Cumulative exposure to DM or higher IR beginning in early adulthood adversely impacts LV remodeling and function at middle age.

Objectives We investigated the relationship of body mass index (BMI) and its 25-year change to left ventricular (LV) structure and function. Background Longstanding obesity may be associated with clinical cardiac dysfunction and heart failure. Whether obesity relates to cardiac dysfunction during young adulthood and middle age has not been investigated. Methods The Coronary Artery Risk Development in Young Adults (CARDIA) enrolled white and black adults aged 18-30 years in 1985-86 (Year-0). At the Year-25, cardiac function was assessed by conventional echocardiography, tissue Doppler imaging (TDI), and speckle tracking echocardiography (STE). Twenty-five year change in BMI (classified as Low:<27 Kg/m2 and High:≥27 Kg/m2) was categorized into four groups (Low-Low, High-Low, Low-High, and High-High). Multiple linear regression was used to quantify the association between categorical changes in BMI (Low-Low as reference) with LV structural and functional parameters obtained in middle age, adjusting for baseline and 25-year change in risk factors. Results The mean BMI was 24.4 kg/m2 in 3,265 participants included at Year-0. Change in BMI adjusted for risk factors was directly associated with incipient myocardial systolic dysfunction assessed by STE (High-High:β-coefficient=0.67; Low-High:β-coefficient=0.35 for longitudinal peak-systolic strain) and diastolic dysfunction assessed by TDI (High-High:β-coefficient=-074; Low-High:β-coefficient=-0.45 for e′) and STE (High-High:β-coefficient= -0.06 for circumferential early-diastolic strain rate). Greater BMI was also significantly associated with increased LV mass/height (High-High:β-coefficient=26.11; Low-High:β-coefficient=11.87). Conclusions Longstanding obesity from young adulthood to middle age is associated with impaired LV systolic and diastolic function assessed by conventional echocardiography, TDI, and STE in a large bi-racial cohort of adults aged 43-55 years.

Objectives To define the mechanism of preserved ejection fraction (EF) despite depressed myocardial strains in hypertension (HTN). Background Concentric left ventricular (LV) remodeling in HTN may have normal or supra-normal EF despite depressed myocardial strains. The reason for such discordance is not clear. The aim of this study was to comprehensively evaluate the LV mechanics in a well defined HTN population to define underlying reasons for such a paradox. Methods 67 patients with resistant HTN and 45 healthy control subjects were studied by cardiac magnetic resonance imaging and tissue tagging with 3-dimensional analysis. Amplitude and directional vector of longitudinal (Ell), circumferential (Ecc) and principal strain for maximal shortening (E3) were computed at basal, mid and distal LV levels respectively. LV torsion defined as the rotation angle of apex relative to base and LV twist which accounts for the effects of differential LV remodeling on torsion for comparison among the two groups, were also calculated. Results LV mass index and LV mass/LV end diastolic volume ratio were significantly higher in HTN compared to controls consistent with concentric LV remodeling. Ell and Ecc were significantly decreased in amplitude with altered directional vector in HTN compared to controls. However, the amplitude of E3 was similar in the two groups. Torsion and twist were significantly higher in HTN, which was mainly due to increase in apical rotation. HTN demonstrated significantly increased LV wall thickening compared to controls that resulted in greater LVEF in HTN compared to controls (70 vs. 65%, P <0.001 respectively). Conclusions In compensated LV remodeling secondary to HTN, there is increased LV wall thickening with preserved E3 and increased torsion compared to normal controls. This, therefore, contributes to supra-normal LVEF fraction in HTN despite depressed longitudinal and circumferential strains.

Background Tagged cardiac magnetic resonance (CMR) provides detailed information on regional myocardial function and mechanical behavior. T1 mapping by CMR allows non-invasive quantification of myocardial extracellular expansion (ECE) which has been related to interstitial fibrosis in previous clinical and sub-clinical studies. We assessed gender associated differences in the relation of ECE to LV remodeling and myocardial systolic and diastolic deformation in a large community based multi-ethnic population. Methods and Results Mid-ventricular mid-wall peak circumferential shortening and early diastolic strain rate (EDSR); LV torsion and torsional recoil rate were determined using CMR tagging. Mid ventricular short axis T1 maps were acquired in the same examination pre and post-contrast injection using Modified Look-Locker Inversion Recovery sequence (MOLLI). Multivariable linear regression (B= estimated regression coefficient) was used to adjust for risk factors and sub-clinical disease measures. Of 1230 participants, 114 participants had visible myocardial scar by late gadolinium enhancement. Participants without visible myocardial scar (n=1116) had no previous history of clinical events. In the latter group, multivariable linear regression demonstrated that lower post-contrast T1 times, reflecting greater ECE were associated with lower circumferential shortening (B=−0.1, p=0.0001), lower end diastolic volume index (LVEDVi) (B=0.6, p=0.0001) and lower LV end diastolic mass index (LVMi) (B=0.4, p=0.0001). In addition, lower post-contrast T1 times were associated with lower EDSR (B=0.01, p=0.03) in women only; and lower LV torsion (B=0.005, p=0.03) a lower LV ejection fraction (B=0.2, p=0.01) in men only. Conclusions Greater ECE is associated with reduced LVEDVi and LVMi in a large multi-ethnic population without history of previous cardiovascular events. In addition, greater ECE is associated with reduced circumferential shortening, lower EDSR, and a preserved ejection fraction in women; while in men, greater ECE is associated with greater LV dysfunction manifested as reduced circumferential shortening, reduced LV Torsion and reduced ejection fraction.