A sudden heartbeat can be caused by autonomic disorders, myocardial ischemia, arrhythmia and other conditions. 1. Autonomic nerve disorder: If you are often sleep deprived and drink alcohol, it may lead to the stimulation of the nerves of the human body, thus triggering autonomic nerve disorder, which is more likely to stimulate the heart to beat faster. 2. Myocardial ischemia: the myocardium may be narrowed because of the narrowing of blood vessels and the reduction of oxygen supply, which is likely to lead to violent contractions of the heart, which is more likely to lead to the human body to produce the symptom of a sudden violent heartbeat. 3. Arrhythmia: Arrhythmia will make the patient’s heart beat at an abnormal rate, which may cause the patient to have a sudden heartbeat in normal life. After the symptoms of sudden heartbeat, we must cooperate with the doctor to carry out the relevant examination, to avoid the delay of the disease leads to the worsening of the heart, affecting the patient’s life and health.