Abstract 4121348: Impairments in Left Atrioventricular Coupling Underpins Reductions in Skeletal Muscle Mass and Function in Ageing Older Adults

Background: Age-related cardiovascular disease (CVD) may manifest with changes in left ventricular (LV) systolic or left atrial (LA) dysfunction. Alterations in functional performance between the LV and LA chambers characterized by LA-LV coupling may be a sensitive marker representative of impairments in global cardiac performance, compared to either chamber alone. The increasing relevance of skeletal muscle function towards cardiac health in ageing, motivated our current work that investigated associations between skeletal muscle function and LA-LV coupling. Aim : Using advanced cardiac magnetic resonance (CMR) that characterizes cardiac volumetric parameters and strain functions, we determined the association between handgrip strength (HGS) and appendicular lean mass (ALM) with left atrioventricular coupling index (LACI). Methods: Community older adults without CVD underwent simultaneous assessment of HGS by hand dynamometer, height-square adjusted ALM by bio-impedance, and LA phasic function (namely reservoir, conduit, booster strain) as well as LA and LV volumetric parameters by CMR feature tracking. LACI is defined as the ratio of the ratio of LA to LV end-diastolic volumes. We performed linear regression and multivariable logistic regression to examine the relationship between HGS/ALM and LACI. Results: Among 251 study participants (mean age: 71 ± 9.1 years, female 44.7%), 149 (59%) had impaired LACI. HGS was linearly associated with LACI (β=-0.004, p=0.003) and LVEDV (β=1.62, p<0.0001), and ALM was linearly associated with LA volume (β=0.55, p=0.018) and LVEDV (β=3.45, p<0.0001) (Figure.1). Participants with impaired LACI (> 25%) had lower HGS (mean=22.8 ± 7.1 kg vs 26.1 ± 6.4 kg, p= 0.0002), lower ALM (16.4 ± 4.2 kg/m2 vs 17.7 ± 3.8 kg/m2, p=0.014), higher LA volume (36.8 ± 15.2 ml vs 22.0 ± 5.5 ml, p < 0.0001) and lower LV end-diastolic volume (101.0 ± 24.2 ml vs 111.9 ± 27.3 ml, p = 0.0011). The association between impaired LA-LV coupling and lower HGS (β=-0.0647, 95%CI -0.0255, -0.1040, p=0.001) and lower ALM (β=-0.0776, 95%CI -0.0107, -0.1444, p=0.011) persisted after adjusting for age. Conclusion: Reduced HGS and ALM among community-dwelling older adults was associated with impaired LA-LV coupling suggestive of underlying early-stage LA remodelling and impairments in left atrioventricular compliance. Detection of reduced HGS and ALM in community cohorts may prompt early identification of older adults at risk of dysfunctional cardiac aging.