Characterization of biatrial sports adaption in a large, highly trained athletes cohort using feature tracking cardiac magnetic resonance
Authors: Juhasz V , Szabo L , Dohy Z , Balla D , Toth A , Suhai I F , Merkely B , Vago H 
Published: May 2023

Abstract

Funding Acknowledgements
Type of funding sources: Public grant(s) – National budget only. Main funding source(s): Project no. TKP2021-NKTA-46 has been implemented with the support provided by the Ministry of Innovation and Technology of Hungary from the National Research, Development and Innovation Fund, financed under the TKP2021-NKTA funding scheme. This project was also supported by a grant from the National Research, Development, and Innovation Office (NKFIH) of Hungary (K135076 to BM).

Introduction
Feature tracking strain analysis using cardiac magnetic resonance (CMR) imaging enables the appreciation of complex mechanics of the athlete’s heart without adding extra sequences and increasing image acquisition time.

Purpose
We evaluated the associations of the left (LA) and right atrial (RA) functional and strain parameters with sports activity and demographic characteristics in a large cohort of competitive athletes. We compared the athlete’s biatrial remodelling with healthy, sex-matched control subjects.

Methods
We performed a retrospective analysis on native CMR cine images acquired between 2009 and 2021. Standard two-chamber and four-chamber long-axis cine movies were analyzed using Medis Suite software. We excluded images with foreshortening or apparent planning flaw. Subjects were categorized into four groups based on their weekly training loads (&lt;6 hours, 6-10 hours, 11-20 hours and 21&lt; hours).

Results
We performed CMR on 510 subjects, of which 375 were highly trained athletes (median age 20 ys, IQR 16-25; 244 male). A group of 135 healthy volunteers [median (mdn) age 25 ys, IQR 23-28, 64 male] served as controls. Left atrial global longitudinal strain (GLS) was lower (p=.002) in athletes (mdn 41%) than in controls (mdn 43%), whereas RA GLS showed a more pronounced decrease (mdn 32% vs 43%, p&lt;.0001). Between male athletes and controls, LA global circumferential strain [(GCS), mdn 40% vs 47%, p=.0001], LA conduit (mdn 26% vs 28%, p=.025), RA GLS (mdn 31% vs 38%, p&lt;.0001), RA GCS (mdn 17% vs 20%, p=.024), RA booster (mdn 10% vs 9%, p&lt;.001) and RA conduit (mdn 21% vs 24%, p=.001) strain values showed a difference. Between female athletes and controls, RA GLS (mdn 34% vs 44%, p&lt;.0001), RA GCS (mdn 19% vs 29%, p&lt;.001), RA booster (mdn 9% vs 13%, p=.006), and RA conduit (mdn 25% vs 32%, p&lt;.001) were significantly different, while LA strain values were comparable. We found a significant difference between male and female athletes in terms of LA GLS (mdn 39%, vs 43%, p=.0001), LA GCS (mdn 40% vs 42%, p=.01) and LA conduit strain (mdn 26% vs 29%, p&lt;.001). Regarding the right atrium, GLS (mdn 31% vs 34%, p=.047) and conduit strain (mdn 21% vs 25%, p=.004) were significantly lower in male athletes.
LA GLS only differed between the lowest and highest training volumes (p=0.048). LA GCS was higher in the least trained group (p&lt;.001) than in the other three categories.
Interestingly, the LA end-diastolic volume index was less (r=0.13, p=0.008) correlated to weekly training volume than the left ventricular end-diastolic volume index (r=0.51, p&lt;.0001).

Conclusion
The atrial adaptation of the athlete’s heart shows distinct mechanic properties, which are further stratified with exercise level and sex. The RA seems to be more prone to increasing exercise load than the LA. Sophisticated atrial function characterization by strain analysis might provide novel insight into healthy sports adaptation.