XYZ,
I can empathise with you regarding these "automatic" ECG assesments, It is stressful in itself to have these results come back, I myself had a similar situation last Jan, and did the whole shebang - stress ecg & echo but not the 24hr job.
Belfast Child is correct in what he says, my self reporting ECG machine reported an ST Elevation and Myocardial Infact and I had to wait a very uncomfortable mentally 2 weeks to find out it was early reploarization (re-alignment of heart position) due to my stature (tall and thin).
Only advice I can give is relax, stay off booze, and stimulants and you'll find in most cases that its a false alarm.