K181502 · iRhythm Technologies, Inc. · DQK · Aug 29, 2018 · Cardiovascular
Device Facts
Record ID
K181502
Device Name
Zio AT ECG Monitoring System, ZEUS System
Applicant
iRhythm Technologies, Inc.
Product Code
DQK · Cardiovascular
Decision Date
Aug 29, 2018
Decision
SESE
Submission Type
Traditional
Regulation
21 CFR 870.1425
Device Class
Class 2
Attributes
AI/ML, Software as a Medical Device
AI Performance
Output
Algorithm
Acceptance
Observed
Dev DS
Dev Readers
Test DS
Test Readers
Arrhythmia detection
Deep-learning based rhythm classification algorithm
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Indications for Use
The device is intended to capture, analyze and report symptomatic and asymptomatic cardiac events and continuous electrocardiogram information for long-term monitoring. While continuously recording patient ECG, both patient-triggered and automatically-detected arrhythmia events are transmitted to a monitoring center for reporting. After wear, a final report is generated based on the beat-to-beat information from the entire ECG recording. It is indicated for use on patients 18 years or older who may be asymptomatic or who may suffer from transient symptoms such as palpitations, shortness of breath, dizziness, lightheadedness, pre-syncope, syncope, fatigue, or anxiety and patients who are asymptomatic. The reports are provided for review by the intended user to render a diagnosis based on clinical judgment and experience. It is not intended for use on critical care patients.
Device Story
ZEUS System is an ECG analysis and reporting software component of the Zio AT ECG Monitoring System. It processes single-lead ECG data recorded by the Zio AT Patch. The system downloads, stores, and analyzes ECG data to generate reports for review by certified cardiographic technicians and clinicians. The core modification involves updating the rhythm classification algorithm from a rule/machine-learning implementation to a deep-learning (ECGDL) basis, integrated with the existing machine-learning (ECGML) implementation. The system identifies various arrhythmias, including atrial fibrillation, heart blocks, pauses, and tachycardias. The output is a clinical report used by healthcare providers to render diagnoses based on clinical judgment. The device benefits patients by providing long-term, continuous cardiac monitoring to detect transient symptoms, facilitating timely clinical decision-making.
Clinical Evidence
Bench testing only. The modified ZEUS System was evaluated in accordance with AAMI ANSI EC57:2012 (Testing and Reporting Performance Results of Cardiac Rhythm and ST-Segment Measurement Algorithms) and IEC 60601-2-47:2012 (Particular requirements for the basic safety and essential performance of ambulatory electrocardiographic systems). Verification and system-level regression testing confirmed the device meets all design specifications.
Technological Characteristics
Software-based ECG analysis system. Utilizes a deep-learning (ECGDL) and machine-learning (ECGML) rhythm classification algorithm. Operates on a PC/Server platform. Complies with AAMI ANSI EC57:2012 and IEC 60601-2-47:2012 standards. Integrated analysis tool architecture.
Indications for Use
Indicated for patients 18 years or older, symptomatic (palpitations, shortness of breath, dizziness, lightheadedness, pre-syncope, syncope, fatigue, anxiety) or asymptomatic, requiring long-term ECG monitoring. Not for critical care patients.
Regulatory Classification
Identification
A programmable diagnostic computer is a device that can be programmed to compute various physiologic or blood flow parameters based on the output from one or more electrodes, transducers, or measuring devices; this device includes any associated commercially supplied programs.
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August 29, 2018
iRhythm Technologies, Inc. Rich Laguna Director of Quality and Regulatory Affairs 650 Townsend Street, Suite 500 San Francisco, California 94103
Re: K181502
Trade/Device Name: Zio AT ECG Monitoring System Regulation Number: 21 CFR 870.2800 Regulation Name: Medical Magnetic Tape Recorder Regulatory Class: Class II Product Code: DSH, DOK, DSI, DXH Dated: June 5, 2018 Received: June 7, 2018
Dear Rich Laguna:
We have reviewed your Section 510(k) premarket notification of intent to market the device referenced above and have determined the device is substantially equivalent (for the indications for use stated in the enclosure) to legally marketed predicate devices marketed in interstate commerce prior to May 28, 1976, the enactment date of the Medical Device Amendments, or to devices that have been reclassified in accordance with the provisions of the Federal Food. Drug, and Cosmetic Act (Act) that do not require approval of a premarket approval application (PMA). You may, therefore, market the device, subject to the general controls provisions of the Act. Although this letter refers to your product as a device, please be aware that some cleared products may instead be combination products. The 510(k) Premarket Notification Database located at https://www.accessdata.fda.gov/scripts/cdrh/cfdocs/cfpmn/pmn.cfm identifies combination product submissions. The general controls provisions of the Act include requirements for annual registration, listing of devices, good manufacturing practice, labeling, and prohibitions against misbranding and adulteration. Please note: CDRH does not evaluate information related to contract liability warranties. We remind you, however, that device labeling must be truthful and not misleading.
