EP-3518744-B1 - SYSTEM AND METHOD FOR CARDIAC MONITORING USING RATE-BASED SENSITIVITY LEVELS

Inventors

• CHAKRAVARTHY, NIRANJAN
• KATRA, RODOLPHE

Dates

Publication Date

20260513

Application Date

20170927

Claims (9)

1. A method (400) of detecting arrhythmic electrocardiogram (ECG) signals, the method comprising: determining (402) whether a patient is at rest based on one or more physiological parameters; measuring (404) a basal/resting heart rate of the patient in response to a determination that the patient is at rest; defining (406) a plurality of threshold heart rates and rate-dependent sensitivity levels for detecting arrhythmic ECG episodes, wherein more clinically relevant heart rates are assigned rate-dependent sensitivity levels with higher sensitivities, wherein the plurality of threshold heart rates are defined based on the measured basal/resting heart rate, wherein the plurality of threshold heart rates include a plurality of heart rate thresholds associated with tachycardia thresholds and a plurality of heart rate thresholds associated with bradycardia thresholds, and wherein higher rate tachycardia thresholds are assigned a higher sensitivity level than lower rate tachycardia thresholds, and lower rate bradycardia thresholds are assigned a higher sensitivity level than higher rate bradycardia thresholds; monitoring (408) ECG signals associated with the patient using a monitoring device; and processing (410), using a processing module, the monitored ECG signals using the plurality of threshold heart rates and rate-dependent sensitivity levels to detect and capture arrhythmic ECG segments.
2. The method of claim 1, wherein the monitoring device processes the monitored ECG signals locally, and wherein captured arrhythmic ECG segments are communicated to a remote monitoring center for review.
3. The method of claim 1, wherein monitored ECG signals are communicated to a remote monitoring center for processing of the monitored ECG signals using the plurality of threshold heart rates and rate-dependent sensitivity levels.
4. The method of claims 1-3, wherein the plurality of heart rate thresholds are selected based on one or more patient characteristics, including one or more of patient age, weight, sex, and/or basal/resting heart rate.
5. The method of claims 1-4, wherein captured arrhythmic ECG segments are reviewable at a remote monitoring center, wherein the captured arrhythmic ECG segments includes one or more tags that can be utilized to filter and search the plurality of captured arrhythmic ECG segments, wherein the tags include one or more of a heart-rate threshold that triggered capture of the ECG segment, a rate-based sensitivity level associated with the heart-rate threshold, ratio of beats exceeding the heart-rate threshold, trigger arrhythmic condition, and patient activity level.
6. A system for monitoring electrocardiogram, ECG, signals and detecting arrhythmic ECG episodes, the system comprising: a monitoring device (100, 600, 700) having one or more electrodes (612A, 612B, 612C, 612D, 704, 706) and sensing circuitry (630) for monitoring ECG signals associated with a patient; and a processing module (100, 102P, 106P) configured to receive the monitored ECG, wherein the processing module utilizes a plurality of heart-rate thresholds and rate-dependent sensitivity levels to detect and capture arrhythmic ECG segments, wherein more clinically relevant heart rates are assigned rate-dependent sensitivity levels with higher sensitivities, wherein the plurality of threshold heart rates include a plurality of heart rate thresholds associated with tachycardia thresholds and a plurality of heart rate thresholds associated with bradycardia thresholds, and wherein higher rate tachycardia thresholds are assigned a higher sensitivity level than lower rate tachycardia thresholds, and lower rate bradycardia thresholds are assigned a higher sensitivity level than higher rate bradycardia thresholds, wherein the processing module determines whether the patient is at rest based on one or more physiological parameters, measures a basal/resting heart rate of the patient in response to a determination that the patient is at rest, wherein the plurality of threshold heart rates are defined based on the measured basal/resting heart rate.
7. The system of claim 6, wherein the processing module (100, 102P, 106P) is included on the monitoring device (100, 600, 700) and includes memory for storing the plurality of heart-rate thresholds and rate-dependent sensitivity levels and a processor for processing the monitored ECG signals using the heart-rate thresholds and rate-dependent sensitivity levels, wherein the processing module further includes wireless communications circuitry for communicating captured ECG segments to a remote monitoring center for review.
8. The system of claims 6-7, wherein the plurality of heart rate thresholds are selected based on one or more patient characteristics, comprising one or more of patient age, weight, and/or sex.
9. The system of claim 6-8, wherein the captured arrhythmic ECG segments communicated to a remote monitoring center (106) include one or more tags that can be utilized to filter and search the plurality of captured arrhythmic ECG segments, wherein tags comprise one or more of a heart-rate threshold that triggered capture of the ECG segment, a rate-based sensitivity level associated with the heart-rate threshold, ratio of beats exceeding the heart-rate threshold, trigger arrhythmic condition, and patient activity level.

