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Background: Cardiovascular disease disproportionately affects North American Indigenous populations. Ethnic differences in cardiac responses to exercise are known, though Indigenous populations response is unknown. To evaluate cardiac responses to aerobic exercise among Canadian Indigenous and European adults. Methods: Indigenous (N = 12, 4 females, 1 male incomplete) and European (N = 12, all completed) Canadian age and sex-matched adults 19-40 years and free of cardiovascular disease or diabetes completed a cycle ergometer maximal aerobic power test and 30 min at 60% maximal aerobic capacity on two separate days. Echocardiographic assessments preceded and immediately followed exercise. Results: Responses to maximal exercise were similar among ethnicities including decreases in stroke volume index, cardiac output index and ejection fraction, and increases in arterial-ventricular coupling. However, following submaximal exercise, only Indigenous adults demonstrated reductions in end systolic volume, end diastolic volume (154.8 ± 40.6 mL to 136.5 ± 33.0 mL, p = 0.01, vs. 149.4 ± 22.4 mL to 147.1 ± 27.0 mL; p = 0.81), stroke volume index (44.9 ± 8.7 mL m−2 to 38.0 ± 6.5 mL m−2, p = 0.002, vs. 46.4 ± 7.1 mL m−2 to 44.0 ± 6.5 mL m−2; p = 0.28) and arterial compliance. Conclusion: Indigenous and European adults demonstrated similar cardiac responses to maximal exercise, though only Indigenous adults demonstrated cardiac responses to submaximal exercise. [ABSTRACT FROM AUTHOR]

Background: Hypertrophic cardiomyopathy (HCM) is usually associated with marked diastolic dysfunction, characterized by impaired myocardial relaxation and increased myocardial stiffness. The noninvasive evaluation of diastolic function in these patients remains a challenge since usual methods have shown a modest correlation with invasive measurements of left ventricular (LV) relaxation and filling pressures. Methods and Results: We retrospectively analyzed 44 patients with obstructive HCM who underwent cardiac catheterization and echocardiography performed within 48 hours. Standard echocardiographic diastolic parameters and systolic and diastolic myocardial mechanics (including longitudinal and circumferential strain [S] and strain rate [Sr]), LV rotation, and early reverse rotation rate (fraction of early apical reverse rotation [FEARR]) were correlated with diastolic hemodynamic indices. Estimated LA pressure by echo and the LV end-diastolic pressure (LVEDP) or the LV pre-A pressure did not correlate. Longitudinal strain was low and circumferential strain was abnormally higher than normal. FEARR and negative dp/dt inversely correlated (R =−0.57, P = 0.0001), and early diastolic Sr to systolic Sr ratio (SrE/SrS) correlated with the LVEDP (r = 0.61, P < 0.0001). Furthermore, a SrE to SrS ratio ≥0.79 had a sensitivity of 87% and a specificity of 75% for predicting elevated LVEDP (≥15 mmHg). Average circumferential strain rate during atrial contraction and LV pre-A pressure (r =−0.62, P < 0.001) inversely correlated. Conclusions: FEARR is decreased in HCM and appears to be a good measure of diastolic dysfunction. Myocardial mechanics can be used to assess LV relaxation and filling pressures in patients with obstructive HCM. [ABSTRACT FROM AUTHOR]

Objectives: Anderson-Fabry disease (AFD) is a lysosomal storage disease, which can involve the heart, mimicking hypertrophic cardiomyopathy (HCM). The underlying mechanism of disease in AFD is an infiltrative, diffuse process, whereas HCM is a primary heart muscle condition with patchy distribution, which may prompt differences in myocardial mechanics. The aim of this study was to assess myocardial mechanics in AFD according to the presence of left ventricular hypertrophy (LVH) compared to nonobstructive HCM (NHCM) and healthy controls. Methods and Results: We carried out a single-center, retrospective study in a small, genetically confirmed AFD cohort, which was divided into a subgroup with LVH (LVH+, n = 19), and without LVH (LVH-, n = 21). Comparison groups were healthy controls (n = 40) and NHCM patients (n = 19). Vector Velocity Imaging was applied to two-dimensional echocardiography studies for assessment of longitudinal strain (LS), circumferential strain (CS), and base-to-apex CS gradients. AFD LVH+ patients had lower global LS than AFD LVH- patients (-14 ± 4% vs -17 ± 3%, P < 0.05), but similarly lowered global CS (-24 ± 5% vs -22 ± 5%, P = ns). AFD LVH+ and NHCM had similarly lowered global LS compared to normals, but significantly lower global CS was observed in AFD LVH+ (-24 ± 5% vs -28 ± 4%, P < 0.05), whereas it was significantly increased in NHCM (-31 ± 2% vs -28 ± 4%, P < 0.05). Unlike NHCM, in both AFD subgroups, patients lost their normal base-to-apex CS gradient. Conclusions: AFD patients without LVH already show abnormal systolic myocardial mechanics. Relevant differences in myocardial mechanics between AFD patients with LVH compared to NHCM reflect the different underlying mechanisms of disease. [ABSTRACT FROM AUTHOR]