A clinical trial presented at the British Cardiovascular Society (BCS) Conference is hoping to find out if early treatment to control abnormal heart rhythms can prevent strokes in people with atrial fibrillation (AF).

An abnormal heart rhythm, or arrhythmia, means that your heart is beating too fast, too slow, or with an irregular pattern. Atrial fibrillation is the most common abnormal heart rhythm disorder, which affects over one million people in the UK, and increases the risk of stroke by 4 or 5 times.

In atrial fibrillation the irregular heartbeat can cause blood to pool and clot in the heart. If this clot breaks loose and is swept up into the brain, it can cause a stroke. It is estimated that AF causes a fifth of the 235,000 strokes which happen in the UK every year. Strokes caused by AF are the most severe and are associated with even higher disability and death rates. These strokes have a 50 per cent likelihood of death within one year.

Previously, scientists have shown that atrial fibrillation causes damaging changes to the atria - two of the four chambers in the heart - which may still be reversible during early stages of the arrhythmia. The clinical trial, led by the German Atrial Fibrillation Network (AFNET) association and by the European Heart Rhythm Association (EHRA), and known as the EAST trial, will be putting this theory to the test by seeing whether using early treatment to restore and maintain normal rhythm in AF patients can reduce cardiovascular complications, such as strokes, by reversing the damaging effects that the condition has on the heart.

The current standard therapies for AF include drugs which prevent blood from clotting, called anticoagulants, as well as drugs to slow and control the heart rate. But even with the use of these medications, major cardiovascular complications such as potentially fatal strokes or heart attacks are common.

In the EAST - AFNET 4 trial patients with early onset AF will be randomly split into two groups - one will receive the usual care according to the best available evidence, and the other will receive early rhythm control therapy on top of usual care. Early rhythm control therapy can include cardioversion (a non-invasive procedure), catheter ablation (a medical procedure sometimes used to treat AF) and antiarrhythmic drug therapy. Patients will be followed up until completion of the study, expected in a few years.

This large pan-European trial has currently enrolled almost 2000 patients from over 100 centres across 11 European countries, with plans to enrol 800 more by 2016. The trial is led by Professor Paulus Kirchhof under the responsibility of AFNET.

Professor Paulus Kirchhof, the lead investigator on the trial and a BHF Senior Research Fellow, from the University of Birmingham said:

"Atrial fibrillation is a growing problem today, with the number of people with AF expected to increase by two and a half times by 2050. This will lead to more people suffering from deadly and disabling strokes, premature cardiovascular death, and hospitalisations.

"It is highly possible that early treatment of AF will mean patients are less likely to need to go to hospital with cardiovascular complications and will also reduce their risk of a stroke.

"If the results of this trial support our hypothesis that early rhythm control therapy is sensible to prevent AF getting worse and improve outcomes, they could lead to an immediate and important change in the treatment for early onset atrial fibrillation"

Dr Mike Knapton, Associate Medical Director at the BHF, said:

"We know that 1.1 million people in the UK are living with atrial fibrillation, putting many people at risk of strokes and the life-changing disabling consequences they can have.

"Upon completion this clinical trial may offer hope to people with newly diagnosed atrial fibrillation - changing and improving the way we treat patients early on to restore and control the heart rhythm and reduce the high risk of stroke associated with the condition."