HEART-SAFE algorithm flags a terminal arrest from Watch5 Pro PPG

Amsterdam UMC case: a Samsung Watch5 Pro worn after treatment withdrawal captured PPG; the HEART-SAFE algorithm, run afterwards, marked circulatory arrest in step with the ECG; the patient died.

AI system

System

HEART-SAFE photoplethysmography cardiac-arrest detection algorithm applied to Samsung Watch5 Pro sensor data

Model

HEART-SAFE, a rule-based algorithm that compares pulse amplitude with thresholds.

Release

Exact release not established.

Application developer

HEART-SAFE project (Amsterdam UMC with Utek B.V. and MiBida) for the algorithm; Samsung for the Watch5 Pro

Role

Not assessed

Configuration

Researchers applied HEART-SAFE after the event to data from a Samsung Watch5 Pro. The algorithm did not run live or send an alert.

Inputs and outputs

Not assessed

Autonomy

Not assessed

Workflow

A consumer smartwatch collecting green-light PPG through the project's own data-collection software. Reference ECG, arterial pressure and clinical PPG to time the arrest. Retrospective application of the HEART-SAFE peak-detection algorithm with minimum-amplitude safeguards.

Human oversight

Not assessed

Relation to AI

The algorithm was applied after the fact to exported green-PPG data. It marked the arrest when residual pulse amplitude fell below its thresholds, shortly before the monitor flatlined, with no false alarms. It was not running on the watch and triggered nothing. Only the developers' own papers describe the event. They describe peak detection with amplitude safeguards rather than machine learning. Samsung's role is limited to the hardware.

AI contribution

The algorithm was applied after the fact to exported green-PPG data. It marked the arrest when residual pulse amplitude fell below its thresholds, shortly before the monitor flatlined, with no false alarms. It was not running on the watch and triggered nothing. Only the developers' own papers describe the event. They describe peak detection with amplitude safeguards rather than machine learning. Samsung's role is limited to the hardware.

Benefits

Outcome identifiers

Not assessed

Benefit

Amsterdam UMC case: a Samsung Watch5 Pro worn after treatment withdrawal captured PPG; the HEART-SAFE algorithm, run afterwards, marked circulatory arrest in step with the ECG; the patient died.

Category

Improved Task Accuracy

Status

Not assessed

Beneficiary groups

People. Society.

Beneficiaries

Not assessed

Reach

Not assessed

Distribution and access

Not assessed

Duration

Not assessed

Expected?

Yes

Costs and harms

Not assessed

Measurement

Studies

Not assessed

Study design

Not assessed

Measurement

Not assessed

Setting and sample

Not assessed

Measures

Not assessed

Comparison

the clinical reference signals (ECG, invasive arterial pressure and clinical photoplethysmography) recorded alongside the watch

Results

Result: The algorithm accurately identified the moment of cardiac arrest in concordance with the clinical reference signals.

Additional value from AI

Not assessed

Limitations

Not assessed

Denominators

Not assessed

Materials for replication

Not assessed

Money

Kind of value

Not assessed

Amount

Not assessed

Currency and prices

Not assessed

Period and unit

Not assessed

Realization

Not assessed

Recipients and payers

Not assessed

Gross or net

Not assessed

Included costs

Not assessed

Comparison

Not assessed

Method

Not assessed

Return and payback

Not assessed

People and places

Participants

Developer: HEART-SAFE project (Amsterdam UMC with Utek B.V. and MiBida) for the algorithm; Samsung for the Watch5 Pro. Operator: Amsterdam UMC intensive care unit (feasibility evaluation with institutional review board approval).

Jurisdictions

Benefit: Amsterdam, the Netherlands. Developer: Netherlands. Operator: Netherlands.

Ownership and control

Not assessed

Dependencies

Not assessed

Cross-border connections

Not assessed

Geopolitical implications

Not assessed

Follow-up

Conditions for replication

A live on-device implementation, which the authors deliberately did not use. Specificity high enough not to overburden emergency services, which the 2025 study says is still needed. Transfer from a slow, bradycardic end-of-life arrest to sudden arrhythmic out-of-hospital arrests, which the authors say the case does not represent.

Replication attempts

1 follow-up entries. Benefit recurred: 1.

Later findings

Nothing dated after the January 2026 case report was found; the group's proof-of-principle study predates it and the accompanying editorial reports no trial.

Availability

Not assessed

Institutional decision

Not assessed

Grounds

Not assessed

Action and result

Not assessed

Success criterion

Not assessed

Evidence

Source numbers

AIBD-0299-source-0001–0005

Citations

Numbered references below.

Language

Not assessed

Source relationships

Developer, Independent

Original evidence

Not assessed

Access and versions

Not assessed

Supported findings

Not assessed

Evidence strength

Not assessed

Missing evidence

Not assessed

Grades

Assessed benefits

People. Society.

Depth

Not assessed

Reasons

People: The patient died as expected under palliative withdrawal. The detection was retrospective and no alert, treatment or resuscitation followed. Society: The authors present the case as a step toward real-world detection of unwitnessed arrests. No deployment or survival outcome exists.

Observed or intended

Not assessed

Rubric

Not assessed

Assessor and date

Not assessed

Alternative assessments

Not assessed

Fill

The makers' claim

Entry details

Kind

Not assessed

Field

Emergency medicine / resuscitation. Research use of a consumer smartwatch for automated cardiac-arrest detection.

Purpose

The HEART-SAFE project builds device-independent software to detect circulatory arrest from smartwatch photoplethysmography and alert emergency services. This case tests the detection half on a true arrest.

Dates

Date basis unassessed: 2026 (precision unassessed). Updated: 21 October 2026.

Stage

Not assessed

Version

SHA-256: 635582fad217…

References

Other identifiers

Not assessed

Category mappings

Not assessed

Brief

Not assessed

Revisions

5 revisions. Latest: 21 October 2026.

Sources

  1. Peer-reviewed study Developer

    van den Beuken WMF, Nideröst B, Goossen SA, Kooy TA, Demirtas D, Autar D, Loer SA, Eberl S, van Halm VP, Winkler BE, van Schuppen H, Tuinman PR, Schwarte LA, Schober P (2025). Automated cardiac arrest detection and emergency service alerting using device-independent smartwatch technology: proof-of-principle. Resuscitation 213:110657; doi:10.1016/j.resuscitation.2025.110657.

  2. Case report Developer

    van den Beuken WMF, Tuinman PR, Nideröst B, Goossen SA, van Schuppen H, Loer SA, Schwarte LA, Schober P (2026). First automated detection of a cardiac arrest using a commercially available smartwatch: a case report. Resuscitation Plus 28:101247 (PMC12914423). Authors are the algorithm's developers (HEART-SAFE).

  3. Other Independent author

    Veigl C, Billig S (2026). A digital witness for cardiac arrest: are wearables ready for real-world use? Resuscitation Plus 28:101246 (editorial accompanying the case report; PMC12914390).