I had these "palpitations" too--you'd think that palpitations would just be your heart pounding like crazy or something, but these literally feel like the organ is trying to get up and move around (and taking the arteries with it) It is the FREAKIEST thing....
I know that your dr diagnosed you with various deficiencies, but what if the Mirena is CAUSING the deficiencies?
The hormone or delivery system they are using has REALLY wreaked havoc with our bodies...it's not inconceivable that it would interfere with your bodies processing of various vitamins/minerals.
Anyway, take care and know that you're not the only one with the heart thing...
M