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Thursday, March 5, 2015
Thyroid Function and Cardiac Symptoms
I have been experiencing cardiac type symptoms for several months which include rapid pulse, palpatations, chest pressure, shortness of breath, lightheadedness, fatigue. And many seemingly unrelated symptoms like muscle fatigue, chills, intolerence to cold, eye twitch, skin dryness and itchiness. I have had many cardiac tests which come back negative. My blood work indicates a TSH of 1.071 and a T4 of 14.6. I am a 40 y/o female. My doctor said my thyroid function was good but with the high T4 number I wonder if I should press for more testing. What do you suggest?
The normal TSH really makes it extremely unlikely that your symptoms are related to your thyroid. Most of the thyroid hormone in the blood is protein-bound, and if for any reason there is a mild elevation in the binding protein level, there will be a mild elevation in the total T4. However, the free T4 (which is the active form of the hormone) remains normal. Any questions could be resolved by measuring a free T4 instead of a total T4, but, again, the fact that the TSH is normal makes it very likely that the free T4 will come back normal.
Thomas A Murphy, MD, FACP, FACE
Associate Professor of Medicine
School of Medicine
Case Western Reserve University