Relationship between cardiovascular risk factors and myocardial strain values of both ventricles in asymptomatic Asian subjects: measurement using cardiovascular magnetic resonance tissue tracking

The purpose of this study was to evaluate the association between myocardial deformation parameters and cardiovascular risk factors in asymptomatic Asian subjects and to provide reproducibility for deformation parameters of both ventricles using cardiovascular magnetic resonance (CMR) tissue tracking (TT). We enrolled 129 asymptomatic healthy adults who underwent CMR and assessed the cardiovascular risk factors in all individuals. All subjects had normal left ventricular systolic function. Commercial software was used to derive myocardial deformation parameters of both ventricles from short-axis cine images and long-axis cine images with two-, three-, and four-chamber views. Linear regression analysis was performed for evaluation of the association with all strain parameters for each age and systolic blood pressure. Intra class correlation was also calculated in CMR-TT to determine interobserver variability. In all 129 patients, the strain values for the left ventricle (LV) were 48.90 +/- 9.05 for radial strain (RS, %), -22.30 +/- 2.33 for circumferential strain (CS, %), and -19.76 +/- 2.22 for longitudinal strain (LS, %). The strain values for the right ventricle (RV) were 18.63 +/- 6.52 for RS, -10.60 +/- 3.33 for CS, and -25.06 +/- 3.01 for LS. In all 129 patients (male, n=105), all strain parameters of LV and RV was significantly different among males and females (all p values<0.05). The LV strain parameters were significantly associated with age by univariate linear regression analysis: RS, beta=0.219, p=0.002; CS, beta=-0.668, p=0.014 (except for LS, beta=-0.104, p=0.720). With regard to hypertension, diabetes mellitus and dyslipidemia, the values of all strain parameters in both ventricles were not significantly different between individuals with or without risk factors. Inter-observer agreement for three strain variables of LV and RV was 0.915 and 0.715 by iota index, and intra-observer agreement of LV and RV was 0.955 and 0.959 by iota index. The strain parameters by CMR-TT showed an association with age and significant difference in gender, on the other hands, not significantly different between with or without of the other conventional cardiovascular risk factors. The reproducibility of three LV strain parameters was higher than that of the respective RV strain parameters.