A cardiac pacing system having a pulse generator for generating therapeutic electric pulses, a lead electrically coupled with the pulse generator having an electrode, a first sensor configured to monitor a physiological characteristic of a patient, a second sensor configured to monitor a second physiological characteristic of a patient and a controller. The controller can determine a pacing vector based on variables including a signal received from the second sensor, and cause the pulse generator to deliver the therapeutic electrical pulses according to the determined pacing vector. The controller can also modify pacing characteristics based on variables including a signal received from the second sensor.

A medical device is configured to sense a cardiac signal that includes far field ventricular event signals and determine a ventricular activity metric from the sensed cardiac signal. The ventricular activity metric may be representative of a ventricular rate or an atrioventricular time interval. The medical device is configured to determine an atrioventricular synchrony metric based on the ventricular activity metric and generate an output based on the atrioventricular synchrony metric. The device may include a memory configured to store data corresponding to the atrioventricular synchrony metric.

A medical device includes a processor, an acceleration sensor, and memory. The acceleration sensor is configured to generate acceleration data that comprises a plurality of acceleration measurements. The memory comprises instructions that when executed by the processor, cause the processor to: obtain the acceleration data from the acceleration sensor; and determine, based on the acceleration data, that the medical device has flipped.

Systems and methods for monitoring and treating patients with heart failure are discussed. The system can store in a memory stimulation parameters, including stimulation timing parameters for a plurality of heart rate ranges. The system includes a plurality of timers with respective durations for the plurality of heart rate ranges. A stimulation control circuit can identify a target heart range in which a detected heart rate falls, and measure an atrioventricular (AV) conduction characteristic value in response to the timer for the target heart range being expired at the detected heart rate. The stimulation control circuit can update a stimulation parameter corresponding to the target heart rate range using the measured AV conduction characteristic. The updated stimulation parameter can be used in cardiac stimulation.

Systems and methods for calibrating an orientation of an implantable device in a patient is described. An exemplary system includes a calibration circuit that can receive acceleration information sensed from an implantable medical device (IMD) implanted in a patient, and receive reference acceleration information sensed from a reference device associated with the patient. The acceleration information and the reference acceleration information are acquired when the patient assumes a first posture or in a first position. The calibration circuit determines a spatial relationship between an orientation of the IMD and a reference orientation of the reference device using the received acceleration information and the received reference acceleration information, and calibrate subsequent acceleration information sensed from the IMD using the determined spatial relationship to correct for the orientation of the IMD.

According to an embodiment of a method for providing neural stimulation, activity is sensed, and neural stimulation is automatically controlled based on the sensed activity. An embodiment determines periods of rest and periods of exercise using the sensed activity, and applies neural stimulation during rest and withdrawing neural stimulation during exercise. Other embodiments are provided herein.

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, devices, and methods for pacing a heart of a patient are disclosed. An illustrative method may include determining a motion level of the patient using a motion sensor of an implantable medical device secured relative to a patient's heart, and setting a pacing rate based at least in part on the patient's motion level. The patient's motion level may be determined by, for example, comparing the motion level sensed by the motion sensor during a current heart beat to a motion level associated with one or more previous heart beats. Noise may occur in the motion level measurements during those heart beats that transition between an intrinsically initiated heart beat and pace initiated heart beat. Various techniques may be applied to the motion level measurements to help reduce the effect of such noise.

This document discusses, among other things, systems and methods to receive physiologic information from a patient during different first and second pacing periods having respective, different first and second atrioventricular (AV) delays, determine first and second physiologic parameters using respective received physiologic information from the first and second pacing periods, and adjust the first AV delay using the determined first and second physiologic parameters, wherein the second AV delay is longer than the first AV delay

This document discusses, among other things, systems and methods to generate a first pacing waveform during a first pacing period and a second pacing waveform during a second pacing period, and alternate the first and second pacing periods to provide pacing-based hypertension therapy to a heart of a patient to reduce patient blood pressure, wherein the first pacing waveform has a first atrioventricular (AV) delay and the second pacing waveform has a second AV delay longer than the first AV delay. Physiologic information can be received from the patient, and one of the first or second pacing period for delivery to the patient can be determined using the received physiologic information.