The Zio QX ECG Monitoring System is intended to capture, analyze and report symptomatic and asymptomatic cardiac events and continuous electrocardiogram (ECG) 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 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, light-headedness, pre-syncope, fatigue, or anxiety. 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 Description

The Zio® QX ECG Monitoring System consists of three key device components: (1) Zio QX Patch Recorder with Bluetooth technology, (2) Zio QX Wireless Gateway with both Bluetooth and cellular technology, and (3) the Zio ECG Utilization Service (ZEUS) System for data analysis and reporting.

The Zio® QX Patch is a non-sterile, single-patient-use ECG monitor that provides a continuous, single-channel recording in addition to asymptomatic and symptomatic data transmission for up to 14 days. The Zio® QX Patch is applied and activated by the patient. Once activated, the Patch records ECG without patient interaction, with the goal of improving patient compliance via simplicity of operation. The Zio® QX Patch, in conjunction with the Wireless Gateway and the ZEUS System, has arrhythmia auto-detection capabilities. Additionally, patients have the option of pressing a convenient trigger button which marks the continuous record and initiates the wireless transfer of a 90-second ECG strip. The wireless transfer of data is enabled by the Zio® QX Gateway, which requires Bluetooth proximity to the Patch and cellular network reception but no patient interaction to transmit to the monitoring center. The patient is encouraged to document symptomatic events in either the provided booklet, mobile medical app (iOS 9+, Android 4.4+) or via a patient website, which will support symptom-rhythm correlation in the Zio QX Report.

At the conclusion of the wear period (up to 14 days), the patient removes the Zio® QX Patch and returns it by mail to an iRhythm data processing center.

Upon receipt of both symptomatic/asymptomatic transmissions (during wear) and downloaded continuous ECG data (post wear) at iRhythm's Clinical Center (iCC), the data is processed through the ZEUS detection algorithm and delivered to the QA Tool module where the results are reviewed and/or adjusted by iRhythm's Certified Cardiographic Technicians (CCTs) for accuracy. iRhythm employed and trained Patch in-take and CCT personnel follow internal procedures for processing and are made aware of performance limitations and anomalies with both the detection algorithms and software workflow tools. All anomalies are visible to and, where appropriate, are manually corrected by iRhythm Technologies CCTs during the QA review and/or Patch Report edits. The CCT generates a final report (Zio QX Report) of the ECG findings contained within the data, thereby providing a complete ECG processing and analysis service.

Upon explicit request from a clinician responsible for the patient's healthcare, longer segments of ECG data from the continuous recording on the Patch can also be wirelessly retrieved during the wear period. Alternatively, such periods are also available for inclusion in the final report, where the entire ECG recording is available for review and selective inclusion based on clinical relevance.

AI/ML Overview

The provided FDA 510(k) summary for the Zio® QX ECG Monitoring System (K163512) describes the device's acceptance criteria and the study conducted to prove it meets them.

Here's an analysis of the provided information:

1. Table of Acceptance Criteria and Reported Device Performance

The document states: "Automated ECG analysis performance was quantified for any claimed analysis metrics. The resulting statistics demonstrate sensitivity and positive predictivity levels which satisfy requirements."

However, the specific quantitative acceptance criteria (e.g., minimum sensitivity of X%, minimum PPV of Y% for specific arrhythmia types) and the actual reported performance metrics (e.g., Sensitivity = A%, PPV = B%) are NOT explicitly provided in the excerpt. The document only makes a general statement that the device satisfies requirements.

Without the actual numbers, a precise table cannot be constructed.

2. Sample Size Used for the Test Set and Data Provenance

The document states: "No clinical testing was performed in support of this premarket notification." and "All necessary performance testing was conducted on the Zio® QX ECG Monitoring System to ensure performance as intended per specifications and to support a determination of substantial equivalence to the predicate devices."

This indicates that the primary performance evaluation for the automated ECG analysis was done as part of non-clinical testing. This likely means simulated or pre-recorded ECG datasets were used.

