EBME Forums Forums Maintenance Technical Assistance Testing APC Medical E4170 Bedside Pacemaker

Hi fellow Biomeds

Can anyone help with regards to methods for checking APC Medical related external pacemakers?

I have been looking into testing everything that they ask you to do, using a more dedicated Pacemaker Analyzer. I have here the Fluke SigmaPace 1000 Analyser.

I have managed to do most tests, but find it difficult to get the Manufacturer's spec for SRP (Sensed Refractory Period) of 150ms. I get a value of around 237ms using the Fluke analyser.

I found it quite difficult to translate what APC want you to do, using the pacemaker analyser. Any others have this issue?

Any external pacemaker geeks out there with in hints or resources to get my teeth into the operation and testing of these?

All help and advice is appreciated.

I have not used the Fluke tester but in the past with other testers the output waveforms had to be the correct shape for the tester to read this time correctly.
If you do not have a square wave the tester has to measure the time from a rising voltage, where exactly does it take the start and stop times (at what voltage) for the timer?
Either the tester is expecting a square wave or is making a calculation (estimation) based on the rise time of the waveform.

You have to check the settings on the tester and pacemaker are correct.

Robert

The SigmaPace certainly seems comphrensive enough. I would love to have a play!

Meanwhile I'm wondering what APC recommends when it comes to testing this kit? What test equipment do they suggest, and all the rest?

Cheers RoJo, that helps in understanding what the test entails.

Hi Geoff, APC Medical recommend using a function generator, oscilloscope, a counter, and a delay unit used to trigger the function generator in ms.

We just don't have that type of kit around anymore that is calibrated regularly. Hence, the query in relation to using the Pacemaker Analyzer.

For the reasions that Robert describes most pacemker testers will in effect only give you an indication of function.

If you want to be accurate then the only real method is from 1st principles and some good basic electronic test equipment. Therefore in no order of priority, normally the following is required:

Manufacturers test proc sheet with test limits - this will normally give you the method, test equipment settings, and the range of acceptable results.
Oscilloscope
Multimeter
Suitable Test Body / test load
Function Generator for sq and triangular wave signals - must have variable amplitude and frequancy abilities
Counter timer with external trigger abilities
Power Supply.

Shed loads of patiance can also be useful.

Sounds like an annual return for cal by APC might be a sensible option here.

Either that or sending off to some third-party or other able to check these things out properly. If, indeed, such a third-party exists!

Yet another area, perhaps, where a specialist referral workshop within the NHS (that is, one with all the test kit) might also be a good idea! Any volunteers?

Yee Gods,
I am a bit worried that we as a profession don't have what I would regard as the essential basics around any more. The fact that we seem to have to moved a reliance an specfic "test kit" which is actually only functional inspection and verification kit is quite scarey really. May be I'm just getting too old.

In relation to these devices yeah the list of equipment does seem a bit excessive and the process a tad anal but it does work, really don't take that long to do; is well with the abilities of any engineering prectitioner with a good general electronics background and is really the only true way of adjusting these types of devices.

However I do agree that you can adjust these devices using units like the sigma pace or the pma or others, and indeed we do here, but you need to know exactly what you are looking at when read the displays of these devices. Mine are told that devices such as Sigma pace - which is very nice indeed are for indication only- if they have an doubt about what they are seeing then back to Mr. 1st Principles. That by the way goes for everything not just these devices.

After all Geoff is this not the true art of "biomedism" that we should all be practising? Because if we don't and we are placing all our reliance on automated or semiautomated "testing and inspection" equipment where we don't fully understand what its doing and why its doing it then we are on a very sticky slope indeed.

Indeed, Paul. Back to Basics (along with its Mate, Thinking Simple) always gets my vote!

And you can use the scope, function generator etc. to test other medical kit rather than having to fork out for more specialist test equipment.

And I am sure the calibration certificates for this kit would be far less than the manufacturer/distributer of the medical test kit would charge as they have the monopoly.

Robert

I have to agree with the above statements in regards to competency in 'biomed' skills, but, these analysers are on the market and we did buy one. I would therefore like to get the full functionality out of it.

It has been a bit of a relearning curve for me this week in regards to thinking about first principles, using a custom made piece of test equipment. I have also found myself writing a test protocol to accomodate manufacturer's specification, but in light of using our Fluke Analyser.

I have sent a pacemaker back to APC to do, as they only charge £100 for the privilege. I want to see a full service report with documented results so I can replicate them using the Analyser.