The heart produces small electrical impulses which spread across the heart muscle to make the heart contract and expand, pumping away the blood to the body. These impulses are detected by the ECG machine.
An ECG is done to find the cause of symptoms such as palpitations or chest pain and to assess other dysfunctioning in the heart.
The ECG or electrocardiogram test is absolutely painless and has no side effects.
How is it done?
Small metal electrodes are stuck on to your arms, legs and chest. These are connected by small wires with an ECG machine, which detects and amplifies the electrical signals that make your heart pump and records them on to a paper or computer. The test takes no more than 5 to 6 minutes.
The patient is made to lie still because movement in body can affect the results.
What ECG detects?
The heart disorders that can be detected by doing an ECG or electrocardiogram include,
- Abnormal rhythms of heart - if the heart rate is fast, slow or irregular. Various types of irregular heart rhythm have characteristic ECG patterns.
- A heart attack (myocardial infarction) - if it was recent or occurred some time ago. When there is a history of heart attack, it causes damage to heart muscle and the damaged muscles heal with scar tissue. This unusual scarring can be detected by abnormal ECG patterns.
- An enlarged heart (cardiomegaly) - this causes bigger impulses in ECG than normal.