When you say palpitations do you mean skipped heart beats or just a fast heart rate? If I take the wrong combination of minerals I got skipped heart beats in the past, but haven't so much recently.
I will tell you my experience with Spirulina (the Pacifica strain) was not pleasant. My pancreatic pain worsened and my hypoglycemia spun out of control. No one understands when I tell them this since Spirulina is traditionally used to treat hypoglycemia. For me, it made it worse.
No experience with the other herb you mentioned so I don't know.