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What is Atrial Fibrillation?


What is Atrial Fibrillation?

Dr Husain Shabeeh BSc MBBS PhD FRCP Consultant Cardiologist & Cardiac Electrophysiologist

What is AF?

Atrial fibrillation (AF) is a common abnormal heart rhythm, especially with the increasing age of the population. It is estimated that it affects 1-2% of the population, with incidence increasing with age, especially over the age of 65. The causes of AF can be related to a variety of reasons including heart disease, lung disease, thyroid dysfunction, as well as lifestyle factors such as increased weight and alcohol intake

Sometimes there is no obvious cause.

In AF, the heart beats irregularly which can cause symptoms such as tiredness, breathlessness and palpitations. However, in many cases AF is symptomless and is found incidentally, for example at a routine pulse check or ECG. This means that there is a large proportion of patients that may have AF and remain undiagnosed.

Dr Husain Shabeeh What causes AF?

AF can occur in bursts (paroxysmal AF) or can be present all the time (persistent AF). There are variousmedications that are used tocontrol the heart rate which canoften be fast, as well as options to control the heart rhythm to maintain normal sinus rhythm.

Importantly, over 20% of strokes may be due to AF. The risk of stroke is estimated to be five times greater for those with AF. The chambers of the heart where blood collects are the atrium, and these quiver (fibrillate) and hence do not contract properly. This allows blood to collect which can then form clots, which in turn can break off to the brain causing stroke.

Diagnosis of AF

A large proportion of people with AF remain undiagnosed. Whether AF is causing symptoms or not, the risk of stroke is present. This therefore means that there are a large proportion of people with AF who remain undiagnosed and are at risk of stroke. Early detection of AF is therefore paramount, as it allows for appropriate initiation of anticoagulant therapy (“blood thinners”) to significantly reduce the risk of stroke.

Detection of AF may be easier in those who have symptoms, with ECG being the key investigation. It may be that patients have symptoms all the time, but there are those where symptoms come and go. Various devices such as ECG monitors and even personal wearable devices can be used to obtain an ECG at the time of symptoms.

Higher risk groups not displaying symptoms can potentially be screened with pulse checks, ECG and increasing awareness.

What happens after
a diagnosis?

Once a diagnosis of AF has been established, patients are assessed for their stroke risk. A large proportion of these are deemed to require initiation of anticoagulant therapy, with a variety of oral anticoagulants available for AF that significantly reduce the risk of stroke. It is felt that identifying AF and then prescribing appropriate anticoagulation could prevent thousands of strokes per year in the UK, in turn saving thousands of lives.

Procedures to treat AF

AF can affect the haemodynamics of the heart by loss of the atrial component of filling, an irregular ventricular rhythm and high ventricular rates. AF can be a cause or exacerbator of heart failure, or cause symptoms itself. Currently in UK around 1% of total healthcare spending is for AF. It is important to ensure the heart rate is controlled to minimize the risk of developing heart failure. There are also treatments available to keep people out of AF if deemed appropriate.

These include stronger anti-arrhythmic medication, shock treatments (cardioversion) to shock the heart out of AF and also catheter ablation procedure. Catheter ablation is a procedure carried out with minimal access from the veins of the leg up to the heart. Areas where the triggers for AF initiate from are targeted with heat or freezing energy. The procedure is usually carried out under general anaesthetic either as a day case or one night stay in hospital. Indication for catheter ablation is either heart failure or symptoms despite adequate rate control.

AF is the commonest heart rhythm disorder, with a significant burden on the health of people and healthcare spending. Early detection with subsequent protection from stroke and management of the rate or rhythm is key

Dr Husain Shabeeh

Dr Shabeeh BSc MBBS MRCP PhD CCDS is a medical expert who specialises in the investigation and management of heart disease. He is a Consultant Cardiologist in London and his NHS practice is based at one of London’s premier teaching hospitals, King’s College Hospital and Croydon University Hospital. He trained in all aspects of cardiology at world renowned cardiac centres in London including The Royal Brompton Hospital, Harefield Hospital and King’s College Hospital.