I have been taking synthroid for 13 years. Had heart palpitation...

I have been taking synthroid for 13 years. Had heart palpitations and irregular heart beat - ER dr put me on heart medication. I am seeing psycholgist for anxiety. He suggested that medication can contribute / cause my anxiety. Was doing research on-line for side effects and found this website. Good to know others have had similar side effects. I doubt I need to be on the heart medication since it seems that the synthroid may be the reason for the heart problems. Is there another thryoid med out there for hypothyroidism? All the dr told me was that it is a synthetic form of what my body normally produces - I had no idea it could have side effects or even contribute to other problems!