Is Endurance Training Harmful to Older Athletes in the Long Run? An Interesting Case of Exercise-Induced Ventricular Tachycardia

There is limited data on how endurance training can impact cardiac function and arrhythmogenesis. Intense endurance training has been associated with pathological remodeling of the right ventricle (RV) that can act as a substrate for fatal ventricular arrhythmias in older athletes. A previously healthy 63-year-old female marathon runner presented with symptomatic monomorphic ventricular tachycardia (VT) while exercising. Transthoracic echocardiogram (TTE) demonstrated no structural or functional abnormalities. Electrophysiology study (EPS) with three-dimensional mapping and programmed electrical stimulation was performed demonstrating significant scarring of the RV, including RV outflow tract and RV free wall. VT ablation was successfully performed. Unfortunately, exclusion of arrhythmogenic right ventricular cardiomyopathy (ARVC) was limited due to the lack of cardiac magnetic resonance imaging (MRI). Therefore, a single chamber implantable cardioverter defibrillator (ICD) was placed for secondary prevention. Currently, the clinical significance of exercise-induced ventricular arrhythmias in trained athletes without cardiovascular disease is still unknown. This case highlights the need for investigation with larger studies and longer follow up to help us understand the mechanism of exercise-induced scar formation and standardize our management regarding screening, exercise recommendations, and ICD placement in older athletes.