Tachycardia clinically refers to sinus tachycardia, which usually manifests as sinus heart rate frequency >100 beats/min in adults. Common causes of sinus tachycardia can be divided into physiological factors and pathological factors. I. Causes: 1. Physiological factors: common in healthy people after exercise, emotional excitement, drinking certain beverages (such as strong tea, coffee, wine), smoking, etc. Transient tachycardia; 2. Pathological factors: common in fever, organic heart disease, hyperthyroidism, anemia, myocardial ischemia, heart failure, shock, and the application of adrenocorticotropic hormones and atropine. Treatment: 1. Transient tachycardia: no treatment is needed, quiet rest is sufficient; 2. Tachycardia caused by non-cardiac factors: active treatment of the original disease, correction of anemia, control of hyperthyroidism, etc.; 3. Tachycardia caused by cardiac factors: the type of tachycardia should be determined according to the electrocardiogram. Different types of tachycardia need to be treated with different drugs, commonly used drugs are metoprolol, propafenone, verapamil, etc. Precautions: For the treatment of tachycardia caused by cardiac factors, the drugs used to treat tachycardia can cause bradycardia. Therefore, the dosage and speed of the drugs should be controlled, not adjusted by oneself, and the heart rate and blood pressure should be monitored at all times and reviewed regularly.