Myofiber Developmental Plasticity in Fetal and Adult Pig Hearts Delineated with Diffusion Tensor MRI

Lei Zhang¹, Huiying Zhang¹, Gregory M. Lanza¹, Samuel A. Wickline¹, Junjie Chen¹

Cardiac function in pre and post-natal stages are different because of reduced workload of right ventricle relative to left ventricle after birth. We hypothesize that myocardial fiber structure in fetal hearts differs from that of adult hearts as a response to the change of cardiac function. Diffusion tensor MRI was used to quantitatively evaluate myofiber structure in mid-gestation, pre-born and adult pig hearts. Helix angle and transverse angle in septum and LV/RV fusion sites were compared between the three groups. Our results showed that contributions of RV myofibers to septum was higher in fetal pig hearts than adult pig hearts. The current observations were in agree with change of cardiac function and reflect the plasticity of myocardial fiber development in response to programmed differential contractile functions before and after birth.