Old School! I agree wholeheardedly. I used to play doctor too till I got old and smart and retired! Internet sites are really a bad place to get any kind of medical advice. And comparing one persons's problem to another is even worse! There are literally dozens of totally different heart problems, every one different, the treatments different, their significances different. Like the engine in your cars which give 'trouble' - wonder how many different things can give 'trouble' in an engine? 50? 75? Each needing a different 'fix!'
?Atrial tachycardia? What kind? Like PAT? ?PAC's, ? WPW Syndrome?? or some other of the many kinds of supraventricular tachycardias or just a simple sinus tachycardia that probably only means you've been drinking too much coffee, maybe are uptight and stressed, OR looking at too many bikini's at the beach! Hah!
Beta Blockers given for the right conditions and indications at the correct dosages are great meds! As other meds can be, but they all have their own uses and potential side effects. I see a lot of feedback from the heart rate worshipers who don't feel they have exercised till their hear rate gets up to some magic number from a chart on their $300.00 monitor! Heh! Sorry guys and gals, this is probably meaningless with a lot of conditions. I exercise pretty hard all the time but haven't a clue what my heart rate does or is right now! Why should I care in the total absence of symptoms from the darned thing? Sometimes its best not to get too introspective. As a country we spend billions in unnecessary gadgetry, food supplements and health care of little proven benefit. Don't smoke, exercise, keep weight down, eat correctly, have a physical exam every year or so, and you've already done 98% of the important stuff. Sorry to get philosophical.......
But ask your cardiologist again, and if you are still not satisfied with the answer you could see another one. Doesn't sound too serious to me, although not having any clue about any of the dozens of required details of your health history, labs, physical exam and EKG's any advice coming from ANYONE is meaningless. That's why you won't see a board certified cardiologist answer queries on things like this. They have to know "the rest of the story!"