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Masimo W1™ and the integrated Masimo W1 module are intended for the spot-check determination of Heart Rate using a single-channel electrocardiogram (ECG). The Masimo W1 and the integrated Masimo W1 module records, stores, transfers, and displays the single-channel ECG for the manual interpretation of heart rate. It is worn on the wrist and also provides other continuous parameters technologies (e.g., pulse oximetry).

The Masimo W1 ™ and the integrated Masimo W1 module are also intended for the spot-checking of functional oxygen saturation of arterial hemoglobin (SpO2) and pulse rate (PR). The Masimo W1 and the integrated Masimo W1 Module are indicated for adults in hospitals, clinics, long-term care facilities, and homes.

The Masimo W1 is a watch that incorporates the W1 Module, which is the device that is responsible for the physiological signal detection and algorithm in providing the supported parameters. The module incorporates ECG functionality for Heart Rate Monitoring and Masimo SET Pulse Oximetry technology so that it can provide both ECG (Heart Rate parameter) and Masimo SET Pulse Oximetry parameter output from the W1 Module is displayed on the touchscreen watch interface.

As part of the Masimo W1 watch, the Masimo W1 Module is integrated into the Masimo W1 watch platform, which consists of a typical IT hardware platform to enable other non-medical smart watch features (e.g., step counting, walking, running, fall detection and rise to wake).

The provided text describes the regulatory clearance of the Masimo W1 device. It details various non-clinical and clinical tests performed to demonstrate its performance and substantial equivalence to a predicate device.

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

1. Table of Acceptance Criteria and Reported Device Performance

The document doesn't explicitly lay out a table of "acceptance criteria" in a pass/fail format with specific thresholds before the study results. Instead, it states the device's performance specifications as the target, and then presents the study results demonstrating that the device meets or exceeds these.

Here's a table based on the "Performance Specifications" listed in Table 1 and the "Clinical Performance Testing" results:

Note: For Pulse Rate and Heart Rate, the document states that testing supported the claimed performance, rather than providing a specific numerical ARMS or bias/precision value for these parameters from the clinical study itself. However, the stated acceptance criteria (specifications) are given.

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

• SpO2 Clinical Testing:
  • Sample Size: 31 healthy volunteer subjects (13 light, 12 medium, 6 dark pigmented subjects).
  • Data Provenance: Prospective clinical study. Country of origin is not specified, but typically conducted in the country of submission (USA in this case, given FDA submission).
• Heart Rate (HR) Clinical Testing:
  • Sample Size: 61 subjects.
  • Data Provenance: Prospective clinical study. Country of origin is not specified.
• ECG Waveform Quality Testing:
  • Sample Size: Not explicitly stated for specific subjects, but relates to "ECG waveforms collected by the Masimo W1."
  • Data Provenance: Not explicitly stated if prospective or retrospective, but implied from clinical validation.

3. Number of Experts Used to Establish the Ground Truth for the Test Set and Qualifications

• ECG Waveform Quality Testing:
  • Number of Experts: Three (3)
  • Qualifications: Board certified cardiologists.

For SpO2 and Heart Rate, the ground truth was established by reference devices (e.g., FDA cleared ECG reference measurement for HR, likely CO-oximetry for SpO2, in accordance with ISO 80601-2-61). The expertise for these would be in the operation and interpretation of these reference standards, not necessarily by individual expert review of each measurement.

4. Adjudication Method for the Test Set

• ECG Waveform Quality Testing: The text states, "the ECG waveforms collected by the Masimo W1 were compared to Lead I of a gold standard reference of a 12-Lead ECG by three board certified cardiologists." It doesn't specify an explicit adjudication method (e.g., 2+1, 3+1). It implies independent review by each, leading to an overall assessment of acceptability. Given "compared to... by three board certified cardiologists," it suggests independent assessments that would then be aggregated or reconciled for the overall conclusion of "acceptability."
• SpO2 and Heart Rate: No human adjudication method described. Ground truth was established using objective reference standards.

5. If a Multi-Reader Multi-Case (MRMC) Comparative Effectiveness Study was Done

No, an MRMC comparative effectiveness study involving human readers assisting with AI vs. without AI assistance was not described. The device's performance was evaluated for its ability to accurately measure physiological parameters (HR, SpO2, PR) against reference standards, and for the interpretability of its ECG waveforms by cardiologists, not for its role in assisting human interpretation or decision-making in a comparative setting.

6. If a Standalone (i.e., algorithm only without human-in-the-loop performance) was Done

Yes, for the primary physiological parameters (SpO2, Pulse Rate, Heart Rate), the device's performance relies on its integrated module and algorithms. The studies evaluate the accuracy of these measurements compared to reference standards, which is a standalone performance assessment.

• For ECG HR, the W1 module "detects and calculates the heart rate" and the single-channel ECG for the manual interpretation of heart rate. The clinical study for HR compared W1 measurements to an FDA cleared ECG reference. This suggests a standalone algorithmic performance for heart rate detection from the ECG signal.
• For SpO2 and PR, the W1 module "continuously detects and processes the optical signals" and "utilizes multiple wavelengths of light and advanced signal processing techniques" to determine these. This is a standalone algorithmic performance.

While the ECG waveform itself is for "manual interpretation of heart rate," the accuracy of the Heart Rate determination by the device itself is a standalone function.

7. The Type of Ground Truth Used

• SpO2: Clinical study results for SpO2 were conducted "in accordance with the ISO 80601-2-61," which typically means comparison to arterial blood gas measurements (CO-oximetry) as the reference standard. This is an objective, gold-standard reference method.
• Heart Rate (HR): Ground truth established by an "FDA cleared ECG reference measurement." This is an objective, reference standard device.
• ECG Waveform Quality: Ground truth established by comparison to "Lead I of a gold standard reference of a 12-Lead ECG by three board certified cardiologists." This involves expert consensus/interpretation against a clinical gold standard.

8. The Sample Size for the Training Set

The document does not provide information on the sample size used for the training set of the device's algorithms. The provided details focus on the data used for performance validation (i.e., test set). Medical device submissions often do not disclose the specifics of internal development and training datasets.

9. How the Ground Truth for the Training Set was Established

As the training set information is not provided, the method for establishing its ground truth is also not detailed in this document.

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