San Francisco, March 31, 2025

iRhythm Technologies, Inc. (NASDAQ: IRTC) unveiled groundbreaking results from two comprehensive retrospective studies during the American College of Cardiology (ACC) 2025 Scientific Sessions in Chicago, IL. Analyzing data from over 1.1 million patients utilizing iRhythm's Zio® long-term continuous monitoring (LTCM) ECG devices, these studies dispelled myths regarding short-term arrhythmia monitoring, particularly highlighting the inadequacies of traditional 24-48 hour Holter monitoring.

Major Takeaways from the Studies:

1. Alarmingly High Undetected Rates: For patients experiencing daily symptoms, 64% of actionable arrhythmias went undetected during the initial 48 hours of monitoring. This shocking statistic reveals the dangers of relying solely on standard Holter devices, especially for those reporting consistent symptoms.

2. Non-Daily Symptoms Yield More Discoveries: Surprisingly, the group of patients with infrequent symptoms showed an 80.9% arrhythmia detection rate, compared to just 69.1% among those with daily symptoms. This indicates that symptom frequency does not necessarily relate to the burden of arrhythmias, revealing a critical flaw in the current monitoring approach.

3. Extended Monitoring is Key: The studies demonstrated that the mean time to detect an arrhythmia episode exceeded 48 hours across all arrhythmia types, irrespective of symptom frequency. This underscores the urgent need for longer monitoring periods to ensure accurate diagnosis and treatment.

Unreliable Symptoms: A False Sense of Security

Fewer than 20% of patients documented a symptom correlating with their arrhythmias. Alarmingly, even atrial fibrillation (AF), typically associated with significant symptoms, presented as asymptomatic in over half of the cases analyzed.

Serious arrhythmias such as ventricular tachycardia and AV block were commonly recorded without accompanying patient-reported symptoms, indicating a critical lapse in the efficacy of relying on symptoms for diagnosis.

Dr. Mintu Turakhia, Chief Medical and Scientific Officer at iRhythm, stated, "These findings challenge the long-held belief that frequent symptoms justify short-duration monitoring, reinforcing the limitations of Holter monitoring and revealing the immense value derived from our Zio LTCM, which offers continuous monitoring up to 14 days."

The Growing Impact of Arrhythmias

Arrhythmias affect up to 5% of the general population—approximately 16 million Americans. When left uncontrolled, these cardiac irregularities can be severely damaging, increasing risks for stroke and heart issues, leading to dire health consequences and exorbitant costs for healthcare systems. Alarmingly, undiagnosed atrial fibrillation alone costs the U.S. around $3 billion annually!

Implications for Health Care

As healthcare continues shifting towards value-based care models, it's crucial to recognize the failures of 24-48 hour Holter monitoring, particularly as 64% of daily-symptom patients with actionable arrhythmias remain undetected. With Zio LTCM, healthcare providers can offer uninterrupted monitoring for up to 14 days, drastically improving patient outcomes.

The CAMELOT study further validates that Zio LTCM not only delivers superior arrhythmia detection but also reduces the need for repeat testing. These findings have profound implications for healthcare providers and payers as they seek to optimize patient care practices.

The Next Steps for Monitoring Arrhythmias

These studies enhance the already robust clinical evidence supporting iRhythm’s LTCM, which is built upon thousands of hours of curated data and millions of patient reports. As the medical community acknowledges the critical need for improved arrhythmia monitoring technologies, the Zio monitor remains at the forefront, set to transform patient experiences and outcomes in cardiac care.

In Conclusion: Don’t Let Your Heart Go Unmonitored!

With the urgent need for comprehensive monitoring in arrhythmia detection, the introduction of long-term monitoring technologies holds the key to better health outcomes. As more research emerges, understanding the gaps in symptom-based monitoring could pave the way for new policies and practices in the healthcare industry.