1. A method comprising: selecting a pair of electrodes located in a patient; acquiring position information during one or more cardiac cycles for the pair of electrodes wherein the acquiring comprises using each of the electrodes for measuring one or more electrical potentials in an electrical localization field established in the patient; calculating one or more vector metrics based on the acquired position information for a vector defined by the pair of electrodes; and analyzing the one or more vector metrics to assess cardiac performance during the one or more cardiac cycles.