/2017
• Est. Priority Date: 10/23/2015
• Status: Active Grant

• Current Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Original Assignee: Cardiac Pacemakers Incorporated (Boston Scientific Corporation)
• Inventors: Brisben, Amy Jean, Allavatam, Venugopal, Siejko, Krzysztof Z., Mahajan, Deepa, Wika, Kevin G., Herrmann, Keith L., Hahn, Stephen J.
• Granted Patent: US 10,321,834 B2
• Time in Patent Office: Days
• CPC Class Codes: A61B 5/02416 using photoplethysmograph signals, e.g. generated by infrared radiation A61B5/14552 takes precedence
• CPC Class Codes: A61B 5/0245 by using sensing means generating electric signals, i.e. ECG signals
• CPC Class Codes: A61B 5/283 Invasive
• CPC Class Codes: A61B 5/287 Holders for multiple electrodes, e.g. electrode catheters for electrophysiological study [EPS]
• CPC Class Codes: A61B 5/316 Modalities, i.e. specific diagnostic methods
• CPC Class Codes: A61B 5/318 Heart-related electrical modalities, e.g. electrocardiography [ECG]
• CPC Class Codes: A61B 5/327 Generation of artificial ECG signals based on measured signals, e.g. to compensate for missing leads
• CPC Class Codes: A61B 5/341 Vectorcardiography [VCG]
• CPC Class Codes: A61B 5/349 Detecting specific parameters of the electrocardiograph cycle
• CPC Class Codes: A61B 5/35 by template matching
• CPC Class Codes: A61B 5/352 Detecting R peaks, e.g. for synchronising diagnostic apparatus; Estimating R-R interval
• CPC Class Codes: A61B 5/364 Detecting abnormal ECG interval, e.g. extrasystoles, ectopic heartbeats
• CPC Class Codes: A61B 5/366 Detecting abnormal QRS complex, e.g. widening
• CPC Class Codes: A61B 5/686 Permanently implanted devices, e.g. pacemakers, other stimulators, biochips A61B5/6861 takes precedence
• CPC Class Codes: A61B 5/6869 Heart
• CPC Class Codes: A61B 5/72 Signal processing specially adapted for physiological signals or for diagnostic purposes character recognition, recognising digital ink, document-oriented image-based pattern recognition G06V30/00; recognition or understanding of postal images G06V30/424
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal
• CPC Class Codes: A61B 5/7221 Determining signal validity, reliability or quality A61B5/7207 and A61B5/7217 take precedence
• CPC Class Codes: A61N 1/046 Specially adapted for shock therapy, e.g. defibrillation
• CPC Class Codes: A61N 1/05 for implantation or insertion into the body, e.g. heart electrode A61N1/06 takes precedence
• CPC Class Codes: A61N 1/0563 : specially adapted for defibrillation or cardioversion
• CPC Class Codes: A61N 1/3622 : comprising two or more electrodes co-operating with different heart regions
• CPC Class Codes: A61N 1/3625 : External stimulators
• CPC Class Codes: A61N 1/36514 : controlled by a physiological quantity other than heart potential, e.g. blood pressure controlled by two or more physical parameters A61N1/36585
• CPC Class Codes: A61N 1/3704 : Circuits specially adapted therefor, e.g. for sensitivity control
• CPC Class Codes: A61N 1/3925 : Monitoring; Protecting
• CPC Class Codes: A61N 1/3956 : Implantable devices for applying electric shocks to the heart, e.g. for cardioversion
• CPC Class Codes: A61N 1/3987 : characterised by the timing or triggering of the shock

Abstract

Methods and devices for combining multiple signals from multiple sensing vectors for use in wearable or implantable cardiac devices. A preferred sensing configuration may be selected at a given point in time, for example under clinical conditions. Signal quality for the preferred sensing configuration is then monitored, and if the signal quality degrades under selected conditions, re-analysis may be performed to select a different sensing vector configuration for at least temporary use. If signal quality increases for the preferred sensing configuration, temporary use of the different sensing vector configuration may cease and reversion to the preferred sensing configuration takes place if certain conditions are met. The conditions for reversion may depend in part of a history of sensing signal quality for the preferred sensing configuration.

