Description: Free-breathing cardiac diffusion tensor imaging (DTI) is a promising but challenging technique for the study of fiber structures of the human heart in vivo. This work proposes a clinically compatible and robust technique to provide three-dimensional (3-D) fiber architecture properties of the human heart. To this end, 10 short-axis slices were acquired across the entire heart using a multiple shifted trigger delay (TD) strategy under free breathing conditions. Interscan motion was first corrected automatically using a nonrigid registration method. Then, two post-processing schemes were optimized and compared: an algorithm based on principal component analysis (PCA) filtering and temporal maximum intensity projection (TMIP), and an algorithm that uses the wavelet-based image fusion (WIF) method. The two methods were applied to the registered diffusion-weighted (DW) images to cope with intrascan motion-induced signal loss. The tensor fields were finally calculated, from which fractional anisotropy (FA), mean diffusivity (MD), and 3-D fiber tracts were derived and compared. The results show that the comparison of the FA values $({rm FA}_{{{{rm PCATMIP}}}} =0.45 pm 0.10, {rm FA}_{{{{rm WIF}}}} =0.42 pm 0.05, {rm P}=0.06)$ showed no significant difference, while the MD values ( ${rm MD}_{{{{rm PCATMIP}}}}=0.83 pm 0.12times 10^{{{-3}}}$ mm $^{{{2}}}$ /s, ${rm MD}_{{{{rm WIF}}}}=0.74pm 0.05times 10^{{{-3}}}$ mm $^{{{2}}}$ /s, ${rm P}=0.028$ ) were significantly different. Improved helix angle variations through the myocardium wall reflecting the rotation characteristic of c- rdiac fibers were observed with WIF. This study demonstrates that the combination of multiple shifted TD acquisitions and dedicated post-processing makes it feasible to retrieve in vivo cardiac tractographies from free-breathing DTI acquisitions. The substantial improvements were observed using the WIF method instead of the previously published PCATMIP technique.