An ECG is a recording of the heart's electrical activity using electrodes placed on the skin. It provides quick and important information about heart rate, rhythm and the heart's electrical conduction system.
It may be requested for palpitations, chest pain, shortness of breath, fainting or a suspected rhythm disorder; for monitoring some medications or heart conditions; and in other situations the doctor considers necessary. It may also be added to the assessment before exercise or sport, depending on the person's history, examination and risk profile; it does not need to be done routinely for everyone.
The test takes a few minutes. Electrodes are placed on the chest, arms and legs, and you are asked to stay still for a short time during the recording. The ECG machine does not send electricity into the body; it only records the electrical signals produced by the heart.
Once the recording is complete, the result is assessed by the doctor. If you have previous ECGs, comparing them can help show changes that have developed over time.
A standard ECG only shows electrical activity during the short period when the recording is taken. With palpitations or rhythm problems that come and go, the ECG may be normal; in such cases your doctor may recommend a longer recording, such as a Holter, or other tests.