ECG (Electrocardiogram)
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Overview
An ECG (Electrocardiogram, sometimes called EKG) records the electrical activity of your heart. It is one of the most common tests in medicine — quick, painless, and remarkably informative for the size of a single piece of paper. An ECG is often the first test done when there are symptoms that could relate to the heart — chest pain, palpitations, breathlessness, or before surgery.
What is this test?
Small sticky electrodes are placed on your chest, arms, and legs. They pick up the small electrical signals your heart produces with every beat. These signals are recorded as a tracing on paper or on screen.
From this tracing, a doctor can detect arrhythmias (abnormal heart rhythms), evidence of past or current heart attack, certain inherited heart conditions, and a range of other problems.
Why your doctor may order it
- Assessment of chest pain
- Investigation of palpitations or fainting
- Suspected heart attack (urgent indication)
- Before surgery, especially in patients over 40 or with risk factors
- Monitoring a known heart condition
- Annual health check-up in adults with cardiac risk factors
- Before starting some medications that can affect the heart
How long does it take?
The recording itself takes only a minute or two. Including positioning of the electrodes and removal afterwards, the whole test is usually done in 5 to 10 minutes.
How to prepare
- No fasting is required.
- Avoid using oily or moisturised lotions on your chest, arms, or legs on the day of the test — they can stop the electrodes from sticking properly.
- Wear a top that can be easily removed or opened at the front. Women may want to wear a separate top and bottom rather than a one-piece dress.
- Bring your prescription and any previous ECG reports for comparison.
- Avoid heavy exercise just before the test — your heart rate should ideally be at rest.
What to expect during the test
You will lie on a couch. The technician will clean small areas of skin on your chest, wrists, and ankles. Sticky electrodes are placed on these spots and connected by wires to the ECG machine. You need to lie still and breathe normally for about a minute while the recording is taken. There is no sensation — no shock, no current — the machine only listens. Once done, the electrodes are removed (which may pull at chest hair slightly) and you can dress and leave.
After the test
- There is no recovery — you can resume normal activities immediately.
- The tracing is reviewed by a cardiologist and the report is usually available the same day.
- Your doctor will go through the result. If the ECG is abnormal, further tests (such as an echocardiogram, treadmill test, or Holter monitor) may be ordered.
Do's and Don'ts
- Lie still and breathe normally during the recording.
- Tell the team about all heart medications you are taking.
- Bring previous ECGs — comparison often matters more than the new tracing alone.
- Mention any pacemaker or implanted device.
- Tell us straight away if you develop chest pain during the test — this is important.
- Don't apply body lotion, oil, or talcum on the chest or limbs on the day of the test.
- Don't exercise vigorously just before the test
- Don't worry if the test takes a moment to repeat — sometimes a second tracing is needed for clarity.
- Don't assume a normal ECG means your heart is perfectly fine — an ECG is one snapshot; some conditions are intermittent.
- Don't ignore symptoms (chest pain, breathlessness) just because an old ECG was normal.
Understanding your results
An ECG report describes the heart rhythm, rate, and waveforms. “Normal sinus rhythm” means a normal heart rhythm. Specific findings — such as “ST elevation,” “left ventricular hypertrophy,” or “atrial fibrillation” — describe specific patterns and have specific implications. A single ECG is a snapshot. Some heart problems are intermittent and do not show up unless captured during an episode. If your symptoms suggest a heart problem but the ECG is normal, your doctor may recommend a Holter monitor (24-hour ECG) or other tests.
Frequently asked questions
No. An ECG only listens to your heart's own electricity. It does not send any current into the body.
Yes, immediately. There are no restrictions after a routine ECG.
To detect any heart problems that might increase the risk of anaesthesia or surgery. Even people with no symptoms can have unrecognised heart issues.
Sometimes. An ECG looks at the heart's electricity. An echocardiogram looks at the heart's structure and pumping. They give different information, and both may be needed depending on your symptoms.
An ECG can be done on request, but interpretation should always be discussed with a doctor. Self-interpreting a tracing is rarely useful and often misleading.