Cardiopulmonary Exercise Test InterpretationPACE-ReaderNCT07833137
AI-Assisted Anaerobic Threshold Interpretation in Cardiopulmonary Exercise Testing
A study testing AI-Assisted Anaerobic Threshold Interpretation and Unassisted Cardiopulmonary Exercise Test Interpretation in people with Cardiopulmonary Exercise Test Interpretation, run by Shanghai Zhongshan Hospital at 1 site in China.
Trial summary
This prospective randomized two-period crossover reader study will evaluate whether assistance from a frozen artificial intelligence model improves physicians' interpretation of the anaerobic threshold (AT) in cardiopulmonary exercise testing (CPET). Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Cardiopulmonary Exercise Test Interpretation
- What is being tested?
- AI-Assisted Anaerobic Threshold Interpretation and Unassisted Cardiopulmonary Exercise Test Interpretation
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 16 participants
- Where
- 1 siteChina
- Study dates
- 25 Sep 2026to 25 Nov 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Age 18 years or older.
- Licensed physician or physician enrolled in a recognized postgraduate clinical training program at the study institution.
- Eligible for one of the two prespecified seniority strata: senior physicians are attending physicians or above with at least 5 years of independent CPET interpretation experience; junior physicians are residents or specialty trainees with less than 5 years of independent CPET interpretation experience.
- Able to interpret CPET examinations and use the study interface after standardized orientation.
- Willing and able to complete both study periods and the prespecified washout interval.
- Provides written informed consent.
Who cannot join
- Direct involvement in development, training, hyperparameter selection, or checkpoint selection of the PACE-Former model.
- Prior access to the study case libraries, reference-standard annotations, or model outputs for the study examinations.
- Unable to complete the required interpretation tasks or the 14 ± 3 day washout interval.
- Withdrawal of consent before completion of study procedures.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
China1 site
Zhongshan Hospital, Fudan University
Shanghai, Shanghai Municipality, 200032
Cong Wang, MD, PhD, +86-21-64041990, wang.cong1@zs-hospital.sh.cn
About this study
Official title: A Randomized Two-Period Crossover Reader Study of Artificial Intelligence-Assisted Anaerobic Threshold Interpretation in Cardiopulmonary Exercise Testing
This prospective randomized two-period crossover reader study will evaluate whether assistance from a frozen artificial intelligence model improves physicians' interpretation of the anaerobic threshold (AT) in cardiopulmonary exercise testing (CPET). Sixteen physicians, including 8 senior and 8 junior readers, will each interpret 150 de-identified CPET examinations once without AI assistance and once with AI assistance. The primary outcome is the within-physician difference in absolute AT localization error between the assisted and unassisted conditions. Secondary outcomes include signed timing error, agreement on whether AT is present, estimates within 15 and 30 seconds of the reference, inter-reader reliability, interpretation time, and whether the effect of AI assistance differs by physician seniority.
Read the detailed description
The 150 de-identified CPET examinations will be divided into two non-overlapping case libraries, X and Y, with 75 examinations in each library. The libraries will be balanced, as far as feasible, by clinical severity and acquisition characteristics. None of the reader-study examinations will be used for model training, hyperparameter selection, or checkpoint selection.
Within each seniority stratum, physicians will be randomized in a 1:1 ratio to Sequence A or Sequence B. In period 1, Sequence A will interpret library X without AI assistance and library Y with AI assistance; Sequence B will receive the opposite conditions. Following a 14 ± 3 day washout, the assistance conditions will be reversed in period 2. Case order will be randomized within each period, and new blinded task identifiers will be assigned in period 2. Thus, every physician will interpret every examination once without AI assistance and once with AI assistance, yielding 4,800 interpretations.
In the assisted condition, the interface will display the frozen model's predicted AT time. In the unassisted condition, no model output will be shown. Readers will be masked to case source, routine-report and reference-standard labels, other readers' annotations, and their own annotations from the previous period. For each examination, the reader will classify AT as confirmed, not reached, or unable to confirm. When AT is confirmed, the reader will record the AT time and the interpretive method used. Interpretation time will also be recorded.
The reference standard will be prespecified from unassisted senior-physician annotations. AT will be considered present when at least 6 of 8 senior physicians confirm it, and the reference AT time will be the median of the confirming senior estimates. AT will be considered not reached when at least 6 of 8 senior physicians make that classification. Discordant cases will undergo adjudication by an additional senior physician who is masked to model output and reader identity. For analyses of senior readers, a leave-one-reader-out reference will be used.
