Embodiments of close loop optimization of atrio-ventricular (A-V) delay interval and/or inter-ventricular (V-V) timing are disclosed. An implantable medical device includes a housing that supports a processing means adapted for implantation in a patient. There can be two or more electrodes electrically coupled to the processing means where the two or more electrodes can be used for sensing a patient's cardiac signals, which include a far-field EGM. The processing means can determine a width of a P-wave from the sensed far-field EGM. Also included can be a means for delivering an adapted cardiac pacing therapy based upon the width of the P-wave, including revised A-V delay and/or V-V temporal intervals.
