Relationship of Cardiorespiratory Fitness and Adiposity With Left Ventricular Strain in Middle-Age Adults (from the Dallas Heart Study)

Low cardiorespiratory fitness (CRF) and obesity are significant risk factors for heart failure (HF). However, given the inverse association between CRF and obesity, the independent contributions of low CRF and adiposity toward HF risk are not well established. We evaluated the association of CRF and measures of adiposity with left ventricular (LV) peak systolic strain—a subclinical measure of LV dysfunction—among the Dallas Heart Study phase II participants without cardiovascular disease who had CRF estimated using a submaximal treadmill test and LV systolic circumferential strain assessment by tissue-tagged cardiac magnetic resonance imaging. Peak midwall systolic circumferential strain (Ecc) was determined by harmonic phase imaging. Associations of CRF and adiposity measures with Ecc were determined using adjusted linear regression analysis. A total of 1,617 participants were included in the analysis. After adjustment for baseline risk factors, higher waist circumference (WC) and lower CRF were associated with higher Ecc (WC: β = 0.07; p = 0.01; CRF: β = −0.17; p = < 0.0001), whereas % body fat and body mass index were not associated with Ecc. The relationship between WC and Ecc was attenuated completely after additional adjustment for CRF. In contrast, the association between CRF and Ecc did not attenuate after additional adjustment for WC and other measures of LV structure and function (β = −0.18; p = < 0.0001). Taken together, our study findings suggest that lower CRF, but not measures of adiposity, is associated with greater impairment in LV strain independent of LV mass and ejection fraction.