Abstract #0015

Ennis D, Wigstrm L, Skare S, Nguyen T, Ingels N, Miller D, Bammer R

The complex, but highly ordered arrangement of myofibers in the ventricular wall is closely related to regional myocardial function. This work uses DTMRI measures in 5 sheep to demonstrate that midwall myofibers are not oriented in the circumferential direction in all regions of the left ventricle and furthermore that regional gradients in myofiber orientation are heterogeneous. In the lateral midwall fibers are oriented at an angle of ?=-13.98.0. In comparison, septal midwall fibers average 9.611.8. Regional differences of myofiber arrangement should impact regional function in addition to having implications for the interpretation of MRI tissue tagging strains.