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The Zio ECG Utilization Service (ZEUS) System is intended to analyze and report symptomatic and asymptomatic cardiac events and continuous electrocardiogram information for long-term monitoring by Zio XT or Zio AT Patch, a final report is generated based on the 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 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.

The ZEUS System is an electrocardiogram (ECG) processing and analysis system, designed to handle continuously recorded, single-lead ECG data. It downloads, stores, analyzes and aggregates the ECG data for a Certified Cardiographic Technician (CCT) to review and generate a report of the findings contained within the data; thereby enabling the provision of a complete ECG processing and analysis service.

The provided text is a truncated 510(k) submission summary for the Zio® ECG Utilization Service (ZEUS) System. Unfortunately, it does not contain the detailed information necessary to answer all parts of your request regarding acceptance criteria and the specific study that proves the device meets those criteria.

Specifically, 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 and minimize safety or efficacy concerns." However, it does not present the specific acceptance criteria (e.g., target sensitivity/predictivity values) nor does it provide a table of acceptance criteria alongside reported device performance. It also explicitly states, "No clinical testing was performed in support of this premarket notification." Therefore, the detailed study information you requested (sample sizes, ground truth establishment, expert qualifications, MRMC studies, standalone performance details, training set info) is not present in this document.

Based on the available text, here's what can be extracted:

1. Table of acceptance criteria and the reported device performance:

   • Acceptance Criteria (Implied): The device was expected to demonstrate sensitivity and positive predictivity levels that "satisfy requirements and minimize safety or efficacy concerns" for "any claimed analysis metrics."
   • Reported Device Performance: The document states, "The resulting statistics demonstrate sensitivity and positive predictivity levels which satisfy requirements..." However, no specific numerical values or a table comparing criteria to performance are provided.

2. Sample sized used for the test set and the data provenance (e.g. country of origin of the data, retrospective or prospective):

   • This information is not provided in the document.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts (e.g. radiologist with 10 years of experience):

   • This information is not provided in the document. The text mentions that a "Certified Cardiographic Technician (CCT) to review and generate a report of the findings contained within the data," but this refers to the intended use of the device for clinical review, not the establishment of ground truth for a performance study.

4. Adjudication method (e.g. 2+1, 3+1, none) for the test set:

   • This information is not provided in the document.

5. If a multi reader multi case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

   • No, an MRMC comparative effectiveness study is not mentioned or implied. The document explicitly states, "No clinical testing was performed in support of this premarket notification."

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:

   • The document states, "Automated ECG analysis performance was quantified for any claimed analysis metrics." This suggests standalone algorithm performance was evaluated, but the results and methodology are not detailed.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc):

   • This information is not explicitly provided. Given the nature of ECG analysis, it would typically be expert annotation/consensus, but the document does not confirm this.

8. The sample size for the training set:

   • This information is not provided in the document.

9. How the ground truth for the training set was established:

   • This information is not provided in the document.

Summary of available information regarding performance evaluation:

• Device Name: Zio® ECG Utilization Service (ZEUS) System
• Purpose of Evaluation (Implied): To quantify automated ECG analysis performance for claimed metrics, demonstrating sensitivity and positive predictivity.
• Type of Testing: "Automated ECG analysis performance was quantified." This was part of "Overall system performance testing" and "Software verification testing" as "nonclinical testing."
• Result (General): "The resulting statistics demonstrate sensitivity and positive predictivity levels which satisfy requirements and minimize safety or efficacy concerns."
• Lack of Detail: The document explicitly states "No clinical testing was performed" and does not provide specific numerical results, acceptance thresholds, sample sizes, methodology for ground truth, or details of expert involvement in performance studies.

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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 patient-triggered 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.

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 provided text describes the 510(k) premarket notification for the Zio AT ECG Monitoring System, specifically focusing on the modifications made to the ZEUS System's rhythm classification algorithm from a rule and machine-learning implementation to a deep-learning basis.

Here's an analysis of the acceptance criteria and the study that proves the device meets them, based on the provided text:

1. A table of acceptance criteria and the reported device performance:

The document states that "Safety and performance of the modified ZEUS System has been evaluated and verified in accordance with design specifications and applicable performance standards." and "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."

However, there is no specific table of acceptance criteria with corresponding performance metrics provided in the text. The document broadly refers to compliance with standards like AAMI ANSI EC57: 2012 and IEC 60601-2-47:2012. These standards typically outline performance requirements for ECG analysis systems (e.g., sensitivity, specificity for various arrhythmias), but the specific numerical targets set as acceptance criteria by iRhythm and the reported device performance against those targets are not detailed in this public FDA letter.

2. Sample size used for the test set and the data provenance:

The document mentions that "The modified device's arrhythmia algorithm detection was tested in accordance to AAMI ANSI EC57: 2012". While AAMI ANSI EC57: 2012 provides guidelines for testing and reporting performance, it does not explicitly state the sample size (number of patients or recordings) used for the test set.

Data Provenance: The document does not specify the country of origin of the data, nor does it explicitly state whether the data was retrospective or prospective.

3. Number of experts used to establish the ground truth for the test set and the qualifications of those experts:

The document mentions that the ZEUS System enables "iRhythm's Certified Cardiographic Technicians (CCTs) to generate and distribute a report of the findings contained within the data". However, it does not specify the number of experts used to establish the ground truth for the test set used to validate the deep-learning algorithm, nor does it explicitly state their qualifications (e.g., number of years of experience, specific certifications beyond "Certified Cardiographic Technicians").

4. Adjudication method (e.g., 2+1, 3+1, none) for the test set:

The document does not describe any adjudication method used for the test set to establish ground truth. It implies that CCTs generate reports, but not the process for an independent adjudicated ground truth for testing.

5. If a multi-reader multi-case (MRMC) comparative effectiveness study was done, If so, what was the effect size of how much human readers improve with AI vs without AI assistance:

The document does not mention an MRMC comparative effectiveness study where human readers' performance with and without AI assistance was evaluated. The focus of this submission is on the technological change to the algorithm itself and demonstrating its substantial equivalence to the predicate device.

6. If a standalone (i.e. algorithm only without human-in-the-loop performance) was done:

Yes, the document implies that standalone performance testing of the algorithm was done. It states: "The modified device's arrhythmia algorithm detection was tested in accordance to AAMI ANSI EC57: 2012" and "The ZEUS System is an electrocardiogram (ECG) analysis and reporting software system, designed to process continuously recorded, signal-lead ECG data." This suggests that the algorithm's performance in detecting arrhythmias was evaluated independently.

7. The type of ground truth used (expert consensus, pathology, outcomes data, etc.):

The document indicates that "iRhythm's Certified Cardiographic Technicians (CCTs) generate and distribute a report of the findings contained within the data". This implies that the ground truth for the data used in the system's operation is established by CCTs. For the testing data, it's highly probable that expert review (likely by CCTs, and potentially also by cardiologists as part of a gold standard process not explicitly detailed here) was used to establish ground truth for the arrhythmias. However, it does not explicitly state "expert consensus" or provide details on how many experts.

8. The sample size for the training set:

The document does not specify the sample size for the training set used for the deep-learning algorithm. It only states that the algorithm was updated "from a rule and machine-learning implementation to a deep-learning basis."

9. How the ground truth for the training set was established:

The document does not explicitly state how the ground truth for the training set was established. Given that 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," it is highly probable that the training data and their corresponding labels (ground truth) were derived from previous ECG recordings marked up by these Certified Cardiographic Technicians or similar qualified personnel.

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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.

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.

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.

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