If your device is classified (see above) into either class II (Special Controls) or class III (PMA), it may be subject to additional controls. Existing major regulations affecting your device can be found in the Code of Federal Regulations, Title 21, Parts 800 to 898. In addition, FDA may publish further announcements concerning your device in the Federal Register.
Please be advised that FDA's issuance of a substantial equivalence determination does not mean that FDA has made a determination that your device complies with other requirements of the Act or any Federal statutes and regulations administered by other Federal agencies. You must comply with all the Act's requirements, including, but not limited to: registration and listing (21 CFR Part 807); labeling (21 CFR Part
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801); medical device reporting of medical device-related adverse events) (21 CFR 803) for devices or postmarketing safety reporting (21 CFR 4, Subpart B) for combination products (see https://www.fda.gov/CombinationProducts/GuidanceRegulatoryInformation/ucm597488.htm); good manufacturing practice requirements as set forth in the quality systems (QS) regulation (21 CFR Part 820) for devices or current good manufacturing practices (21 CFR 4. Subpart A) for combination products; and, if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.
Also, please note the regulation entitled, "Misbranding by reference to premarket notification" (21 CFR Part 807.97). For questions regarding the reporting of adverse events under the MDR regulation (21 CFR Part 803), please go to http://www.fda.gov/MedicalDevices/Safety/ReportaProblem/default.htm.
For comprehensive regulatory information about mediation-emitting products, including information about labeling regulations, please see Device Advice (https://www.fda.gov/MedicalDevices/DeviceRegulationandGuidance/) and CDRH Learn (http://www.fda.gov/Training/CDRHLearn). Additionally, you may contact the Division of Industry and Consumer Education (DICE) to ask a question about a specific regulatory topic. See the DICE website (http://www.fda.gov/DICE) for more information or contact DICE by email (DICE@fda.hhs.gov) or phone (1-800-638-2041 or 301-796-7100).
Sincerely.
# Arielle Drummond -S
for
Bram D. Zuckerman, M.D. Director Division of Cardiovascular Devices Office of Device Evaluation Center for Devices and Radiological Health
Enclosure
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#### DEPARTMENT OF HEALTH AND HUMAN SERVICES Food and Drug Administration
### Indications for Use
K181502
Device Name
Zio AT ECG Monitoring System
#### Indications for Use (Describe)
510(k) Number (if known)
The device is intended to capture, and report symptomatic and asymptomatic cardiac events and continuous electrocardiogram information for long-term monitoring. While continuously recording patient ECG, both patienttriggered and automatically-detected arthythmia events are transmitted to a monitoring center for reporting. After wear, a final report is generated based on the beat information from the entire ECC recording. It is indicated for use on patients 18 years or older who may be asymptomatic or who may suffer from transient symptoms such as palpitations, shortness of breath, dizziness, light-headedness, pre-syncope, fatigue, or anxiety and patients who are asymptomatic. The reports are provided for review by the intended user to render a diagnosis based on clinical judgment and experience. It is not intended for use on critical care patients.
X Prescription Use (Part 21 CFR 801 Subpart D)
Over-The-Counter Use (21 CFR 801 Subpart C)
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## SECTION 5. 510(k) Summary
## 1. GENERAL INFORMATION
#### 510(k) Sponsor
iRhythm Technologies, Inc.
