Having been one to have the palpitations of which I believe was Iodine chasing bromides out of the heart I wish to add something here.
Those palps were very scary, and a peaceful prayerful mind is important. Having said that, oxygenation is important too. If one finds themselves in that situation in the future, remember this:
Breathe deeply through the nose, and rhymically exhale through pursed lips. This will help keep your heart pumping through the process of the bromides getting chased out of your heart.