Shortening of the P-R interval is a condition called pre-excitation syndrome, which is usually caused by tachycardia. shortening of the P-R interval is caused by emotional and sympathetic excitement, etc. shortening indicates that the patient’s heart rate is too fast, but if symptoms such as panic, chest tightness and shortness of breath occur, you need to go to the hospital for relevant tests in a timely manner. Most of the preexcitation syndrome is caused by diseases on the heart. Due to the function of the human body, the heart provides the power for life, and when the heart has problems, it will cause a series of problems. Part of this series of problems is the pre-excitation syndrome, which is likely to occur if you suffer from diseases such as myocardial infarction and congenital heart disease.