MEDILOG FD4

K970902 · Oxford Instruments Medical Systems · DSH · May 5, 1997 · Cardiovascular

Device Facts

• Record ID: K970902
• Device Name: MEDILOG FD4
• Applicant: Oxford Instruments Medical Systems
• Product Code: DSH · Cardiovascular
• Decision Date: May 5, 1997
• Decision: SESE
• Submission Type: Traditional
• Regulation: 21 CFR 870.2800
• Device Class: Class 2

Intended Use

The Medilog FD4 Holter 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 ischaemia. The ECG data is used by the physician as an aid in the diagnosis of the patient’s 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 Story

Ambulatory Holter monitor; records 3-channel ECG signals via chest electrodes. Input signals amplified, filtered, digitized, and losslessly compressed; stored on removable PCMCIA Flash ATA card. Used in clinical or hospital settings; operated by healthcare professionals. Post-recording, flash card removed; data replayed/analyzed on Oxford Instruments ECG Analysis System. Physician reviews ECG data to aid diagnosis of arrhythmias and myocardial ischemia. Benefits include improved signal fidelity, increased dynamic range, and elimination of tape-related noise/variations compared to analog predecessors.

Clinical Evidence

Bench testing per AAMI EC38 and BS5724 (input dynamic range, gain accuracy, noise, crosstalk, frequency response). Clinical trial: 29 recordings (17 tandem with MR63) using programmable simulators, EKG generators, and human volunteers. Endpoints: signal quality, recording reliability, download success, patient event detection, and heart rate variability. All recordings met success criteria; signal quality and gain comparable to predicate.

Technological Characteristics

Polycarbonate/ABS case; 3/5/7 lead configurations. Sensing: disposable chest electrodes. Energy: 2xAA alkaline or NiMh batteries. Digital acquisition module with PCMCIA Flash ATA card storage. Fiber optic output for isolated data transfer. Software-based gain adjustment. Frequency response 0.05Hz-40Hz. Dynamic range 10µV to 10mV.

Indications for Use

Indicated for patients requiring ambulatory ECG monitoring for the diagnosis of cardiac disorders, including cardiac arrhythmias and myocardial ischemia.

Regulatory Classification

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.

Predicate Devices

• Medilog MR63 (K943862)

Submission Summary (Full Text)

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MAY - 5 1997

# OXFORD

K970902

510k SUMMARY

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OXFORD

Oxford Instruments
Medical Systems Division
11526 53rd Street N
Clearwater, Florida 34620
Telephone [phone]
Fax [phone]

# 510(k) Summary

Date of summary: 26 February 1997

Contact: Charles Holz
Regulatory Affairs Manager

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

## Description

The Medilog FD4 uses the same case, mechanics, electrodes and input circuitry as the Medilog MR63. Visually, 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.

## Intended use

The Medilog FD4 Holter 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 ischaemia.

The ECG data is used by the physician as an aid in the diagnosis of the patient’s 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.

## 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 BS5724- Medical 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 tandem 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 repeatable and recognisable 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
- 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

| | MR63 | FD4 | Impact on effectiveness | Impact on safety |
| --- | --- | --- | --- | --- |
| Type of device | Holter ECG recorder | Holter ECG recorder | N/A | N/A |
| Device class | non-critical Regulatory Class II | non-critical Regulatory Class II | no change | no change |
| designed to comply with... | IEC 601-1, UL 544, 93/42/EEC (MDD) | IEC 601-1, UL 2601-1, AAMI EC38, 93/42/EEC (MDD) | Improved, updated standards including EC38 performance. | none |
| EMC | IEC 601-1-2 | IEC 601-1-2 | no change | no change |
| Environmental | 5 °C to 40 °C 10 to 95% RH | 0 °C to 45 °C 10 to 95% RH | improved operating range. | 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 primary alkaline or 1.2v NiMh rechargeable | 2xAA 1.5v primary alkaline or 1.2v NiMh rechargeable | no change | no change |
| Electrode system | 3/5/7 lead configurations using yoke cable and individual electrode leads | 3/5/7 lead configurations using yoke cable and individual electrode leads | no change | no change |
| Recording medium | C-60 cassette | 20Mb flash ATA card | improved frequency response (no tape variations) | none |
| Recording method | Direct | Digitised and compressed without loss. | Improved (no replay variations) | none |
| Display | 4 digit + colon 7 segment LCD displays time | 4 digit + colon 7 segment LCD displays time and additional error codes | More effective use of display to show useful information | none |
| Audible sounder | 4kHz bleeper used to provide feedback during time/date setting and patient events | Frequency of bleeping variable | Provide more effective feedback and to distinguish between various sounds | none |
| Patient event marking | encoded onto data track of cassette. Resolution 1 second | Stored in file header. Resolution 1/128 th sec | Higher resolution patient event timing an advantage | none |
| External controls | Patient event button (also used for time/date setting). Head arm switch | Patient event button (also used for time/date setting) plus ON/OFF slide switch under recorder lid | Need ON/OFF switch to replace head arm switch of tape mechanism. | none |
| Signals recorded | 3 x analogue ECG | 3 x digitised ECG | improved | none |
| Setting up | Analogue monitor socket (not isolated) for all 3 ECG channels | Fibre optic output producing ECG signals in digital format at real-time | Attaches directly to existing OXFORD replay systems. No need for separate write-out unit | Provides patient isolation by virtue of plastic optical fibre. |
| Method of isolation during monitoring | XE-45 write-coupler | Automatically provided by plastic fibre optic cable | none | Plastic fibre optic inherently safer than relying on use of safe writer coupler. |
| Data recorded | Time/Date & patient events | Time/date & patient events | no change | no change |
| Data format | Pulse width modulated | Digital format in file header. | Better reliability-not sensitive to tape variations | none |
| Channel gain adjustment | Hardware gain adjustment using digital potentiometers. | Software gain adjustment to give optimum signal amplitude | Ensures high fidelity reproduction of small & large ECG signals | none |
| Dynamic range | 50 μV to 10 mV | 10 μV to 10 mV | Improved. Allows accurate recording of larger range of ECG amplitudes. | none |

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| | MR63 | FD4 | Impact on effectiveness | Impact on safety |
| --- | --- | --- | --- | --- |
| Overall recorder/replay bandwidth | 0.5Hz - 25Hz | 0.05Hz - 40 Hz | No frequency response limitation due to tape recording/replay. Frequency response only due to hardware filters. | none |
| Typical pk-pk noise over input bandwidth | <50 µV | <12 µV | Lack of tape eliminates tape noise from overall system noise | none |
| Data compression | analogue- none | Lossless compression. No data is lost - just packed more efficiently onto disk | Ensures 24 hours of data fit onto 20Mb flash card. No degradation of signal. | none |
| Replay & analysis system | Medilog Optima & Excel 2 | Medilog Optima & Excel 2 | none | none |
| Analysis features in recorder | none | none | N/A | N/A |
| Alarms, warnings | none | none | N/A | N/A |
| control over other equipment | none | none | N/A | N/A |