Myocardial Fibrosis as a Pro-Arrhythmic Substrate in Veteran Male Endurance Athletes

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Data Quality: STRONG
Summary of   Journal of Preventive Cardiology https://doi.org/10.1093/eurjpc/zwag021 
Dr. Wasim Javed  et al.

Points

Researchers conducted a two year study of over one hundred veteran male athletes to investigate how chronic exercise levels and acute training sessions influence the development of dangerous heart rhythms.
Findings revealed that one in four participants experienced ventricular tachycardia during or immediately after exercise with seventy five percent of those individuals already possessing significant scarring within their heart tissue.
The study concluded that chronic training volume was not a risk factor for arrhythmia but acute intense exertion acts as a trigger for those with an underlying pro arrhythmic substrate.
All three cases of sustained and potentially fatal ventricular tachycardia occurred during active training sessions and every single one of those athletes was found to have preexisting myocardial fibrosis tissue.
Clinicians recommend that older male endurance athletes undergo regular cardiac health screenings to detect heart scarring which may otherwise remain asymptomatic until triggered by high intensity physical activity and training routines.

Summary

This study investigated the relationship between exercise training patterns and the incidence of ventricular arrhythmia in veteran male endurance athletes. The cohort consisted of 106 healthy males over age 50 who had performed more than 10 hours of running or cycling weekly for at least 15 years. Using implantable loop recorders synchronized with wearable activity trackers, the researchers monitored heart rhythms in real-time to determine if chronic exercise volume or acute intensity served as a primary driver for potentially fatal arrhythmias.

The findings demonstrated that approximately 25% of participants experienced ventricular tachycardia (VT) during the two-year study period. While the majority of these events were non-sustained ventricular tachycardia (NSVT), three cases of sustained VT occurred, all during active exercise. Critically, 75% of the athletes who developed these abnormal rhythms possessed preexisting myocardial fibrosis. The data indicated that while chronic exercise load was not associated with arrhythmia risk, acute physical exertion served as a specific trigger for those with underlying heart scarring.

The research highlights myocardial fibrosis as a pro-arrhythmic substrate in veteran athletes, often remaining asymptomatic until triggered by intense activity. Because nine in 10 sudden cardiac deaths during sport occur in older males, these results underscore the clinical necessity of regular cardiac screenings for this demographic. Integrating long-term wearable data with clinical rhythm monitoring provides a framework for personalized health management, allowing athletes with identified scarring to moderate intensity and reduce the risk of sudden cardiac complications.

Link to the article: https://academic.oup.com/eurjpc/advance-article/doi/10.1093/eurjpc/zwag021/8417747?login=false

References

Javed, W., Brown, B., Chambers, B., Levelt, E., Graham, L., Greenwood, J. P., Plein, S., & Swoboda, P. P. (2026). The timing and relationship of ventricular arrhythmia with exercise patterns in veteran male endurance athletes. European Journal of Preventive Cardiology, zwag021. https://doi.org/10.1093/eurjpc/zwag021