Occasional rapid heartbeat can be caused by a variety of factors, such as emotional excitement and other physiological factors, but also can be a symptom of a certain disease, such as hyperthyroidism, arrhythmia and so on. 1. Emotional excitement: When a person is in an emotional state, such as anger or fear, it may lead to rapid heartbeat. 2. Hyperthyroidism: It is a disease caused by excessive production of thyroid hormones and can be caused by excessive iodine intake, genetics and other factors. The main symptoms may be irritability and agitation, rapid heartbeat, weight loss, etc. 3. Arrhythmia: It is a disease in which the rhythm of the heart beats abnormally, which can be caused by coronary heart disease and heart surgery. The main symptoms may be palpitations, fatigue, occasionally accompanied by intermittent rapid heartbeat. When exclude physiological factors occasionally appear heartbeat acceleration, should go to the hospital in time, hospital related examination, in order to clarify the cause of the disease, and actively cooperate with the doctor’s treatment.