I started taking potassium 3 days ago because of shortness of breath due to methylated b. I took 900mgs today and am breathing well for the first time in days. However, I 'm having heart palpitations from the potassium. I actually got them the first day when I took only one 99mg. I took my last 300mgs today around 3 1/2 hrs ago and am still having palpitations. I know that is a sign of low and high potassium. Has anyone else experienced palpitations taking potassium?