@feruze-- Do you have any uncommon symptoms like pain in the chest area, arms or difficulty breathing?
I think if your doctor wants more tests done, you should definitely get it checked out. I think doctors also look for symptoms of coronary heart disease when there is a borderline ECG test to continue looking into it. Even if you don't have symptoms, I think it's worth having it done. I don't mean to worry you but I've heard of people who have had a stroke or heart attack without any symptoms whatsoever.
You should probably get a second interpretation with your ECG results from another doctor or have the test repeated if you don't trust your current doctor about this.