Firstly sorry for my bad english. You may be having deficiency in Vitamin B12, B3, B6, and protein. Because Vit B and protein are needed to regulate and maintain nerves and heart working properly. The cause may be celiac disease. Celiac disease is a condition that damages the lining of the small intestine and prevents it from absorbing parts of food that are important for staying healthy. The damage is due to a reaction to eating gluten, which is found in wheat, barley, rye, and possibly oats. The only known effective treatment is a lifelong gluten-free diet. For now, what you need to do are intake high dosage Vit B12 twice a day. Vit B Complex twice a week, and high protein everyday - you need take this Vitamins and protein this for at least 6 months. Hopefully this will help.
Have you been to a cardiologist? Get another eeg too. Tilt table test to check autonomic dysfunction. Sleep study?