Increased sympathetic excitability may result in cardiac complaints such as palpitations, angina, or even a sense of near death. Cardiac activity is regulated by both the sympathetic and vagus nerves. Sympathetic nerve excitation, through the release of norepinephrine neurotransmitters, causes enhanced heart beat, increased heart rate and accelerated conduction, at which time the heart’s oxygen consumption increases, and, if there is an underlying cardiac disease, may cause a series of myocardial ischemia symptoms, such as palpitations, angina pectoris, or even a sense of near-death, and a sense of cardiac discomfort. When the sympathetic excitability of healthy people increases, they will feel the heart beat faster, usually not accompanied by obvious discomfort, and the above symptoms are transient, and can return to normal after the elimination of nervousness. The symptoms of cardiac discomfort need to be taken seriously, and it is recommended to consult a doctor as soon as possible and follow the doctor’s instructions in order to avoid delaying the condition.