Abstract: Cardiac dyssynchrony of a patient may be evaluated based on electrical activity of a heart of the patient and corresponding chest wall motion of the patient sensed via an external accelerometer. In one example, an acceleration signal indicative of the chest wall motion is generated by an external accelerometer positioned on the chest wall of the patient. A processor of a diagnostic device integrates the acceleration signal to generate a velocity signal and temporally correlates the velocity signal and an electrical cardiac signal. The processor determines a time delay between a deflection of the electrical cardiac signal indicating ventricular electrical activation and a subsequent greatest peak of the velocity signal. The time delay may indicate a degree of electromechanical delay of the left ventricle. In some examples, the processor generates an output indicative of a cardiac dyssynchrony status based on the time delay.

Abstract: Methods and devices for analyzing posture-induced changes to physiological parameters of a patient (e.g., ejection time, heart rate, etc.) to provide an assessment of one or more conditions of the patient.

Abstract: Methods and devices for analyzing posture-induced changes to physiological parameters of a patient (e.g., ejection time, heart rate, etc.) to provide an assessment of one or more conditions of the patient.

Abstract: Methods and devices for analyzing posture-induced changes to physiological parameters of a patient (e.g., ejection time, heart rate, etc.) to provide an assessment of one or more conditions of the patient.

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: Methods and devices for analyzing posture-induced changes to physiological parameters of a patient (e.g., ejection time, heart rate, etc.) to provide an assessment of one or more conditions of the patient.

Abstract: The disclosure describes techniques for diagnosing premature contractions of a patient's heart. This system may differentiate premature atrial contractions (PACs) and premature ventricular contractions (PVCs) from atrial fibrillation by identifying changes in R-wave intervals, i.e., R-R intervals, on a Lorenz plot, measuring a coupling interval between R-waves, and analyzing a morphology of the premature contractions, e.g., the QRS complex. These techniques may also identify when severe premature contractions, or bigeminy, are present. In response to the type of premature contractions detected, the system may alert a user of the premature contractions and/or deliver cardiac pacing at an increased pacing rate to eliminate the abnormal intrinsic contractions. The system may also adjust the pacing rate and pacing rate duration for persistent premature contractions.

Abstract: Methods and devices for analyzing posture-induced changes to physiological parameters of a patient (e.g., ejection time, heart rate, etc.) to provide an assessment of one or more conditions of the patient.

Abstract: Cardiac dyssynchrony of a patient may be evaluated based on electrical activity of a heart of the patient and corresponding chest wall motion of the patient sensed via an external accelerometer. In one example, an acceleration signal indicative of the chest wall motion is generated by an external accelerometer positioned on the chest wall of the patient. A processor of a diagnostic device integrates the acceleration signal to generate a velocity signal and temporally correlates the velocity signal and an electrical cardiac signal. The processor determines a time delay between a deflection of the electrical cardiac signal indicating ventricular electrical activation and a subsequent greatest peak of the velocity signal. The time delay may indicate a degree of electromechanical delay of the left ventricle. In some examples, the processor generates an output indicative of a cardiac dyssynchrony status based on the time delay.

Abstract: A method for use in an implantable medical device system, comprising: selecting a first sensing electrode operatively disposed in a first heart chamber; setting a first sensing window corresponding to cardiac electrical events occurring in a second heart chamber; enabling a first sense amplifier coupled to the first sensing electrode during the first sensing window; sensing a first signal corresponding to cardiac electrical events occurring in the second heart chamber during the first sensing window using the first sensing electrode; and transmitting the first signal from an implantable medical device to an external monitor.

Abstract: Methods and devices for analyzing posture-induced changes to physiological parameters of a patient (e.g., ejection time, heart rate, etc.) to provide an assessment of one or more conditions of the patient.

Abstract: The disclosure describes techniques for diagnosing premature contractions of a patient's heart. This system may differentiate premature atrial contractions (PACs) and premature ventricular contractions (PVCs) from atrial fibrillation by identifying changes in R-wave intervals, i.e., R-R intervals, on a Lorenz plot, measuring a coupling interval between R-waves, and analyzing a morphology of the premature contractions, e.g., the QRS complex. These techniques may also identify when severe premature contractions, or bigeminy, are present. In response to the type of premature contractions detected, the system may alert a user of the premature contractions and/or deliver cardiac pacing at an increased pacing rate to eliminate the abnormal intrinsic contractions. The system may also adjust the pacing rate and pacing rate duration for persistent premature contractions.

Abstract: An implantable medical device and associated method deliver cardiac resynchronization therapy in a patient having right bundle branch block by measuring an interval between a right atrial depolarization and a first heart sound and selecting a right atrial-ventricular (AV) pacing interval in response to the measured interval. Pacing pulses are delivered to the right ventricle of a patient's heart at the selected right AV pacing interval to synchronize the right ventricle with an intrinsic left ventricle depolarization.

Abstract: The invention is directed to techniques for providing cardiac resynchronization therapy by synchronizing delivery of pacing pulses to the left ventricle with intrinsic right ventricular depolarizations. An implantable medical device measures an interval between an atrial depolarization and an intrinsic ventricular depolarization is measured. In various embodiments, the intrinsic ventricular depolarization may be an intrinsic right or left ventricular depolarization. The implantable medical device delivers pacing pulses to the left ventricle to test a plurality of pacing intervals. The pacing intervals tested may be within a range around the measured interval between the atrial depolarization and the intrinsic ventricular depolarization. One of the pacing intervals is selected based on a measured characteristic of an electrogram that indicates ventricular synchrony. For example, the pacing interval may be selected based on measured QRS complex widths and/or Q-T intervals.

Abstract: In general, the invention is directed to techniques for detecting and addressing pacemaker syndrome. When a pacemaker detects a risk of pacemaker syndrome, the pacemaker paces one or more chambers of the heart to reduce the risk of pacemaker syndrome. One pacing technique is to apply ventricular paces, thereby reducing the delay between the atrial activation and the ventricular activation. Another technique, available to a patient who receives atrial pacing, is to decrease the atrial pacing rate.

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: The invention is directed to techniques for providing cardiac resynchronization therapy by synchronizing delivery of pacing pulses to the left ventricle with intrinsic right ventricular depolarizations. An implantable medical device measures an interval between an atrial depolarization and an intrinsic ventricular depolarization is measured. In various embodiments, the intrinsic ventricular depolarization may be an intrinsic right or left ventricular depolarization. The implantable medical device delivers pacing pulses to the left ventricle to test a plurality of pacing intervals. The pacing intervals tested may be within a range around the measured interval between the atrial depolarization and the intrinsic ventricular depolarization. One of the pacing intervals is selected based on a measured characteristic of an electrogram that indicates ventricular synchrony. For example, the pacing interval may be selected based on measured QRS complex widths and/or Q-T intervals.