Cardio neuropathy is something that can happen in diabetics, and has a range of symptoms, though only effects a small percentage of diabetics. High resting pulse rate is one of the symptoms, another is non changing heart rate with exercise, or slump in blood pressure with postural changes; but there are lots of things that affect heart rate so don't panic just yet. Monitor for a few weeks and see what happens. And as always, if concerned, see your GP.