What is an ECG?

fingers on the KardiaMobile electrode next to a phone showing the single lead EKG on a desk with a pencil and glasses

Learn what an ECG is and why it’s useful for managing heart health.

You may have seen a heart being monitored at a hospital, or even on TV, and wondered what the beeping sounds and the moving lines meant. That’s an electrocardiogram, also referred to as ECG or EKG. Each time your heart beats, an electrical impulse travels through your heart causing the muscles to contract and pump blood to the rest of your body. This electrical impulse is seen as line tracings on a moving strip of paper, or digitally as a moving line on a screen. An ECG records these electrical signals as spikes and dips, called ECG waves.

a mobile device showing a normal reading in the Kardia App

Detecting changes in how your heart is functioning is important, as it may signal early signs of a developing condition. ECGs are one of the best ways to detect and monitor a heart condition before it worsens or becomes a serious health problem. An ECG can also provide reassurance that your heart is functioning the way it should be—whether you have a heart condition or you’re just health conscious.

What is the difference between heart rate, pulse, and rhythm?

Your heart rate—also called pulse—is the number of times your heart beats per minute, where each beat pumps blood to the rest of your body. Your heart rhythm is the pattern of your heart rate, which can be normal, too slow (bradycardia), or too fast (tachycardia). Your heart rate and rhythm are both shown on an ECG strip, and a doctor uses both to analyse your heart’s activity.

When and how is an ECG used?

If you have symptoms such as chest pain, heart palpitations, breathlessness, rapid pulse, or weakness, an ECG may be used to better understand the underlying causes and help your doctor develop a proper treatment plan.

An in-hospital ECG machine records 12 leads (or angles) of heart data through 10-12 electrodes, which are placed on the chest and limbs. The machine records your heart’s electrical activity and displays it as waves, seen in the picture above. Your doctor will review the ECG recording and look for any signs of abnormalities in your heart rate, heart rhythm, or even structural abnormalities.

You can take your own ECG at home

Frequent ECGs can be an easy, effective way to monitor your heart function and health, but you don’t always have to go to the doctor’s office to take an ECG. While an in-hospital, 12-lead ECG gives doctors the most detailed picture of your heart’s electrical activity, there are also personal ECGs that record less leads but can still detect significant rhythm abnormalities. With AliveCor’s personal ECGs, KardiaMobile (single lead) and KardiaMobile 6L (six lead), you can check in on your heart from anywhere. And, Kardia devices can detect more arrhythmias than any other personal ECG. There’s no patches, wires, or gels required and it records your heart data right to your smartphone in just 30 seconds. It’s never too soon or too late to start paying attention to your heart health.