Assessment of Variation in Ambulatory Cardiac Monitoring Among Commercially Insured Patients
Real-World Evidence Using a Large Commercial Claims Database
The Assessment of Variation in AmbuLatory Cardiac MONitoring (AVALON) study—the largest real-world study of ambulatory cardiac monitoring (ACM) in a commercial setting—found that the Zio® long-term continuous monitoring (LTCM) service was associated with the highest likelihood of new arrhythmia diagnosis and the lowest likelihood of having a cardiovascular event at 1 year.1-5
Zio LTCM service was associated with1,4:
Study Design1
Conducted using one of the largest commercial claims databases.
Analyzed 428,707 commercially insured, diagnostic-naive adults (≥18 years).
Patients were monitored with one of three ACM types: LTCM, Holter monitors, or event monitors.
Key Findings
The AVALON study revealed key information about the diagnostic proficiency and clinical benefits associated with the Zio LTCM service compared to Holter, event, and non-iRhythm LTCM1,4:
ZIO LTCM SERVICE WAS MORE LIKELY TO DIAGNOSE ARRHYTHMIAS WITHIN 90 DAYS2,3
Time to diagnosis was also shorter for Zio LTCM (9 days) compared to Holter (12 days), non-iRhythm LTCM (21 days), and event (30 days).3,6,7
ZIO LTCM SERVICE SHOWED LOWER ODDS OF RETESTING WITHIN 180 DAYS
ZIO LTCM SERVICE HAD A LOWEST LIKELIHOOD OF CV EVENTS AT 1 YEAR8
On the manufacturer level, the Zio LTCM service was linked to a higher likelihood of arrhythmiadiagnosis, lower likelihood of retesting, and lower likelihood of a CV event within 1 year compared to Bardy, BioTelemetry, and Preventice LTCM services.1-4,7,8
The Zio LTCM service was also associated with reduced healthcare resource utilizationcompared to Holter, event, and non-iRhythm LTCM services.1,4
HEALTHCARE RESOURCE UTILIZATION
These differences persisted after adjustment for patient demographics, comorbidities, and socioeconomic factors.
Over 700,000 patients across Medicare and commercial populations were evaluated through the CAMELOT9 and AVALON1 studies. CAMELOT was the first large-scale real-world study to demonstrate variation in outcomes by ACM type in a Medicare population. AVALON expanded on CAMELOT by including a commercial audience spanning the social and economic spectrum. Both CAMELOT and AVALON drew the same conclusions: long-term continuous monitoring, especially with the Zio LTCM service, enhanced diagnostic capability, reduced healthcare resource utilization, and improved patient outcomes.1-4,6,9-11
From Medicare beneficiaries to commercially insured adults across the social and economic spectrum, these landmark real-world analyses provide robust evidence that monitoring strategy matters and that LTCM is associated with differences that extend well beyond detection alone.
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Keep reading
- Russo et al. Assessment of variation in ambulatory cardiac monitoring among commercially insured patients. Am J Manag Care. August 13, 2025. doi:10.37765/ajmc.2025.89782
- The Zio LTCM service facilitates a diagnosis as determined by a physician.
- Arrhythmias were defined by a panel of clinical experts and study investigators.
- Zio LTCM service refers to Zio XT and Zio monitor service.
- CV events are defined by the study protocol.
- The Zio service facilitates a diagnosis as determined by a physician.
- The time to diagnosis was defined as the number of days between the CPT code for the technical component to the ICD-10 code for an actionable arrhythmia diagnosis.
- CV events were defined by the study protocol.
- Reynolds et al. Comparative effectiveness and healthcare utilization for ambulatory cardiac monitoring strategies in Medicare beneficiaries. Am Heart J. 2024;269:25-34. doi:10.1016/j.ahj.2023.12.002
- A specified arrhythmia refers to an arrhythmia encounter diagnosis as per Hierarchical Condition Categories (HCC) 96.
- 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.
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