Evaluation of rule-based approaches for the incorporation of skeletal muscle fiber orientation in patient-specific anatomies

Skeletal muscle fiber orientation is important for the realistic calculation of body surface ECGs. However if computer models of patient-specific anatomies are created, usually no information about the muscle fiber arrangement is available. In this work we evaluated a published rule based approach to describe skeletal muscle fiber orientation together with two new methods. The quality of the respective fiber orientation approximation was assessed by comparing the forward calculated body surface potential maps (BSPMs) with the BSPM that was derived from a gold standard. Although all three methods showed comparable results the complete omission of skeletal muscle fiber orientation enhanced the BSPM even further. Thus it can be concluded that the characterization of skeletal muscle fiber orientation using a simplified approach is not feasible. In cases where no detailed information about the skeletal muscle fiber arrangement is available, it is better to entirely neglect its anisotropic influence.