Ambulatory Cardiac Monitoring Devices: Is Your Evidence Compelling or Just Adequate?

Regulatory clearance for an ambulatory cardiac monitoring device is not the same thing as market traction. The evidence that satisfies an ambulatory ECG (AECG) device submission (signal quality, noise floor, analyzable time, patient compliance) answers a different set of questions than the ones cardiologists and payers are actually asking.

The gap between evidence that clears the regulatory bar and evidence that changes clinical practice is where too many cardiovascular clinical trial management programs fall short. Closing it cannot be accomplished by simply doing more studies. It’s a matter of designing the right studies.

What Regulatory Requires vs What the Market Demands

AECG regulatory performance benchmarks focus on device signal acquisition and patient compliance. These are necessary and the standard is clear. But patient compliance alone will not persuade a cardiologist to change their practice, nor will it move a payer.

Cardiologists want to see:

• Diagnostic yield by indication and monitoring duration
• Time to detection of clinically actionable arrhythmias
• Evidence of additive benefit over shorter or less capable monitoring alternatives

Payers want economic benefit:

• Can the device reduce hospital stays?
• Can it support safely discharging post-procedure patients earlier?
• Can it reduce emergency department visits in syncope populations?

Those questions demand a different evidence strategy than the one that drives clearance, and teams that don’t plan for both up-front are likely to discover that gap at the worst possible time.

Why Detection Rates Are No Longer Enough

The field broadly accepts that a longer ambulatory cardiac monitoring duration detects more arrhythmias. But whether more detection leads to better outcomes is still actively debated, and clinicians are well aware of it. The more important question now — and the one that guidelines and key opinion leaders are increasingly focused on — is not total detection rate but two more specific measures:

Time to detection and arrhythmic burden.

Time to detection is population-dependent in ways that matter enormously for study design. For post-transcatheter aortic valve replacement (TAVR) patients, AV block risk was historically thought to peak in the first 48 hours. Ambulatory monitoring studies, however, have shown clinically significant events continuing through 6 to 7 days post-procedure, with current guidance recommending continuous ambulatory monitoring for 7 to 30 days, depending on the conduction pattern observed.¹ For syncope patients, the diagnostic yield of ambulatory monitoring increases substantially with monitoring duration, with longer periods capturing arrhythmic events that shorter Holter-equivalent windows miss entirely.²

Burden matters because the pattern of an arrhythmia drives clinical decisions. High AF burden versus low-density paroxysmal AF, continuous versus infrequent episodes: These distinctions inform risk stratification and treatment decisions in a way that a simple positive detection rate does not.³ Sponsors who report burden alongside detection rates are building evidence that guideline committees can act on. Those who don’t are not reporting their most persuasive data.

Fit for Purpose Means Population Specific

Ambulatory cardiac monitoring evidence does not transfer across indications. A 14-day patch monitor studied in post-stroke patients is generating a different evidence base than one studied post-TAVR or in unexplained syncope.

The 2024 ACC Expert Consensus on Arrhythmia Monitoring After Stroke recommends at least 14 days of monitoring for patients with ischemic stroke from presumed small- or large-vessel disease, with atrial fibrillation (AF) episodes of 5 minutes or more triggering anticoagulation decisions. Monitoring this threshold requires both duration and detection sensitivity to be fit for that clinical context.³ Applying the same study parameters across a different population produces evidence that satisfies neither the specific indication nor the broader coverage question.

This is also where payer scrutiny is likely to be most active. Coverage decisions for near-real-time monitoring are facing more pushback for broader populations. The burden of proof is on the manufacturer to demonstrate that near-real-time capability produces superior patient benefit over standard mail-in monitoring for the specific indication being claimed. That body of evidence is still being built for multiple device categories.

The Adequate vs Compelling Self-Check

Adequate evidence demonstrates consistent signal with high analyzable time (typically well above 90%) and an acceptable safety profile. Compelling evidence does that, but it then goes further. Before finalizing a study design, teams should ask:

• Does the evidence show the benefit of the prescribed monitoring duration over a shorter or less capable alternative, in a clearly defined population?
• Is time to detection reported along with total detection rates?
• Is arrhythmic (e.g., AF or VT) burden quantified and included in the study outputs?
• Does the evidence match what current clinical practice guidelines, key opinion leaders, and payer coverage decisions are prioritizing?

Teams that don’t report time to detection and arrhythmic burden are leaving the most persuasive elements of their evidence behind. The move toward AF burden as a predictor of stroke risk and ablation failure is well underway at major cardiovascular conferences, and sponsors whose study designs don’t account for it are already behind.⁴

Build Evidence That Earns Confidence

Ready to build cardiovascular clinical trial evidence that holds up beyond the regulatory submission? Connect with RQM+’s clinical specialists to stress test your evidence strategy before your study design is finalized. 

Frequently Asked Questions

References

1. Glikson, M., Nielsen, J., Kronborg, M., et al. (2021). 2021 ESC Guidelines on cardiac pacing and cardiac resynchronization therapy. European Heart Journal, 42(35), 3427–3520. https://doi.org/10.1093/eurheartj/ehab364
2. Shen, W.K., Sheldon, R.S., Benditt, D.G., et al. (2017). 2017 ACC/AHA/HRS Guideline for the Evaluation and Management of Patients With Syncope. Circulation, 136(5), e60–e122. https://www.ahajournals.org/doi/10.1161/cir.0000000000000499
3. Spooner, M., Messé, S., Chaturvedi, S., et al. (2024). 2024 ACC Expert Consensus Decision Pathway on Practical Approaches for Arrhythmia Monitoring After Stroke. Journal of the American College of Cardiology. https://www.jacc.org/doi/10.1016/j.jacc.2024.10.100
4. Van Gelder, I.C., Rienstra, M., Bunting, K.V., et al. (2024). 2024 ESC Guidelines for the management of atrial fibrillation. European Heart Journal, 45(36), 3314–3414. https://doi.org/10.1093/eurheartj/ehae176

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