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Date: Sun, 9 Jan 2000 10:38:19 -0800 (PST)
Date: Sun, 9 Jan 2000 00:23:48 -0800 (PST)
From: P. O. Box 2321 (Trevor Blake)
Dead medium: Del Mar CardioCorder
Source(s): Personal experience; further references at the end of the text.

Recently (late 1999) I have been diagnosed with 'tachycardia' - for no particular reason, my heart begins to beat very fast. So far the doctors are suggesting it is a genetic condition called Wolff-Parkinson-White Syndrome. In a 'normal' heart, the electric pulse that causes the heart to beat starts at the top, travels down to the bottom, then beats again. WPWS hearts have extra neurological paths like short circuits on electronic breadboards: the pulse gets halfway down, meets in the middle and then beats again, getting faster and faster while not pumping blood efficiently if at all. Most of the time this just means an occasionally fast-beating heart, but sometimes it means a backward-pumping or non-beating heart. A surgical remedy is available and I hope to have it within the next few months - wish me luck.

But for now, please allow me to share the high point of my WPWS experience: wearing the Del Mar CardioCorder, Model 459. Part of my diagnosis included wearing a heart monitoring device that is an honest to goodness dead media. This description of the Del Mar CardioCorder is based on personal observations, Web research and conversations with the fellow who put it on me: details of function may be sketchy or incorrect.

The Del Mar CardioCorder Model 459 is the size of a larger, first-generation Walkman. It is a tape recorder, using normal c60 tapes, but on a single side recorded all my heartbeats for 24 hours - so the thing runs slowly! There was a port like the kind computer network cables use that ran to the sticker pads that were patched on me. There was an 'EVENT' button and a 'TEST SOCKET' (small audio plug size) but I don't know what they do. It had three channels, but I don't know what that means either. And LCD display was likewise not instructive to me. I did, however, understand the 9 volt battery that powered it.

The manufacturer was "Del Mar Avionics / 1601 Alton Ave. / Irvine CA 92714-4878." There was no date on this model but the plus-four postal code is a hint.

Here is the complete text from the inside door of the CardioCorder...

[begin quote]

Refer to model 459 Operator's Manual for complete instructions (manual No. 87-9).

Patient Preparation 1. Apply electrodes (see operator's manual). 2. Connect patient cable to recorder input. 3. Install fresh battery. 4. Set GAIN switch to "FULL" and TEST OUTPUT switch to Ch1,2. 5. Verify proper application of electrodes by connecting a UNIVERSAL TEST cable to the recorder's TEST jack and charting an ECG strip with the gain of the ECG machine set at X1. 6. Set TEST OUTPUT switch to ch1,3 and repeat step 5. 7. Set GAIN switch to "HALF" only when any ECG is larger than 30mm.

FINAL PREPARATION 1. Remove battery. 2. Press arm release to swing arm open. 3. IMPORTANT: Before installing cassette, center start of dark tape in middle window and remove all slack. 4. Insert bottom of cassette under front spring clip and press cassette down. 5. Swing arm to close and latch. 6. Re-install battery to start six minutes of calibration recording. Check cassette and verify tape movement. 7. Enter start time in patient's diary. * NOTE: internal calibration may be terminated by pressing the Patient Event Button.


[end quote]

The hospital I was tested at is replacing these cassette-based recorders with digital ones, and even Del Mar isn't manufacturing this model any more. A dead media may have saved my life!


Wolff-Parkinson-White Syndrome "My Heart Surgery" by Michael Roeder

Del Mar Avionics:

Current Generation of Del Mar CardioCorders:

Post Office Box 2321 Portland OR 97208-2321 USA

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