What does an abnormal ECG mean?

I am looking for clear information about ECG test. What does an abnormal ECG mean?

What does an abnormal ECG mean is a common cardiology question. The answer depends on your age, symptoms, medical history, medicines and overall cardiovascular risk. In general, ECG test should be interpreted in context rather than from one symptom, reading or test result alone. A cardiologist may use the history and physical examination together with tests such as blood pressure measurement, ECG, blood tests, echocardiography, stress testing or coronary imaging when clinically appropriate. No single heart test answers every question: for example, a normal resting ECG does not exclude every form of coronary artery disease or intermittent rhythm problem. Results should therefore be matched with the person's symptoms and risk factors. Arrange medical review if symptoms are new, recurrent, worsening, occur with exercise, or are associated with fainting, significant breathlessness or chest discomfort. For people searching for information about ECG test, heart health, cardiology symptoms, heart disease prevention and cardiac tests, the safest approach is an individualized assessment rather than self-diagnosis from internet information. This information is educational and does not replace advice from a qualified doctor or cardiologist.