Cardiac structure and function in elite Native Hawaiian and Pacific Islander Rugby Football League athletes: an exploratory study

Abstract

The aim of this exploratory study was to define the Athletes Heart (AH) phenotype in Native Hawaiian & Pacific Islander (NH&PI) Rugby Football League (RFL) athletes. Specifically, (1) to describe conventional echocardiographic indices of left ventricle (LV) and right ventricle (RV) structure and function in NH&PI RFL players and matched RFL Caucasian controls (CC) and (2) to demonstrate LV and RV mechanics in these populations. Ethnicity is a contributory factor to the phenotypical expression of the AH. There are no data describing the cardiac phenotype in NH&PI athletes. Twenty-one male elite NH&PI RFL athletes were evaluated using conventional echocardiography and myocardial speckle tracking, allowing the assessment of global longitudinal strain (ε) and strain rate (SR); and basal, mid and global radial and circumferential ε and SR. Basal and apical rotation and twist were also assessed. Results were compared with age-matched Caucasian counterparts (CC; n = 21). LV mass [42 ± 9 versus 37 ± 4 g/(m^2.7)], mean LV wall thickness (MWT: 9.5 ± 0.7 and 8.7 ± 0.4 mm), relative wall thickness (RWT: 0.35 ± 0.04 and 0.31 ± 0.03) and RV wall thickness (5 ± 1 and 4 ± 1 mm, all p < 0.05) were greater in NH&PI compared with CC. LV and RV cavity dimensions and standard indices of LV and RV systolic and diastolic function were similar between groups. NH&PI demonstrated reduced peak LV mid circumferential ε and early diastolic SR, as well as reduced global radial ε. There was reduced basal rotation at 25-35% systole, reduced apical rotation at 25-40% and 60-100% systole and reduced twist at 85-95% systole in NH&PI athletes. There were no differences between the two groups in RV wall mechanics. When compared to Caucasian controls, NH&PI rugby players have a greater LV mass, MWT and RWT with concomitant reductions in circumferential and twist mechanics. This data acts to prompt further research in NH&PI athletes.

Keywords: Athletes heart; Echocardiography; Ethnicity; Left ventricle; Right ventricle; Strain imaging.

Fig. 1

Box plot demonstrating, a LV mass, b mean wall thickness, c relative wall thickness between NH&PI and CC

Fig. 2

Left ventricular longitudinal, mid circumferential, radial and right ventricular longitudinal ε and strain rate—grey area denotes statistical significance (p < 0.05). AVC Aortic valve closure, PVC pulmonary valve closure

Fig. 3

Left ventricular basal rotation, apical rotation and torsion—grey area denotes statistical significance (p < 0.05)

Fig. 4

Circumferential and radial mechanics