Next-generation Mobile Cardiac Telemetry: Clinical Value of Combining Electrocardiographic and Physiologic Parameters

Abstract

The ZOLL Arrhythmia Monitoring System, a mobile cardiac telemetry (MCT) device from ZOLL Corporation (Chelmsford, MA, USA), records single-channel electrocardiogram (ECG) signals, heart rate, activity, respiratory rate, and posture. Comprehensive reporting from these multiple biometrics may provide a global evaluation of arrhythmic or other cardiovascular risks in individual patients and insights into the patient's overall wellness and health status. The objective of the study was to evaluate the physician-perceived utility of adding biometric data to the traditional ECG-only-based assessment and subject-reported symptoms. This prospective study recruited candidates for MCT. Independent event and end-of-use (EOU) reports based on ECG and biometrics data were provided to physicians. To document whether the biometric data affected treatment plan decisions or added value over the ECG-alone data, physicians completed a questionnaire for each report. Additionally, they completed the questionnaire to understand the utility of the subject wellness information provided in the EOU report. From December 2020 to July 2021, 583 patients were enrolled by 27 physicians from 18 cardiology practices in the United States. When using biometrics data compared to the ECG alone, this study found that 96% of the physicians made changes to the treatment plan that initially was based on the ECG alone. The biometrics-based changes involved 64% of all patients (n = 535), and included modifications to medications, follow-up, and lifestyle in 18%, 19%, and 63% of the subjects, respectively. In this largest MCT study conducted to date, next-generation MCT, by providing multiple biometric parameters along with ECG data, improves physicians' ability to make patient management decisions. This added functionality and clarity may replace traditional "ECG with diary"-based monitoring.

Keywords: Biometrics; patient management; remote monitoring.

Figure 1:

The ZOLL Arrhythmia Management System consists of an adhesive patch, sensor, gateway, and remote server.

Figure 2:

A: Sample event report consisting of a 6-s electrocardiogram strip with rhythm interpretation. B: Biometrics data include heart rate, respiratory rate, posture, and activity trends. The biometrics trend information is provided in 1-min intervals (X-axis in panel B) 90 min before and 30 min after the event (gray vertical line).

Figure 3:

End-of-use report consisting of the arrhythmia and symptom summary, along with the (A) atrial fibrillation burden and heart rate (HR) trends and (B–D) wellness information. B contains the summary statistics for upright activity duration, sleep duration, HR, and respiratory rate (RR). Also displayed is the summary of the arrhythmia and symptom onsets experienced by the subject during the monitoring period. C contains the median HR trend data during the day (daytime) and during the night (nocturnal) as well as the duration of upright activity and sleep for each of the monitored days along with any arrhythmia or subject-reported symptom onsets. D contains the median daytime and nocturnal RR trends and graphical representation of the median RRs during subject-reported symptom onsets and arrhythmia onsets, and the technician summary section provides a concise review of the percentage of the time arrhythmias or symptoms occurred during activity and sleep.

Figure 3:

End-of-use report consisting of the arrhythmia and symptom summary, with (E) an event summary of the arrhythmia and/or symptoms detected during the monitoring period along with a chronological listing of the events for the entire monitoring period.

Figure 4:

Forrest plot of (A) arrhythmias and (B) subject-reported symptoms occurring during activity versus inactive/sleep. Shown are the point estimate of the odds ratio (OR) and the 95% confidence interval along with the P values. An OR of 1 indicates that a particular arrhythmia or symptom has an equal likelihood of occurring when the subject is active or inactive/sleep in comparison to other arrhythmias or symptoms. Note, in A, the OR value for the second-/third-degree atrioventricular block (AVB) is not displayed since none of the AVB events occurred during activity.

Figure 5:

A: A 6-s electrocardiogram tracing at the onset of atrial fibrillation (AF) with controlled ventricular response. B–E: The biometric trend data. The gray vertical line depicts the time stamp of the onset of the AF event. Heart rate (B), respiratory rate (C), posture (D), and activity (E) trend data are shown in 1-min intervals 90 min before and 30 min after the AF onset (gray vertical line). Note, active is defined as posture > 35° and activity of ≥30 s/min.

Figure 6:

Select wellness trend data from the end-of-use report for 1 subject. A: Sleep duration for each day of monitoring along with a summary of arrhythmias and symptomatic events. Over several days during the monitoring period, the subject experienced several second-/third-degree atrioventricular block when sleeping as detected by the arrhythmia monitoring system device. Note, sleep is defined as posture ≤ 35° and activity of <12 s/min. B, C: Median heart rate and respiratory rate data are reported for each monitoring time day and night.