650 Townsend Street, Suite 500
San Francisco, CA. 94103
#### Correspondence Person
Rich Laguna
Director of Quality and Regulatory Affairs
#### Contact Information
Email: rlaguna@irhythmtech.com
Phone: (415) 632-5749
Date Prepared
08/29/2018
#### 2. PROPOSED DEVICE
#### Proprietary Name
Zio® AT ECG Monitoring System
#### Common Name
Zio® AT ECG Monitoring System
#### Classification Name
Medical magnetic tape recorder [21 CFR§870.2800]
Programmable diagnostic computer [21CFR8870.1425]
Telephone electrocardiograph transmitter and receiver [21CFR§870.2920]
Arrhythmia detector and alarm (including ST-segment measurement and alarm) [21
CFR§870.1025]
#### Regulatory Class
Class II
#### Product Codes
DSH, Recorder, Magnetic Tape, Medical
DQK, Computer, Diagnostic, Programmable
DXH, Transmitters And Receivers, Electrocardiograph, Telephone
DSI, Detector And Alarm, Arrhythmia
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## 3. PREDICATE DEVICE (ORIGINALLY CLEARED DEVICE)
iRhythm Technologies, Inc. Zio AT ECG Monitoring System (K163512)
### 4. DEVICE DESCRIPTION
The ZEUS System was most recently 510(k) cleared under K163512 as part of the Zio AT ECG Monitoring System ("Zio" AT"). The original cleared ECG monitoring system components consisted of the 1) Zio AT Patch Recorder Device 2) Zio AT Wireless Gateway Device with Bluetooth and Cellular Technology, and 3) ZEUS System for analysis and reporting. This submission discusses the changes made to the ZEUS System only. The ZEUS System is an electrocardiogram (ECG) analysis and reporting software system, designed to process continuously recorded, signal-lead ECG data. The ZEUS System downloads, stores, analyzes and sorts the ECG data to allow iRhythm's Certified Cardiographic Technicians (CCTs) to generate and distribute a report of the findings contained within the data, thereby enabling the provision of a complete ECG processing and analysis service.
The ZEUS System is considered modified as a result of updating its rhythm classification algorithm from a rule and machine-learning implementation to a deep-learning basis. The comparison to the originally cleared device and performance test results demonstrate that the modified ZEUS System is substantially equivalent to the original ZEUS System cleared under K163512, and that the intended use of the device can be consistently fulfilled as originally cleared.
#### 5. INDICATIONS FOR USE
The device is intended to capture, analyze and report symptomatic and asymptomatic cardiac events and continuous electrocardiogram information for long-term monitoring. While continuously recording patient ECG, both patient-triggered and automatically-detected arrhythmia events are transmitted to a monitoring center for reporting. After wear, a final report is generated based on the beat-to-beat information from the entire ECG recording. It is indicated for use on patients 18 years or older who may be asymptomatic or who may suffer from transient symptoms such as palpitations, shortness of breath, dizziness, lightheadedness, pre-syncope, syncope, fatigue, or anxiety and patients who are asymptomatic. The reports are provided for review by the intended user to render a diagnosis based on clinical judgment and experience. It is not intended for use on critical care patients.
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#### 6. SUBSTANTIAL EQUIVALENCE SUMMARY
The indications for use statement for the modified ZEUS System is an identical reflection of the indications for use as represented in the originally cleared device. The performance testing results demonstrate that the differences in the technological characteristics between the devices do not raise new issues of safety or effectiveness. Therefore, the modified ZEUS System is determined to be substantially equivalent to the original ZEUS System device. A comparison table outlining the differences and similarities between the modified and original ZEUS System is provided in Table 5.1.
| Feature/<br>Function | Original Device:<br>Zio AT ECG Monitoring<br>System (K163512) | Modified Device:<br>ZEUS System | |
|-------------------------------|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|--|
| General Characteristics | | | |
| Classification | Class II | Class II | |
| Classification Regulation(s) | 21 CFR 870.2800<br>21 CFR 870.1425<br>21 CFR 870.2920<br>21 CFR 870.1025 | 21 CFR 870.2800<br>21 CFR 870.1425<br>21 CFR 870.2920<br>21 CFR 870.1025 | |
| Product Code | DSH, DQK, DXH, DSI | DSH, DQK, DXH, DSI | |
| Patient Environment | Ambulatory | Ambulatory | |
| Patient Population | Non-pediatric, non-critical<br>care patients | Non-pediatric, non-critical care<br>patients | |
| Technological Characteristics | | | |
| Data Input | Digital long-term continuous<br>and transmission ECG | Digital long-term continuous<br>and transmission ECG | |
| Data Download | Yes | Yes | |
| Data Storage | Yes | Yes | |
| ECG Analysis | Beat<br>Runs<br>Rhythm Types<br>Heart Rates | Beat<br>Runs<br>Rhythm Types<br>Heart Rates | |
| Rhythm Detection Algorithm | ECGML | ECGML and ECGDL | |
| Feature/<br>Function | Original Device:<br>Zio AT ECG Monitoring<br>System (K163512) | Modified Device:<br>ZEUS System | |
