1. A method of classifying a cardiac response to one or more pacing pulses, comprising: sensing a plurality of composite cardiac signals using a plurality of implantable electrodes; performing a source separation using the sensed plurality of composite cardiac signals; producing one or more cardiac signal vectors associated with all or a portion of one or more cardiac activation sequences based on the source separation; and classifying a cardiac response to the one or more pacing pulses using one or more characteristics associated with one or both of the one or more cardiac signal vectors and the signals associated with the one or more cardiac signal vectors.