iRhythm Clinical Library of Evidence
The iRhythm clinical library highlights key studies across a range of clinical focus areas, including atrial fibrillation detection, ventricular arrhythmias, monitoring duration, and health system impact. Over 135 original scientific manuscripts demonstrate the value of Zio® long–term continuous monitoring (LTCM) service.1 Our commitment to research reflects our dedication to advancing medical knowledge and shaping the standard of care worldwide.
1. Data on file. iRhythm Technologies, 2026.
Explore the clinical evidence that supports the accuracy, efficiency, and real-world value of the Zio® LTCM service.
Select a category below.
Featured Clinical Evidence
AF DETECTION & MONITORING ACCURACY
AI Matching Cardiologists
Hannun et al., Nature Medicine, 2019
Cardiologist-level arrhythmia detection and classification in ambulatory electrocardiograms using a deep neural network
Hannun et al. Nature Medicine. 2019.
Study Design:
Model development and validation study evaluating a deep neural network (DNN) trained to detect arrhythmias using a large (n=53,549) real-world ECG dataset from Zio® LTCM devices.
The DNN was trained using 91,232 ECG recordings and classified 12 rhythm types, including atrial fibrillation, tachycardia, and bradyarrhythmia. Performance was evaluated against consensus labels from board-certified cardiologists.
Key Findings:
The AI model with scalable, high-accuracy arrhythmia detection matched or exceeded average cardiologist performance across most arrhythmia types, which could reduce the amount of misdiagnosed computerized ECG interpretations.1
- Hannun et al. Cardiologist-level arrhythmia detection and classification in ambulatory electrocardiograms using a deep neural network. Nat Med. 2019;25:65-69. https://doi.org/10.1038/s41591-018-0268-3
Detecting AF in Patients After Stroke
Kaura et al. Eur J Med Res. 2019.
Early prolonged ambulatory cardiac monitoring in stroke (EPACS): an open-label randomised controlled trial
Kaura et al. European Journal of Medical Research. 2019.
Study Design:
Open-label, randomized controlled trial comparing early use of Zio LTCM service versus conventional Holter monitoring in adults (n=116) with recent (<72 hours) cryptogenic stroke or transient ischemic attack (TIA) and no known history of atrial fibrillation (AF).
Participants were randomized to receive either a 14-day Zio monitor or a short-duration Holter. The primary endpoint was the detection of paroxysmal atrial fibrillation (PAF) ≥ 30 seconds within 90 days.
Key Findings:
Early and prolonged patch-based monitoring resulted in a higher likelihood of AF diagnosis and greater anticoagulant use compared to short-duration Holter, supporting prolonged 14-day monitoring in cryptogenic stroke or TIA patients.1
- Kaura et al. Early prolonged ambulatory cardiac monitoring in stroke (EPACS): an open-label randomised controlled trial. Eur J Med Res. 2019;24(1):25. doi:10.1186/s40001-019-0383-8
Zio LTCM Matches Pacemaker Accuracy
Eysenck et al. J Interv Card Electrophysiol. 2019.
A randomized trial evaluating the accuracy of AF detection by four external ambulatory ECG monitors compared to permanent pacemaker AF detection.
Eysenck, et al. Journal of Interventional Cardiac Electrophysiology. 2019.
Study Design:
Simultaneous wear study comparing 14-day LTCM arrhythmia detection to pacemakers in patients (n=21) with paroxysmal or persistent atrial fibrillation (AF) who also had an implantable pacemaker.
Each patient wore four monitors sequentially: Zio XT, NUUBO Vest, Carnation Ambulatory Monitor (CAM), and Novacor ‘R’ Test 4 (RT), the current standard in Europe. Each monitor was worn for 2 weeks.
Key Findings:
Zio LTCM service matched the gold standard in AF burden detection.1–3
- Eysenck et al. A randomized trial evaluating the accuracy of AF detection by four external ambulatory ECG monitors compared to permanent pacemaker AF detection. Journal of Interventional Cardiac Electrophysiology. 2019;57(3):361-369. doi:https://doi.org/10.1007/s10840-019-00515-0
- The study is based on the previous generation Zio XT device data. The devices used in the Zio LTCM monitoring service are deemed substantially equivalent. Additional data on file.