| Rhythm Types | - Atrial fibrillation<br>- Complete heart block<br>- Second degree AV<br>block-type II<br>- Pause >3 seconds<br>- Sinus rhythm<br>- Supraventricular<br>tachycardia<br>- Ventricular bigeminy<br>- Ventricular fibrillation<br>- Ventricular tachycardia<br>- Ventricular trigeminy | - Atrial fibrillation<br>- Complete heart block<br>- Second degree AV block-<br>type II<br>- Pause >3 seconds<br>- Sinus rhythm<br>- Supraventricular tachycardia<br>- Ventricular bigeminy<br>- Ventricular fibrillation<br>- Ventricular<br>tachycardia<br>- Ventricular trigeminy<br>- Second degree AV block-<br>type I<br>- Ectopic atrial rhythm<br>- Junctional rhythm<br> | |
| Result Integrator | Algorithm Controller | Algorithm Controller, updated to<br>initiate ECG Analysis through<br>ECGDL, and integrate the<br>ECGML and ECGDL labels | |
| Architecture | Integrated Analysis Tool | Integrated Analysis Tool | |
| Platform | PC / Server Mix to<br>Clinician & Patient<br>Websites | PC / Server Mix to Clinician &<br>Patient Websites | |
| QA Tool | Yes | Yes, updated to support the<br>expanded rhythms | |
| Report Output | Yes | Yes | |
| ZEUS Web Services | Store and retrieve the<br>integrated ECGML Labels<br>to ZEUS Database | Store and retrieve the integrated<br>ECGML and ECGDL Labels to<br>ZEUS Database | |
#### Table 5.1: Substantial Equivalence Summary Table
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#### 7. PERFORMANCE DATA
Safety and performance of the modified ZEUS System has been evaluated and verified in accordance with design specifications and applicable performance standards. The modified device's arrhythmia algorithm detection was tested in accordance to AAMI ANSI EC57: 2012, Testing and Reporting Performance Results of Cardiac Rhythm and ST-Segment Measurement Algorithms; it was also evaluated according to 60601-2-47:2012, Medical Electrical Equipment- Part 2-47: Particular requirements for the basic safety and essential performance of ambulatory electrocardiographic systems. Additionally, the information presented in this submission has been developed in consideration of the recommendations contained in FDA Guidance documents, "Guidance for the Content of Premarket Submissions for Software Contained in Medical Devices" and "Content of Premarket Submission for Management of Cybersecurity in Medical Devices".
The nonclinical verification and performance test results established that the device meets its design requirements and intended use, that the modifications to the originally cleared device do not raise new questions of safety and efficacy. During the development, potential hazards were evaluated and controlled by the risk management activities, including risk analysis, risk mitigation, verification and risk-benefit analysis. The verification and full system-level regression testing demonstrate that the device meets all its specifications.
#### 8. CONCLUSION
Based on the information submitted in this premarket notification, and based on the indications for use, technological characteristics and performance testing comparison to the originally cleared device, the modified ZEUS System raises no new questions of safety and effectiveness and is substantially equivalent to the predicate device.
Two short videos show you everything — or skip straight to the written tutorial if you'd rather read. You can reopen this any time from the Tutorial button in the top bar.
Part 1 — Search, results, and everyday workflows 16 min
Part 2 — Embeddings: the galaxy map 3 min
1. Search: exact and fuzzy
Type a phrase like "coronary artery calcification" into the search box. You get two kinds of results. Exact results match the literal phrase — prefix searches work ("coronary artery calcificati") but suffix searches do not. Fuzzy results match on the meaning and intent of your phrase rather than the exact words, and are sorted by relevance score. Hover over the Exact or Fuzzy badge on any row to see exactly why it matched.
Use the checkboxes above the results to narrow: SaMD keeps only software-only devices, AI / ML keeps only devices with AI.
Exact vs. fuzzy search: what's the difference?
Exact matches on the literal phrase (prefix search works, suffix does not). Fuzzy matches on the meaning and intent of the phrase rather than the exact words. Hover over the badge on any row to see why it matched.
You search "coronary artery calcification" and want only software devices with AI. What two filters do you apply?
Narrow by SaMD (software-only devices), then narrow by AI/ML (devices with AI).
2. The results table
Scroll right in the results table. The intended use is extracted for you — no need to open the PDF. The device story gives a high-level snapshot of what the device does and how it's used. The AI Performance sub-table shows each output name, acceptance criteria, observed values, and development/test dataset descriptions — the same format Innolitics uses for regulatory strategy outputs, and the fastest high-level fingerprint of an AI device. It is AI-generated but has been very reliable in practice.
Where do you find a device's intended use without opening the PDF?
Scroll right in the search results table. The intended use column is extracted for you; no need to dig into the 510(k) summary PDF.
What does the AI Performance sub-table show, and why is it useful?
Output name, acceptance criteria, observed values, development dataset description, and test dataset description. It's the same format we use for regulatory strategy output and Fast 510(k) input, and the fastest high-level fingerprint of an AI device. AI-generated but reliable in practice.
