Abstract 1752: Age-Related Differences in Left Ventricular Structure and Function: The Multi-Ethnic Study of Atherosclerosis
Background: Age-related alterations in LV structure and function that may predispose to myocardial dysfunction are not completely understood. We examined the association between older age and indices of LV remodeling in asymptomatic participants of the Multi-Ethnic Study of Atherosclerosis.
Methods: We used cardiac MRI to measure LV indices in 5004 participants free of CV disease (ages 45–84) and representing 4 racial/ethnic groups (non-Hispanic white, black, Hispanic, and Chinese); 1099 participants received additional strain analyses. We used linear regression to assess the association between age and LV indices while adjusting for multiple variables, including traditional CV risk factors.
Results: Absolute LV mass decreased with age, but this effect was attenuated when mass was indexed to body size (Table⇓). However, age was associated with markedly increased mass-to-volume (M/V) ratio (50 mg/mL per decade, p<0.001); this was driven by a substantial reduction in LV end-diastolic volume with older age, a trend that remained significant after indexing volume to body size and adjusting for CV risk factors. Older age was also independently associated with increased ejection fraction but decreased stroke volume and, importantly, with reduced peak systolic strain and strain rate as well as decreased diastolic strain rate.
Conclusion: Older age is associated with increased M/V ratio, driven not by increased LV mass but by decreased LV volumes. This age-related remodeling is independently associated with asymptomatic systolic and diastolic myocardial dysfunction and progressively reduced stroke volume in the face of maintained chamber systolic performance indexed by ejection fraction. These data indicate that aging itself confers alterations in LV structure and function that predispose to reduced cardiac output and limited circulatory reserve in the presence of preserved ejection fraction.