What you are describing is what I have had for 28 years and have just had an ablation - sounds like PSVT or proximal supra ventricular tachycardia. Bending over, turning around quickly, reaching up, STRESS, all brought on events exactly as you describe...
I took Atenolol for 15 years and this helped a lot. My dx during the abaltion was AVNRT which is the most common SVT and the most easily treated. Your symptoms to me suggest that you have the same condition.
What you have is a benign heart condition. However, try and do something about it sooner than later. The way to go now is ablation as opposed to long term medical intervention.
Hope this helps and best of luck..
A lot of questions here, I'll try to answer =)
PSVT = SVT. The P just imples that the SVT is not permanent, but happens occationally. There is no such thing as a "permanent" SVT, though.
IST (inappt. sinustachycardia) is a permanent condition, with constantly elevated "normal" heart rate. Though sinus tachycardia is pr definition a "supraventricular tachycardia" (and not a ventricular tachycardia) it's rarely included in the "SVT" term, because it's essentially a normal phenomenon and not an arrhythmia.
If your heart rate increases gradually, it's more likely to be sinus tachycardia than SVT, but if your heart rate increases to 180 by bending over, this is more likely to be SVT. Impossible to be sure, of course, and sinus tachycardia can also be "brutal" and extremely quick.
Beta blockers are great preventing adrenaline/stress induced tachycardia or skipped beats. I use a small dosage each day, and my problems are gone. It doesn't work for everyone, but if your cardiologist prescribed them, who are we to argue?
If you get dizzy or your heart rate get very low (< 45) by using beta blockers, you need to report this to your doctor immediately.
Keep in mind, by the way, that SVT essentially is a benign, though annoying phenomenon, as long as it doesn't last for hours and days.