Wow, glad to see you here but not under these circumstances. I know your smart so I am going to post a great site that will explain to you how the electrical conduction system of the heart works normally.
From what your Dr. seems to think, you my have a problem with the atria of your heart. The 24 hour heart monitor is used to help diagnose arrhythmias that come and go. One of these arrhythmias is atrial fibrillation which many people learned about in 1991 when President George Bush was dx with this disorder.
Here is the link that will help you understand a bit better:
I love the comment re hooking up the ECG wires backwards and truthfully, I have seen this happen but not twice in a row.
Keep on talking with us as we are here to help in any way we can.