Test Set Sample Size: Not explicitly provided.
Data Provenance: The document does not specify the country of origin of the data or whether it was retrospective or prospective. Given "nonclinical testing," it's likely a retrospective analysis of existing datasets or simulated data.

3. Number of Experts Used to Establish Ground Truth and Qualifications

The document describes the role of human experts in the data processing workflow:

"...the data is processed through the ZEUS detection algorithm and delivered to the QA Tool module where the results are reviewed and/or adjusted by iRhythm's Certified Cardiographic Technicians (CCTs) for accuracy."
"All anomalies are visible to and, where appropriate, are manually corrected by iRhythm Technologies CCTs during the QA review and/or Patch Report edits."
"The CCT generates a final report (Zio QX Report) of the ECG findings contained within the data, thereby providing a complete ECG processing and analysis service."

From this, we can infer:

Number of Experts: Not explicitly stated as a fixed number for establishing a ground truth dataset for the purpose of the regulatory submission's performance study. However, it implies that multiple CCTs are involved in the standard operational workflow for quality assurance and report generation. For the study proving acceptance criteria, the number of experts used to establish the "ground truth" for the test set is not specified.
Qualifications of Experts: "iRhythm's Certified Cardiographic Technicians (CCTs)" are mentioned. Their specific experience (e.g., 10 years) is not provided. It also doesn't specify if a higher level of expertise (e.g., cardiologists) was involved in establishing the ground truth for the performance claim.

4. Adjudication Method for the Test Set

The document states that CCTs review and adjust the algorithm's results. This implies a human-in-the-loop system where the CCTs serve as a final arbiter. However, for the non-clinical performance testing used for the regulatory submission, the specific adjudication method to build the "ground truth" dataset is not described. General methods like "2+1" or "3+1" are not mentioned. It's possible that a single CCT or a panel of CCTs established the ground truth in the datasets used for testing.

5. Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study

The document explicitly states: "No clinical testing was performed in support of this premarket notification."

Therefore, a MRMC comparative effectiveness study involving human readers improving with AI vs. without AI assistance was NOT done for this submission. The device is a "monitoring system" with an automated analysis component that produces a report for human review; the study focuses on the algorithm's performance and the general process, not on human-AI collaboration effectiveness.

6. Standalone (Algorithm Only) Performance

Yes, a standalone performance evaluation of the algorithm was conducted. The document states:

"Automated ECG analysis performance was quantified for any claimed analysis metrics."
This falls under "Nonclinical testing."

The device description also clarifies the algorithm's role: "...the data is processed through the ZEUS detection algorithm...". This "ZEUS detection algorithm" is the standalone component whose performance was quantified.

7. Type of Ground Truth Used

The document indicates that CCTs review and "adjust" results to ensure "accuracy" and manually "correct" anomalies. This suggests the ground truth for the performance evaluation (or at least the operational ground truth for report generation) is established by expert consensus/adjudication by Certified Cardiographic Technicians (CCTs). It's not explicitly stated whether a higher level of ground truth (e.g., pathology, clinical outcomes, or adjudication by cardiologists) was used for the non-clinical test set.

8. Sample Size for the Training Set

The document does NOT provide any information regarding the training set's sample size. The focus of the 510(k) summary is on the testing that demonstrates substantial equivalence, not on the details of algorithm development (training, validation).

9. How Ground Truth for the Training Set Was Established

The document does NOT provide any information on how the ground truth for the training set was established. This is typical for a 510(k) submission, which focuses on the validation of the final product.

