R-R interval analysis for ECG waveforms to assess autonomic response to vagus nerve stimulation

Patent metadata

Field	Value
Publication number	US-11786732-B2
Application number	US-201917054982-A
Country	US
Kind code	B2
Filing date	May 13, 2019
Priority date	May 15, 2018
Publication date	Oct 17, 2023
Grant date	Oct 17, 2023

Abstract

An assessment system is provided for vagus nerve stimulation treatment with a neurostimulator configured to deliver a stimulation signal having a plurality of ON-periods and OFF-periods. The assessment system includes a wand assembly configured to generate a delivery detection signal indicating delivery of the stimulation signal, a lead assembly configured to acquire an ECG signal, and a data acquisition system configured to capture the delivery detection and ECG signals. The assessment system further includes a processor and a non-transitory computer-readable memory storing instructions that, when executed by the processor, cause the assessment system to record the ECG signal over at least one successive pair of ON- and OFF-periods, determine a heart rate dynamic response from the ECG signal, and determine an instantaneous heart rate for each determined R-R interval to determine heart rate dynamics for assessment of autonomic engagement in response to the vagus nerve stimulation treatment.

First claim

What is claimed is:

1. An assessment system for vagus nerve stimulation therapy treatment for congestive heart failure in a subject implanted with a neurostimulator configured to deliver a periodic stimulation signal having a plurality of ON-periods and OFF-periods, each ON-period being defined as a time between an initiating pulse and a terminating pulse of a plurality of stimulation pulses delivered to the subject, each OFF-period being defined as a time between consecutive ON-periods, the assessment system comprising:
a wand assembly in communication with the neurostimulator, the wand assembly configured to detect a delivery of the periodic stimulation signal from the neurostimulator to the subject and to generate a delivery detection signal indicating the detected delivery of the periodic stimulation signal;
a lead assembly configured to acquire an ECG signal of the subject over the plurality of ON-periods and OFF-periods;
a data acquisition system coupled to the wand and lead assemblies and configured to capture each of the delivery detection signal and the ECG signal; and
a processor and a non-transitory computer-readable memory storing instructions that, when executed by the processor, cause the assessment system to:
record the ECG signal over at least one successive pair of ON- and OFF-periods including, for each pair of ON- and OFF-periods, synchronizing a start of the recorded ECG signal using the delivery detection signal to provide a first portion of the recorded ECG signal corresponding to the ON-period and a second portion of the recorded ECG signal corresponding to the OFF-period;
determine a heart rate dynamic response from the ECG signal, including:
detecting each QRS complex in each of the first and second portions of the recorded ECG signal;
identifying each potential R-wave in each QRS complex in each of the first and second portions of the recorded ECG signal;
verifying each identified R-wave in each of the first and second portions of the recorded ECG signal; and

determining an R-R interval between each pair of successive verified R-waves;
determine an instantaneous heart rate for each determined R-R interval to determine heart rate dynamics for assessment of autonomic engagement in response to the vagus nerve stimulation therapy treatment; and
display the recorded ECG signal in real-time.

2. The system of claim 1 , wherein the instructions further cause the assessment system to differentiate between the first and second portions of the ECG signal and display the instantaneous heart rates for at least one ON-period and for at least one OFF-period.

3. The system of claim 1 , wherein the instructions further cause the assessment system to differentiate between the first and second portions of the ECG signal and display a cumulative average of the instantaneous heart rates for at least one ON-period and a cumulative average of the instantaneous heart rates for at least one OFF-period.

4. The system of claim 1 , wherein the instructions further cause the assessment system to determine heart rate reduction as a difference between a cumulative average of the instantaneous heart rates for at least one ON- period and a cumulative average of the instantaneous heart rates for at least one OFF-period.

5. The system of claim 1 , wherein the instructions cause the assessment system to record the ECG signal continuously for a plurality of successive pairs of ON- and OFF-periods.

6. The system of claim 1 , wherein the instructions cause the assessment system to determine a real-time heart rate by averaging instantaneous heart rates of the last three R-R intervals.

7. The system of claim 1 , wherein the instructions cause the assessment system to determine heart rate variability from each determined R-R interval in each of the first and second portions of the recorded ECG signal.

8. The system of claim 7 , wherein the instructions cause the assessment system to differentiate between the first and second portions of the ECG signal and display the heart rate variability for at least one ON-period and for at least one OFF-period.

9. The system of claim 8 , wherein the instructions cause the assessment system to determine the heart rate variability from each determined R-R interval within 25% of a mean R-R interval for each of the first and second portions of the recorded ECG signal.

10. The system of claim 1 , wherein the data acquisition system is configured to sample the ECG signal at a rate of at least 200 samples per second.

11. The system of claim 1 , wherein the stimulation signal ramps up at a constant rate from the OFF-period to the initiating pulse for each successive pair of ON- and OFF- periods.

12. The system of claim 1 , wherein the stimulation signal ramps down at a constant rate from the terminating pulse to the OFF-period for each successive pair of ON- and OFF-periods.

13. An assessment system for vagus nerve stimulation therapy treatment for congestive heart failure in a subject, the assessment system comprising:
a wand assembly in communication with a neurostimulator, the wand assembly configured to detect a delivery of a periodic stimulation signal of vagus nerve stimulation delivered to the subject from the neurostimulator and to generate a delivery detection signal indicating the detected delivery of the periodic stimulation signal;
a lead assembly configured to acquire an analog ECG signal of the subject over a delivery period of the periodic stimulation signal of the vagus nerve stimulation delivered to the subject and defined by an initiating pulse and a terminating pulse, the delivery period being a time between the initiating and terminating pulses;
a data acquisition system coupled to the wand and lead assemblies and configured to convert the analog ECG signal to a digital ECG signal over the delivery period; and
a processor and a non-transitory computer-readable memory storing instructions that, when executed by the processor, cause the assessment system to:
synchronize a start of the digital ECG signal to the delivery period using based on the delivery detection signal;
detect each QRS complex in the digital ECG signal over the delivery period;
identify each potential R-wave in each QRS complex of the digital ECG signal;
confirm each R-wave of the digital ECG signal;
determine a time interval between each pair of successive confirmed R-waves of the digital ECG signal;
determine an instantaneous heart rate from each determined time interval; and
determine a cumulative average of the instantaneous heart rates during the delivery period.

14. The system of claim 13 , wherein the digital ECG signal of the delivery period is a first ECG signal;
wherein the lead assembly is configured to acquire an analog ECG signal of the subject over a resting period, the resting period being a time after the terminating pulse in which no stimulation is delivered to the subject, and wherein the data acquisition system is configured to convert the analog ECG signal over the resting period to a second ECG signal being a digital ECG signal of the resting period; and
wherein the instructions further cause the assessment system to determine a time interval between each pair of successive confirmed R-waves of the second ECG signal and determine an instantaneous heart rate from each determined time interval of the second ECG signal.

15. The system of claim 14 , wherein the instructions further cause the assessment system to determine a cumulative average of the instantaneous heart rates during the resting period and determine a difference between the cumulative averages of the instantan

Assignees

• Livanova Usa Inc

Inventors

• Libbus Imad
• Stubbs Scott R
• Mazar Scott
• Kenknight Bruce
• Amurthur Badri

Classifications

• A61N1/36114 Primary

  Cardiac control, e.g. by vagal stimulation (stimulating the heart A61N1/362) · CPC title

• A61N1/36139

  with automatic adjustment · CPC title

• A61N1/36178

  Burst or pulse train parameters · CPC title