Isolated Subepicardial RVOT Scar in Athletes With VT
Can electroanatomical scar pattern in patients with sustained ventricular tachycardia (VT) distinguish exercise-induced arrhythmogenic remodeling from arrhythmogenic right ventricular cardiomyopathy (ARVC) and post-inflammatory cardiomyopathy?
In 57 consecutive patients (48 ± 16 years, 83% male) undergoing catheter ablation for scar-related RV VT, two distinct scar distributions were identified: 1) scar involving the subtricuspid RV in 46 patients (group A), and 2) scar restricted to the anterior subepicardial RV outflow tract (RVOT) in 11 patients (group B).
Definite ARVC or post-inflammatory cardiomyopathy was diagnosed in 40 of 46 (87%) group A patients, but in none of group B patients. All group B patients performed intensive endurance training for a median of 15 hours/week for a median of 13 years. Catheter ablation resulted in complete procedural success in 10 of 11 (91%) group B patients compared with 26 of 46 (57%) group A patients (p = 0.034). During a median follow-up of 27 months, 50% of group A patients and none of group B had VT recurrence.
The authors have identified a novel clinical entity of an isolated subepicardial RVOT scar serving as substrate for fast VT in high-level endurance athletes. This scar pattern may allow distinguishing exercise-induced arrhythmogenic remodeling from ARVC and post-inflammatory cardiomyopathy.
Athletes who train intensely are at risk of RV dysfunction, and intense physical conditioning is ill advised in patients with ARVC. The pattern of electroanatomic substrate observed during an electrophysiologic study by taking multiple endocardial voltage points throughout the right ventricle may be able to differentiate patients with ARVC and inflammatory cardiomyopathy, whose substrates are usually subtricuspid, and an isolated subepicardial RVOT scar, exclusively observed in endurance athletes. The ability to differentiate ARVC and post-inflammatory cardiomyopathy from exercise-induced arrhythmogenic remodeling has significant prognostic implications. The isolated subepicardial substrate can be successfully ablated epicardially. It appears that cardiac magnetic resonance imaging with gadolinium contrast may not be sensitive enough to detect this subepicardial scar in athletes. Interestingly, anterior subepicardial RVOT scar has also been described in patients with Brugada syndrome and Brugada-type electrocardiograms.
Clinical Topics: Arrhythmias and Clinical EP, Diabetes and Cardiometabolic Disease, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Sports and Exercise Cardiology, Implantable Devices, Genetic Arrhythmic Conditions, SCD/Ventricular Arrhythmias, Atrial Fibrillation/Supraventricular Arrhythmias, Magnetic Resonance Imaging, Exercise, Sports and Exercise and Imaging
Keywords: Arrhythmias, Cardiac, Arrhythmogenic Right Ventricular Dysplasia, Athletes, Brugada Syndrome, Catheter Ablation, Electrocardiography, Electrophysiologic Techniques, Cardiac, Endocardium, Exercise, Magnetic Resonance Imaging, Physical Endurance, Tachycardia, Ventricular
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