Scarring in veteran male athlete’s hearts linked to risk of dangerous heart rhythms, study suggests

The study, led by a team at the University of Leeds, suggests that male endurance athletes who have spent decades training and competing are more likely to have scarring in their hearts than non-athletes.  

 

Athletes with scarring were over 4.5 times more likely to experience an abnormal heart rhythm episode – which is linked with an increased risk of sudden cardiac arrest – compared to those without scarring, the findings suggest. 

Dr Peter Swoboda, Associate Professor in Cardiology and Consultant Cardiologist at the University of Leeds, led the study. He said: “In our study, the athletes who experienced dangerous heart rhythms often had symptoms first. I’d encourage anyone who experiences blackouts, dizziness, chest pain or breathlessness, whether during sport or at rest, to speak to their doctor and get it checked out.  

 

“These results shouldn’t put people off regular exercise. Our study focused on a very select group, and not all the athletes involved were found to have scarring in their hearts. We can all benefit from being more active, and this study is an important step towards helping people take part in sport as safely as possible.” 

 

Scarring is seen in many heart conditions, and in recent years studies have shown that some lifelong endurance athletes – particularly older men – have scarring in their hearts. It’s thought this could be caused by their levels of exercise, as during endurance sports like long-distance running and cycling, the heart has to work even harder to pump blood. 

 

But, as these athletes often don’t have any other symptoms of heart problems, doctors were not previously certain what this meant for their health. 

The new study involved 106 healthy male endurance athletes, aged over 50, without symptoms or a diagnosis of cardiovascular disease. Everyone involved was a competitive cyclist or triathlete, who had been exercising for 10 or more hours every week for at least 15 years. Many still competed at a local, national or international level. 

Scans showed that 50 of the athletes (47 per cent) had scarring in their hearts, most commonly in the bottom of their left ventricle – the main pumping chamber. Athletes with scarring were on average slightly older (61.8 years compared with 57.0 years). 

 

This was more than four times higher than in a group of non-athletes, matched for age and sex, who took part in up to three hours of exercise per week. Only 11 per cent of this group (three of 27) had signs of scarring in their hearts.  

During the two-year study, more than a fifth of the endurance athletes (23 of 106) had at least one episode of ventricular tachycardia. Of these, most (78 per cent) had evidence of scarring in their hearts on MRI scans. 

 

Three athletes had one or more episodes of sustained ventricular tachycardia (lasting longer than 30 seconds) which in certain circumstances can be life threatening. All three were previously found to have scarring in their hearts. 

Ongoing research is expanding this study into female endurance athletes, to investigate whether they also experience scarring and an increased risk of abnormal heart rhythms. 

 

Dr Sonya Babu-Narayan, our Clinical Director and consultant cardiologist, said: “There’s no doubt that exercise is good for our hearts. It helps to reduce blood pressure and cholesterol, manage our weight, and it boosts our mental health. But in some veteran male athletes, this early research suggests that intense exercise over many years may have affected their heart health.  

 

“More research in veteran endurance athletes – both in men and women – will be needed to identify the small number of people who have the kind of heart scarring, together with other risk factors, that mean their life could be saved by having an implantable defibrillator.”