The primary analysis will compare absolute AT localization error between assisted and unassisted interpretations using a crossed mixed-effects model. Fixed effects will include assistance condition, physician seniority, the assistance-by-seniority interaction, period, randomized sequence, and case library. Random intercepts will be included for physician and examination. Estimates will be reported with 95% confidence intervals. No simulated or pilot-result data will be included in the prospective study analysis.
- Being tested
- AI-Assisted Anaerobic Threshold Interpretation, Unassisted Cardiopulmonary Exercise Test Interpretation
- Keywords
- Artificial Intelligence, Anaerobic Threshold, Cardiopulmonary Exercise Testing, Clinical Decision Support, Reader Study, Human-AI Collaboration
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
AI-Assisted Anaerobic Threshold InterpretationOther
A frozen PACE-Former model provides a predicted anaerobic threshold time within the CPET review interface. Physicians retain responsibility for the final classification and AT time annotation. No other model output or reference label is displayed.
Unassisted Cardiopulmonary Exercise Test InterpretationOther
The physician reviews the same de-identified CPET data using the study interface without display of any model prediction or AI-generated suggestion and independently classifies AT status and records the AT time when confirmed.
| Study group | Role | What they receive |
|---|---|---|
| Sequence A | Experimental | Period 1: library X interpreted without AI assistance and library Y interpreted with AI assistance. Period 2, after a 14 ± 3 day washout: library X interpreted with AI assistance and library Y interpreted without AI assistance. Receives: Other: AI-Assisted Anaerobic Threshold Interpretation; Other: Unassisted Cardiopulmonary Exercise Test Interpretation |
| Sequence B | Experimental | Period 1: library X interpreted with AI assistance and library Y interpreted without AI assistance. Period 2, after a 14 ± 3 day washout: library X interpreted without AI assistance and library Y interpreted with AI assistance. Receives: Other: AI-Assisted Anaerobic Threshold Interpretation; Other: Unassisted Cardiopulmonary Exercise Test Interpretation |
What is being measured
The primary outcome is the main question the study is designed to answer.
Difference in Absolute Anaerobic Threshold Localization Error
Absolute difference, in seconds, between the physician-selected AT time and the prespecified expert reference AT time. The primary estimand is the within-physician difference between AI-assisted and unassisted interpretations, analyzed across the same examinations using a crossed mixed-effects model.
Measured: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Secondary outcomes (7)
Signed Anaerobic Threshold Localization Error
Signed difference, in seconds, between the physician-selected AT time and the prespecified expert reference AT time. Negative values indicate earlier placement and positive values indicate later placement relative to the reference.
Measured: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Proportion of Anaerobic Threshold Estimates Within 15 Seconds of the Reference
Proportion of interpretable examinations for which the physician-selected AT time is within 15 seconds, in either direction, of the prespecified expert reference AT time.
Measured: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Proportion of Anaerobic Threshold Estimates Within 30 Seconds of the Reference
Proportion of interpretable examinations for which the physician-selected AT time is within 30 seconds, in either direction, of the prespecified expert reference AT time.
Measured: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Agreement With the Reference Anaerobic Threshold Status
Agreement between the physician classification (AT confirmed, AT not reached, or unable to confirm) and the prespecified expert reference classification. Results will be summarized as overall agreement and condition-specific classification performance.
Measured: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Inter-Reader Reliability
Reliability among physicians for AT timing and AT-status classification under AI-assisted and unassisted conditions, summarized using appropriate intraclass correlation and chance-corrected agreement statistics with 95% confidence intervals.
Measured: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Interpretation Time per Examination
Elapsed time, in seconds, from opening the blinded CPET task to submission of the physician's AT classification and, when applicable, the selected AT time.
Measured: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Interaction Between AI Assistance and Physician Seniority
Difference in the effect of AI assistance between senior and junior physicians, estimated from the prespecified assistance-by-seniority interaction term in the crossed mixed-effects model for absolute AT localization error.
