Ventricular-vascular coupling at rest and immediately following maximal exercise in adults with and without multiple...

Multiple sclerosis (MS) may impair ventricular-vascular coupling (VVC), a measure of the interaction between the cardiac and vascular systems. We evaluated if VVC differed between individuals with and without MS with similar age-predicted fitness. Individuals with MS (n = 20) and without (CON, n = 18) underwent VVC measurement before and immediately after a maximal incremental cycle test with peak oxygen consumption (VO₂peak) measurement. VVC was quantified as the ratio of arterial elastance (E_A: end-systolic pressure (ESP)/stroke volume) to ventricular elastance (E_LV: ESP/end-systolic volume). ESP was assessed with radial applanation tonometry, and cardiac volumes were obtained from apical four-chamber echocardiography. Sex, BMI and VO₂peak were not different between groups. Individuals with MS were older, had higher E_A (p < 0.01) and E_LV (p = 0.02), but VVC did not differ between groups. After adjustment for age, the group differences in E_A and E_LV remained significant. VVC was similar between individuals with and without MS, before and immediately after maximal exercise. However, individuals with MS had higher E_A and E_LV, suggesting higher arterial and ventricular loads. Our data suggest that individuals with MS with similar fitness to controls exhibit higher E_A and E_LV with preserved coupling.