Experimental Study On Architecture Of Ventricular Myocardial Fibers

ObjectivesOur purposes were to explore non-invasive and simplified method of example's preparation before diffusion tensor magnetic resonance imaging (DT-MRI) scanned; acquired entire spatial information of the ventricular myocardial fibers within excised animal and human hearts. We visualized and reconstructed the myocardial fibers and measured the relative myofiber angle, then observed and analyzed disposition of myocardial fibers in normal and reorientation in chronic heart failure by DT-MRI.Methods and materials1. 8 pig hearts were randomly divided into A and B group. A group (n=4) was fixed by solution with agarose gel and Copper Sulphate; B group (n=4) was put directly into sterile water solution. Heart sample accepted DT-MRI scans at once and visualized and reconstructed the myocardial fibers. We contrasted effect of reconstruction, observed spatial orientation of ventricular myocardial fibers, measured the myofiber helix angle and transverse angle at each myofiber tracking point and then statistically analyzed.2. 15 postmortem patient's hearts were divided into non-chronic heart failure (n=8) and chronic heart failure group (n=7). Two groups heart all accepted DT-MRI scans and visualized and reconstructed the myocardial fibers. Then we observed spatial orientation of ventricular myocardial fibers, measured the myofiber helix angle and transverse angle at each myofiber tracking point and statistically analyzed and contrasted.Results1. The myofiber reconstruction of pig heart kept coincidence about orientation and shape with two differently prepared methods. Reconstruction of myocardial fibers showed that ventricular myocardial fibers kept entire continuity and specified orientation; left ventricular wall's myofiber formed two nearly perpendicular and dominant populations. Measured results of myofiber helix angle and transverse angle revealed that orientation of endocardial,midwall and epicardial fibers in basal and middle regions of left ventricular approached, while obviously distinguished to apical regions.2. The myofiber reconstruction of human hearts showed that architecture of ventricular myocardial fibers was similar to pig hearts. Measured results of myofiber helix angle and transverse angle revealed that orientation of endocardial and epicardial fibers in basal and middle regions of left ventricular was closer level state, meanwhile midwall and epicardial fibers appeared more circum-orientation from intruded direction in chronic heart failure group than non-chronic heart failure group.ConclusionNon-invasive and simplified method of example's preparation can be used to research architecture of myocardial fibers by DT-MRI. Orientation of the ventricular myocardial fibers in pig and human hearts was correspond to depiction of the ventricular myocardial band theory. Reorientation of myocardial fibers in human hearts also had coincidence with presumption of the ventricular myocardial band theory in chronic heart failure.