Suddenly rapid heartbeat can be seen in tachyarrhythmia, which may be paroxysmal supraventricular tachycardia or atrial fibrillation, as well as coronary artery disease, hyperthyroidism, and other diseases, and also physiological causes of mental stress. Suddenly accelerated heartbeat is often indicative of tachyarrhythmia, such as paroxysmal supraventricular tachycardia, atrial fibrillation, etc., which can be seen in simple tachyarrhythmia. Coronary artery disease is a common cause of tachyarrhythmia. During an episode of myocardial ischemia, a sudden increase in heart rate can occur, leading to episodes of palpitations and chest pain. A sudden increase in heart rate can also be seen in hyperthyroidism, where elevated levels of thyroid hormones in the patient’s body can lead to sudden onset of sinus tachycardia or atrial fibrillation. Suddenly rapid heartbeat can also be seen in normal people, such as overstimulation, which is physiological and does not require special treatment. If the symptoms are obvious, you should go to the hospital in time to get a clear diagnosis and treatment under the guidance of a physician.