A leadless cardiac pacemaker (LCP) configured to sense and pace a patients heart includes a sensor configured to sense a parameter related to cardiac contractility of the patients heart and a power management unit that is operatively coupled to the sensor. The power management unit is configured to place the sensor in a higher power sense mode during times when sensing the parameter related to cardiac contractility is desired and to place the sensor in a lower power mode during times when sensing the parameter related to cardiac contractility is not desired.