Measured: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted22 Sep 2026
- Study start25 Sep 2026 (estimated)
- Primary completion25 Nov 2026 (estimated)
- Study completion25 Nov 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Cardiopulmonary Exercise Test InterpretationStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Model description
- Randomized, stratified, two-period crossover reader study. Sixteen physicians (8 senior and 8 junior) are randomized within seniority strata to two sequences. The 150 de-identified CPET examinations are divided into libraries X and Y (75 each). In period 1, Sequence A interprets X without AI and Y with AI, whereas Sequence B receives the opposite conditions. After a 14 ± 3 day washout, conditions are reversed in period 2. Each physician interprets every case once without AI and once with AI, yielding 4,800 interpretations.
- Masking
- None (open label)
- Enrolment
- 16 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Shanghai Zhongshan Hospital
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
- Investigators
- Cong Wang, MD, PhD, Principal investigator, Fudan University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07833137
- Sponsor's protocol ID
- PACE-AT-READER-01
- Acronym
- PACE-Reader
- Status last verified
- Sep 2026
- First submitted
- 16 Sep 2026
- Last updated
- 22 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 22 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A Randomized Two-Period Crossover Reader Study of Artificial Intelligence-Assisted Anaerobic Threshold Interpretation in Cardiopulmonary Exercise Testing
- ClinicalTrials.gov ID
- NCT07833137
- Acronym / sponsor ID
- PACE-Reader / PACE-AT-READER-01
- Keywords
- Artificial Intelligence, Anaerobic Threshold, Cardiopulmonary Exercise Testing, Clinical Decision Support, Reader Study, Human-AI Collaboration
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 16 participants (estimated)
- Lead sponsor
- Shanghai Zhongshan HospitalUniversity, hospital or other
- Study start
- 25 Sep 2026 (estimated)
- Primary completion
- 25 Nov 2026 (estimated)
- Study completion
- 25 Nov 2026 (estimated)
- First posted
- 22 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
This prospective randomized two-period crossover reader study will evaluate whether assistance from a frozen artificial intelligence model improves physicians' interpretation of the anaerobic threshold (AT) in cardiopulmonary exercise testing (CPET). Sixteen physicians, including 8 senior and 8 junior readers, will each interpret 150 de-identified CPET examinations once without AI assistance and once with AI assistance. The primary outcome is the within-physician difference in absolute AT localization error between the assisted and unassisted conditions. Secondary outcomes include signed timing error, agreement on whether AT is present, estimates within 15 and 30 seconds of the reference, inter-reader reliability, interpretation time, and whether the effect of AI assistance differs by physician seniority.
Detailed description
The 150 de-identified CPET examinations will be divided into two non-overlapping case libraries, X and Y, with 75 examinations in each library. The libraries will be balanced, as far as feasible, by clinical severity and acquisition characteristics. None of the reader-study examinations will be used for model training, hyperparameter selection, or checkpoint selection.
Within each seniority stratum, physicians will be randomized in a 1:1 ratio to Sequence A or Sequence B. In period 1, Sequence A will interpret library X without AI assistance and library Y with AI assistance; Sequence B will receive the opposite conditions. Following a 14 ± 3 day washout, the assistance conditions will be reversed in period 2. Case order will be randomized within each period, and new blinded task identifiers will be assigned in period 2. Thus, every physician will interpret every examination once without AI assistance and once with AI assistance, yielding 4,800 interpretations.
In the assisted condition, the interface will display the frozen model's predicted AT time. In the unassisted condition, no model output will be shown. Readers will be masked to case source, routine-report and reference-standard labels, other readers' annotations, and their own annotations from the previous period. For each examination, the reader will classify AT as confirmed, not reached, or unable to confirm. When AT is confirmed, the reader will record the AT time and the interpretive method used. Interpretation time will also be recorded.
The reference standard will be prespecified from unassisted senior-physician annotations. AT will be considered present when at least 6 of 8 senior physicians confirm it, and the reference AT time will be the median of the confirming senior estimates. AT will be considered not reached when at least 6 of 8 senior physicians make that classification. Discordant cases will undergo adjudication by an additional senior physician who is masked to model output and reader identity. For analyses of senior readers, a leave-one-reader-out reference will be used.
The primary analysis will compare absolute AT localization error between assisted and unassisted interpretations using a crossed mixed-effects model. Fixed effects will include assistance condition, physician seniority, the assistance-by-seniority interaction, period, randomized sequence, and case library. Random intercepts will be included for physician and examination. Estimates will be reported with 95% confidence intervals. No simulated or pilot-result data will be included in the prospective study analysis.
