MEDILOG FD4 by OXFORD INSTRUMENTS MEDICAL SYSTEMS

The Medilog FD4 Hoher monitor is intended to be used in the diagnosis of various cardiac disorders by the recording of ECG in an ambulatory mode. These disorders principally include cardiac arrhythmia's and myocardial ischeamia.

The ECG data is used by the physician as an aid in the diagnosis of the patients condition. In some circumstances the patient may be hospitalised as part of the medical evaluation and Holter monitoring may be performed in conjunction with other non-invasive or invasive procedures. In such cases there is no interaction between the FD4 and other equipment.

Device Description

Decer poton it looks like an MR63. The difference being the analogue cassette mechanism has been replaced with a digital acquisition module containing a slot for a PCMCIA Flash ATA card.

The patient is connected to the FD4 via disposable electrodes attached to the chest. These detect the electrical signals generated by the heart, which are then transferred to the recorder via the electrode leads and patient cable. In the recorder, these signals are amplified, filtered, digitised and compressed without loss before being stored on a removable PCMCIA Flash ATA card. At the completion of recording the flash memory card is removed and the recorded ECG data is replayed and analysed on the Oxford Instruments ECG Analysis System.

AI/ML Overview

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

Acceptance Criteria and Device Performance

1. Table of Acceptance Criteria and Reported Device Performance

Acceptance Criteria Category	Specific Criteria	Reported Device Performance (FD4)
Performance Bench Tests	Input dynamic range meets American National Standard EC38 requirements.	FD4 meets all requirements of American National Standard EC38.
	Gain accuracy meets American National Standard EC38 requirements.	FD4 meets all requirements of American National Standard EC38.
	System noise meets American National Standard EC38 requirements.	FD4 meets all requirements of American National Standard EC38.
	Multichannel crosstalk meets American National Standard EC38 requirements.	FD4 meets all requirements of American National Standard EC38.
	Frequency response meets American National Standard EC38 requirements.	FD4 meets all requirements of American National Standard EC38.
	Minimum feature size meets American National Standard EC38 requirements.	FD4 meets all requirements of American National Standard EC38.
	Meets draft British Standard Electrical Equipment - part 2: Particular requirements for safety - section 2.47: specification for ambulatory electrocardiographic monitors.	FD4 meets all requirements of the draft British Standard.
Trial Performance	Recording lasted for its intended duration.	All recordings (29 total) met this criterion.
	Patient events detected.	All recordings (29 total) met this criterion.
	Signal quality and gain comparable with the predicate device (Medilog MR63), where applicable.	All recordings (29 total) met this criterion.
	No problems with either the recording or the replay.	All recordings (29 total) met this criterion.
	Successful review by Oxford Instruments clinical specialist.	All recordings (29 total) met this criterion.
Technical Specifications	Improved, updated standards including EC38 performance (compared to MR63).	FD4 complies with IEC 601-1, UL 2601-1, AAMI EC38, 93/42/EEC (MDD). The MR63 complied with older standards (IEC 601-1, UL 544, 93/42/EEC).
	Improved operating range (temperature).	FD4: 0 °C to 45 °C (compared to MR63: 5 °C to 40 °C).
	Improved frequency response (due to digital recording).	FD4: 0.05Hz - 40 Hz (compared to MR63: 0.5Hz - 25Hz).
	Lower typical peak-to-peak noise over input bandwidth.	FD4: <12 μV (compared to MR63: <50 μV).
	Higher resolution patient event timing.	FD4: 1/128th sec (compared to MR63: 1 second).
	Improved dynamic range.	FD4: 10 μV to 10 mV (compared to MR63: 50 μV to 10 mV).
	Provides patient isolation by virtue of plastic optical fiber.	FD4: Automatically provided by plastic fibre optic cable (compared to MR63: XE-45 write-coupler).

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

Sample Size: A total of 29 recordings. 17 of these were performed in tandem with the predicate device (MR63).
Data Provenance: The data came from a variety of sources:
- A programmable simulator (giving "researchiseble" EKGs - likely representative samples)
- An EKG generator (providing real patient data from a database of recordings - likely retrospective, but no specific country of origin is mentioned)
- Human volunteers (prospective data, but no specific country of origin is mentioned)

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

Number of Experts: The document states "Successful review by Oxford Instruments clinical specialist." This implies at least one clinical specialist was involved.
Qualifications of Experts: The qualification provided is "clinical specialist" at Oxford Instruments. Further specifics (e.g., years of experience, specific medical specialty like cardiology or electrophysiology) are not provided.