Summary

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November 15, 2023

iRhythm Technologies, Inc. Rich Laguna Director Qa/ra 650 Townsend Street Suite 380 San Francisco, California 94103

Re: K163512

Trade/Device Name: Zio AT ECG Monitoring System Regulation Number: 21 CFR 870.1025 Regulation Name: Arrhythmia detector and alarm (including ST-segment measurement and alarm) Regulatory Class: Class II Product Code: QYX, DSH, DQK, DXH, DSI

Dear Rich Laguna:

The Food and Drug Administration (FDA) is sending this letter to notify you of an administrative change related to your previous substantial equivalence (SE) determination letter dated June 2, 2017. Specifically, FDA is updating this SE Letter because FDA has created a new product code to better categorize your device technology.

Please note that the 510(k) submission was not re-reviewed. For questions regarding this letter please contact Jennifer Kozen, OHT2: Office of Cardiovascular Devices, 301-796-5813, jennifer.kozen@fda.hhs.gov.

Sincerely.

Jennifer W. Shih -S

Jennifer Kozen Assistant Director Division of Cardiac Electrophysiology, Diagnostics and Monitoring Devices Office of Cardiovascular Devices Office of Product Evaluation and Quality Center for Devices and Radiological Health

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Food and Drug Administration 10903 New Hampshire Avenue Document Control Center - WO66-G609 Silver Spring, MD 20993-0002

June 2, 2017

iRhythm Technologies, Inc. Rich Laguna Director of Quality & Regulatory Affairs 650 Townsend Street Suite 380 San Francisco, CA 94103

Re: K163512

Trade/Device Name: Zio QX ECG Monitoring System Regulation Number: 21 CFR 870.2800 Regulation Name: Medical Magnetic Tape Recorder Regulatory Class: Class II Product Code: DSH, DQK, DXH, DSI Dated: May 2, 2017 Received: May 3, 2017

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. 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 801); medical device reporting (reporting of medical devicerelated adverse events) (21 CFR 803); good manufacturing practice requirements as set forth in

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the quality systems (QS) regulation (21 CFR Part 820); and if applicable, the electronic product radiation control provisions (Sections 531-542 of the Act); 21 CFR 1000-1050.

If you desire specific advice for your device on our labeling regulation (21 CFR Part 801), please contact the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm. 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 the CDRH's Office of Surveillance and Biometrics/Division of Postmarket Surveillance.

You may obtain other general information on your responsibilities under the Act from the Division of Industry and Consumer Education at its toll-free number (800) 638-2041 or (301) 796-7100 or at its Internet address

http://www.fda.gov/MedicalDevices/ResourcesforYou/Industry/default.htm.

Sincerelv.

M.A. Hilleman

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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Indications for Use

510(k) Number (if known) K163512

Device Name Zio® QX ECG Monitoring System

Indications for Use (Describe)

X Prescription Use (Part 21 CFR 801 Subpart D)

Over-The-Counter Use (21 CFR 801 Subpart C)

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510(k) Notification K163512

l. GENERAL INFORMATION [21CFR807.92(a)(1)]

Applicant:

iRhythm Technologies, Inc. 650 Townsend Street, Suite 500 San Francisco, CA 94103 U.S.A. Phone: 415-632-5700 Fax: 415-632-5701

Contact Person:

Rich Laguna Director Quality & Regulatory Affairs Phone: 415-632-5749 Email: rlaguna@irhythmtech.com

Date Prepared: May 2, 2017

ll. DEVICE INFORMATION [21CFR708.92(a)(2)]

Trade Name: Zio® QX ECG Monitoring System

Generic/Common Name:

Medical magnetic tape recorder

Classification Names:

Medical magnetic tape recorder [21 CFR§870.2800] Programmable diagnostic computer [21CFR§870.1425] 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 (special controls)

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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iRhythm Technologies, Inc.

510(k) SUMMARY

III. PREDICATE DEVICES [21CFR708.92(a)(3)]

The following predicate devices have been selected:

iRhythm Technologies, Inc. Zio® SR ECG Monitoring System [K143513] (primary)
Medtronic, Inc. SEEQ™ Mobile Cardiac Telemetry (MCT) System [K133701] -

No reference devices were used in this submission.

DEVICE DESCRIPTION [21CFR708.92(a)(4)] IV.

