If a patient is found to have a rapid heart rate during an electrocardiogram, the cause of the rapid heart rate should be identified, such as primary myocardial disease causing a rapid heart rate or secondary to other diseases producing a rapid heart rate, and the patient should be monitored for the entire heart rate, blood pressure, pulse rate, and arterial oxygen saturation. If the patient has paroxysmal supraventricular tachycardia, antiarrhythmic drugs and radiofrequency ablation can be applied. If the patient has premature beats, the premature beats should be actively controlled according to the primary cause. If the patient has tachycardia due to secondary factors, the patient should be actively treated according to the cause, for example, if the patient’s heart rate is too fast due to high fever, the patient can be treated with antipyretics, such as intramuscular injections of Advil, and the patient’s heart rate should be observed.