Associations between Skeletal Muscle and Myocardium in Aging: A Syndrome of "Cardio-Sarcopenia"?

Objectives The link between skeletal muscle and heart disease remains intriguing. It is unknown how skeletal muscle may be associated with aspects of myocardial structure and function, particularly in the presence of aging-related sarcopenia. We hypothesize that among aging adults with sarcopenia, alterations in myocardial structure and/or function may exist, resulting in a syndrome of "cardio-sarcopenia." Methods Participants derived from a community cohort study underwent same-day bioimpedance body composition analysis that measured skeletal muscle in sites such as the trunk, upper limb, and lower limb, and echocardiography for assessment of myocardial structure and function. Sarcopenia was diagnosed using the Asian Working Group for Sarcopenia criteria. Results We studied a total of 378 participants, of whom 88 (23.3%) had sarcopenia. Participants with sarcopenia had smaller left ventricular (LV) sizes (lower LV internal diameter end diastole (4.1 +/- .7 vs 4.5 +/- .6 cm; P < .0001), lower LV internal diameter end systole (2.3 +/- .5 vs 2.5 +/- .4 cm; P = .010), lower LV posterior wall end diastole (.7 +/- .1 vs .8 +/- .1 cm; P = .0036), and lower LV posterior wall end systole (1.4 +/- .3 vs 1.5 +/- .2 cm; P = .0031). Sarcopenic participants also had lower LV mass (106 +/- 35 vs 126 +/- 53; P = .0014) and lower left atrial (LA) volume (33 +/- 13 vs 36 +/- 13; P = .033). Adjusting for age and diabetes mellitus, skeletal muscle mass was associated with LV diameter (beta = .06; 95% confidence interval [CI] = .03-.09; P < .0001), LV mass (beta = 4.04; 95% CI = 1.78-6.29; P = .001), LA diameter (beta = .05; 95% CI = .01-.09; P = .007), and LA volume (beta = 1.26; 95% CI = .38-2.13; P = .005). A positive linear correlation was observed between LV mass and handgrip strength (r = .25; P < .0001). Conclusion Among a community sample of older adults with preserved heart function, sarcopenia is associated with reductions in LV and LA sizes. Skeletal muscle mass was independently associated with specific indices of myocardial structure.