- Zio LTCM service refers to Zio XT and Zio monitor service.
COMPARE: Patch vs MCT
Garg et al., Heart Rhythm, 2023
Simultaneous comparison of patch versus multi-electrode cardiac monitoring for the detection of arrhythmias: The COMPARE study
Garg et al. Heart Rhythm. 2023.
Study Design:
Prospective, observational study evaluating simultaneous wear of a multi-electrode mobile cardiac telemetry (MCT) device and the Zio LTCM service prescribed for 14 days in 50 patients.
Key Findings:
Over a 14-day period, the average analyzable time with Zio LTCM was significantly higher than with the MCT device.1
- Garg et al. Simultaneous comparison of patch versus multielectrode cardiac monitoring for the detection of arrhythmias: The COMPARE study. Heart Rhythm. 2023;20(8):1202-1203. doi:10.1016/j.hrthm.2023.04.011
BENEFITS OF 14-DAY MONITORING
Diagnostic Utility of a Leadless Device
Turakhia, et al. American Journal of Cardiology. 2013.
Diagnostic utility of a novel leadless arrhythmia monitoring device
Turakhia, et al. American Journal of Cardiology. 2013.
Study Design:
Retrospective analysis of first-time users of Zio LTCM to assess wear time, signal quality, and diagnostic yield for arrhythmia detection during extended ambulatory ECG monitoring. Consecutive patients (n=26,751) prescribed extended monitoring wore Zio monitors continuously for up to 14 days.
Key Findings:
Longer wear time maximizes diagnostic yield compared with 24-48 hours of monitoring, such as monitoring with Holter.
1. Turakhia et al. Diagnostic Utility of a Novel Leadless Arrhythmia Monitoring Device. The American Journal of Cardiology. 2013;112(4):520-524. doi:https://doi.org/10.1016/j.amjcard.2013.04.017
2. The study is based on the previous generation Zio XT device data. The devices used in the Zio LTCM monitoring service are deemed substantially equivalent. Additional data on file.
3. Zio LTCM service refers to both Zio XT and Zio monitor service.
Zio Uncovers Clinically Actionable VT Arrhythmias
Solomon et al., BMC Cardiovasc Disord, 2016
Incidence and timing of potentially high-risk arrhythmias detected through long term continuous ambulatory electrocardiographic monitoring
Solomon et al. BMC Cardiovascular Disorders. 2016.
Study Design:
Retrospective analysis of Zio LTCM service data collected from 2011 to 2013 to examine incidence and timing of ventricular arrhythmias across adults undergoing ambulatory cardiac monitoring in routine outpatient care (n=122,815). The timing of first arrhythmia detection and the cumulative diagnostic yield by day of monitoring were evaluated.
Key Findings:
65.5% of sustained ventricular tachycardia (VT) and 38% of non-sustained VT were detected by 48 hours. Extended wear increased diagnostic yield for all arrhythmias.1
- Solomon et al. Incidence and timing of potentially high-risk arrhythmias detected through long term continuous ambulatory electrocardiographic monitoring. BMC Cardiovasc Disord. 2016;16:35. doi:10.1186/s12872-016-0210-x
Longer Monitoring to Detect PVCs
Krumerman et al., Heart Rhythm, 2024
Premature ventricular complexes: Assessing burden density in a large national cohort to better define optimal ECG monitoring duration1
Krumerman et al. Heart Rhythm. 2024.
Study Design:
Retrospective analysis of Zio LTCM data across 106,705 patch monitors to evaluate the monitoring duration needed for accurate premature ventricular complex (PVC) burden classification and VT detection. The adult patients were categorized into low (5 to <10%), moderate (10 to <20%), or high (≥20%) PVC burden groups.
