London Heart

Abnormal Heart Rhythms (Arrhythmia)

What is arrhythmia or abnormal heart rhythm?

Leading London cardiologist and arrhythmia specialist Dr Syed Ahsan treats a wide range of patients with arrhythmia – the term used to describe an abnormal heart rhythm or irregular heartbeat/heart rhythm disorder. This might mean the heart is beating too fast or slow, or in irregular, unsteady patterns. This can be constant or might happen in intermittent episodes. Arrhythmias usually occur due to disruptions within the electrical signals in the heart which regulate the heart’s pumping action.

While it’s normal for our heart rate to increase during strenuous exercise or while under stress, a normal resting heart rhythm is generally considered to be steady – beating at regular intervals – at a rate of around 60-100 beats per minute. However, some people can fall outside of the normal range but still be perfectly healthy.

Arrhythmias are very common and affect around two million people a year in the UK, and there are lots of different types and causes. They can affect people of all ages and fitness levels, although some types are more common in certain groups (such as people with certain pre-existing health conditions, smokers, and over-65s).

Are abnormal heart rhythms serious and what are the treatment options?

Some arrhythmias are not a serious threat to your health, although they may still be alarming and impact your quality of life, and some abnormal heart rhythms can be very serious if untreated and unmanaged. A key example is atrial fibrillation (AF), which is particularly common in over-65s. It’s characterised by an irregular heartbeat, which is sometimes, but not always, faster than normal, and can cause blood to pool in the heart’s upper chambers, which may result in clots forming. Atrial fibrillation is a leading risk factor for major strokes – but it can be easily diagnosed and managed with the correct lifestyle advice and treatment. You can find more information in our Atrial Fibrillation page and information videos.

Another fairly common form of arrhythmia is supraventricular tachycardia (SVT), which also causes a very fast and irregular heartbeat. While not associated with serious complications like AF, SVT can cause symptoms such as dizziness and breathlessness which can be distressing and difficult to live with. SVT can be tricky to diagnose as it often occurs in episodes that might not be very frequent for many years, and the symptoms are often mistaken for anxiety or panic attacks. You can find more information on our Supraventricular Tachycardia page. Other forms of arrhythmia which can be common include ectopic heartbeats and atrial flutter.

Treating arrhythmias often depends on the underlying cause and severity of symptoms. Treatments can include lifestyle measures, medication, as well as procedures such as ablation, a minimally-invasive technique used to correct the disruption of the electrical signals in the heart. As a leading London ablation expert, Dr Syed Ahsan has extensive experience in carrying out the procedure, which can have transformative results. You can find more information in our ablation information videos.

How do I know if I have an abnormal heart rhythm?

You might ‘feel’ an abnormal heart rhythm, as you’ll be aware of your heart beating far more quickly (or slowly) and/or that the beats have become irregular or more powerful (palpitations). You might feel extra beats, or that your heart is ‘skipping beats’. Other symptoms include dizziness, feeling lightheaded and breathlessness, plus persistent fatigue/tiredness.

However, some people with an arrhythmia experience no symptoms at all, and the problem might be detected during routine testing, or tests carried out for other reasons.

For those who do notice symptoms, they can range from mild to severe – but the severity of the symptoms doesn’t always indicate the seriousness of the underlying problem. Some very serious heart rhythm disorders can cause barely any symptoms and vice versa.

The only way to accurately diagnose an abnormal heart rhythm is through seeing a specialist. They may be able to detect warning signs through your symptom history and measuring your pulse but other tests – such as an Electrocardiogram (ECG) – will be required in order to confirm a diagnosis. You can find more information about the tests available on our Cardiac Diagnostic Tests page.

What if I’m just getting palpitations?

Palpitations – where it feels like your heart is beating much harder than usual – are very common. Although sometimes distressing, they are rarely serious and often caused by anxiety and panic attacks, drinking too much coffee or alcohol, or smoking. However, they can also be a symptom of an underlying problem that may need to be managed and treated, so shouldn’t be ignored. And even if there’s nothing wrong with your heart, it’s useful to investigate the root cause of palpitations, as often simple lifestyle measures and management techniques can make a big difference. You can find more information on our Palpitations page.

When should I see a doctor about my heart rhythm?

If you’re experiencing any ongoing or worrying symptoms that could be a sign of an irregular or abnormal heart rhythm, it’s a good idea to see a doctor and get them checked out – whatever your age and fitness levels. Because AF is so common and a major risk factor for stroke, it’s especially important for over-65s to be aware of symptoms and routine checks are a good idea. Being aware of warning signs and routine checks can also be helpful for people with a family history of arrhythmia.


If you are concerned about symptoms such as palpitations and breathlessness, or have already been diagnosed with an abnormal heart rhythm and wish to explore treatment options, leading London heart specialist Dr Syed Ahsan is here to help.

Dr Syed Ahsan is widely regarded as the best cardiologist in London and is a heart rhythm specialist. Watch this introduction to Dr Syed Ahsan to learn more.

To enquire, call us on 0203 303 0325 or email enquiries@thelondonheartclinic.london, or book a consultation via our online booking form.