Abstract: Techniques are provided for equipping sensing/pacing leads with physiological sensors without requiring additional conductors within the leads. In a bipolar lead example for use with a pacemaker, a sensor is connected between tip and ring conductors of the lead. The sensor is configured to be activated only in response to enhanced pacing pulse (EPPs) having magnitudes or durations greater than typical pacing pulses or in response to impedance detection pulses (IMPs). In a unipolar example, the sensor is connected to the tip conductor and includes an output terminal on the external housing of the lead for providing a return current path to the pacemaker. The sensor of the unipolar lead is likewise configured to respond only to EPPs or IMPs. In other examples, the sensors are configured to be fitted to the external housing of the lead and to derive power from the lead via electromagnetic induction. Still other examples include actuators rather than sensors.

Abstract: An exemplary method includes delivering a cardiac pacing therapy that includes an atrio-ventricular delay and an interventricular delay, providing a paced propagation delay associated with delivery of a stimulus to a ventricle, delivering a stimulus to the ventricle, sensing an event in the other ventricle caused by the stimulus, determining an interventricular conduction delay value based on the delivering and the sensing, determining a interventricular delay (?Sur) based on the interventricular conduction delay and the paced propagation delay and determining an atrio-ventricular delay based at least in part on the interventricular delay (?Sur). Other exemplary methods, devices, systems, etc., are also disclosed.

Abstract: An antenna assembly is configured for use with an external device that is configured to wirelessly communicate with an implantable medical device (IMD). The antenna assembly may include an antenna member pivotally secured to a structure through a feed post, and a fixed tail fixed to the structure. The antenna member may be pivotal between a first orientation in which the antenna member electrically connects to the fixed tail, and a second orientation in which the antenna member is disconnected from the fixed tail. The antenna member and the fixed tail cooperatively operate in a first antenna mode when the antenna member is in the first orientation. The antenna member is configured to operate in a second antenna mode when the antenna member is in the second orientation.

Abstract: Techniques are provided for use with an implantable medical device for detecting and assessing heart failure and for controlling cardiac resynchronization therapy (CRT) based on impedance signals obtained using hybrid impedance configurations. The hybrid configurations exploit right atrial (RA)-based impedance measurement vectors and/or left ventricular (LV)-based impedance measurement vectors. In one example, current is injected between the device case and a ring electrode in the right ventricle (RV) or RA. RA-based impedance values are measured along vectors between the device case and an RA electrode. LV-based impedance values are measured along vectors between the device case and one or more electrodes of the LV. Heart failure and other cardiac conditions are detected and tracked using the measured impedance values. CRT delay parameters are also optimized based impedance.

Abstract: A method for operating an implantable medical device includes delivering a plurality of pacing pulses to an atria of a patient's heart and monitoring intrinsic atrial activity to detect intrinsic atrial contractions between one or more of the plurality of pacing pulses. The method further includes detecting atrial undersensing as a function of the detection of intrinsic atrial contractions.

Abstract: A method is provided to determine pacing parameters for an implantable medical device (IMD) and collects heart sounds during the cardiac cycles. The method comprises changing a value for a pacing parameter between the cardiac cycles and analyzing a characteristic of interest from the heart sounds. The method comprises setting a desired value for the pacing parameter based on the characteristic of interest from the heart sounds. The system comprises inputs configured to be coupled to at least one lead having electrodes to sense intrinsic events and to deliver pacing pulses over cardiac cycles. The system has a sensor for collecting heart sounds during cardiac cycles and controller to control delivery of pacing pulses based on pacing parameters. The controller changes a value for at least one of the pacing parameters between the cardiac cycles and provides an analysis module to analyze a characteristic of interest from the heart sounds.

Abstract: Methods for monitoring a patient's level of B-type natriuretic peptide (BNP), and implantable cardiac systems capable of performing such methods, are provided. A ventricle is paced for a period of time to provoke a ventricular evoked response, and a ventricular intracardiac electrogram (IEGM) indicative of the ventricular evoked response is obtained. Based on the ventricular IEGM, there is a determination of at least one ventricular evoked response metric (e.g., ventricular evoked response peak-to-peak amplitude, ventricular evoked response area and/or ventricular evoked response maximum slope), and the patient's level of BNP is monitored based on determined ventricular evoked response metric(s). Based on the monitored level's of BNP, the patients heart failure (HF) condition and/or risks and/or occurrences of certain events (e.g., an acute HF exacerbation and/or an acute myocardial infarction) can be monitored.

