Atrial fibrillation vs atrial flutter: what’s the difference? 

Atrial fibrillation (AF) and atrial flutter are both abnormal heart rhythms, also called arrhythmias. They occur when there is an issue with the electrical signals and pathways in your atria – the upper chambers of the heart.

These signals help the heart to beat in an organised and effective way, so when they’re not working properly the heart may beat in a disorganised and less effective way.

How do AF and atrial flutter differ?

The heart has four chambers – 2 at the top called the atria and 2 at the bottom called the ventricles.

When the heart is working properly, the atria contract and push blood into the ventricles, which is what we refer to as a 'beat'.

Typically, the heart beats 60 to 100 times a minute when you are at rest – this is called your resting heart rate.

Both atrial fibrillation and atrial flutter can make your heart beat too quickly. But they differ:

• Atrial fibrillation (AF) – the atria beat too quickly in an irregular way, making them go out of sync with the ventricles.
• Atrial flutter – the atria beat too quickly in a regular way, so they beat faster but still in sync with the ventricles.

Both conditions can make your resting heart rate faster than 100 beats per minute (bpm).

What is the atrial flutter rhythm?

Atrial flutter has a specific rhythm.

With a normal heart rhythm, you have 1 atrial beat for every 1 ventricular beat. But with atrial flutter you can have multiple atrial beats to 1 ventricular beat.

This can be detected by a cardiac specialist on an ECG (electrocardiogram), which is the test doctors use to diagnose you for both atrial flutter and atrial fibrillation.

The image at the top of the page shows an ECG reading of atrial flutter. 

What are the symptoms of AF vs atrial flutter?

Atrial fibrillation is more common than atrial flutter, affecting about 1 in 45 people in the UK, while atrial flutter affects around 1 in 1,000.

However, you can have both conditions. Around 4 in 5 people with atrial flutter also have atrial fibrillation and 1 in 5 people with atrial fibrillation also have atrial flutter.

If you have both, you may get periods of atrial flutter followed by periods of atrial fibrillation.

The 2 conditions can have similar symptoms:

• feeling faint
• tiredness
• palpitations
• shortness of breath
• dizziness
• tightness in the chest.

Symptoms vary from person to person.

If you have atrial fibrillation, you may not have any symptoms, or your symptoms may start and stop on their own or stop after treatment. And eventually, your symptoms may become permanent.

Often, atrial flutter does not cause any symptoms, but some people may experience them.

Palpitations are a common symptom of both conditions – and because palpitations can feel like the heart is fluttering, atrial fibrillation and atrial flutter are sometimes referred to as ‘heart flutter’.

If you’ve not already been diagnosed with atrial fibrillation or atrial flutter and you feel like your heart is pounding, fluttering, skipping a beat or beating too fast, make an appointment to see your GP.

If you experience any of the symptoms below, you should seek emergency medical care:

• chest pain
• severe shortness of breath
• fainting.

Why do they need to be treated?

Both conditions carry an increased risk of other cardiovascular diseases such as stroke.

This is why, whether you have atrial fibrillation or atrial flutter, it’s vital to be diagnosed early so you can get the right treatment to reduce your risk of stroke.

Treatment for both conditions can involve medicines to prevent your heart rate from becoming too fast.

Your doctor may also prescribe blood thinners like direct oral anticoagulants (DOACs) or warfarin to help lower your risk of stroke.

Another treatment is cardioversion, which resets the electrical signals in the heart to work normally. This can be done with medicines or using an external defibrillator device.

A procedure called catheter ablation can also be performed for both conditions and is usually considered the best treatment for atrial flutter.

This uses either heat (radiofrequency ablation) or extreme cold (cryoablation) to destroy the area inside your heart that’s causing the abnormal heart rhythm. It’s minimally invasive and usually done under local anaesthetic.

If your heart rate remains uncontrolled, you may also be offered a special pacemaker that helps the chambers of the heart beat stronger and at the same time.

• Learn more about pacemakers.

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