I see a few things you can look at, but most obvious is the fact that having been a diabetic for 15+ yrs, there is a good likelihood that you have some moderate CAD, maybe even severe enough that you need an intervention/surgery to treat the CAD. Having worked Cardiac for about 9 and a half years, I can tell you that often times when a patient is hypoglycemic, they do have increased numbers of PVC's, though I am not sure of the pathology of why this occurs, I would assume it is due to a changing metabolism as the bodies is deficient of sugar. But I would CAUTION against using the "Cake Decorator" sugar supply without following up with some complex carbohydrates!!! I learned this the hard way while still a student in nursing school. Feeling the low sugar come on, I did what I thought right, and drank a regular Coke. I was heading out to dinner with a friend and we stopped by the hosp. to see her mom, (yes she, myself and her mother, my wife, and a bunch of family and friends are all nurses) and I was still not "seeing right," shaky, sweaty, and not fully functional. So her mom checked my sugar and it was a 31!!!! I learned a few years later that the simples are great to treat initial hypoglycemia, but then you need to follow up with some protein and complex carb's too to prevent "REBOUND HYPOGLYCEMIA," which is probably what I did.
I am sure there are many "Subject Matter Experts" here on CAD, but I will lend my advice as needed if I can, feel free to PM me. However, I will be leaving thursday (Aug 25th at noon for a 12 day elk hunt in CO). If you Cardiologist hasn't done a stress test of heart cath by the time I am back, you should FIRE HIM(seriously, you should fire him if he hasn't at least scheduled one or the other), and find a real cardiologist!!!! Good Luck!!!