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What is an arrhythmia?

Your heart


What is an arrhythmia?

Arrhythmia is a fault in the heart’s electrical system, which affects your heart’s pumping rhythm.

Key takeaways

6 min read

  • Arrhythmia is a fault in the heart’s electrical system, which affects your heart’s pumping rhythm. 

  • Heart arrhythmias are a range of conditions, which have a range of outcomes.  

  • Common symptoms include: shortness of breath, weakness, dizziness, light-headedness, fainting or feeling fainting, a racing heart or palpitations and chest pain or discomfort. 

  • Most arrhythmias are not life-threatening, but can still cause complications that are best managed with your healthcare team. 

The heart has its own electrical system. Electrical impulses are essential to make your heart beat to pump blood to your entire body. Your heart has four chambers, two on the right and two on the left. It has two upper chambers (atria) and two lower chambers (ventricles). In a healthy heart, regular electrical signals cause these four chambers to contract and relax in a steady rhythm of 60 to 100 beats per minute. 

What is arrhythmia? 

Arrhythmia is a fault in the heart’s electrical system, which affects your heart’s pumping rhythm. The abnormal electrical activity makes the heart muscle beat too fast, slow or in an irregular way.

In a healthy heart, you don’t feel your heartbeat. That’s why if you feel your heart beating too fast, too slowly or irregularly, you should see your doctor. Most arrhythmias are not life-threatening, but can still cause complications that are best managed with your healthcare team. 

Types of arrhythmias 

There are many different types of arrhythmia. They’re classified by whether they start in the atria or ventricles. They’re also classified by the speed of heart rate they cause: fast heartbeat (tachycardia), slow heartbeat (bradycardia) or irregular heartbeat.

Abnormal electrical activity in the heart’s top chambers overwhelms the heart’s electrical system. This causes the heart’s electrical messages to become chaotic. As a result, the heart’s top two chambers (atria) twitch rather than contract. The atria beat rapidly and out of rhythm with the heart’s lower two chambers (ventricles). Read more about atrial fibrillation, the most common arrhythmia. 

Atrial flutter is similar to atrial fibrillation. However, in this condition the heart rhythm is more regular and less chaotic than the abnormal rhythm in atrial fibrillation. Sometimes an atrial flutter can develop into atrial fibrillation and vice versa.  

Normally, you don’t feel your heart beating. A heart palpitation is when you can feel your heart beat, and it feels like it is pounding or racing. An ectopic heartbeat happens when your heart misses a beat or adds an extra beat. These arrhythmias can feel alarming when they happen, but in most cases they are harmless. If palpitations or ectopic heartbeats last a long time, are getting worse, or if you have a history of heart problems, you should see your GP.

This is when the arrhythmia starts and stops suddenly. Episodes of paroxysmal arrhythmia can last for seconds, minutes, hours or up to a week. Paroxysmal arrhythmias may have certain triggers. 

Heart block – also known as atrioventricular (AV) heart block and bundle branch block – is a delay or a blockage of the heart’s electrical messages. This may cause your heart to pump abnormally or your heart rate to slow to less than 60 beats per minute. 

Each of these can cause fast and irregular heartbeats. These conditions are related to a specific abnormality in the heart electrical system that can lead to fainting spells or even cardiac arrest.

These are a group of arrhythmias caused by abnormal electrical activity in the heart’s atria. This causes the heart rate to increase very suddenly to over 100 beats per minute. 

This arrhythmia occurs because of a problem with your heart’s natural pacemaker (sinus node), a part of its electrical system. This causes the heart rate to vary from very fast to very slow. 

This arrhythmia is caused by abnormal electrical activity in the heart’s ventricles. This causes a fast heartbeat that can start very quickly and last for seconds, or go on for longer. If it continues, it must be treated as soon as possible due to the risk of cardiac arrest. 

Ventricular fibrillation is caused by abnormal electrical activity in the heart’s ventricles that causes a very fast, erratic and ineffective pumping rhythm. When the heart does not pump effectively, cardiac arrest occurs and urgent treatment is required to restart the heart rhythm and save the person’s life.  

Are arrhythmias serious? 

Arrhythmias are a range of conditions, which have a range of outcomes. Some arrhythmias can be well managed by your doctor as a long-term condition. Other arrhythmias are life-threatening and require urgent treatment. Sometimes, an arrhythmia is a symptom of an underlying condition that requires management by your doctor.  

Arrhythmia symptoms 

An irregular heartbeat can be a sign of arrhythmia, or another heart condition. That’s why if you feel your heart beating too fast, too slowly or irregularly, you should see your GP.

Occasionally, people with a healthy heart may have an irregular heart rhythm or palpitation during a time of emotional or physical stress. This is normal. Noticeable palpitations don't necessarily mean you have a serious problem.

Arrhythmia symptoms include: 

  • Anxiety 

  • Chest pain 

  • Fainting (syncope) 

  • Fatigue 

  • Fluttering or pounding in your chest 

  • Light-headedness or dizziness 

  • Racing heartbeat when feeling at the wrist (tachycardia) 

  • Slow heartbeat when feeling at the wrist (bradycardia)  

  • Shortness of breath 

  • Sweating

Some arrhythmias don’t cause any symptoms. Your GP might find you have an arrhythmia before you do, during a check-up.  

Causes of arrhythmia  

There are some conditions that can lead to an arrhythmia, including: 

  • A heart attack 

  • Congenital heart disease  

  • Coronary heart disease  

  • Diabetes 

  • High blood pressure 

  • Heart failure 

  • Obstructive sleep apnea (OSA) 

  • Structural heart abnormalities – such as from cardiomyopathy, valve disease or scarring from a previous heart attack. 

