A borderline ECG, generally also called a limbic ECG, is a diagnostic term for an ECG test that falls between normal and abnormal. The most common type of borderline EKG is the change in the ST-T segment on the EKG. Borderline ECGs can occur for a variety of reasons, such as improper technique by the physician, an agitated patient, or a patient under the influence of medication. It may also be caused by cardiovascular disease or other systemic diseases, such as coronary heart disease, there may be changes in the ST-T segment, not all ST-T changes can be diagnosed as coronary heart disease, the patient may also not have any heart disease. When borderline ECG occurs, it is recommended to follow the doctor’s instructions for further examination, clarify the cause with the help of the doctor, and carry out targeted treatment or therapy. It is also recommended to have regular medical checkups and early treatment when abnormalities are detected.