3. Judging fuzzy relevance
Fuzzy results trail off in relevance as you scroll. Use three signals to decide how far down to go: the fuzzy badge explanations, the intended use column, and whether your target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, you're past the relevant zone. A top hit with a low score (~0.4) and a stretched explanation is a hint the closest predicates are far away — the project may be headed for De Novo. Note the fuzzy search is a pattern match: it doesn't handle negation ("not") well, and hardware devices can appear — filter by SaMD/AI ML to cut them.
How do you judge how far down fuzzy search results to go?
Use the relevancy signals: the fuzzy badge explanations, the intended use column, and whether the target output (e.g., Cobb angle) still appears in the AI Performance sub-table. Once it stops appearing, results are trailing off in relevancy.
4. Device detail page: chat and citations
Click a device name to open its detail page: device facts on the left, a chat window on the right. Ask something like "Describe the training data". The answer carries little citation bubbles — click one to jump to the highlighted passage in the source PDF, so you can verify every AI answer against the document. There's also a Download PDF button for sharing.
How do you verify an AI chat answer on the device detail page?
Click the citation bubbles to jump to the relevant highlight in the source document.
Reading rule for every project: how many summaries do you read in full?
At least the three most relevant 510(k) or De Novo summaries, in full. After that, use targeted chat questions to confirm your memory quickly. The tool supports this professional habit — it doesn't replace it.
5. Side-by-side comparison
Select multiple rows in the results table (aim for under ~10), then open the PDF Viewer tab. Ask one question — it goes to all selected devices in parallel, each with citations. This is the fastest way to compare and contrast devices: training data, PCCP scope, how they handled adding new scanners, and so on.
What does the side-by-side PDF viewer mode do?
Select multiple devices, open the PDF viewer tab, and ask one question (e.g., "Describe the training data"). It queries all selected devices simultaneously with citations, so you can compare and contrast quickly.
6. Collections
With rows selected, go to the Collections tab and create a labeled collection (e.g., "Cobb Angle Project"). Reload that selection any time — before a client call, pull up the collection and ask questions across all of its devices at once.
How do you save a set of selected devices for later use?
Select the rows, go to the Collections tab, and create a labeled collection (e.g., "Cobb Angle Project"). You can reload the selection anytime and carry it into the PDF viewer and other tabs that support selections.
7. Product codes and the regulations tree
Click a product code in the results to jump to it in the regulations tree — identification text, sibling product codes, and devices you can open in a PDF viewer on the right. Click a regulation number to see its identification, special controls, and related product codes. You can also search by product code or regulation number at the top of the tree. Always read the special controls if any exist for your device — it broadens your search and sharpens pre-kickoff research.
What can you do from the regulations tree view?
Browse product codes and regulation numbers, read the identification text and special controls, browse sibling product codes, open device PDFs on the right, and search by product code or regulation number at the top of the tree.
8. Chart view
Click Show Chart and segment by regulation number (or product code) to see which regulations dominate your result set. Clicking a regulation takes you into the regulations tree. Great for spotting that most matches are, say, hardware laparoscopic devices — a cue to go back and filter.
How do you see which regulations dominate a search result set?
Click "Show Chart" and segment by Regulation Number. Clicking a regulation takes you to the regulations tree.
9. The predicate graph
Open the Predicates tab for a family-tree view of predicate relationships. Click a node to trace its parents and children; selections from search carry over pre-selected. Commonly predicated devices are worth reading — a lot of people predicated them for a reason. The visual lineage is also handy on client calls, e.g. to show how a predicate family evolved and justify why your predicate still holds.
In the predicate graph, why are commonly predicated devices worth reading?
A lot of people predicated them for a reason. Clicking a node traces parents and children, and selections from search carry over pre-selected.
10. Embeddings: the galaxy map
The Embeddings tab plots every matching document in a 2-D "galaxy map" where semantically similar devices cluster together. Hover or click clusters to explore, and let AI label the clusters for you. Embeddings beat product codes for grouping: two devices can carry different product codes (LLZ vs. QIH) yet do the same thing — the embedding captures the meaning of the intended use and device story. This is also exactly how retrieval-augmented generation (RAG) works under the hood, and it makes a great visual on client calls.
Try it yourself
Head to the search page and work through a few of these AI/ML fuzzy searches to build intuition: perivascular fat on CT · aortic valve calcification opportunistic screening on noncontrast CT · breast cancer prediction on digital pathology slides · autism detection · gestational age prediction · a hearing aid that can also detect a pulse · foundation model based analysis of ECG · large language models · penetration test. Watch how the relevance scores, intended use, and AI Performance tables tell you when results stop being meaningful.