I AM NOT A PHYSICIAN, but someone who has had problems with waking up from a sound sleep with anxiety related heart palpitations. After doing some research I tried adding magnesium supplement to my daily routine. I noticed almost immediately this problem disappeared. I noticed so often certain deficiencies in our bodies will manifest itself in some really weird ways, and for me, adding magnesium really helped for this particular problem. Maybe this might help someone who may be having this same problem. Don't forget to always consider your doctor if the case warrants. (For myself, my doctor isn't always available or helpful for matters such as this and I have to so often do tons of research on my own).