What is electrocardiography (ECG, EKG)?
Electrocardiography is a test that measures your heart’s electrical activity. It's quick, painless, and harmless.
The results of that test are shown in an electrocardiogram. It looks like a wavy line with spikes on a grid (a tracing). The electrocardiogram gives doctors information about:
The part of your heart that triggers each heartbeat
Your heart's electrical pathways
Your heart's rate and rhythm
Why would I need an ECG?
You may have an ECG:
As part of a routine checkup, if you're middle-aged or older
As a way for the doctor to evaluate symptoms that could be from a heart problem, such as chest pain Chest Pain Chest pain is a very common complaint. Pain may be sharp or dull, although some people with a chest disorder describe their sensation as discomfort, tightness, pressure, gas, burning, or aching... read more , trouble breathing, a fast or abnormal heartbeat Palpitations Palpitations are the awareness of heartbeats. The sensation may feel like pounding, fluttering, racing, or skipping beats. Other symptoms—for example, chest discomfort or shortness of breath—may... read more , or swelling Swelling Swelling is due to excess fluid in the tissues. The fluid is predominantly water. Swelling may be widespread or confined to a single limb or part of a limb. Swelling is often in the feet and... read more in your legs
How is an ECG done?
Small, round sensors (electrodes) that stick to the skin are placed on your arms, legs, and chest
Wires that snap on to the sensors are connected to a machine
As your heart beats, the sensors measure your heart’s electrical currents
The machine records information from each sensor and develops an ECG (a wavy line with spikes) for your doctor to read
Are there any side effects to an ECG?
There are no side effects. An ECG won't hurt at all during or after the test.
What can my doctor learn from my ECG?
An ECG helps your doctor learn many things about your heart, including:
If your heart isn't getting enough blood and oxygen
If the muscular wall of your heart is too thick
If there are bulges in weak areas of your heart’s walls (the bulge is called an aneurysm)
Should I carry a copy of my ECG?
If you've had heart problems, you might want to keep a copy of your ECG with you (ask your doctor if you should). That way, if you have an emergency, the doctor treating you can compare your older ECG with a new ECG.