A shortened P-R interval generally indicates that the electrical activity of the heart is traveling from the atria to the ventricles in a shorter period of time, which suggests that the patient may be suffering from a cardiac abnormality. The P-R interval is usually determined by an electrocardiogram (ECG), and the normal range of the P-R interval should be around 120-200 milliseconds. If the ECG result shows that the P-R interval is lower than 120 milliseconds, it can be determined that the patient has a shortened P-R interval. The physician should combine this with a cardiac ultrasound to confirm the cause of the shortened P-R interval. Patients with P-R interval shortening usually do not have self-conscious symptoms, but a few patients may experience palpitations, chest tightness, panic attacks and other discomfort, and in severe cases, fainting may occur. Therefore, when the test results show P-R interval shortening, the patient should actively cooperate with the physician’s treatment program to avoid the deterioration of the condition.