CARDIOVASCULAR JOURNAL OF AFRICA • Volume 35, No 1, January – April 2024 44 AFRICA Right atrial strain in a normal adult African population according to age Nyange Mushitu, Ruchika Meel Abstract Background: Right atrial longitudinal strain (RALS) is a useful parameter to define right atrial (RA) subclinical dysfunction prior to changes in RA dimension and volume. We sought to establish normal values for RALS in a subSaharan African population. Methods: This was a retrospective, cross-sectional study from 2017 to 2019 of 100 normal individuals. All echocardiographic measurements were done as per the standard guidelines. Results: Mean RALS was 32.7 ± 10.5%. The mean RA volume indexed to body surface area was 19.5 ± 5.7 ml/m2. There was a negative correlation between RALS and age but it was not statistically significant (r = –0.15, p = 0.129). Males had a tendency towards higher RA volume indexed and RALS measurements compared to females (20.8 ± 6.3 and 18.7 ± 5.2 ml/m2, p = 0.07; 34.6 ± 9.6 and 31.4 ± 10.9%, p = 0.141, respectively). Body mass index was an independent predictor of RALS (r = –0.43, p = 0.003). Conclusion: We have provided normative data for RALS in an African population. This study provides a platform for future larger studies on RALS. Keywords: right atrium, right atrial longitudinal strain, age, African, echocardiography Submitted 25/2/22, accepted 7/2/23 Published online 31/5/23 Cardiovasc J Afr 2024; 35: 44–51 www.cvja.co.za DOI: 10.5830/CVJA-2023-004 In the last 20 years, there has been great interest in research on right atrial (RA) function, because recent data have demonstrated that assessment of RA volumetric parameters on echocardiography is an essential predictor of morbidity and mortality in various cardiovascular disorders.1-3 There are several imaging studies that have described RA anatomy and function. RA dimensions, volume and strain have been studied using the gold standard, cardiac magnetic resonance (CMR), computed tomography, echocardiography (two- and three-dimensional) and recently speckle-tracking echocardiography (STE). Two-dimensional echocardiography (2DE) has become the most clinically relevant non-invasive technique for evaluating the right atrium.4-6 It is important to define normative values of RA strain using 2DE, because RA subclinical dysfunction, as measured by strain, has been observed in several cardiovascular disorders prior to changes in the traditional indices of RA and right ventricular (RV) function such as volume, size and ejection fraction. Such cardiovascular disorders include pulmonary arterial hypertension (PAH), coronary artery disease (CAD) and heart failure with reduced ejection fraction (HFrEF). RA strain had additive prognostic value to other clinical measures, including RV strain, RA area and RA pressure in patients with PAH.7-11 The difference between normal and abnormal RA dimension and function is therefore clinically pertinent. Most of the available studies on the parameters of RA dimension in a normal population depend on data from North America and Europe and are in line with the guidelines of the American Society of Echocardiography (ASE) and European Society of Cardiology (ESC).12-15 These values do not effectively represent the diverse racial and ethnic groups of the world. The study by Soulat-Dufour et al. with the World Alliance Societies of Echocardiography (WASE) have suggested that there might be significant differences in normal values among different populations.16 Currently, limited data exist regarding RA volume (RAV), size and strain in a normal black African adult population. Age-related changes in vascular and cardiac function contribute to cardiovascular mortality. Aging is associated with abnormalities in left-sided functional parameters. However, studies on age-related changes in right-sided functional parameters are scarce.17-19 Therefore, in this study, we sought to establish normal values for RAV and RA longitudinal strain (RALS), and its correlation with age, in a sub-Saharan black African population, using 2DE and STE. Methods This study was a retrospective analysis of echocardiographic findings in healthy normal controls that formed part of a study (M170389) conducted at Chris Hani Baragwanath Academic Hospital (CHBAH). It is a secondary analysis of the data collected in these healthy controls. The study was approved by the University of the Witwatersrand ethics committee and conforms to the principles outlined in the Declaration of Helsinki. Permission to use data from the parent study was obtained. The study was approved by the Human Research Ethics Committee of the University of the Witwatersrand (clearance certificate number: M 200822). Echocardiograms were obtained according to a standardised protocol on a Phillips iE 33 ultrasound system (Amsterdam, The Netherlands) equipped with an S5-1 transducer that transmits Department of Internal Medicine, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa Nyange Mushitu, MB ChB, nyangemush@gmail.com Division of Cardiothoracic Surgery, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa Ruchika Meel, MB ChB, MMed, Cert Cardiology (SA), PhD, FEACVI, FESC, RuchikaMeel@gmail.com
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