60 years old, 210 lbs, 6 tall, not much history. I ve had shortness of breath when I mildly exercise, rapid heartbeat, erratic BP. Taking metropolol right now which controls most of it. Have some dizzy spells. Have had several heart tests - all say that I have an electrical problem which causes lack of oxygen. 3 different doc s have said there s no stroke of heart attack concerns. Could this be caused by electromagnetic fields? too much computer usage?