Description

TECHNICAL FIELD The present disclosure is related in general to patient monitoring and in particular to detecting cardiac rhythm disorders. BACKGROUND Cardiac monitoring - particularly ambulatory monitoring - includes long-term monitoring of ECG signals to detect various type of heart rhythm disorders. The amount of ECG data collected, however, precludes human operator/technician review of the data. Automatic processing of the collected ECG data is utilized to detect and capture ECG segments corresponding with detected heart rhythm disorders. However, while some of the ECG segments captured correspond with an actual heart rhythm disorders (i.e., a true positive event), other ECG segments were incorrectly identified as corresponding to a heart rhythm disorder (i.e., a false positive event). In addition, each captured ECG segment identified as corresponding to a heart rhythm disorder and captured represents a cost. That cost includes the cost of storing the captured ECG segment either on the monitoring device or externally, the cost of power required to communicate the captured ECG segment from the monitoring device to a remote monitoring center, and time required for a HCP to review the captured ECG episode and determine whether action is required. Thus, it is beneficial to reduce the ECG segments incorrectly identified as corresponding to a heart rhythm disorder (i.e., minimize false positive events). However, it is also important to ensure that heart rhythm disorders are detected and corresponding ECG segments captured and provided to a human HCP for review (i.e., avoid missing detection of positive events, or false negative). It would therefore be beneficial to provide a monitoring system that balances these concerns to ensure clinically relevant ECG segments are captured while maintaining a low-cost system. US2011257535A1 describes a system for monitoring a heart of a patient, wherein the monitoring results include information indicative of: (a) a heart rate of the patient during a monitoring period; (b) at least one first time period in which the heart rate of the patient exceeded a first threshold; and (c) at least one second time period in which the heart rate of the patient exceeded both the first threshold and a second threshold. US2007213599A1 describes systems and methods using constant false alarm rate techniques for event detection. WO2015066430A1 relates to devices and methods for monitoring, identifying, and determining risk of congestive heart failure (CHF) hospitalization. Methods include determining physiological values of a patient by electrocardiogram (ECG), bioimpedance, and 3-axis accelerometer, filtering the physiological values, comparing physiological values to baseline parameters and determining CHF risk. BRIEF SUMMARY OF THE INVENTION According to an exemplary embodiment, a method of detecting arrhythmic electrocardiogram (ECG) segments comprises defining a plurality of threshold heart rates and rate-dependent sensitivity levels for detecting arrhythmic ECG episodes, wherein more clinically relevant heart rates are assigned rate-dependent sensitivity levels with higher sensitivities. ECG signals associated with a patient are monitored using a monitoring device and the monitored ECG signals are processed using the plurality of threshold heart rates and rate-dependent sensitivity levels to detect and capture arrhythmic ECG segments. According to another exemplary embodiment, a system for monitoring electrocardiogram (ECG) signals and detecting arrhythmic ECG episodes comprises a monitoring device and a processing module. The monitoring device includes one or more electrodes and sensing circuitry for monitoring ECG signals associated with a patient. The processing module is configured to receive the monitored ECG signal, and to utilize the plurality of heart-rate thresholds and rate-dependent sensitivity levels to detect and capture arrhythmic ECG segments. According to another exemplary embodiment, a medical device comprises a sensing unit, a memory unit, and a processor. The sensing unit is capable of monitoring an electrocardiogram (ECG) signal of the patient. The memory unit stores a plurality of heart-rate thresholds and rate-dependent sensitivity levels, and the processor processes the monitored ECG signal to detect and capture arrhythmic ECG segments based on the plurality of heart-rate thresholds and rate-dependent sensitivity levels. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 illustrates a schematic view of a monitoring and/or treatment system that monitors electrocardiogram (ECG) signals and communicates ECG episodes representative of detected arrhythmias to a monitoring center according to an embodiment of the present invention.FIGS. 2a and 2b are charts illustrating rate-dependent sensitivity and specificity thresholds, respectively, utilized for arrhythmia detection according to an embodiment of the present invention.FIG. 3 is a flowchart that illustrates a method of personaliz