Why are hyperthyroidism patients often combined with atrial fibrillation? Hyperthyroidism is a disease of the endocrine system in which the thyroid gland synthesizes and releases excessive amounts of thyroxine. Thyroxine is a hormone that promotes the body’s metabolism and increases neuroexcitability. Therefore, patients may lose weight, become easily agitated, have hand tremors, have a rapid heartbeat, etc. Some patients also develop atrial fibrillation. For these patients, the first treatment for atrial fibrillation is hyperthyroidism, and if atrial fibrillation still exists after hyperthyroidism is cured, catheter ablation should be chosen to treat atrial fibrillation.