Electrocardiogram (EKG)

An electrocardiogram (EKG) is a quick, painless test that records the electrical signals your heart produces with every beat, giving doctors a picture of how your heart is working.

Every time your heart beats, a tiny electrical impulse travels through the heart muscle, telling it to contract and pump blood. An EKG captures these impulses through small sensors called electrodes that are placed on the skin of your chest, arms, and legs. The machine draws these signals as a series of waves on a graph. A doctor then reads that graph to check whether your heart is beating in a normal rhythm, whether blood flow to the heart is healthy, and whether the heart muscle shows any signs of stress or damage.

Doctors use an EKG both to investigate symptoms a patient is already feeling and to screen for heart problems in people who appear healthy. It is one of the most widely used first steps in cardiology (the branch of medicine concerned with the heart).

• Chest pain or tightness that may point to a heart attack or reduced blood supply to the heart muscle (ischaemia)
• Palpitations (the sensation that your heart is racing, fluttering, or skipping beats)
• Arrhythmia (an irregular heartbeat) — to identify which type and how serious it is
• Fainting or unexplained dizziness that may have a heart-related cause
• Shortness of breath that doctors want to investigate further
• Monitoring of known conditions such as heart failure or a previous heart attack
• Routine check before surgery or before starting certain medications that can affect the heart
• Screening for people with risk factors such as high blood pressure, diabetes, or a family history of heart disease

Because an EKG is safe and non-invasive (nothing enters the body), there are very few situations where it cannot be performed. In rare cases, severe skin conditions or large wounds on the chest may make it difficult to place the electrodes correctly, and your doctor will decide on an alternative approach.

An EKG is considered one of the safest tests in medicine because it only reads electrical signals from the body and does not send any electricity into it. The recognised risks are minor and uncommon.

• Mild skin irritation or redness where the adhesive electrodes were placed — this usually fades within a few hours
• Slight discomfort when the electrode patches are removed, similar to peeling off a sticking plaster
• In people with a lot of chest hair, the electrodes may need to be repositioned or the area shaved, which can cause brief skin sensitivity
• Very rarely, an allergic reaction (skin rash or itching) to the adhesive used on the electrodes

An EKG requires very little preparation compared with most medical tests. There is no need to fast (stop eating or drinking) beforehand. You do not need to stop any regular medications unless your doctor specifically asks you to. Avoid applying lotions, oils, or creams to your chest, arms, or legs on the day of the test, as these can prevent the electrodes from sticking properly and reduce signal quality.

Try to avoid heavy exercise, smoking, and large amounts of caffeine (such as strong coffee or energy drinks) for at least a couple of hours before the test, as these can temporarily change the heart's normal rhythm and affect the reading. Wear clothing that is easy to remove from the upper body, since you will need to expose your chest.

No special blood tests or imaging are required before an EKG. In some cases, your doctor may order an EKG alongside other tests — such as a blood test or chest X-ray — as part of a broader assessment, but these are not required to prepare for the EKG itself.

The procedure itself typically follows these steps:

• You will be asked to lie flat on an examination table and relax as much as possible.
• A technician will clean small areas of skin on your chest, arms, and legs where the electrodes will be attached.
• Small sticky patches (electrodes) are placed on these areas. In some hospitals, small suction cups or clips are used instead.
• Leads (thin wires) connect the electrodes to the EKG machine.
• You will be asked to lie still and breathe normally for a short time — usually less than a minute — while the machine records your heart's electrical activity.
• The technician will then remove the electrodes and leads. The recording is complete.
• A cardiologist (heart specialist) or your doctor will review the graph and discuss the results with you, usually the same day or shortly after.

Because an EKG is non-invasive and takes only a few minutes, there is no recovery period. You can return to your normal daily activities — including eating, drinking, and driving — immediately after the test. There are no wounds to care for, no devices left in the body, and no restrictions on movement.

• If you notice any lingering skin irritation where the electrodes were placed, a gentle moisturiser usually helps. If a rash develops or does not settle within a day, let your doctor know.
• Wait for your doctor to interpret the results before drawing conclusions. An EKG graph contains many details that require medical training to read accurately.
• If the EKG was ordered as part of an investigation into chest pain, palpitations, or fainting, your doctor may schedule follow-up tests — such as an echocardiogram (an ultrasound scan of the heart) or a Holter monitor (a small device that records the heart over 24 hours or more) — depending on what the EKG shows.
• If you are taking medications that affect the heart's rhythm, your doctor will discuss whether any changes are needed based on the EKG findings.
• For routine or pre-surgical EKGs with normal results, no further cardiac follow-up may be needed, but your doctor will advise you based on your overall health.