Department of Cardiovascular Sciences


Atrial Fibrillation and the risk of stroke in veteran athLETES: a pilot heart and brain Magnetic Resonance Imaging study.

An MRI study looking at the heart and brains of veteran endurance athletes

Principal investigator: Dr Susil Pallikadavath. MRCP(UK); MBChB(honors); BSc(hons).
Chief investigator: Professor Gerry McCann. BSc; MBChB; MRCP (UK); Dip Sports Med; MD.
We are group of clinical researchers from the University of Leicester and Glenfield hospital performing a study in competitive athletes with and without atrial fibrillation who are willing to come to Glenfield Hospital Leicester to have an MRI scan of both their heart and brain. This webpage contains some information about this study.

If you think you may fall into any of the categories listed below, please respond to this email address ( and we will provide you with further information and a participant information leaflet.

What is the purpose of the study?

Participation in exercise has many benefits to the heart. However, recent data suggests that it can also increase the risk of an irregular heart rhythm called atrial fibrillation. In atrial fibrillation, blood flow within the heart can become sluggish. This may increase the risk of blood clots forming which can then travel up the blood vessels to the brain, completely blocking blood flow and causing symptoms of a stroke. If the clots are very small, these may not cause any symptoms at all even though there may be tiny areas of damage to the brain.

The risk of a clot forming in people with atrial fibrillation is higher in some individuals. We use a scoring system to decide who is at higher risk. Blood thinning treatment is offered to those with higher risk which dramatically reduces the risk of having a stroke. Many athletes with atrial fibrillation would be considered to be at low risk of stroke, due to leading a healthy lifestyle which has positive effects on the risk factors for stroke.  However, athletes, particularly those involved in endurance sports such as running, swimming, cycling and triathlon, tend to have larger hearts and slower heart rates than the general population. The impact of these changes is not known but they may increase the risk of blood clots forming.

We performed an international survey of almost 1000 athletes. This showed that there were a disproportionate number of athletes with atrial fibrillation who had a stroke, even those deemed to be at a low risk. We now want to understand why otherwise fit athletes with atrial fibrillation may be at higher risk of stroke.  This study will use MRI (a type of scan) to look at the hearts and brains of older male “veteran” athletes with and without atrial fibrillation as well as non-athletic controls. The MRI scan will assess heart size, function, muscle damage and the pattern of blood flow in the heart.  The MRI scan will also look at the brain to see if there is any evidence of brain damage or small strokes that may have occurred due to blood clots.  

Who can take part?

To be defined as an athlete, you must have competed in an organised event at regional level or above, in an endurance sport (such as cycling, running, rowing, swimming, triathlon etc), have trained for 10 years or more, on average for 6 hours per week. You must be between 40-64 years of age. Please consider getting in touch with us if you need the following criteria:

  1. I am an athlete with atrial fibrillation and I have NOT been diagnosed with a stroke.
  2. I am an athlete and I do not have atrial fibrillation.
  3. I am an athlete with atrial fibrillation AND I have had a stroke.

We also need healthy individuals, who do not have a history of atrial fibrillation nor a stroke and do not meet the criteria for being an athlete.

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