Hi,
Don't worry if the holter monitor doesn't show anything up, it doesn't mean that the palpitations aren't happening, you have to be lucky to have it catch anything.
In fact you can guarentee that the only time you will feel perfectly ok is when you have a monitor on. You can feel bad the day before and the day after but when you have it on your heart behaves perfectly. I'm sure it knows when it is being monitored.
I have had so many of theses things since I was born (probably about 30) and they have only caught things a few times.
I have even sat in hospital for a week attached to a monitor after complaining of racing/palpitations etc... and have had absolutely nothing happen.
Very very annoying. The doctors are quite used to this happening and would probably be surprised if it did catch anyhing.
Lindsay