Systems and methods for optimizing CRT are disclosed. According to an aspect, a method includes receiving, during at least two time periods of a cardiac cycle, electrical signals communicated by two or more electrodes of a CRT device positioned one or more of on a surface of a body, within a thorax of the body, a heart of the body, a surrounding venous structure of the body, and a surrounding subcutaneous structure of the body. The method also includes calculating, based on the received electrical signals, spacing between the two or more electrodes during the at least two time periods of the cardiac cycle. Further, the method includes controlling output of the CRT device to the electrodes based on the calculated spacing between the two or more electrodes.
