Young athletes' ECG: Incomplete right bundle branch block vs crista supraventricularis pattern

Abstract

Background Incomplete right bundle branch block (IRBBB) is prevalent among athletes, but its etiology remains to be clearly elucidated and the commonly advocated mechanism, an intraventricular conduction delay, does not explain all cases. In the general population, an apparently similar phenomenon but with different pathophysiology and potential consequences, “crista supraventricularis pattern” (CSP, defined as QRS ≤ 100 ms, S wave <40 ms in I or V6 together with an RSR´ pattern in lead‐V1) has been described. Yet, this manifestation has not been studied in athletes. Given that IRBBB can be associated with some serious conditions (including Brugada syndrome, arrhythmogenic cardiomyopathy, or atrial septal defects) the differentiation between IRBB and CSP could enhance the accuracy of the pre‐participation screening (PPS). We thus aimed to determine the prevalence of CSP in young athletes. Methods Observational study of standard 12‐lead resting ECG in a cohort of children (5‐16 years) attending a PPS program (August 2018–May 2019). Results 6,401 children (mean ± SD age 11.2 ± 2.9 years, 99.2% Caucasian, 93.8% male, 97.2% soccer players) were studied. We found CSP in 850 participants (prevalence = 13.3% [95% confidence interval 12.5‐14.1]) whereas 553 (8.6%) had IRBBB. The proportion of athletes showing an S1S2S3 pattern was higher in those with CSP compared with the other QRS morphologies (P < .05). Conclusions CSP might have been overlooked in previous reports of sports PPS for children and misdiagnosed as IRBBB, as the proportion of the former condition was higher. Our findings might add useful information to improve the interpretation of the young athletes’ ECG and thus the diagnostic value of PPS.

The “V1 continuum” in the athletes’ ECG

“…Of note, the athletes in our study 3 were much younger than in the Ollitrault et al 2 study (mean age of 11 vs 27 years, respectively). Thus, several years of regular, intense exercise training are usually needed before ECG singularities appear, with the latter thus more prevalent in the more experienced young athletes 4 .…”

“…Our findings on the presence of the crista supraventricularis pattern (CSP, ie , QRS width ≤100 ms with an RSR morphology in lead V1 and a narrow S [≤40 ms] in I or V6) in young healthy athletes 3 might also reflect, at least partly, a sports‐induced RV remodeling. Remodeling of contiguous areas of the RV (such as the subpulmonic or outflow tract region) might indeed be among the numerous cardiac electromechanical adaptations to sports participation, which in turn can be reflected in ECG tracings as CSP or RSR’S’ patterns.…”

“…Remodeling of contiguous areas of the RV (such as the subpulmonic or outflow tract region) might indeed be among the numerous cardiac electromechanical adaptations to sports participation, which in turn can be reflected in ECG tracings as CSP or RSR’S’ patterns. In this regard, the fact that the athletic cohorts of both studies 2,3 showed a very narrow QRS ( ie , <100 ms) largely rules out the presence of a conduction delay in the His‐Purkinje network as the pathophysiologic substrate—instead of RV remodeling—for these two patterns.…”

The “V1 continuum” on the surface ECG of apparently healthy athletes

“…We read with great interest the recent publication by Diaz‐Gonzalez et al entitled “Young athletes’ ECG: incomplete right bundle branch block vs crista supraventricularis pattern” 1 . Long‐term exposition to intense training induces electrical and morphological remodeling of the heart.…”

“…We read with great interest the recent publication by Diaz-Gonzalez et al entitled "Young athletes' ECG: incomplete right bundle branch block vs crista supraventricularis pattern". 1 Long-term exposition to intense training induces electrical and morphological remodeling of the heart. The complex (patho)physiology of the athlete's heart remains elusive, especially concerning the right ventricle (RV) remodeling and in special populations such as young athletes (ie, <18 years old).…”