Claims

1. A cardiac rhythm management device having operational circuitry for analyzing cardiac signals including a least first and second cardiac sensing vectors and first and second sensing channels, wherein the operational circuitry is configured to use the at least first and second sensing vectors as follows:

comparing one or more sensing quality metrics of the at least first and second cardiac sensing vectors;

selecting one of the at least first and second cardiac sensing vectors as a preferred sensing configuration;

implementing the preferred sensing configuration to analyze cardiac signals;

identifying low sensing signal quality for the preferred sensing configuration and;

re-analyzing sensing quality metrics of the at least first and second cardiac sensing vectors;

identifying a better sensing configuration than the preferred sensing configuration, at least as assessed at the time of the low sensing quality of the preferred sensing configuration;

if one or more first preconditions are met, implementing the better sensing configuration to analyze cardiac signals; and

monitoring signal quality of the preferred sensing configuration until the low sensing quality for the preferred sensing configuration improves and one or more second preconditions are met, at which time the operational circuitry is configured to return to using the preferred sensing configuration.

2. The device of claim 1 wherein the preferred sensing configuration uses data from a single cardiac sensing vector, and the better sensing configuration uses data from plural cardiac sensing vectors.

3. The device of claim 2 wherein the preferred sensing configuration uses data from a single cardiac sensing vector, and the better sensing configuration uses data from a different cardiac sensing vector than the preferred sensing configuration.

4. The device of claim 2 wherein the preferred sensing configuration uses data from a single cardiac sensing vector, and the better sensing configuration uses data from either:

the same cardiac sensing vector, but with a different application of one or more filtering or amplification characteristics than the preferred sensing configuration;

or

a different cardiac sensing vector than the preferred sensing configuration.

5. The device of claim 1 wherein the operational circuitry is configured to sense a posture of the patient and at least one of the preconditions comprises determining that the patient is remaining in a single posture.

6. The device of claim 1 wherein the operational circuitry is configured to detect an activity level of the patient and at least one of the preconditions comprises determining that the patient'"'"'s activity level is below or above a threshold.

7. The device of claim 1 wherein the operational circuitry is configured to initialize the better sensing configuration before the better sensing configuration is implemented.

8. The device of claim 7 wherein:

the operational circuitry is configured to initialize the better sensing configuration at least by seeding a value for cardiac cycle rate from memory, without reference to a signal detected using the better sensing configuration; and

the operational circuitry is configured to use a detection profile for analyzing cardiac signals by applying a time varying detection threshold to cardiac signals to detect cardiac cycles, the time varying detection threshold being defined by the detection profile, wherein the detection profile changes in accordance with cardiac cycle rate, such that seeding a value for cardiac cycle rate affects the detection profile of the better sensing configuration.

9. The device of claim 7 wherein:

the operational circuitry is configured to initialize the better sensing configuration at least by determining a cardiac rate using an autocorrelation analysis and storing the cardiac rate; and

the operational circuitry is configured to use a detection profile for analyzing cardiac signals by applying a time varying detection threshold to cardiac signals to detect cardiac cycles, the time varying detection threshold being defined by the detection profile, wherein the detection profile changes in accordance with cardiac rate, such that storing a cardiac rate affects the detection profile of the better sensing configuration.

10. The device of claim 7 wherein:

the operational circuitry is configured to initialize the better sensing configuration at least by seeding a value for cardiac cycle amplitude from memory, without reference to a signal detected using the better sensing configuration; and

the operational circuitry is configured to use a detection profile for analyzing cardiac signals by applying a time varying detection threshold to cardiac signals to detect cardiac cycles, the time varying detection threshold being defined by the detection profile and an estimate of cardiac cycle amplitude, such that seeding a value for cardiac cycle amplitude affects the detection profile of the better sensing configuration.

