Techniques for determining an attachment stability of leadless pacing device (LPD) implanted within a patient are described. For example, the LPD may detect one or more stability metrics from one or more electrodes of the LPD and/or an activity sensor within the LPD. Based on one or more of these stability metrics, e.g., a mechanical motion of the LPD, a stability module within the LPD may determine the attachment stability of the LPD within the patient. If the attachment stability is insufficient to provide efficacious therapy or indicates at least partial dislodgement of the LPD from tissue, the LPD may wirelessly transmit stability information to an external device. In some examples, the LPD may be implanted within a chamber of the heart.