  • Thyroid problems

 Risk factors for arrhythmia are: 

  • Aging 

  • Being overweight 

  • Drinking too much alcohol

  • Drug abuse 

  • Electrolyte imbalance 

  • Genetics 

  • Smoking 

  • Some medications and supplements, including over-the-counter cold and allergy medications and weight loss or nutritional supplements 

  • Stress or anxiety. 

Arrhythmia triggers 

If you have an irregular heartbeat that comes and goes (paroxysmal arrhythmia), there are certain triggers that may include:  

  • Alcohol 

  • Caffeine 

  • Nicotine (either cigarettes or e-cigarettes) 

  • Tiredness 

  • Unrelated illness such as a cold or flu 

  • Some medications (either over-the-counter or prescription).  

  • Stress (physical or emotional). 

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

Talk to your doctor if you think your medication may trigger your arrhythmia. Never stop taking prescription medication without talking to your doctor first.

In some people, certain types of exercise may trigger your arrhythmia. If you think this is happening to you, talk to your doctor. Physical activity is very important for your heart health and overall wellbeing and should not be avoided without talking to your doctor first.

Your doctor can help you manage your health and suggest alternative medication or activities that are suitable for you. 

Diagnosing arrhythmia 

To diagnose an arrhythmia, your doctor will review your signs and symptoms and conduct a physical examination.   They may perform the following diagnostic tests to confirm arrhythmia or rule out other conditions: 

  • Electrocardiogram (ECG) – This test measures your heart’s electrical signals and  the timing and duration of each electrical phase in your heartbeat. 

  • Holter monitor – This is a portable ECG. It records your heart's activity for 24 hours or longer. 

  • Event recorder – This is also a portable ECG. It records your heart's activity over weeks to months. 

  • Echocardiogram – This test creates moving pictures of your heart. It may diagnose structural heart disease or blood clots in your heart. 

  • Implantable loop recorder – This may be implanted under your skin in the chest area to continually record your heart's electrical activity and detect abnormal heart rhythms. 

  • Stress test (exercise testing) – This test measures arrhythmias triggered by exercise. 

  • Tilt table test – This test monitors your heart rate and blood pressure as you lie flat on a table and how your heart responds when you stand up. 

  • Electrophysiological testing and mapping – In this test, electrodes can map the spread of electrical impulses through your heart. Doctors can use the electrodes to stimulate the heart to trigger an arrhythmia. 

Arrhythmia treatment

Arrhythmia treatment may only be required if the arrhythmia is life-threatening, or causes significant symptoms or serious health problems. Treatment depends on the cause of the arrhythmia and how it impacts your health.  These include:  

  • Electrical cardioversion – An electrical shock to the chest done under general anaesthesia to restore the heart’s normal electrical rhythm. 

  • Catheter ablation – A procedure performed in hospital using a catheter to destroy (ablate) the area inside the heart that is causing the abnormal rhythm. If your doctor recommends an ablation, they will discuss the benefits and risks with you. 

  • Medication – Regular medication can be given to normalise the heart’s rhythm (anti-arrhythmic agents) or slow the heart rate (beta-blockers, some calcium channel blockers and digoxin). Blood thinning (anticoagulation) medications may be prescribed if your doctor feels your arrhythmia increases your risk of stroke.   

  • Pacemaker – A small implantable device that electrically stimulates the heart to maintain a regular heart rhythm. 

  • Implantable cardiac defibrillator (ICD) – To continuously monitor and correct your abnormal heart rhythms as needed. 

  • Automate External Defibrillation (AED) – A mild electrical current is used to ‘reset’ your heart rhythm in a cardiac arrest.  

Living with an arrhythmia 

If you’ve been diagnosed with an arrhythmia, you may have a lot of questions. You may wonder how serious your condition is and what it means for the future.

It's normal to feel many emotions such as fear, anxiety and low mood. Talk to your doctor if these feelings last longer than two weeks. There are steps you can take to help you manage your condition and relieve any worries you may have.

To help manage your condition, you can: 

  • Ask your doctor questions to understand your arrhythmia and its treatment 

  • Identify your arrhythmia triggers 

  • Avoid or reduce alcohol intake 

  • Always take your medication as prescribed 

  • Know when to seek urgent help 

  • Stay physically active 

  • Manage your risk factors for heart attack, as they are also important in management of arrhythmias 

  • Attend cardiac rehabilitation – structured exercise and education about heart health.

You might also be interested in...

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Automated implantable cardioverter defibrillator (ICD or AICD)

This is a device inserted into your chest to return abnormal heart rhythms to normal using electrical impulses.

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What is atrial fibrillation?

Atrial fibrillation is a type of arrhythmia where your heart beats irregularly and fast.

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What is heart failure?

Heart failure is a condition where your heart isn’t pumping blood to the rest of your body as well as it should. If your heart is damaged or not pumping properly, it can become enlarged, weak or stiff.

  1. NHFA CSANZ Atrial Fibrillation Guideline Working Group, Brieger D, Amerena J, et al. National Heart Foundation of Australia and the Cardiac Society of Australia and New Zealand: Australian Clinical Guidelines for the Diagnosis and Management of Atrial Fibrillation 2018. Heart Lung Circ. Oct 2018;27(10):1209-1266. doi:10.1016/j.hlc.2018.06.1043
  2. National Health Service UK. National Health Service.
  3. nidirect Government Services. Heart palpitations and ectopic beats.
  4. SADS Foundation. Sudden Arrhythmia Death Syndromes.

  5. Dakkak W, Doukky R. Sick Sinus Syndrome. StatPearls. 2024.

  6. Foth C, Gangwani MK, Ahmed I, Alvey H. Ventricular Tachycardia. StatPearls. 2024.

  7. Ludhwani D, Goyal A, Jagtap M. Ventricular Fibrillation. StatPearls. 2024.

Last updated13 March 2024