The heart rate is still fast after T3T4 is normal, which may be related to physiological reasons, potassium deficiency, anemia, etc., and can be treated by following the doctor’s instructions to supplement potassium salt and iron supplements. 1. Physiological reasons: drinking coffee, staying up late, after strenuous activities, emotional excitement and other physiological reasons may lead to t3t4 normal heart rate is still very fast, you can drink less coffee, regular work and rest, relaxation and so on to improve the symptoms. 2. Potassium deficiency: Hyperthyroidism patients may have a decrease in blood potassium, low blood potassium can easily lead to increased excitability of cardiomyocytes, resulting in increased heart rate, resulting in 3t4 normal heart rate is still very fast symptoms. It can be treated with oral potassium supplementation and antithyroid drugs such as methimazole and propylthiouracil. 3. Anemia: Anemia will lead to the lack of oxygen in the body cells, and the heart will accelerate the beating compensatory to deliver blood to the periphery to meet the oxygen demand of the whole body. Anemia can be treated with iron supplements, vitamins, folic acid and other medications. After t3t4 normal heart rate is still very fast should go to the hospital in time to improve the examination, clear cause to give targeted treatment.