Study design
- Primary purpose
- Diagnosis
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Randomized, stratified, two-period crossover reader study. Sixteen physicians (8 senior and 8 junior) are randomized within seniority strata to two sequences. The 150 de-identified CPET examinations are divided into libraries X and Y (75 each). In period 1, Sequence A interprets X without AI and Y with AI, whereas Sequence B receives the opposite conditions. After a 14 ± 3 day washout, conditions are reversed in period 2. Each physician interprets every case once without AI and once with AI, yielding 4,800 interpretations.
| Arm | Type | Receives |
|---|---|---|
| Sequence A | Experimental | Other: AI-Assisted Anaerobic Threshold Interpretation, Other: Unassisted Cardiopulmonary Exercise Test InterpretationPeriod 1: library X interpreted without AI assistance and library Y interpreted with AI assistance. Period 2, after a 14 ± 3 day washout: library X interpreted with AI assistance and library Y interpreted without AI assistance. |
| Sequence B | Experimental | Other: AI-Assisted Anaerobic Threshold Interpretation, Other: Unassisted Cardiopulmonary Exercise Test InterpretationPeriod 1: library X interpreted with AI assistance and library Y interpreted without AI assistance. Period 2, after a 14 ± 3 day washout: library X interpreted without AI assistance and library Y interpreted with AI assistance. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (6 listed)
- Age 18 years or older.
- Licensed physician or physician enrolled in a recognized postgraduate clinical training program at the study institution.
- Eligible for one of the two prespecified seniority strata: senior physicians are attending physicians or above with at least 5 years of independent CPET interpretation experience; junior physicians are residents or specialty trainees with less than 5 years of independent CPET interpretation experience.
- Able to interpret CPET examinations and use the study interface after standardized orientation.
- Willing and able to complete both study periods and the prespecified washout interval.
Key exclusion criteria (4 listed)
- Direct involvement in development, training, hyperparameter selection, or checkpoint selection of the PACE-Former model.
- Prior access to the study case libraries, reference-standard annotations, or model outputs for the study examinations.
- Unable to complete the required interpretation tasks or the 14 ± 3 day washout interval.
- Withdrawal of consent before completion of study procedures.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| AI-Assisted Anaerobic Threshold InterpretationA frozen PACE-Former model provides a predicted anaerobic threshold time within the CPET review interface. Physicians retain responsibility for the final classification and AT time annotation. No other model output or reference label is displayed. | Other | Sequence A, Sequence B |
| Unassisted Cardiopulmonary Exercise Test InterpretationThe physician reviews the same de-identified CPET data using the study interface without display of any model prediction or AI-generated suggestion and independently classifies AT status and records the AT time when confirmed. | Other | Sequence A, Sequence B |
Primary outcome
Difference in Absolute Anaerobic Threshold Localization Error
Time frame: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Absolute difference, in seconds, between the physician-selected AT time and the prespecified expert reference AT time. The primary estimand is the within-physician difference between AI-assisted and unassisted interpretations, analyzed across the same examinations using a crossed mixed-effects model.
7 secondary outcomes
Signed Anaerobic Threshold Localization Error
Time frame: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Proportion of Anaerobic Threshold Estimates Within 15 Seconds of the Reference
Time frame: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Proportion of Anaerobic Threshold Estimates Within 30 Seconds of the Reference
Time frame: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Agreement With the Reference Anaerobic Threshold Status
Time frame: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Inter-Reader Reliability
Time frame: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Interpretation Time per Examination
Time frame: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Interaction Between AI Assistance and Physician Seniority
Time frame: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 22 Sep 2026.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
Cong Wang, MD, PhD principal investigator
Fudan University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing AI-Assisted Anaerobic Threshold Interpretation and Unassisted Cardiopulmonary Exercise Test Interpretation in people with Cardiopulmonary Exercise Test Interpretation, run by Shanghai Zhongshan Hospital at 1 site in China.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 6 inclusion and 4 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 22 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in China. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Cong Wang, MD, PhD (+86-21-64041990, wang.cong1@zs-hospital.sh.cn), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Difference in Absolute Anaerobic Threshold Localization Error (time frame: Recorded immediately after each case interpretation and analyzed after completion of both study periods, up to 2 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 22 Sep 2026.