At the conclusion of the wear period (up to 14 days), the patient removes the Zio® QX Patch and returns it by mail to an iRhythm data processing center.

Upon explicit request from a clinician responsible for the patient's healthcare, longer segments of ECG data from the continuous recording on the Patch can also be wirelessly

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retrieved during the wear period. Alternatively, such periods are also available for inclusion in the final report, where the entire ECG recording is available for review and selective inclusion based on clinical relevance.

V. INDICATIONS FOR USE [21CFR708.92(a)(5)]

The Indications for Use statement for the Zio® QX ECG Monitoring System is as follows:

The Zio QX ECG Monitoring System is intended to capture, analyze and report symptomatic and asymptomatic cardiac events and continuous electrocardiogram (ECG) 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 beatto-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, light-headedness, pre-syncope, syncope, fatigue, or anxiety. 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.

The Indications for Use statement for the Zio® QX ECG Monitoring System differs slightly from that of the primary predicate device to address automatically detected events during wear; however, these differences do not alter the intended use of the device. Collectively, the subject device has the same intended use in cardiac arrhythmia diagnostics as the two predicate devices. Differences in the proposed Indications for Use statement are not critical to the intended use of the device, nor do they affect the safety and effectiveness of the subject device relative to the predicate devices. Therefore, the subject device can be considered substantially equivalent to the predicate devices.

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COMPARISON OF TECHNOLOGICAL CHARACTERISTICS WITH PREDICATE DEVICES VI. [21CFR708.92(a)(6)]

The proposed indications for use statement for the Zio® QX ECG Monitoring System reflect the same intended use as represented in the cleared Indications for Use statements for the predicate devices. The performance testing results demonstrate that the differences in the technological characteristics between the devices do not raise any new issues of safety or effectiveness, demonstrating that the subject device is as safe and as effective as the predicate devices. Therefore, the Zio® QX ECG Monitoring System is determined to be substantially equivalent to the predicate devices. A comparison table outlining the differences and similarities between the subject device, the Zio® QX ECG Monitoring System, and the predicate devices is provided in Table 1.

	Subject device:	Primary predicate:	Predicate:
	iRhythm Technologies	iRhythm Technologies	Medtronic, Inc.
	Zio® QX ECG MonitoringSystem	Zio® SR ECG MonitoringSystem	SEEQ™ MCT System
Feature	[K163512]	[K143513]	[K133701]
General Characteristics
Classification	Class II	Class II	Class II
ClassificationRegulation(s)	21CFR§870.280021CFR§870.142521CFR§870.292021CFR§870.1025	21CFR§870.280021CFR§870.142521CFR§870.2920	21CFR§870.1025
Product Code(s)	DSH, DQK, DXH, DSI	DSH, DQK, DXH	DSI
PatientEnvironment	Ambulatory	Same	Same
PatientPopulation	Non-pediatric, non-critical care patients	Same	Non-critical carepatients
Technological Characteristics
Key SystemComponents	1) Zio® QX Patch(wearable sensor)2) Zio® QX Gateway(transmitter)3) ZEUS System(software)	1) Zio® SR Patch(wearable sensor)2) Zio® SR Gateway(transmitter)3) ZEUS System(software)	1) SEEQ™ MCTWearable Sensor2) SEEQ™ MCTTransmitter3) Software
Event Trigger	Manually by patient orautomatically byarrhythmia detectionalgorithm	Manually by patient	Manually by patientor automatically byarrhythmia detectionalgorithm

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VII. PERFORMANCE DATA [21CFR708.92(b)]

There are no required FDA performance standards for the Zio® QX ECG Monitoring System. All necessary performance testing was conducted on the Zio® QX ECG Monitoring System to ensure performance as intended per specifications and to support a determination of substantial equivalence to the predicate devices.

