An implantable pacemaker is configured to sense a cardiac electrical signal received by a pair of electrodes coupled to the pacemaker, start a pacing escape interval to control a time that a pacing pulse is delivered in a heart chamber, and detecting if the sensed cardiac electrical signal is a crosstalk event that is an electrical pulse delivered to the patient by a different device than the implantable pacemaker. The implantable pacemaker withholds restarting the pacing escape interval in response to sensing the cardiac electrical signal based on detecting the sensed cardiac electrical signal as the crosstalk event.
