Benign clinical significance of J-wave pattern (early repolarization) in highly trained athletes

Background

J wave/QRS slurring (early repolarization) on 12-lead ECG has been associated with increased risk for ventricular fibrillation in the absence of cardiovascular (CV) disease.

Objective

The purpose of this study was to assess the prevalence and clinical significance of J wave/QRS slurring in a large population of competitive athletes.

Methods

Seven hundred four athletes (436 males [62%], age 25 ± 5 years) free of CV disease who had engaged in 30 different sports were examined. Serial clinical, ECG, and echocardiographic evaluations were available over 1 to 18 years of follow-up (mean 6 ± 4 years).

Results

J wave was found in 102 athletes (14%) and was associated with QRS slurring in 32 (4%). It was found most commonly in anterior, lateral, and inferior leads (n = 73 [72%]), occasionally in lateral leads (n = 26 [25%]), and rarely in inferior leads (n = 3 [3%]). Most of 102 athletes (n = 86 [84%]) also showed ST-segment elevation. J wave/QRS slurring was associated with other training-related ECG changes (ie, increased R/S-wave voltages in 76%) and left ventricular (LV) morphologic remodeling (LV mass 199 ± 48 g vs 188 ± 56 g, P <.05). During follow-up, no athlete with J wave experienced cardiac event or ventricular tachyarrhythmias, or developed structural CV disease.

Conclusion

In athletes, early repolarization pattern usually is associated with other ECG changes, such as increased QRS voltages and ST-segment elevation, as well as LV remodeling, suggesting that it likely represents another benign expression of the physiologic athlete’s heart. J wave (early repolarization) is common in highly trained athletes and does not convey risk for adverse cardiac events, including sudden death or tachyarrhythmias.

Introduction

Over the past several years, interest has heightened regarding the etiology and mechanisms of sudden cardiac death in young athletes, with attention directed toward strategies capable of identifying individuals at risk due to underlying (but otherwise unsuspected) cardiovascular (CV) diseases.¹ In particular, the 12-lead ECG has been promoted as a test to screen large populations of competitive athletes for timely detection of such conditions² and currently is part of the screening protocol advised by scientific societies (European Society of Cardiology [ESC]) and sports governing bodies (International Olympic Committee [IOC], Fédération Internationale de Football Association [FIFA]).3, 4 However, in trained athletes, ECG patterns show a variety of alterations that can overlap with or mimic those observed in patients with pathologic cardiac conditions.5, 6 Therefore, accurate interpretation of ECG patterns in trained athletes, which often proves challenging, represents a current scientific priority, particularly with regard to broad-based population screening.⁷

Specifically, the early repolarization pattern consisting of J wave (ie, positive deflection inscribed in the terminal S wave) and QRS slurring (at the transition from QRS to ST segment), with or without associated ST-segment elevation8, 9 has been reported as the sole ECG alteration in some patients vulnerable to ventricular fibrillation (VF), even in the absence of cardiac disease, raising concern that these ECG patterns are potential markers for increased vulnerability to cardiac arrest.8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19

This association of J wave (and QRS slurring) with the incidence of VF is concerning to the sporting community, given that early repolarization occurs not uncommonly in apparently healthy individuals, including trained athletes.20, 21, 22, 23 At present, uncertainty persists regarding the clinical significance and appropriate management of young active individuals presenting with this unique ECG pattern, and particularly its potential impact in the setting of athlete preparticipation CV screening.²⁴ The present investigation addresses this unresolved issue by assessing the clinical correlates and outcome of a large population of young athletes free of CV disease with or without early repolarization pattern, engaged at the elite level in a wide variety of competitive sports.