I have had palpitations since changing from levothyroxine onto NDT Thiroyd a month ago. Yesterday morning I was getting palpitations and thumping in chest and got so fed up that I booked an appointment with Dr P. But in the afternoon I read a note I had made about potassium and palpitations and eat a large banana and avocado. I went for another walk an hour later and I have not had one palpitation since. Absolutely amazing. Can NDT affect potassium levels? It shows what a vitamin or mineral deficiency can do to the body but sometimes we look for more serious causes. I was so worried I had heart problems. I shall certainly be eating more potassium containing foods. It also stopped my awful night cramps.