Zio LTCM features a prescription-only, patch-based ECG monitor that captures up to 14 days of continuous, uninterrupted data. It also utilizes the ZEUS (Zio ECG Utilization Software) system with an FDA-cleared AI algorithm. The system delivers an end-of-wear report reviewed and validated by qualified cardiac technicians.
A large, real-world, retrospective analysis looked at claims data from a cohort of 428,707 commercially insured patients. It represented the largest real-world comparative evaluation of ambulatory cardiac monitoring (ACM) among this population to date. iRhythm says its AVALON study reinforced the clinical superiority of the Zio LTCM service.
Investigators presented findings at the Heart Rhythm Society (HRS) 2025 Annual Meeting in San Diego. iRhythm also presented findings from a separate analysis evaluating the benefits of its MyZio smartphone accessory app at HRS. The company designed its app to improve patient engagement and enable digital symptom logging. Data showed increased symptom reporting, improved symptom-rhythm correlation, and a greater rate of arrhythmia-correlated dairy entries compared to non-users.
The AVALON data, meanwhile, builds on the CAMELOT study that demonstrated Zio’s superiority in a Medicare population. AVALON evaluated a younger, commercially insured population, with a mean age of 46 years.
“Once again, we have strong real-world evidence that compellingly demonstrates the superiority of Zio’s 14-day, uninterrupted, patch-based monitoring — AVALON extends findings beyond Medicare to patients in common commercial insurance plans,” said Dr. Mintu Turakhia, iRhythm chief medical and scientific officer and EVP of product innovation.
More from the iRhythm AVALON study
AVALON aimed to assess the impact of ambulatory cardiac monitoring strategy on three key clinical outcomes. It looked at diagnostic yield, likelihood of repeat testing and likelihood of CV events. Outcomes reflect both immediate diagnostic effectiveness of Zio and its longer-term clinical implications.
Like CAMELOT, it demonstrated the highest diagnostic yield compared to other ACM modalities and all other LTCM studies. Zio also showed a lower likelihood of repeat testing compared to other LTCM services.
AVALON observed an association between Zio and a lower likelihood of cardiovascular (CV) events, too.
Investigators identified 428,707 commercially insured patients considered diagnostically naïve. This is defined as having no prior cardiac monitoring, arrhythmia diagnosis, or arrhythmia-related procedures or medications in the 12 months prior to the index date (baseline period). Of the records analyzed, 36% of patients used LTCM, 36% used a Holter monitor and 27% used an ambulatory event monitor (AEM).
The study saw new arrhythmia diagnosis come in highest for Zio within the first no days (26.5%). Non-iRhythm LTCM (18.4%) followed, with AEM (17%) and Holter (14.7%) after that.
Zio was also associated with the highest adjusted odds of a new arrhythmia encounter diagnosis compared to other ACM modalities and LTCM services. Compared to Holter monitors, Zio LTCM came in 2.04 times more likely to have a new arrhythmia encounter diagnosis within 90 days. Compared to AEM, that number came in a 1.69 times more likely, then 1.56 times more likely compared to non-iRhythm LTCM.
iRhythm said Zio LTCM service had the lowest adjusted odds of retesting within 180 days compared to all other LTCMs. It also had the lowest adjusted odds of CV events within one year compared to ACM modalities and all other LTCMs.