[21CFR708.92(b)(1)]:

Nonclinical testing included:

System performance testing
Mechanical verification testing
Software verification testing
o Firmware verification testing
Electrical safety and EMC testing

Automated ECG analysis performance was quantified for any claimed analysis metrics. The resulting statistics demonstrate sensitivity and positive predictivity levels which satisfy requirements.

The scope of the nonclinical testing summarized in Table 2 demonstrates that the Zio® QX ECG Monitoring System is in conformance with FDA-recognized consensus standards and FDA guidance documents.

FDA #	Body	Number / Version	Title
5-70	AAMIANSI ISO	14971:2007/(R)2010(Corrected 4 October 2007)	Medical Devices - Applications Of Risk Management ToMedical Devices
19-4	AAMIANSI	ES60601-1:2005/(R)2012 andA1:2012, C1:2009/(R)2012and A2:2010/(R)2012	Medical Electrical Equipment - Part 1: GeneralRequirements For Basic Safety And EssentialPerformance (IEC 60601-1:2005, MOD)
19-12	AAMIANSI IEC	60601-1-2:2014	Medical Electrical Equipment -- Part 1-2: General RequirementsFor Basic Safety And Essential Performance -- CollateralStandard: Electromagnetic Disturbances -- Requirements AndTests
19-1	IEC	60601-1-2Edition 3: 2007-03	Medical Electrical Equipment - Part 1-2: GeneralRequirements For Basic Safety And EssentialPerformance - Collateral Standard: ElectromagneticCompatibility - Requirements And Tests
19-6	IEC	60601-1-11Edition 1.0 2010-04[Including: TechnicalCorrigendum 1 (2011)]	Medical Electrical Equipment - Part 1-11: GeneralRequirements For Basic Safety And EssentialPerformance - Collateral Standard: Requirements ForMedical Electrical Equipment And Medical ElectricalSystems Used In The Home Healthcare Environment
3-127	AAMIANSI IEC	60601-2-47:2012	Medical Electrical Equipment -- Part 2-47: ParticularRequirements For The Basic Safety And EssentialPerformance Of Ambulatory Electrocardiographic

Table 2: FDA-Recognized Consensus Standards & Guidance Document Summary

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FDA #	Body	Number / Version	Title
			Systems
3-52	AAMIANSI	EC12:2000/(R)2010	Disposable ECG Electrodes
3-118	AAMIANSI	EC57:2012	Testing And Reporting Performance Results Of CardiacRhythm And ST-Segment Measurement Algorithms
N/A	U.S. FDA	October 28, 2003	Guidance for Industry and FDA Staff - Class II SpecialControls Guidance Document: Arrhythmia Detector andAlarm
N/A	U.S. FDA	October 2, 2014	Guidance for Industry and FDA Staff – Content ofPremarket Submissions for Management ofCybersecurity in Medical Devices

Table 2: FDA-Recognized Consensus Standards & Guidance Document Summary
-------------------------------------------------------------------------	--

[21CFR708.92(b)(2)]:

No clinical testing was performed in support of this premarket notification.

[21CFR708.92(b)(3)]:

The results confirm by examination and provision of objective evidence that the design output met the design input requirements. The results of the nonclinical testing performed demonstrate that the Zio® QX ECG Monitoring System meets the requirements of established conformance standards and performance specifications necessary for its intended use and does not raise new questions of safety or effectiveness as compared to the predicate devices.

VIII. CONCLUSION

The Zio® QX ECG Monitoring System is substantially equivalent to the predicate devices.

Regulation Number and Section

§ 870.1025 Arrhythmia detector and alarm (including ST-segment measurement and alarm).

(a)
Identification. The arrhythmia detector and alarm device monitors an electrocardiogram and is designed to produce a visible or audible signal or alarm when atrial or ventricular arrhythmia, such as premature contraction or ventricular fibrillation, occurs.(b)
Classification. Class II (special controls). The guidance document entitled “Class II Special Controls Guidance Document: Arrhythmia Detector and Alarm” will serve as the special control. See § 870.1 for the availability of this guidance document.