AFLETES-MRI: A Cardiac and Cerebral Magnetic Resonance Imaging Study in Athletes With Atrial Fibrillation

Atrial Fibrillation and the Risk of Stroke in Veteran athLETES: a Pilot Cardiac and Cerebral Magnetic Resonance Imaging Study - AFLETES-MRI

Participation in exercise improves cardiovascular health. However, long-term endurance exercise may increase the risk of an irregular heart rhythm called atrial fibrillation (AF).

In AF, blood flow is altered, increasing the risk of clot formation in the heart which may enter the circulation and cause a stroke. The risk of stroke can be reduced with the use of blood thinning medication. Athletes with atrial fibrillation, due to their healthy lifestyle, are generally felt to be at low risk of stroke and many would not be offered blood thinning treatment using risk scores used in clinical practice.

In a recent survey of almost one thousand athletes, the investigators found that there was an increased risk of stroke in those with atrial fibrillation, even in those without other risk factors for stroke.

To further investigate these findings, this study will use MRI scanning to look at the hearts and brains of athletes aged between 40-64 years old. The researchers will assess athletes with and without atrial fibrillation, as well as some athletes with atrial fibrillation who have had a stroke previously.

The MRI scans will measure heart size and function as well as blood flow patterns in the heart. The study will determine whether athletes with atrial fibrillation have evidence of stroke on brain MRI and whether these are related to abnormal flow patterns. The results will help us decide whether a larger study should be performed.

Inclusion Criteria:

• Male, atrial fibrillation.

• 40-64 years of age at the time of enrolment.

• Primarily (≥50% of competition) competes in an endurance type sport as defined by European Society of Cardiology 2020 guidelines.

• Competitive athlete*

• CHA2-DS2-VAsc =0/1 (excluding previous stroke).

  • Competitive athlete defined by having trained ≥10 years, 6 hours per week as a self-reported average and having participated in at least one competitive event at regional level or above.

Exclusion Criteria:

• History of pre-existing cardiovascular disease
• Previous myocardial infarction, peripheral arterial disease
• Left ventricular systolic dysfunction (EF <45%)
• Heart muscle disease
• Complex congenital heart disease.
• Moderate or severe valvular disease.
• Uncontrolled hypertension (180/100mmHg)
• Clotting or bleeding disorders, vasculitis
• Inherited cerebral disease
• Known to have an estimated glomerular filtration rate <30 ml/min/1.73m2.