SB- I too had trouble with the mag spray. I quit after about a week. It really dropped my blood pressure and lowered both my Na and K on my last test. I was also taking a much higher dose of oral mag as well.
Those of us with AF and Na/K levels that are still not in the normal range have to be careful with mag. I can only take about 500mg per day and feel good on this. I wonder what your current potassium levels are at. I sure felt bad when mine dropped to 1 again. It hadn't been a 1 in over 1.5 years.
Many of us jumped on the Mag Advocasy group and got caught up in all of the enthusiasm. I think more and more people especially with AF are reporting problems taking high levels of mag. It is an atagonist mineral to Ca, Na and K and must be used responsibily.
All the best to you! I hope you are feeling better soon!