Private electrocardiogram (ECG/EKG) test

An ECG (electrocardiogram) test, sometimes referred to as an EKG, records the rate, rhythm and electrical activity of your heart. The results are reviewed by a cardiologist to assess the health and function of your heart, helping to identify or monitor any underlying conditions. 

If you've been having worrying symptoms, an electrocardiogram scan can help to diagnose conditions such as an abnormal heartbeat (cardiac arrhythmia), heart failure or a heart attack. However, ECG tests are also commonly used as part of routine medical checks and to determine the effectiveness of medication and other treatments.

How does an ECG test work?

Your heartbeat is controlled by electrical signals which contract your cardiac muscles to keep blood flowing around your body. During an ECG test, small sticky patches containing electrodes are placed around various parts of your body to record these electrical impulses.

The electrical signals are then translated into a wave pattern which is displayed on a monitor or printed out. Our expert cardiac teams can then interpret this information to determine how fast your heart is beating, the rhythm it's beating in and the strength and timing of the electrical signals.

Electrocardiogram vs Echocardiogram

Both an electrocardiogram and echocardiogram are common tests that cardiologists use to assess the health of your heart. Depending on your condition you may be recommended to undergo one or both of them.

While an ECG records the electrical activity of your heart, an echocardiogram (also known as an echo test) produces an ultrasound image so a cardiac specialist can assess the condition of your heart muscle and valves.

When is an ECG needed?

Electrocardiogram tests are widely used to diagnose and monitor common heart conditions. Your cardiac consultant may request an ECG if they think you're having symptoms of:

• Cardiac arrhythmia: This a term covering a range of conditions caused by an irregular heartbeat. Over one million people in the UK live with diagnosed heart rhythm disorders. 
• Coronary artery disease: Caused by a narrowing or blocking of the blood vessels that carry oxygenated blood to the heart. This is one of the leading causes of heart attacks.
• A heart attack: A serious medical emergency where your heart doesn't get enough blood to function properly. The longer the event goes on, the more damage is done to the heart muscle. An ECG can also help to determine if you've had a heart attack in the past.
• Heart failure: This is a long-term condition that develops when your heart can't maintain a healthy blood flow around the body. It's often caused by heart damage linked to one of the above and can get worse over time.

An abnormal ECG scan may point to one of the conditions above, but it's not always linked to an underlying heart condition.

If you've already been diagnosed with a heart condition, you may be required to have ECG tests to:

• Monitor health and functioning after a heart attack or diagnosis of heart failure
• Determine how effective heart treatments (such as a pacemaker or catheter ablation) and medicines have been (by comparing new ECG scans to previous ones)

Outside of cardiac diagnosis and care, electrocardiogram machines are used as standard across many healthcare settings. This includes operating theatres during surgery and ambulances where continuous monitoring of heart rate and rhythm is required.

Types of ECG tests

An ECG is usually carried out by a cardiologist or trained cardiac nurse in a hospital, at a healthcare clinic or your local GP surgery. Depending on the reason for your electrocardiogram scan, there are a few different types you may need.

Resting ECG

This is the simplest form of ECG test designed to monitor your heart at base activity levels. It can detect abnormalities in the functioning of your heart, including arrhythmias and coronary artery disease. 

You'll be asked to lie down and remain still while the scan is carried out, so the electrical signals created when your heart beats can be recorded. A resting ECG should last no longer than a few minutes.

Exercise ECG (stress test)

Your heart works harder during exercise because more blood is needed around the body, so an exercise ECG test can assess how tolerant your heart is to stress or activity. You may need this type of ECG if you're experiencing worrying symptoms during exercise or to assess the root cause of other issues involving your heart valves or chambers. If you’re starting an intensive exercise programme, you may also need one as a precaution.

You'll walk on a treadmill or cycle on an exercise bike for the duration of the test, which can last anywhere from 15 minutes to an hour. Starting slow, the difficulty will gradually increase, as will your heart rate, until you reach the desired level or you start experiencing symptoms, when the test will be stopped.

Alternatively, you may be given medicine to raise your heart rate instead of increasing your activity levels.

Ambulatory (continuous) ECG 

Ambulatory ECG monitoring takes place over a longer period, usually 24 hours, 48 hours or up to a week or two. This type of test records the electrical activity of your heart continuously to help detect abnormalities that may have been missed during a shorter ECG scan, which is particularly valuable for conditions such as atrial fibrillation. Continuous monitoring helps to detect and record these irregularities.

Modern ambulatory ECGs, like the Zio patch, are wireless, more discreet and easier to use than older versions that may have been worn around the neck or shoulder. Your medical team will help set this up for you and then you'll be asked to go about daily life while having a continuous ECG taken. At a specified time and date, you'll take or send the recorder back so the results can be examined.

Cardiac event monitoring

For infrequent symptoms, your consultant may suggest having a cardiac event monitor fitted. These devices can be used for longer periods, sometimes up to three years, but are designed to be activated when you feel symptoms, rather than continuously monitoring electrical activity. 

One of the most common types of cardiac event monitors is an implantable loop recorder (ILR). This is inserted under the skin on your chest in a minor surgical procedure but doesn't interfere with daily life. Once fitted, it can help your cardiologist understand why you're having irregular symptoms such as dizzy spells, blackouts and palpitations.