In untreated hypothyroidism, the heart rate does not get faster. Hypothyroidism is a low level of thyroid hormone caused by various reasons. Thyroid hormone increases the body’s metabolic rate, speeds up the metabolic process, strengthens the contractility of the heart muscle, and accelerates the heart rate. When hypothyroidism is caused by various reasons, low metabolism symptoms will appear, such as fear of cold, little or no sweat, swelling of the face and eyelids, weight gain, slow heart rate, slow reaction and other symptoms. Therefore, untreated hypothyroidism patients will not show symptoms of increased heart rate. If patients with hypothyroidism have a rapid heart rate, the following two points should be considered: First, the dose of drug therapy is too large, the drug treatment of hypothyroidism is the use of levothyroxine sodium tablets for replacement therapy, when the dose of replacement therapy is too large, drug hyperthyroidism will occur, resulting in a rapid heart rate. Second, hypothyroidism combined with other tachyarrhythmias, such as ventricular premature beats, atrial premature beats and so on. Therefore, patients with untreated hypothyroidism will not have an accelerated heart rate. If the accelerated heart rate of patients with hypothyroidism is obvious, they need to go to the hospital for further examination.