Abstract 19284: Clinical Determinants of Global and Regional Left Ventricular Systolic Function by Cardiac Magnetic Resonance Imaging: The Jackson Heart Study

Abstract

Introduction: Cardiac MRI (CMRI) provides high-resolution images, along with accurate and reproducible measurements of global and regional left ventricular (LV) systolic function (including LV ejection fraction, stroke volume, global and regional systolic strain). We examined the cross-sectional association of traditional cardiovascular (CV) risk factors with CMRI determined systolic function in a community-based cohort of African Americans (AAs).

Methods: We evaluated 1,322 Jackson Heart Study participants (63% women, mean age 57 years) who had MRI exams performed at Examination 2. Measures of LV systolic function included ejection fraction, stroke volume, global strain (considered the mean peak systolic midwall Eularian strain -averaged for the base, mid-ventricle and apex in all segments) and regional strain (averaged for the mid-ventricle or apex only). Clinical covariates included age, sex, systolic and diastolic BP, BMI, fasting glucose (FG), diabetes status (DM), lipids, smoking, alcohol use, hypertension (HTN) medication, lipid lowering medication, education and income. Multiple stepwise linear regression analysis was used to model the association of clinical covariates (independent variables) with global and regional measures of LV systolic function.

Results: Regression analysis demonstrated that LV ejection fraction was independently and positively associated with systolic BP (p= 0.0002) but inversely associated with male sex and FG (p < 0.0001 and p = 0.011 respectively). Stroke volume was independently and positively associated with male sex, systolic BP, and BMI (p < 0.001 for all) but inversely related to age, diastolic BP, and smoking (p= <0.01 for all). More optimal (more negative) global and mid wall systolic strain were inversely associated with older age, male sex, BMI, and smoking (all p <0.002). Lower (more optimal) apical strain was inversely associated with older age, male sex, HTN status, higher BMI, and smoking (p <0.02 for all) but was positively associated with DM (p= 0.049).

Conclusions: In our cross-sectional study of a large AA community-based cohort, we identified several modifiable CV risk factors (BP, BMI, FG, smoking) associated with global and regional measures of LV systolic function as assessed by CMRI.