Analysis of fiber orientation in normal and failing human hearts using diffusion tensor MRI

The helical arrangement of cardiac myofibers is responsible for equalizing myofiber strain and maximizing the ejection fraction in a normal heart. In one form of chronic heart failure (CHF) known as dilated cardiomyopathy (DCM), the heart dilates, wall stress is increased, and ventricular pump function is reduced. We investigated whether myofiber orientation is altered in DCM by quantifying fiber orientation in excised human hearts using diffusion tensor MRI. Normal hearts (n=4) and failing hearts (n=4) were imaged in the plane of the cardiac short-axis at the base and mid-ventricular levels. There was a shift in the distribution of fiber inclination angles in the CHF hearts to a more oblique orientation at both the base and mid-ventricular levels. These preliminary results provide information about remodeling of the myocardial architecture in heart failure.