4. Adjudication Method for the Test Set

The document mentions "Successful review by Oxford Instruments clinical specialist." This suggests a single expert review. There is no indication of an adjudication method involving multiple experts (e.g., 2+1, 3+1). It appears to be a single-reader review based on the stated acceptance criterion.

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

No, an MRMC comparative effectiveness study was not done in the context of human readers improving with AI vs. without AI assistance.
The study compared the FD4 device's performance to its predicate device (MR63), but this was a technical/signal comparison, not a human reader performance study. The FD4 is a data acquisition device, not an AI interpretation system.

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

This device (Medilog FD4) is a Holter monitor designed for recording ECGs, not for automated interpretation or diagnosis. It records and stores data for later analysis by a physician using a separate "Oxford Instruments ECG Analysis System" (Medilog Optima & Excel 2).
Therefore, the concept of "standalone algorithm performance" as typically applied to AI-based diagnostic devices does not directly apply to the FD4. The performance testing focuses on the quality of the recorded signal and its comparability to the predicate device.

7. The Type of Ground Truth Used

The ground truth for the trial results was based on several metrics:
- Technical/Operational Criteria: Intended recording duration, successful download, signal quality/gain comparability with predicate, absence of recording/replay problems.
- Clinical Relevance: Detection of patient events, heart rate variability monitored and logged for comparison.
- Expert Review: Successful review by an Oxford Instruments clinical specialist.
Given the nature of the device (a recorder), the "ground truth" is less about a definitive medical diagnosis and more about the fidelity and completeness of the ECG data captured and reviewed by an expert. It's a combination of objective technical performance and subjective expert assessment of data utility.

8. The Sample Size for the Training Set

The document does not mention a training set for the FD4 device. This is because the FD4 is a hardware device for acquiring data, not a machine learning algorithm that requires training. The "Medilog Optima & Excel 2" analysis system might potentially incorporate algorithms, but the FD4 itself is a data acquisition unit.

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

As no training set is mentioned for the FD4 device, this question is not applicable.

Summary

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MAY - 5 1997 - 5 1997

K970902

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Oxford Instruments Modical Systems Division 1 1 526 53rd Street N Clearwater, Florida 34620 Telephone (813) 573-4500 Fax (813) 572-6836

510(k) Summary

Date of summary :

Contact : Charles Holz Regulatory Affairs Manager

Name of device : Medilog FD4 Classification name : Monitor - Electrocardiograph Name of predicate : Medilog MR63 K943862

Description

Decer poton it looks like an MR63. The difference being the analogue cassette mechanism has been replaced with a digital acquisition module containing a slot for a PCMCIA Flash ATA card.

Intended use

FD4 performance testing.

Performance bench tests have been carried out on FD4 in accordance with American National Standard EC38 "Ambulatory electrocardiographs" and draft British Standard Electrical Equipment- part 2: Particular requirements for safety- section 2.47: specification for ambulatory electrocardiographic monitors. The performance parameters tested were; input dynamic range, gain accuracy, system noise, multichannel crosstalk, frequency response, and minimum feature size. The FD4 was found to meet all requirements.

Summary of FD4 trial results

A total of 29 recordings, 17 of which were performed in undern with an MR63, were carried out from a variety of sources, with a view to establishing that the FD4 recorder was equivalent to its predicate device, the Medilog MR63. The recording sources were: a programmable simulator (giving researchiseble EKGs); an EKG generator (providing real patient data from a database of recordings); and human volunteers. The recordings were checked for signal quality, reliability of recording and download, detection of patient events and recording duration. In addition the heart rate variability was monitored and logged for comparison with the predicate device. All recordings were archived to optical disk.

All recordings met the criteria for a successful recording as defined below.

Recording lasted for its intended duration ●
Patient events detected 0
Signal quality and gain comparable with the predicate device, where applicable �
No problems with either the recording or the replay ●
Successful review by Oxford Instruments clinical specialist .

