How does HL7 format process ECG (digital) data

Question

Hi,

Is HL7 format able to store(if in XML) and frame ECG data generated on a digital display ECG machine ? If yes, then how does it do it. Is it raw image data (BMP) or tags like XML ?

Any help welcome.

Thanks, Xibee

Answer 1

I am assuming you are using HL7 2.x since 3.x is based on XML and you should not have the question if you are using 3.x.

There aren't a lot of fields that are large enough to hold xml in HL7 2.x. Check if your message structure has OBX or NTE segment, you can put a lot of text in obx-5 or NTE. That is, up to your message receiver's limits. You can add multiple OBX/NTE segments if the text exceeds the size limit set by your message receiver.

You need to escape any HL7 control characters in your XML like you do for any other text field. However how to escape the control characters are up to your interface partner. I do not have experience with partners who follow the standard escape sequence.

You can base-64 encode any kind of binary data.

Answer 2

ECG images can be exchanged via DICOM. It really depends on the ECG machine, and which formats it supports. HL7 is not exactly intended for this purpose, but as mentioned you can base64 anything and stick in in a HL7 segment.

Mirth, a powerful open source HL7 interface engine, supports DICOM via dcm4che:

Answer 3

ECG data is usually stored as raw waveform samples (A/D counts, probably in OBX segments), not images. There's no real standard, though, so each vendor will do it differently.