Decreasing Tachycardia with Supplements/Vitamins

I'm also interested in using supplements/vitamins or natural treatments for Tachycardia.

I know my aunt had really bad tachycardia when she had low potassium. But taking potassium supplements probably wouldn't help if that's not the cause of it

I’m also looking for supplement suggestions! I have not been able to do enough research yet on what might be helpful