Methods for evaluating tissue motion of a tissue location, e.g., a cardiac location, via external continuous field tomography are provided. Aspects of the methods include generating at least one substantially linear continuous field gradient across the tissue location of interest, and using a resultant signal from a sensing element stably associated with the tissue location to evaluate motion of the tissue location. Also provided are systems, devices and related compositions for practicing the subject methods. The subject methods and devices find use in a variety of different applications, including cardiac resynchronization therapy.