A system and method select a pacing site for a cardiac pacing therapy. A change from a baseline mechanical activity is extracted from a signal of mechanical heart activity during pacing at each one of multiple pacing sites along a heart chamber. A change from a baseline electrical activity is extracted from a signal of electrical heart activity during pacing at each of the of pacing sites. The pacing sites are sorted in a first order based upon the changes in mechanical heart activity and in a second order based upon the changes in electrical heart activity. A pacing site is selected from the multiple pacing sites as a common pacing site between the first order and the second order.