terrible dizziness....... heart????

As some of you know - I have a 100%blocked coronay artery, which created it's own bypasses. Haven't had a heart attack, or angina. All other arteries look good, with just minimal soft plaque in LAD - the rest all clean. Echo is perfect, as is EKGs. EF is 60-65%. I'm female, 54, overweight (but can't exercise do to bones shattered in my foot), former smoker, on Toprol, Lipitor,(cholesterol 118, Trig, 66, HDL 28 (I know - bad), Asprin. Today, I suddenly got very, very dizzy! I took my mother to a store, and had to go sit in the car because I was so dizzy - not weak, just dizzy. No other symptoms. Heart rate did go to 80, and it is usually 64. As a matter of fact (because I do have heart phobia), I even went down and walked on the treadmill for 15 minutes to see if I would have any angina (I have NEVER had angina). Heart rate went up from 72 to 95 - when I was done, back to normal in 1 minute 10 seconds. I'm assuming the dizziness is not heart related --- but what do you think? I hate to run to the ER again - they just do an EKG, take blood once and send me home. I am still somewhat dizzy when I move around. Although I must say, when my Husband had his second heart attack on Memorial weekend - his ekgs were normal, as were the first 2 blood draws. They decided to keep him overnight for observation, and it was his third blood draw that showed the troponin level high.