We have a 2 week old newborn and he has been diagnosed with sinus tachycardia since he was born - the doctors say it is common with many newborns(AF doctors, not saying they are different than others, but we are all human) and we should not be worried, however we have a bit of concern as we only want the best for our son. We are living in England with the USAF and we requested to see a cardio specialist for babies in Cambridge, off base. Should we be concerned and looking into other opinions? Any help would be greatly appreciated! Thank you!