Sudden rapid heartbeat may be caused by physiological factors, such as mental tension, or disease factors, such as arrhythmia, hypoglycemia, etc. In addition, it may also be caused by drug factors, such as ephedrine, caffeine and so on. 1. Physiological factors: this situation is the most common, affecting the human heart rate for many reasons, such as mental stress, changes in body position, physical activity, food digestion, emotions and so on. 2. Disease factors: (1) Arrhythmia: such as common tachyarrhythmia, especially supraventricular tachycardia, it will be manifested as a rapid heartbeat, and sudden, sudden stop, without any cause of rapid heartbeat, accompanied by dizziness, palpitations and other discomforts. (2) Hypoglycemia: For example, the occurrence of hypoglycemia can cause a significant increase in heart rate, accompanied by panic, hand tremors, fatigue, sweating, and a significant sense of hunger, which can be significantly relieved by eating. 3. Drugs: Certain drugs can cause a rapid heartbeat, such as sympathetic drugs or parasympathetic nerve blocking drugs. Common ones are ephedrine, caffeine, amphetamines, etc. The causes of sudden fast heartbeat are very complex, such as exclude physiological factors, heart rate continues to accelerate, it is recommended to consult a doctor in a timely manner, under the guidance of the doctor’s systematic treatment.