11. The device of claim 7 wherein the operational circuitry is configured to initialize the better sensing configuration at least by forming a template of normal cardiac cycle activity for the better sensing configuration.

12. The device of claim 1 wherein the operational circuitry is configured to provide an alert to the patient regarding change of the sensing vectors before implementing the better sensing configuration.

13. A cardiac rhythm management device having operational circuitry for analyzing cardiac signals including cardiac signals captured using at least first and second cardiac sensing vectors and first and second sensing channels, wherein the operational circuitry is configured to use the at least first and second sensing vectors as follows:

comparing one or more sensing quality metrics of the at least first and second cardiac sensing vectors;

selecting weighted sum of the at least first and second cardiac sensing vectors as apreferred sensing configuration;

implementing the preferred sensing configuration to analyze cardiac signals;

identifying low sensing signal quality for the preferred sensing configuration and;

re-analyzing sensing quality metrics of the at least first and second cardiac sensing vectors;

identifying a better sensing configuration than the preferred sensing configuration, at least as assessed at the time of the low sensing quality of the preferred sensing configuration;

if one or more first preconditions are met, implementing the better sensing configuration to analyze cardiac signals; and

monitoring signal quality of the preferred sensing configuration until the low sensing quality for the preferred sensing configuration improves and one or more second preconditions are met, at which time the operational circuitry is configured to return to using the preferred sensing configuration.

14. The device of claim 13 wherein the first and second preconditions include a determination that no current tachyarrhythmia is ongoing.

15. The device of claim 13 wherein the second preconditions include a determination that a minimum time period has expired since the better sensing configuration was implemented.

16. The device of claim 15 wherein the operational circuitry is configured to calculate the minimum time period by reviewing history for the device, determining whether low sensing signal quality has been identified for the preferred sensing configuration repeatedly and selecting from:

a first value longer than a second value if low sensing signal quality has been identified for the preferred sensing configuration repeatedly;

or else

the second value.

17. The device of claim 15 wherein the operational circuitry is configured to calculate the minimum time period by reviewing history for the device, determining whether low sensing signal quality has been identified for the preferred sensing configuration repeatedly and selecting from:

a first, default value;

or

a value which exceeds a time period between at least two instances of repeated drops in sensing signal quality.

18. The device of claim 13 wherein the operational circuitry is configured to sense a posture of the patient and at least one of the preconditions comprises determining that the patient is remaining in a single posture.

19. The device of claim 13 wherein the operational circuitry is configured to detect an activity level of the patient and at least one of the preconditions comprises determining that the patient'"'"'s activity level is below or above a threshold.

20. A cardiac rhythm management device having operational circuitry for analyzing cardiac signals including signals captured using at least first and second cardiac sensing vectors, wherein the operational circuitry is configured to use the at least first and second sensing vectors as follows:

selecting a first sensing configuration as a preferred sensing configuration, the first sensing configuration using data from only one of the at least first and second cardiac sensing vectors, and implementing the first sensing configuration to analyze cardiac signals;

identifying low sensing signal quality for the first sensing configuration; and

analyzing a plurality of individual sensing vectors and determining whether any have sensing signal quality that at least exceeds the sensing signal quality of the first sensing configuration and a signal quality threshold, and;

a) if so, identifying a second sensing configuration to replace, at least temporarily, the preferred sensing configuration, the second sensing configuration using data from only one of the at least first and second cardiac sensing vectors, and implementing the second sensing configuration to analyze cardiac signals;

or

b) if not, identifying a third sensing configuration to replace, at least temporarily, the preferred sensing configuration, the third sensing configuration combining data from at least two of the at least first and second cardiac sensing vectors, and implementing the third sensing configuration to analyze cardiac signals.