I was just diagnosed as hypothyroidism 2 weeks ago, even though some doctors doubted me had a swelling thyroid gland for a long time but others could not see it so I did not check it until 3 weeks ago. Now the disease has already been confirmed with the test result: Serum free T4 level 6.0pmol/L Serum TSH level 150, Thyroid peroxidase antibod lev 2000 IU/ul. The doctor prescribed me to take levothyroxine 50ug everyday. But I have Not started taking them yet. The reason I have not taken them is I have sinus rhythm, in the past ECGs, my heart beats would go above 100/m sometimes. Occasionally, because of anxiety(the doctor said), I would have chest pains. Even though all the doctors said there was nothing worth worrying about my heart (The last ECG taken a couple of days ago shows: sinus rhythm, left atrial abnormality, rightward axis, incomplete right bundle bramch block, no significant abnormalities, the heart beat was 71/min). I would like to ask, under my conditions, should I take levothyroxine now? Will it influence my heart? Or should I take it with some heart disease medicine together? Thank you very much!