Ethnic differences in cardiac structure and function assessed by MRI in healthy South Asian and White European people: A UK Biobank Study

Abstract

Background: Echocardiographic studies indicate South Asian people have smaller ventricular volumes, lower mass and more concentric remodelling than White European people, but there are no data using cardiac MRI (CMR). We aimed to compare CMR quantified cardiac structure and function in White European and South Asian people.

Methods: Healthy White European and South Asian participants in the UK Biobank Imaging CMR sub-study were identified by excluding those with a history of cardiovascular disease, hypertension, obesity or diabetes. Ethnic groups were matched by age and sex. Cardiac volumes, mass and feature tracking strain were compared.

Results: 121 matched pairs (77 male/44 female, mean age 58 ± 8 years) of South Asian and White European participants were included. South Asian males and females had smaller absolute but not indexed left ventricular (LV) volumes, and smaller absolute and indexed right ventricular volumes, with lower absolute and indexed LV mass and lower LV mass:volume than White European participants. Although there were no differences in ventricular or atrial ejection fractions, LV global longitudinal strain was higher in South Asian females than White European females but not males, and global circumferential strain was higher in both male and South Asian females than White European females. Peak early diastolic strain rates were higher in South Asian versus White European males, but not different between South Asian and White European females.

Conclusions: Contrary to echocardiographic studies, South Asian participants in the UK Biobank study had less concentric remodelling and higher global circumferential strain than White European subjects. These findings emphasise the importance of sex- and ethnic- specific normal ranges for cardiac volumes and function.

Keywords: Cardiac MRI; Cardiac volumetry; Ethnic differences; Feature tracking; South Asian; Strain; White European.

Central illustration. Cardiac MRI-derived ethnic differences in chamber volumes, mass and function between matched South Asian and White Europeans from the UK Biobank Imaging sub-study. In particular, South Asian participants had lower LV mass:volume than WE participants, female but not male South Asian participants had smaller LA volumes than corresponding White European particiapnts, and despite similar LV EF, systolic strain and diastolic strain rates were lower in White European participants.

Fig. 1

Study profile detailing included participants.

Fig. 2

Left ventricular volumes and mass, stratified by sex and ethnicity.

Fig. 3

Right ventricular volumes, stratified by sex and ethnicity.

Fig. 4

Left ventricular systolic strain, stratified by sex and ethnicity.