Key Findings:
Longer monitoring (≥7 days) with Zio LTCM improved PVC burden accuracy.1
- Krumerman et al. Premature ventricular complexes: Assessing burden density in a large national cohort to better define optimal ECG monitoring duration. Heart Rhythm. 2024;21(8):1289-1295. doi:10.1016/j.hrthm.2024.04.066
Extended Ambulatory ECG Monitoring
Rowin et al. Heart Rhythm. 2024.
Extended ambulatory ECG monitoring enhances identification of ventricular tachycardia in patients with hypertrophic cardiomyopathy1
Rowin et al. Heart Rhythm. 2024.
Study Design:
Prospective observational study evaluating the diagnostic yield of extended ECG monitoring (14 days) using Zio LTCM versus standard 48-hour monitoring for detecting nonsustained ventricular tachycardia (NSVT) in 236 patients with hypertrophic cardiomyopathy (HCM).
Key Findings:
Extended monitoring significantly improves the detection of arrhythmic risk markers in - HCM.1
- 63% of NSVT cases were detected after the first 48 hours
- The 14-day diagnostic yield of high-risk NSVT patterns was 3x higher than 48 hours (p<0.001)
- Rowin et al. Extended ambulatory ECG monitoring enhances identification of higher-risk ventricular tachyarrhythmias in patients with hypertrophic cardiomyopathy. Heart Rhythm. 2025
HEALTH SYSTEM PERFORMANCE & REAL-WORLD IMPACT
CAMELOT: Real-Word Evidence Using a Large Medicare Fee-For-Service Database
Reynolds et al., Am Heart J, 2024
Comparative effectiveness and healthcare utilization for ambulatory cardiac monitoring strategies in Medicare beneficiaries
Reynolds et al. American Heart Journal. 2024.
Study Design:
Retrospective observational cohort study using Medicare claims data across 287,780 beneficiaries to compare diagnostic yield, retesting rates, and downstream clinical impact across four types of ambulatory cardiac monitors (ACMs): Holter, event, mobile cardiac telemetry (MCT), and long-term continuous monitoring (LTCM) with the Zio XT 14-day patch.
Key Findings:
Zio LTCM had the highest initial diagnostic yield of specified arrhythmia diagnosis and the lowest odds of retesting within 6 months.1-5
LTCM, as a category, was also associated with the lowest incremental acute care utilization compared to Holter monitors, event monitors, and MCT.
- Reynolds et al. Comparative effectiveness and healthcare utilization for ambulatory cardiac monitoring strategies in Medicare beneficiaries. Am Heart J. 2024;269:2534. https://doi.org/10.1016/j.ahj.2023.12.002
- The study is based on the previous generation Zio XT device data. The devices used in the Zio LTCM monitoring service are deemed substantially equivalent. Additional data on file.
- Zio LTCM service refers to Zio XT and Zio monitor service.
- A specified arrhythmia refers to an arrhythmia encounter diagnosis as per Hierarchical Condition Categories (HCC) 96.
- The Zio service facilitates a diagnosis as determined by a physician.
AVALON: Real-World Evidence Study Using a Large Commercial Claims Database
Russo et al. AJMC. 2025.
Assessment of variation in ambulatory cardiac monitoring among commercially insured patients
Russo et al. American Journal of Managed Care. 2025.
Study Design:
Retrospective cohort study using a large U.S. commercial claims database across 428,707 diagnostic-naive patients to evaluate new arrhythmia diagnosis, repeat monitoring, cardiovascular (CV) events, and healthcare utilization and total costs. Patients were categorized by ACM type (LTCM, Holter, event) and LTCM manufacturer.
Key Findings:
Compared to other ACM types, Zio LTCM had the highest likelihood of a new arrhythmia diagnosis and the lowest likelihood of a cardiovascular event at 1 year.1-5
- Russo et al. Assessment of variation in ambulatory cardiac monitoring among commercially insured patients. Am J Manag Care. Published online August 13, 2025. doi:10.37765/ajmc.2026.89782
- The Zio service facilitates a diagnosis as determined by a physician.
- CV events were defined by the study protocol.
- Arrhythmias were defined by a panel of clinical experts and study investigators.
- Zio LTCM service refers to Zio XT and Zio monitor service.
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