Abstract: Detection of T wave oversensing in an ICD is accomplished in order to prevent improper application of treatment to a patient. The ICD device senses for electrical impulses representing the R waves of a beating heart. In some instances the ICD device will sense T waves that it will assume to be R waves, because the ICD device expects or assumes that such sensed signals are R waves. Time intervals between each detected, assumed R waves are measured and a list of intervals is generated. The list is transformed into its frequency domain equivalent and analyzed for peaks and randomness criteria to determine whether T wave oversensing has occurred.

Abstract: Methods of processing venous oxygen saturation and hematrocrit information in an implantable sensor are provided. In an embodiment a method for collecting data from an implantable multi-wavelength SvO2 sensor having multiple light sources is provided. The method includes receiving a frame signal that indicates a beginning of the light sources being turned on and receiving a light source signal that indicates a light source is on. The output of a photodetector is sampled to measure the intensity of the transmitted light. The process is repeated for each light source to gather intensity measurements that then can be used to generate venous oxygen saturation and hematocrit measurements.

Abstract: A communication wake-up scheme for an implantable medical device may involve repeatedly activating a receiver to determine whether an external device is attempting to establish communication with the implantable device. To reduce the amount of power consumed by the implantable device in conjunction with the wake-up scheme, the scheme may involve conducting preliminary RF signal detections as a precursor to conducting a full scan. In this way, power may be conserved since the more power intensive full scans may be performed less frequently. This preliminary detection of RF signals also may be adapted to reduce the number of full scans performed by the implantable device that do not result in communication with the external device. In some embodiments the adaptation involves adjusting one or more thresholds that are used in conjunction with the preliminary detection of RF signals.

Abstract: Techniques are provided for use with implantable medical devices for addressing encapsulation effects, particularly in the detection of cardiac decompensation events such as heart failure (HF) or cardiogenic pulmonary edema (PE.) In one example, during an acute interval following device implant, cardiac decompensation is detected using heart rate variability (HRV), ventricular evoked response (ER) or various other non-impedance-based parameters that are insensitive to component encapsulation effects. During the subsequent chronic interval, decompensation is detected using intracardiac or transthoracic impedance signals. In another example, the degree of maturation of encapsulation of implanted components is assessed using impedance frequency-response measurements or based on the frequency bandwidth of heart sounds or other physiological signals.

Abstract: Techniques are provided for use with an implantable cardiac stimulation device equipped with a multi-pole left ventricular (LV) lead having a proximal electrode implanted near an atrioventricular (AV) groove of the heart of the patient. A left atrial (LA) cardioelectrical event is sensed using the proximal electrode of the LV lead and a corresponding LA cardiomechanical event is also detected, either using an implantable sensor or an external detection system. The electromechanical activation delay between the LA cardioelectrical event and the corresponding LA cardiomechanical event is determined and then pacing delays are set based on the electromechanical activation delay for use in controlling pacing. The pacing delays can include, e.g., AV delays for use with biventricular cardiac resynchronization therapy (CRT) pacing. Other techniques described herein are directed to exploiting right atrial (RA) cardioelectrical events detected via an RA lead for the purposes of setting pacing delays.

Abstract: Techniques are provided for detecting and distinguishing stroke and cardiac ischemia based on electrocardiac signals. In one example, the device senses atrial and ventricular signals within the patient along a set of unipolar sensing vectors and identifies certain morphological features within the signals such as PR intervals, ST intervals, QT intervals, T-waves, etc. The device detects changes, if any, within the morphological features such as significant shifts in ST interval elevation or an inversion in T-wave shape, which are indicative of stroke or cardiac ischemia. By selectively comparing changes detected along different unipolar sensing vectors, the device distinguishes or discriminates stroke from cardiac ischemia within the patient. The discrimination may be corroborated using various physiological and hemodynamic parameters. In some examples, the device further identifies the location of the ischemia within the heart.