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Comparison table of FD4/MR63 features & specification

	MIR63	FD4	Impact oneffectiveness	Impact on safety
Type of device	Holter ECG recorder	Holter ECG recorder	N/A	N/A
Device class	non-criticalRegulatory Class II	non-criticalRegulatory Class II	no change	no change
designed tocomply with.....	IEC 601-1, UL 544,93/42/EEC (MDD)	IEC 601-1, UL 2601-1,AAMI EC38,93/42/EEC (MDD)	Improved, updatedstandards includingEC38 performance.	none
EMC	IEC 601-1-2	IEC 601-1-2	no change	no change
Environmental	5 °C to 40 °C10 to 95% RH	0 °C to 45 °C10 to 95% RH	Improved operatingrange.	none
Recording duration	24 hours	24 hours	no change	no change
Mounting method	Belt-mounted pouch	Belt-mounted pouch	no change	no change
Case	Polycarbonate / ABS	Polycarbonate / ABS	no change	no change
Power source	2xAA 1.5v primaryalkaline or 1.2v NiMhrechargeable	2xAA 1.5v primaryalkaline or 1.2v NiMhrechargeable	no change	no change
Electrode system	3/5/7 leadconfigurations usingyoke cable andindividual electrodeleads	3/5/7 leadconfigurations usingyoke cable andindividual electrodeleads	no change	no change
Recording medium	C-60 cassette	20Mb flash ATA card	improved frequencyresponse (no tapevariations)	none
Recording method	Direct	Digitised andcompressed withoutloss.	Improved (no replayvariations)	none
Display	4 digit + colon 7segment LCD displaystime	4 digit + colon 7segment LCD displaystime and additionalerror codes	More effective use ofdisplay to showuseful information	none
Audible sounder	4kHz bleeper used toprovide feedbackduring time/datesetting and patientevents	Frequency ofbleeping variable	Provide moreeffective feedbackand to distinguishbetween varioussounds	none
Patient eventmarking	encoded onto datatrack of cassette.Resolution 1 second	Stored in file header.Resolution 1/128 thsec	Higher resolutionpatient event timingan advantage	none
External controls	Patient event button(also used fortime/date setting).Head arm switch	Patient event button(also used fortime/date setting)plus ON/OFF slideswitch underrecorder lid	Need ON/OFF switchto replace head armswitch of tapemechanism.	none
Signals recorded	3 x analogue ECG	3 x digitised ECG	improved	none
Setting up	Analogue monitorsocket (not isolated)for all 3 ECG channels	Fibre optic outputproducing ECGsignals in digitalformat at real-time	Attaches directly toexisting OXFORDreplay systems. Noneed for separatewrite-out unit.	Provides patientisolation by virtue ofplastic optical fibre.
Method ofisolation duringmonitoring	XE-45 write-coupler	Automaticallyprovided by plasticfibre optic cable	none	Plastic fibre opticinherently safer thanrelying on use of safewriter coupler.
Data recorded	Time/Date & patientevents	Time/date & patientevents	no change	no change
Data format	Pulse widthmodulated	Digital format in fileheader.	Better reliability-notsensitive to tapevariations	none
Channel gainadjustment		Hardware gainadjustment usingdigital		Software gainadjustment to giveoptimum signal	Ensures high fidelityreproduction of small& large ECG signals	none
Dynamic range	potentiometers.50 μV to 10 mV	optimum signal amplitude10 μV to 10 mV	Improved. Allows accurate recording of larger range of ECG signals & large ECG signals amplitudes.	none

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	MR63	FD4	Impact oneffectiveness	Impact on safety
Overallrecorder/replaybandwidth	0.5Hz - 25Hz	0.05Hz - 40 Hz	No frequencyresponse limitationdue to taperecording/replay.Frequency responseonly due to hardwarefilters.	none
Typical pk-pk noiseover inputbandwidth	<50 μV	<12 μV	Lack of tapeeliminates tape noisefrom overall systemnoise	none
Data compression	analogue- none	Lossless compression.No data is lost - justpacked moreefficiently onto disk	Ensures 24 hours ofdata fit onto 20Mbflash card. Nodegradation ofsignal.	none
Replay & analysissystem	Medilog Optima &Excel 2	Medilog Optima &Excel 2	none	none
Analysis featuresin recorder	none	none	N/A	N/A
Alarms, warnings	none	none	N/A	N/A
control over otherequipment	none	none	N/A	N/A

Regulation Number and Section

§ 870.2800 Medical magnetic tape recorder.

(a)
Identification. A medical magnetic tape recorder is a device used to record and play back signals from, for example, physiological amplifiers, signal conditioners, or computers.(b)
Classification. Class II (performance standards).