Magnesium is a likely culprit - palpitations are usually electrolyte problems (magnesium, sodium, potassium, chloride and to a lesser extent calcium)
If you try magnesium, look for a quality supplement (avoid oxides)
Adrenal issues usually present sodium, potassium issues. These need to be in balance with one another and magnesium usually plays a role in this. Do a hair analysis from TEI and see what comes back.
Adrenal activity is most likely caused by toxins, infections, poor nutrition and stressors (emotional, physical etc).