Abstract: A feedthrough assembly for use with implantable medical devices having a shield structure, the feedthrough assembly engaging with the remainder of the associated implantable medical device to form a seal with the medical device to inhibit unwanted gas, liquid, or solid exchange into or from the device. One or more feedthrough wires extend through the feedthrough assembly to facilitate transceiving of the electrical signals with one or more implantable patient leads. The feedthrough assembly is connected to a mechanical support which houses one or more filtering capacitors that are configured to filter and remove undesired frequencies from the electrical signals received via the feedthrough wires before the signals reach the electrical circuitry inside the implantable medical device. The mechanical support may further include an isolation structure that isolates the feedthrough wires.

Abstract: The present invention is a splittable multi-piece hemostasis valve that is held together in an assembled condition via a binder formed about the assembled valve. The binder may be a sleeve of thin polymer material shrink-wrapped about the valve. When the valve needs to be split in order to clear a medical device such as a pacemaker lead, the sleeve is split and the valve is disassembled.

Abstract: Validated atrial and/or ventricular interval decreases are used to discriminate between VT and SVT. Atrial and/or ventricular intervals are monitored in order to detect decreases in such intervals (which are indicative in increases in rate). The atrial intervals can be, e.g., AA intervals, and the ventricular intervals can be, e.g., VV intervals. A detected atrial and/or ventricular interval decrease can be a decrease that is greater than an interval decrease threshold. Detected atrial and/or ventricular interval decreases can be validated by examining atrial and/or ventricular intervals before and after a detected atrial and/or ventricular interval decrease. The use of the validated atrial and/or ventricular interval decreases to classify an arrhythmia as SVT or VT can be called arrhythmia initiation analysis, since it is believed to determine whether the initiation of the arrhythmia is in an atrium or a ventricle.

Abstract: Techniques are provided for use with implantable medical devices equipped to deliver paired postextrasystolic potentiation (PESP) pacing to control the paired pacing rate based on changes in patient activity. In one example, the current activity level of the patient is detected during paired pacing using an accelerometer. The cardiac output level needed to maintain the current activity level of the patient is determined with reference to pre-stored lookup tables relating activity levels with corresponding minimum necessary cardiac output levels for the particular patient. The minimum paired pacing rate sufficient to achieve the cardiac output level is then determined based, e.g., on stroke volume derived from cardiogenic impedance signals. Paired pacing is then delivered at the minimum paired pacing rate sufficient to achieve the needed cardiac output, thereby assuring that the paired pacing rate is sufficient to meet the current physiological demands of the patient without consuming too much oxygen.

Abstract: Methods and systems are provided for determining pacing parameters for an implantable medical device (IMD). The methods and systems provide electrodes in the right atrium (RA), right ventricle (RV) and left ventricle (LV). The methods and systems sense RV cardiac signals and LV cardiac signals at an RV electrode and an LV electrode, respectively, over multiple cardiac cycles, to collect global activation information. The methods and systems identify a T-wave in the LV cardiac signal. The methods and systems calculate a repolarization index based at least in part on a timing of the T-wave identified in the LV cardiac signal. The methods and systems set at least one pacing parameter based on the repolarization index, wherein the at least one pacing parameter that is set represents at least one of an AV delay, an inter-ventricular interval and an intra-ventricular interval.

Abstract: Pacing related timing is determined for an implantable medical device (IMD) by pacing at an RV pacing site, a first LV pacing site and a second LV pacing site in accordance with a first site, a second site and a third site pacing order, and further in accordance with a first inter-electrode pacing delay between pacing at the first site and pacing at the second site and a second inter-electrode pacing delay between pacing at the second site and pacing at the third site. At least one of a sensed event or a paced event is detected for at each of the second site and the third site. The first inter-electrode pacing delay and the second inter-electrode pacing delay are adjusted to avoid sensed events in favor of paced events at each of the second site and the third site. An atrio-ventricular delay may also be adjusted to avoid sensed events or lack of capture due to possible fusion at the first site, in favor of paced events at the first site.

Abstract: A method in a telemetry system for establishing a connection between a base station and an implantable medical device includes the steps of: starting, in the base station, a first timer B-T2; determining, in the base station 4, channels that are free for communication among a number of available channels, and selecting one of the free channels; starting, in the base station, a second timer; transmitting, as long as the first or second timer has not expired, a recognition message on the selected channel to the implantable medical device; and establishing, upon receipt of a recognition reply message from the implantable medical device, communication between the base station and the implantable medical device on the selected channel. The invention is readily adaptable for fulfillment of different requirements, such as stipulated by the ETSI standard.