A methods and devices for capture detection are based on sensing a propagated depolarization from a contralateral cardiac chamber. An intersite sensing interval is determined based on an intersite pacing delay and an intersite conduction delay associated with first and second pacing sites. Pacing pulses are delivered to the first pacing site and the second pacing site, the pacing pulses separated in time by the intersite pacing delay. An intersite sensing interval is timed. The process includes sensing, during the intersite sensing interval, at the first pacing site for a depolarization propagated to the first pacing site from the second pacing site. It a depolarization propagated from the second pacing site is not sensed, then capture of the first and second pacing sites is detected.