Systems, methods, and devices for determining occurrences of a tamponade condition are disclosed. One exemplary method includes monitoring an accelerometer signal of a leadless cardiac pacemaker attached to a heart wall, determining if a tamponade condition of the patient's heart is indicated based at least in part on the monitored accelerometer signal, and in response to determining that the tamponade condition is indicated, providing a notification of the tamponade condition for use by a physician to take corrective action.