An intracardiac ventricular pacemaker is configured to operate in in a selected one of an atrial-tracking ventricular pacing mode and a non-atrial tracking ventricular pacing mode. A control circuit of the pacemaker determines at least one motion signal metric from the motion signal, compares the at least one motion signal metric to pacing mode switching criteria, and, responsive to the pacing mode switching criteria being satisfied, switches from the selected one of the non-atrial tracking pacing mode and the atrial tracking pacing mode to the other one of the non-atrial tracking pacing mode and the atrial tracking pacing mode for controlling ventricular pacing pulses delivered by the pacemaker.

An implantable medical device (IMD) performs, within a first predetermined time following an implantation, a first device test sequence over an evaluation period. The device test sequence includes at least two of: detecting an impedance for at least one electrical path having at least one electrode, and comparing the impedance to a first predetermined impedance threshold to determine a connection status of the IMD; comparing, over an electrogram (EGM) test period, at least one EGM event of the patient against a first predetermined EGM event threshold; determining a first pacing capture threshold of the IMD; and detecting at least one clinical or patient-specific physiologic metric, and comparing the physiologic metric to a first predetermined physiologic metric threshold. The IMD transmits within a second predetermined time a status signal to an external device indicating a status of at least one of the diagnostic tests in the first device test sequence.

A medical electrical lead and methods of implanting medical electrical leads in lumens. Leads in accordance with the invention employ preformed biases to stabilize the lead within a lumen or lumen and to provide feedback to lead implanters.

Implantable medical devices include a first sensor for detecting a magnetic field that indicates an exposure mode of operation is appropriate. The implantable medical devices include a second sensor for detecting whether an MRI characteristic is present that indicates whether MRI or non-MRI post exposure diagnostics and other actions should be implemented and may also indicate whether the exposure mode should be MRI or non-MRI specific. An MRI post exposure diagnostic may perform pacing capture threshold tests and the post exposure pacing amplitude output may be kept at a higher than normal level. The second sensor may be an overvoltage clamp circuit of a telemetry coil that indicates whether an overvoltage condition on the telemetry coil is occurring to indicate whether an MRI characteristic is present. The second sensor may be a second threshold magnetic sensor, an accelerometer, or a microphone to indicate whether an MRI characteristic is present.

Techniques related to classifying a posture state of a living body are disclosed. One aspect relates to sensing at least one signal indicative of a posture state of a living body. Posture state detection logic classifies the living body as being in a posture state based on the at least one signal, wherein this classification may take into account at least one of posture and activity state of the living body. The posture state detection logic further determines whether the living body is classified in the posture state for at least a predetermined period of time. Response logic is described that initiates a response as a result of the body being classified in the posture state only after the living body has maintained the classified posture state for at least the predetermined period of time. This response may involve a change in therapy, such as neurostimulation therapy, that is delivered to the living body.

Systems and methods are provided for using stored physiologic information about a subject to detect a previous treatment event. Physiologic information can be sensed from a subject using one or more sensors. Using a detection circuit, a change in the sensed physiologic information, such as a change from reference physiologic information, can be used to identify a candidate previous treatment event. An alert or other information about the candidate treatment event can be provided to a patient or clinician. In an example, a candidate treatment event can include a heart failure or diuresis treatment that is identified using information about a change in one or more of a subject's circadian pattern, a subject's thoracic impedance, or a subject's respiration status.

Implantable medical devices (IMDs), systems, and methods for use therewith are disclosed. One such method is for use by a leadless pacemaker (LP) configured to perform conductive communication with another implantable medical device (IMD). The method includes the LP storing information that specifies when, within a cardiac cycle, the LP and the other IMD implanted in a patient are likely oriented relative to one another such that conductive communication therebetween should be successful. The method also includes the LP sensing a signal indicative of cardiac activity of the patient over a plurality of cardiac cycles, and outputting one or more conductive communication pulses, during a portion of at least one of the cardiac cycles, wherein the portion of the at least one of the cardiac cycles is identified based on the signal that is sensed and the information that is stored.

Some method examples may include pacing a heart with cardiac paces, sensing a physiological signal for use in detecting pace-induced phrenic nerve stimulation, performing a baseline level determination process to identify a baseline level for the sensed physiological signal, and detecting pace-induced phrenic nerve stimulation using the sensed physiological signal and the calculated baseline level. Detecting pace-induced phrenic nerve stimulation may include sampling the sensed physiological signal during each of a plurality of cardiac cycles to provide sampled signals and calculating the baseline level for the physiological signal using the sampled signals. Sampling the sensed physiological signal may include sampling the signal during a time window defined using a pace time with each of the cardiac cycles to avoid cardiac components and phrenic nerve stimulation components in the sampled signal.

According to some aspects, a cardiac pacemaker for implantation within a subject is provided, the pacemaker including a housing, at least one sensor configured to detect an activity level of the subject, and at least one processor coupled to the sensor configured to detect inactivity of the subject based on output from the at least one sensor, produce a first signal configured to increase the heart rate of the subject to a first heart rate during a first time period, wherein the first heart rate is above a resting heart rate and below 100 beats per minute, and in response to determining that the first time period has elapsed, producing a second signal configured to increase the heart rate of the subject to a second heart rate during a second time period, wherein the second heart rate is between 100 and 140 beats per minute.

A ventricularly implantable medical device that includes a sensing module that is configured to detect an artifact during ventricular filling and to identify an atrial event based at least on part on the detected artifact. Control circuitry of the implantable medical device is configured to deliver a ventricular pacing therapy to a patient's heart, wherein the ventricular pacing therapy is time dependent, at least in part, on the identified atrial event.