Free-breathing isotropic cardiac diffusion tensor MRI (DT-MRI) of the left ventricle can be performed using second moment (M2) motion compensated spin echo encoding and generalized slice dithered enhanced resolution (gSlider). This technique provides substantial improvements in spatial resolution and consequently in the accuracy of diffusion-based indices. However, M2-gSlider’s RF slice encoding is susceptible to through-slice motion, limiting the maximal improvement in slice resolution. Here, we evaluate the addition of a slice tracking respiratory navigator (NAV) to prospectively adjust slice position in real-time. M2-gSlider-NAV was validated in healthy volunteers and tested in a patient with a history of myocardial infarction.