Working Diagnosis:
Paroxysmal narrow-complex tachyarrhythmia due to atrioventricular nodal re-entrant tachycardia, typical slow-fast variant.

Treatment:
Slow pathway radiofrequency catheter ablation was performed in September 2025. Mapping of the triangle of Koch was performed using a SmartTouch catheter with slow pathway potential identification and collision mapping. Radiofrequency energy was applied at 25 to 30 watts at the mid-coronary sinus and tricuspid valve level.
Junctional ectopy with 1:1 ventriculoatrial conduction confirmed slow pathway modification. No atrioventricular block occurred. Post-ablation testing demonstrated normal conduction intervals and non-inducibility. The patient was discharged the same day without complications.

Outcome:
Recovery was uncomplicated. A seven-day Zio patch worn after ablation demonstrated no recurrent supraventricular tachycardia, no atrial fibrillation, no atrioventricular block, and no significant pauses. All 12 patient-triggered events corresponded to sinus tachycardia or rare benign ectopy.
Case Photo #4
The patient reported steady improvement in exercise tolerance and was cleared for full competitive rowing by the sports medicine and electrophysiology attendings following objective confirmation of non-recurrence. No pharmacotherapy was required after ablation. Return to sport followed a rowing-specific protocol: two weeks of rest and wound healing, followed by supervised ergometer training with heart rate monitoring, then graded return to on-water rowing with chase launch oversight and stimulant avoidance.

Author's Comments:
This case illustrates how paroxysmal supraventricular tachycardia can remain undetected for years in a young athlete before a high-rate episode drives formal evaluation. Wearable heart rate data was the pivotal diagnostic signal, providing objective evidence of a 230 beats per minute event that directed the entire workup and should not be dismissed in the clinical setting. Endurance training augments resting vagal tone while sympathetic surges during high-intensity efforts facilitate atrioventricular nodal re-entry, creating a favorable substrate in competitive athletes. Radiofrequency ablation was selected in accordance with current guidelines supporting it as first-line therapy for symptomatic supraventricular tachycardia in athletes, given a cure rate exceeding 95 percent and an atrioventricular block risk below 1 percent. Rowing demands a sport-specific return-to-sport framework given the on-water environment, where rapid extraction is limited and hemodynamic stress is high; objective post-procedural monitoring rather than symptom reporting alone should guide clearance.

Editor's Comments:
Due to the fluctuating nature of paroxysmal supraventricular tachycardia, having a comprehensive workup is important in reaching diagnosis. This case demonstrates the importance of ambulatory monitoring in addition to history, physical exam and EKG to catch the arrhythmia. It also shows the ability for these athletes to return to sport after confirmation of no recurrence along with the guidelines established by the 2025 American Heart Association and the American College of Cardiology. Understanding that the most common symptom in these patients of palpitations will allow providers to detect this condition prior to any significant cardiac event.

References:
1. Page RL, Joglar JA, Caldwell MA, et al. 2015 ACC/AHA/HRS Guideline for the Management of Adult Patients With Supraventricular Tachycardia: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Circulation. 2016;133(14):e471-e505. doi:10.1161/CIR.0000000000000310
2. Lampert R, Chung EH, Ackerman MJ, et al. 2024 HRS expert consensus statement on arrhythmias in the athlete: Evaluation, treatment, and return to play. Heart Rhythm. 2024;21(10):e151-e252. doi:10.1016/j.hrthm.2024.05.018
3. Zipes DP, Link MS, Ackerman MJ, Kovacs RJ, Myerburg RJ, Estes NAM 3rd. Eligibility and Disqualification Recommendations for Competitive Athletes With Cardiovascular Abnormalities: Task Force 9: Arrhythmias and Conduction Defects: A Scientific Statement From the American Heart Association and American College of Cardiology. J Am Coll Cardiol. 2015;66(21):2412-2423. doi:10.1016/j.jacc.2015.09.041
4. Mohamoud A, Jensen J, Buda KG. Consumer-grade wearable cardiac monitors: What they do well, and what needs work. Cleve Clin J Med. 2024;91(1):23-29. Published 2024 Jan 2. doi:10.3949/ccjm.91a.23030
5. Pingitore A, Peruzzi M, Clarich SC, Palamà Z, Sciarra L, Cavarretta E. An overview of the electrocardiographic monitoring devices in sports cardiology: Between present and future. Clin Cardiol. 2023;46(9):1028-1037. doi:10.1002/clc.24073
6. Furlanello F, Bertoldi A, Inama G, Fernando F. Catheter ablation in competitive athletes: indication. J Interv Cardiol. 1995;8(6 Suppl):837-840. doi:10.1111/j.1540-8183.1995.tb00937.x

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