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The MedilogAR4 and MedilogAR12 Digital Holter Recorders are used to record a 3 channel ECG and to measure the time intervals between consecutive R peaks in the ECG. The system is designed for a measuring duration of more than 24h and is therefore worn by the patient throughout the whole day. The preparation for the recording (attaching electrodes, etc.) is undertaken by the technician or doctor. During the recording, the instrument is carried in a special protective pouch which can be attached to a belt.

The instrument is not designed for emergency monitoring purposes (intensive medical monitor); the instrument is only designed to record the ECG and/or information derived from ECG. The recorder is not protected against the effects of defibrillation as outlined in EN60601-2-25.

The instruments also record other information: HF component of the ECG, time point of the Pwave, time point of the T-wave, and time point of the pacemaker pulse.

In addition the MedilogAR12 records the ECG amplitude.

Such monitoring is most frequent used for the indications below:

• Evaluation of symptoms suggesting arrhythmia or myocardial ischemia.
• Evaluation of ECG documenting therapeutic interventions in individual patients or groups of patients.
• Evaluation of patients for ST segment changes (no online ST measurement implemented in recorder)
• Evaluation of a patient's response after resuming occupational or recreational activities (e.g., after M.I. or cardiac surgery)
• Clinical and epidemiological research studies.
• Evaluation of patients with pacemakers
• Reporting of time and frequency domain heart rate variability (no online calculation implemented in recorder)
• Reporting of QT interval (no online QT interval measurement implemented in recorder)

The recorder (type reference AR4 or AR12) is used to record a 3 channel ECG and to measure the time intervals between consecutive R peaks in the ECG. The system is designed for a measuring duration of more than 24h and is therefore worn by the patient throughout the whole day. The preparation for the recording (attaching electrodes, etc.) is undertaken by the technician or doctor. During the recording, the instrument is carried in a special protective pouch which can be attached to a belt. After inserting a memory card and batteries, the instrument can be switched on by pressing and holding the button on the top of the instrument. The recording is stopped by pressing and holding the same button on the top of the instrument or the recorder stops the recording automatically after a pre-set time. The instrument is not designed for emergency monitoring purposes (intensive medical monitor); the instrument is only designed to record the ECG and/or information derived from ECG. The recorder is not protected against the effects of defibrillation as outlined in EN60601-2-25.

As well as measuring the ECG and the beat to beat heart rate, the instrument also records other information: HF component of the ECG (quantifies muscle artefacts or disturbances), time point of the P-wave, time point of the T-wave, and time point of the pacemaker pulse.

In addition the MedilogAR12 records the ECG amplitude - Due to the heart's mechanical connection to the ribcage, breathing causes the electrical heart vector to turn and therefore changes the ECG amplitude. This reveals information about the breathing frequency and QPA (pulse /breathing quotient).

The data is stored digitally on a memory card. After removing the memory card, the data can be read by an appropriate card reader (e.g. PCMCIA slot and adapter).

The MedilogAR4 and MedilogAR12 Digital Holter Recorders measure the voltage difference to derive the electrical ECG from body surface electrodes. A ground electrode is used to keep ground potential of the measured patient and of the recorder at the same level. After amplification the analogue signal is digitised using conventional 16 bit A/D converter. A microprocessor gathers the so sampled data. The microprocessor processes the data before it stores them onto a removable flash memory card (CompactFlash technology). Processing includes:

• Pacemaker spike detection .
• R- peak detection .
• . R-S amplitude measurement
• . PT- wave detection
• . Resample to storage sample rate
• Loss-less delta coding (Huffmann) .

The data stored on the flash memory card is organised in one Windows FAT16 file.

1. Table of Acceptance Criteria and Reported Device Performance:

2. Sample Size and Data Provenance for Test Set:

• R peak detection: MIT, AHA, and NST databases. (No specific sample size for a "test set" is explicitly mentioned for these databases, but these are standard publicly available databases for ECG analysis, implying a pre-defined set of recordings). The data provenance is not explicitly stated in terms of country of origin but is implied to be retrospective as they are existing databases.
• Pacemaker detection: "Phantom artificial ECG signal generator." This indicates synthetically generated data, not patient data.
• PT wave detection: QT database. (Similar to R peak detection, this is a standard publicly available database, implying a retrospective set of recordings).
• RS amplitude measurement (EDR): "A set of recordings with airflow channel." No specific sample size or country of origin is provided. It's implied to be retrospective as they are "recordings."

3. Number of Experts and Qualifications for Ground Truth:

The document does not explicitly state the number of experts or their qualifications used to establish ground truth for the test sets. The mention of "MIT, AHA, NST, and QT databases" suggests that these databases, by their nature, would have established ground truth based on expert consensus or established methodologies inherent to their creation. For the "Phantom artificial ECG signal generator" and "a set of recordings with airflow channel," the method of ground truth establishment is not detailed, and therefore, expert involvement is not specified.

4. Adjudication Method for the Test Set:

No adjudication method (e.g., 2+1, 3+1, none) is mentioned or implied for any of the test sets. The tests are against established databases or a phantom generator, which typically come with pre-defined ground truth labels.

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

No MRMC comparative effectiveness study is mentioned. The document focuses solely on the device's standalone performance against defined benchmarks.

6. Standalone Performance:

Yes, the study describes standalone performance. The acceptance criteria and reported results are solely for the algorithm, as there is no human-in-the-loop component mentioned in the testing.

7. Type of Ground Truth Used:

• R peak detection: Pre-established labels within the MIT, AHA, and NST databases. This would typically be expert annotation.
• Pacemaker detection: Defined characteristics of the "Phantom artificial ECG signal generator."
• PT wave detection: Pre-established labels within the QT database. This would typically be expert annotation.
• RS amplitude measurement (EDR): Likely a reference measurement from the "airflow channel" recordings, possibly compared to a gold standard measurement or expert-derived values from those recordings.

8. Sample Size for the Training Set:

The document does not provide information on the sample size for any training set. The tests described are performance evaluations against established benchmark databases, implying a focus on validation rather than algorithm development/training details.

9. How Ground Truth for the Training Set Was Established:

As no training set information is provided, the method for establishing its ground truth is also not mentioned.

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