I get this problem of arrhythmias when twisting or bending over to the left. As a powerlifter/strength athlete, it is really frustrating. I ended up in the ER with severe, and even somewhat dizzying tachycardia during a workout, and the doctor told me that constantly bulking and gaining and training so intense with my condition (SVT) is a bad choice. It was EXTREMELY disappointing to have to quit the powerlifting team over this, and now I train at my own pace, so I can stop a workout anytime I feel I have to instead of pushing until the coach says stop. I take atenolol (50mg) a day, and split the pill, (half in the morning and half at night). Could my rapid gain in bodymass possibly be the culprit in my increased resting heart rate as of late? I feel I would really have potential in my sports if it weren't for this damn condition.