Douglas...yes, lower levels of potassium can cause heart palpitations but it's not the only thing that can cause them.
One suggestion that I would make is to record what you eat and see if there is a pattern with any particular food or food group (for example, high carb or high sugar foods trigger palps, but low carb or low sugar meals don't). It could also be due to a food sensitivity.
I'd also like to point out that your blood glucose was in the higher than normal range although I have no idea when you last ate when that blood sample was drawn and that could affect the results as well. If it was more than 2 hours since you last ate, I hope that the doctor suggested that you follow up on that. Higher blood sugars after a meal can also trigger palpitations and that might be something for you to track as well by getting (or borrowing) a blood sugar meeter and checking before you eat and at 30 minute intervals after you eat to see how high your blood sugars go and how long it takes them to get back into a normal range. I'm not suggesting that you are diabetic, but you may be developing early signs of glucose intolerance that a fasting blood sugar reading wouldn't pick up.
Having said all that, we're really not in a good position to offer medical advice or diagnose medical problems here and I'd highly encourage you to work closely with your doctor on this problem. We can offer suggestions and possibilities, but not being doctors and able to see you and run tests, all of them could be completely off the mark.
Hope everything works out well for you and they are able to pinpoint the problem!