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

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.

Morphogenetic aspects of the septomarginal trabecula in the human heart

INTRODUCTION

The septomarginal trabecula is a constant element of the anatomy of the human heart, which connects the interventricular septum and the anterior wall of the right ventricle. Considering the diversity of opinions about the structure and numerous studies suggesting its important role in haemodynamics and conduction of electrical impulses in the heart, we decided to study this element in detail.

MATERIAL AND METHODS

The research was conducted on 220 human hearts. Attention was mainly paid to the structure and topography of the trabecula. Its relation to the anterior papillary muscle was also a part of the study.

RESULTS

The presence of this morphologically diverse element was confirmed in each of the studied hearts. In most cases the trabecula originated from the upper part of the interventricular septum, separating at an angle increasing proportionally to the number of branches of the crista supraventricularis as well as the number of secondary trabeculae. The criteria established for the study, which included the course of the trabecula in the lumen of the right ventricle and its relation to the anterior papillary muscle, let us distinguish 4 types of septomarginal trabecula (I, II, III, IV). The most common was type III, the undivided trabecula, tightly connecting with the anterior papillary muscle.

CONCLUSIONS

Based on the results of the following study we propose a hypothesis on the genesis of respective parts of the septomarginal trabecula and a plausible sequence of changes they undergo during human ontogenesis and phylogenesis of the primates.