Kyle,If you need an accurate reading, you should validate your ECG monitor by comparing it with others, such as those in your doctor's office or medical clinics. Most units can take a reading within a minute or two.
Inverted T-waves are not uncommon, and you don’t need to be overly anxious about them as long as you continue to feel well and have normal echocardiograms and stress tests.
When you see your Dr. on Monday perhaps a copy of your personal monitor results and ECG from the office can be compared side by side to see if the abnormality is visible on both ?
I will be watching for an update after your Dr. appointment.
Kindly,
Kitt