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This page describes products and general use; it is not medical advice.
The Zio Patch—developed and manufactured by iRhythm Technologies, Inc.—is a family of prescription-only, FDA 510(k)-cleared Class II wearable single-lead adhesive electrocardiogram (ECG) monitors designed for continuous ambulatory cardiac rhythm recording for up to 14 days. Encompassing the long-term continuous Zio XT, the thinner next-generation Zio Monitor, and the cellular-connected Zio AT mobile cardiac telemetry system, the iRhythm Zio platform replaces multi-wire 24-to-48-hour Holter monitors with a wire-free adhesive biosensor paired with an FDA-cleared deep-learning Software as a Medical Device (SaMD) analytics pipeline.
What Is the Zio Patch? Hardware and Product Variants
Traditional Holter monitors typically capture only 24 to 48 hours of cardiac activity and require external lead wires and belt-worn recording packs that interfere with sleep and showering, frequently missing paroxysmal (intermittent) arrhythmias that occur beyond the 48-hour window. The Zio Patch family addresses these engineering constraints through a single-use, water-resistant adhesive patch applied over the upper left chest:
- Zio XT and Zio Monitor (Long-Term Continuous ECG Monitoring): Single-lead, leadless adhesive patches that record continuous beat-to-beat ECG waveforms for up to 14 days without requiring battery charging, electrode replacement, or external wires. Patients can shower and perform normal daily activities while wearing the biosensor. When experiencing palpitations, dizziness, or syncope, the patient presses the integrated top-surface symptom button (or logs symptoms in the companion myZio smartphone application) to timestamp the ECG trace for symptom-rhythm correlation. At the end of the wear period, the patient peels off the device and returns it in a prepaid postage-paid box to an iRhythm Independent Diagnostic Testing Facility (IDTF).
- Zio AT (Ambulatory Cardiac Telemetry / Mobile Cardiac Telemetry): Combines up to 14 days of continuous beat-to-beat recording with a wireless cellular gateway transceiver that transmits actionable arrhythmia events during the wear period for near-real-time clinical notification alongside a comprehensive end-of-wear report.
| Device Parameter | Traditional 24–48h Holter Monitor | iRhythm Zio XT / Zio Monitor | iRhythm Zio AT (Mobile Telemetry) |
|---|---|---|---|
| Continuous Wear Duration | 24 to 48 hours | Up to 14 days uninterrupted | Up to 14 days uninterrupted |
| Form Factor & Leads | Multi-wire chest electrodes with belt pack | Single-lead wire-free water-resistant adhesive patch | Single-lead adhesive patch plus wireless cellular gateway |
| Data Transmission Model | Returned to clinic after 24–48 hours | Mailed back via prepaid postal mailer at end of wear | Cellular event transmission during wear plus full post-wear analysis |
| Regulatory Pathway | FDA Class II 510(k) ambulatory ECG | FDA Class II 510(k) hardware + ZEUS AI SaMD | FDA Class II 510(k) telemetry + ZEUS AI SaMD |
ZEUS (Zio ECG Utilization Software) AI and Clinical Curation Pipeline
Fourteen days of continuous beat-to-beat cardiac monitoring generates more than 1.2 million heartbeats per patient encounter, making manual beat-by-beat visual inspection impractical without automated signal processing. iRhythm processes returned device data through a two-stage clinical workflow regulated under the FDA 510(k) clearance framework (distinct from the Class III Premarket Approval [PMA] pathway):
- FDA-Cleared ZEUS Deep Neural Network Analysis: Recorded ECG waveform data are ingested into the ZEUS (Zio ECG Utilization Software) system, an FDA 510(k)-cleared deep-learning algorithm trained on millions of annotated ECG beats. ZEUS performs automated noise filtering, beat detection, and rhythm classification across the multi-day recording to identify atrial fibrillation (AFib) burden, supraventricular tachycardia (SVT), ventricular tachycardia (VT),atrioventricular (AV) block, and sinus pauses.
- Certified Cardiographic Technician (CCT) Quality Review: Following algorithmic classification, Certified Cardiographic Technicians at iRhythm’s clinical centers review the algorithm-flagged arrhythmia episodes, patient-triggered symptom markers, and rhythm strips to adjudicate artifacts and compile a structured, physician-ready Zio Report.
- Zio Suite and EHR Interoperability: Completed Zio Reports and discrete diagnostic metrics are delivered to ordering clinicians through the web-based Zio Suite portal or integrated directly into hospital EHRs via HL7 v2 and HL7 FHIR R4 interfaces under HIPAA Security Rule technical safeguards.
How Is the Zio Patch Used in Clinical Research and Decentralized Trials?
Because the Zio XT and Zio Monitor are compact, self-applicable by participants at home, and returnable by standard mail without requiring an in-person clinic visit, the platform has become a cornerstone biosensor in decentralized and hybrid cardiovascular clinical trials:
- The mSToPS Randomized Clinical Trial (JAMA, 2018): In the landmark mHealth Screening to Prevent Strokes (mSToPS) study (Steinhubl et al., JAMA 2018;320(2):146–155), 2,659 participants across a nationwide health plan were enrolled entirely remotely and randomized to immediate vs. delayed home-based screening using self-applied iRhythm Zio XT patches worn for up to 14 days. Immediate continuous patch monitoring resulted in a nearly fourfold higher rate of new atrial fibrillation diagnosis at 4 months (3.9% vs. 0.9%) and sustained higher detection over 1 year (6.7 vs. 2.6 per 100 person-years), validating direct-to-participant mail-out ECG biosensors for pragmatic trial recruitment and endpoint ascertainment.
- Quantitative Arrhythmia Burden Endpoints: Unlike intermittent spot-check ECGs that yield binary presence/absence snapshots, 14-day continuous Zio recordings quantify continuous AFib burden (the exact percentage of monitored time spent in atrial fibrillation), longest episode duration, and circadian heart rate variability—serving as sensitive primary and secondary endpoints in antiarrhythmic drug trials, catheter ablation outcome studies, and cardio-oncology safety monitoring.
Frequently Asked Questions
What is the Zio Patch?
The Zio Patch (including the Zio XT and Zio Monitor by iRhythm Technologies) is a prescription-only, FDA 510(k)-cleared single-lead adhesive electrocardiogram (ECG) biosensor worn on the upper left chest that records continuous beat-to-beat cardiac rhythm data for up to 14 days without external lead wires or battery charging.
How is the Zio Patch used in clinical research and healthcare?
In clinical care, the Zio Patch is prescribed to detect and quantify intermittent cardiac arrhythmias—such as atrial fibrillation, supraventricular tachycardia, and heart block—that 24-to-48-hour Holter monitors frequently miss. In clinical research, its mail-to-participant, self-applied design and FDA-cleared ZEUS deep-learning analytics enable decentralized screening trials (such as the mSToPS trial) and precise measurement of continuous arrhythmia burden.
