In supraventricular tachycardia, the severity of the condition can be determined by the rhythm of the heartbeat, accompanying symptoms, and duration. 1. Heartbeat rhythm: If the patient’s heartbeat suddenly increases and the ventricular rate can reach 160~220 beats per minute, the condition is considered serious. However, if the heart rate exceeds the normal range, but is lower than 160 beats per minute, without obvious dizziness, weakness, chest tightness, blackouts or syncope, the condition is not considered serious. 2. Accompanying symptoms: When supraventricular tachycardia occurs, some patients may experience panic, shortness of breath, chest tightness, sweating, as well as dyspnea, dizziness, headache, syncope and other symptoms, which can also indicate that the condition is more serious and needs to be dealt with in time. If the symptoms are not obvious, no related complications, and can live a normal life, it is generally not serious. 3. Duration: If the duration of supraventricular tachycardia is several minutes or hours, it indicates that the condition is not serious; however, if it lasts for several days, it is considered to be serious, and the cardiac output is relatively low, which is easy to hurt vital organs. If patients with supraventricular tachycardia have the above conditions, the condition is considered serious and needs to be targeted as soon as possible to avoid angina pectoris and cardiac insufficiency.