Tachycardia means that the heart rate exceeds 100 beats/min. An electrocardiogram is needed to clarify which type of arrhythmia is present and also to clarify the severity of the arrhythmia. If the patient with tachycardia is only sinus tachycardia or even atrial tachycardia, if there are no obvious symptoms of panic and chest tightness, he or she can be closely observed temporarily and not given medication. If patients have symptoms of panic and chest tightness, they can take betalactam or calcium antagonists to control the ventricular rate and improve clinical symptoms. However, for some patients with ventricular tachycardia or even ventricular fibrillation, they are acute and critical cases of tachycardia, which usually easily cause hemodynamic changes and require active administration of antiarrhythmic drugs to convert the sinus rhythm as soon as possible and, if necessary, electric defibrillation to save the patient’s life.