Synthroid's sole purpose after a thyroidectomy is to replace the hormones that the thyroid would naturally make. Assuming there isn't any t4 to t3 issues you should do just fine. Finding a dose that suits you is the hardest part.
yes but will the correct dose , give you back you energy , regulte your heart
If those issues are from your thyroid then yes it will help. It just may take a while to find the right dose. Your body will go through tons of changes along with your dose so hang in there and be patient.
Best Wishes for a Easy Surgery.