Abstract: An implantable medical device system and associated method receive a signal from an implantable sensor operatively positioned relative to a vein, the signal being responsive to changes in a diameter of the vein. A diameter of the vein is determined in response to the sensor signal and used in estimating central venous pressure (CVP).

Abstract: An implantable medical device system and associated method receive a signal from an implantable sensor operatively positioned relative to a vein, the signal being responsive to changes in a diameter of the vein. A diameter of the vein is determined in response to the sensor signal and used in estimating central venous pressure (CVP).

Abstract: An implantable medical device and associated method predict syncope based on detecting a change in ejection time. A physiological signal is sensed that is responsive to mechanical changes associated with the cardiac ejection phase. A time interval corresponding to cardiac ejection time is detected from the physiological signal. A sudden change in the time interval is used as a predictor of syncope and causes a patient alert to be generated in response to the detected change.

Abstract: An implantable medical device and associated method predict syncope based on detecting a change in ejection time. A physiological signal is sensed that is responsive to mechanical changes associated with the cardiac ejection phase. A time interval corresponding to cardiac ejection time is detected from the physiological signal. A sudden change in the time interval is used as a predictor of syncope and causes a patient alert to be generated in response to the detected change.

Abstract: An implantable medical device system and associated method receive a signal from an implantable sensor operatively positioned relative to a vein, the signal being responsive to changes in a diameter of the vein. A diameter of the vein is determined in response to the sensor signal and used in estimating central venous pressure (CVP).

Abstract: There is provided a system for regulating ventricular rate in the presence of abnormally high atrial rates, e.g., during episodes of atrial fibrillation. During such an episode, the system, preferably incorporated into an implantable pacemaker, applies subthreshold bursts of stimulus pulses to or proximate to the patient's AV node so as to inhibit conduction of electrical signals through to the ventricle during the bursts. The bursts are timed in relation to the last conducted ventricular signal, and in terms of burst length, to provide a rate of conducted signals through the AV node which results in a substantially regular and reduced ventricular rate. During the inhibition mode of operation, the system monitors to determine the efficacy of inhibition, by tracking the percentage of ventricular senses that occur during the burst periods.