An implantable cardiac stimulation device provides measurement of intrinsic heart activity metrics while sustaining pacing of the heart. The device includes a pulse generator that delivers pacing pulses to a first chamber of corresponding chambers of a heart, and a sensing circuit that senses a conducted evoked response of a second chamber of the corresponding chambers of the heart in response to the pacing pulse to provide an electrical signal representing the conducted evoked response. The device further includes a measuring circuit that measures a metric of the electrical signal to approximate a corresponding metric of an intrinsic electrical feature of the second chamber.
