Arrhythmia (irregular heartbeats)

An arrhythmia is when your heart beats too fast, too slowly or in an uneven, irregular rhythm. Find out about different arrhythmias, and how they’re diagnosed and treated.

In this article

What is an arrhythmia?

In most people, the heart beats at a steady rate of 60 to 100 times a minute.

Sometimes, however, your heart can beat in an abnormal rhythm or rate. This is an arrhythmia. You may also hear it called an abnormal heart rhythm, an irregular heartbeat or a heart rhythm problem. There are two main kinds:

  • Tachycardia: a fast heart rate of more than 100 beats per minute
  • Bradycardia: a slow heart rate of less than 60 beats per minute.

Common types of arrhythmia

There are several different kinds of heart rhythm problems.

Atrial fibrillation (AF) is the most common kind of heart rhythm problem. It causes an irregular and often fast heart rhythm.

Supraventricular tachycardia (SVT) is a heart arrhythmia that starts in the top part of the heart, above the lower chambers (ventricles). With SVT your heart rate increases very suddenly to over 100 beats per minute. This can happen when you’re at rest or when you’re exercising.

Atrial flutter is a fast heart rate that starts in the top chambers of the heart (atria). With atrial flutter your atria often beat at a rate as fast as 300 beats per minute. The rhythm can be regular or irregular. It often occurs in people who also have atrial fibrillation.

Ventricular tachycardia is a fast heart beat that starts in the lower chambers of the heart (ventricles). An episode of VT can start very quickly and last for just a few seconds or minutes, or go on for longer. Sometimes VT stops by itself, but if it continues it must be treated as soon as possible as it puts you at risk of cardiac arrest.

Ventricular fibrillation is an extremely fast, life-threatening heart rhythm which makes the heart ‘quiver’, rather than pumping blood around the body. It can cause cardiac arrest.

Long QT syndrome, Brugada syndrome and Wolff-Parkinson-White (WPW) syndrome are heart conditions which cause fast, irregular heartbeats. This can lead to fainting spells or sometimes cardiac arrest.

Heart block happens when the electrical messages that tell your heart to beat are delayed or blocked. This causes your heart to be at a slow rate of less than 60 bpm. Types of heart blocks include atrioventricular (AV) heart block and bundle branch block.

Tachybrady syndrome (sick sinus syndrome) is a problem with your heart’s sinus node (sometimes called your heart’s natural pacemaker). It includes periods of very fast or very slow heart beats.

Ectopic heartbeats are when your heart misses a beat or adds an extra beat. Usually they’re not serious, however if they’re happening regularly, or you feel unwell, then see your doctor.

Is a heart arrhythmia serious?

People with healthy hearts may have harmless irregular heart rhythms from time to time. However, an irregular heartbeat can be a sign of a heart condition. It’s important to check your pulse regularly. If you notice it’s not beating normally, get it checked with your doctor.

Find out how to check your pulse.

What causes arrhythmias?

There are lots of things that can cause an irregular heart rate or rhythm. These can include:

  • damage to the heart as a result of other heart conditions. Heart conditions such as heart attack, cardiomyopathy, heart failure and high blood pressure can damage heart tissue, which leads to heart rhythm problems
  • congenital heart conditions. Some arrhythmias are caused by heart conditions that you’re born with
  • other medical conditions, such as hyperthyroidism and obstructive sleep apnoea
  • ageing. As you get older your electrical pathways don’t always work so well
  • medications. Certain over-the-counter medications and prescription medications can trigger arrhythmias in some people
  • stimulants such as alcohol, tobacco, and some illegal drugs taken in large amounts over a long period of time can cause arrhythmias in some people
  • being overweight.

What can trigger an arrhythmia?

If you have an irregular heartbeat problem that comes and goes (paroxysmal arrythmia), you’ll find there are certain things that may trigger an episode. Common triggers include:

  • tiredness
  • alcohol
  • nicotine (either in cigarettes or e-cigarettes)
  • caffeine
  • other unrelated illness such as a cold or flu
  • physical or emotional stress
  • some medications, either over-the-counter or prescription. Talk to your doctor if you think medication might be triggering your irregular heartbeat. Never stop taking prescription medication without talking to your doctor first.

It’s a good idea to work out what triggers your heart rhythm problem and avoid those triggers where possible.

For some people, certain types of exercise may trigger heart rhythm problems. However, you shouldn’t stop exercising completely. Physical activity is very important for heart health and overall wellbeing. If you think exercise is triggering your arrhythmia, talk to your doctor. He or she can help you manage the problem and suggest alternative activity might be suitable for you.

Tests to identify arrhythmias

You can measure your own heart rate by taking your pulse. If you think you have an abnormal pulse, it’s important to get it checked by a health professional.

Doctors can use a range of tests to help diagnose an arrhythmia. These can include:

  • an ECG (electrocardiogram test)
  • an echo test (echocardiogram test)
  • an EP study (electrophysiology study).

You can find out more about these tests on our heart tests page.

How to treat arrhythmias

The type of treatment you’ll get for an arrhythmia will depend on the type of irregular heart rhythm you have, and the kind of symptoms that you’re experiencing. 

Common treatments for arrhythmias include:

Your doctor will discuss a plan with you to treat and manage your heart rhythm condition.

Living with an arrhythmia

If you’ve been recently diagnosed with an arrhythmia, you’ve probably got a lot of questions. You may be wondering how serious your condition is and what it means for your future.

It's normal to experience a range of emotions at this time including uncertainty, fear, anxiety and low mood. Talk to your doctor or nurse if it lasts longer than a few weeks.

You have an important role to play in the long-term management of your heart rhythm condition. Having a good understanding of your condition and its treatment can help you manage your condition more successfully.

To help manage your condition, you could:

  • identify your triggers
  • avoid or reduce alcohol intake
  • take your medication as prescribed
  • know when to seek urgent help
  • stay active. Talk to your GP or ask for a green prescription to help get you started
  • maintain a healthy weight
  • manage your blood pressure.

Connecting with others

Sometimes it’s helpful to hear from others living with a heart rhythm condition. You can read personal stories from people who’ve shared their experience as part of our Journeys programme. You’ll find stories from people living with arrhythmias and other kinds of heart conditions.

You can also join a cardiac support group in your local area or see if your local Heart Foundation branch has any events in your area.

Find a cardiac support group

View Heart Foundation events