Myocardial Fibrosis Linked to Ventricular Arrhythmia in Male Endurance Athletes

TUESDAY, July 22, 2025 (HealthDay News) — Myocardial fibrosis is independently associated with the onset of ventricular arrhythmia in male veteran endurance athletes, according to a study published online July 17 in Circulation: Cardiovascular Imaging.

Wasim Javed, Ph.D., from the University of Leeds/Leeds Teaching Hospitals National Health Service Trust in the United Kingdom, and colleagues conducted a prospective observational cohort study involving 106 asymptomatic male competitive cyclists/triathletes (aged 50 years and older) who undertook ≥10 hours/week of exercise over 15 years or more to examine whether myocardial fibrosis on cardiovascular magnetic resonance is associated with incident ventricular arrhythmia.

The researchers found that on cardiovascular magnetic resonance, 47.2 percent of athletes had focal myocardial fibrosis (all nonischemic distribution), predominantly affecting the basal inferolateral left ventricular segment. During follow-up (median, 720 days), 21.7 percent of athletes experienced one or more ventricular arrhythmic episodes: 2.8 percent had sustained ventricular tachycardia, and 18.9 percent had nonsustained ventricular tachycardia. An increased risk for incident ventricular arrhythmia was seen in association with myocardial fibrosis and greater left ventricular end-diastolic volume indexed (hazard ratios, 4.7 and 1.4, respectively), but there was no association for right ventricular insertion point late gadolinium enhancement. After adjustment for left ventricular end-diastolic volume indexed, myocardial fibrosis remained predictive (hazard ratio, 4.7).

“After adjusting for left ventricular dilatation, which to a lesser extent was also associated with ventricular arrhythmia, fibrosis remained significantly associated with ventricular arrhythmia,” the authors write.

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