Some patients bring their ECG to the outpatient clinic for consultation. The physical examination report shows sinus tachycardia, and they have no uncomfortable symptoms, do they need treatment? For this question, first of all, we still need to clarify the diagnosis of sinus tachycardia, causes and other circumstances. 1, what is sinus tachycardia Sinus tachycardia is caused by physiological (such as exercise) or pathological (such as hyperthyroidism)) and other factors. Weakened vagal function can lead to inappropriate sinus tachycardia. Sinus tachycardia can also be caused by changes in body position (upright tachycardia syndrome). Sinus node regurgitant tachycardia or sinoatrial regurgitant tachycardia is caused by regurgitant excitation in the sinus node or its adjacent tissues. It is subdivided into physiological and pathological sinus tachycardia. Normally, sinus node frequency is approximately 60-100 beats/min. Its frequency is regulated by autonomic nerves and is also influenced by many other factors, including hypoxemia, acidosis, temperature, and hormones. Sinus tachycardia is defined as a sinus frequency of more than 100 beats/min during physical activity, emotional stress, pathophysiological or pharmacological stress conditions. Its etiology includes fever, hypovolemia, or anemia. Drugs that cause sinus tachycardia include stimulants (e.g., coffee, alcohol, smoking), prescription drugs (e.g., salbutamol, aminophylline, catecholamines), and certain prohibited drugs (e.g., marijuana). All of these factors affect the frequency of depolarization of the pacing cells in the sinus node. Diagnosis depends on the electrocardiogram to make a clear diagnosis. In terms of treatment, the management of sinus tachycardia begins with finding the cause and treating it for that cause. If the symptomatic sinus tachycardia is caused by emotional excitement or anxiety, it can be relieved by calming down and relaxing; for patients with symptomatic hyperthyroidism, they should actively consult the endocrine clinic to control the hyperthyroidism treatment, and the sinus tachycardia can be relieved by itself. 2.What is inappropriate sinus tachycardia? Does it need treatment? Inappropriate sinus tachycardia refers to the acceleration of sinus heart rate at rest without clear physiological or pathological causes. Possible mechanisms of inappropriate sinus tachycardia: increased autoregulation of the sinus node; abnormal autonomic regulation of the sinus node, excessive increase in sympathetic tone and decreased parasympathetic tone. Inappropriate sinus tachycardia is more common in medical personnel and tends to occur in younger people, probably related to the ease with which medical personnel are aware of their own heart rate. Palpitations are the main symptom, but chest pain, shortness of breath, dizziness, vertigo, and near syncope have also been reported. The degree of discomfort is extremely variable, and patients may be completely asymptomatic and detected only on routine physical examination; those with severe symptoms require medication, supplemented by psychotherapy. Clinical physical examination and routine tests can exclude secondary causes of tachycardia. Treatment of inappropriate sinus tachycardia depends mainly on the presence or absence of symptoms. The risk of cardiomyopathy from tachycardia in untreated patients is unknown, but highly unlikely. For inappropriate sinus tachycardia, patients can be treated with pharmacologic therapy with catheter ablation of the modified sinus node.